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Sample records for spinel cathode materials

  1. Enhanced Electrochemical Performance of Layered Lithium-Rich Cathode Materials by Constructing Spinel-Structure Skin and Ferric Oxide Islands.

    Science.gov (United States)

    Chen, Shi; Zheng, Yu; Lu, Yun; Su, Yuefeng; Bao, Liying; Li, Ning; Li, Yitong; Wang, Jing; Chen, Renjie; Wu, Feng

    2017-03-15

    Layered lithium-rich cathode materials have been considered as competitive candidates for advanced lithium-ion batteries because they are environmentally benign, high capacity (more than 250 mAh·g(-1)), and low cost. However, they still suffer from poor rate capability and modest cycling performance. To address these issues, we have proposed and constructed a spinel-structure skin and ferric oxide islands on the surface of layered lithium-rich cathode materials through a facile wet chemical method. During the surface modification, Li ions in the surface area of pristine particles could be partially extracted by H(+), along with the depositing process of ferric hydrogen. After calcination, the surface structure transformed to spinel structure, and ferric hydrogen was oxidized to ferric oxide. The as-designed surface structure was verified by EDX, HRTEM, XPS, and CV. The experimental results demonstrated that the rate performance and capacity retentions were significantly enhanced after such surface modification. The modified sample displayed a high discharge capacity of 166 mAh·g(-1) at a current density of 1250 mA·g(-1) and much more stable capacity retention of 84.0% after 50 cycles at 0.1C rate in contrast to 60.6% for pristine material. Our surface modification strategy, which combines the advantages of spinel structure and chemically inert ferric oxide nanoparticles, has been shown to be effective for realizing the layered lithium-rich cathodes with surface construction of fast ion diffusing capability as well as robust electrolyte corroding durability.

  2. Solution-combustion synthesized aluminium-doped spinel (LiAl(subx)Mn(sub2-x)O(sub4) as a high-performance lithium-ion battery cathode material

    CSIR Research Space (South Africa)

    Kebede, MA

    2015-06-01

    Full Text Available High-performing (LiAl(subx)Mn(sub2-x)O(sub4) (x = 0, 0.125, 0.25, 0.375, and 0.5) spinel cathode materials for lithium-ion battery were developed using a solution combustion method. The as-synthesized cathode materials have spinel cubic structure...

  3. Stable nickel-substituted spinel cathode material (LiMn1.9Ni0.1O4) for lithium-ion batteries obtained by using a low temperature aqueous reduction technique

    CSIR Research Space (South Africa)

    Kunjuzwa, Niki

    2016-11-01

    Full Text Available A nickel substituted spinel cathode material (LiMn1.9Ni0.1O4) with enhanced electrochemical performance was successfully synthesized by using a locally-sourced, low-cost manganese precursor, electrolytic manganese dioxide (EMD), and NiSO4·6H2O as a...

  4. Solution-combustion synthesized nickel-substituted spinel cathode materials (LiNixMn2-xO4; 0≤x≤0.2) for lithium ion battery: enhancing energy storage, capacity retention, and lithium ion transport

    CSIR Research Space (South Africa)

    Kebede, MA

    2014-01-01

    Full Text Available Spherically shaped Ni-substituted LiNi(subx)Mn(sub2-x)O(sub4) (x=0, 0.1, 0.2) spinel cathode materials for lithium ion battery with high first cycle discharge capacity and remarkable cycling performance were synthesized using the solution...

  5. Preparation of Layered-Spinel Microsphere/Reduced Graphene Oxide Cathode Materials for Ultrafast Charge-Discharge Lithium-Ion Batteries.

    Science.gov (United States)

    Luo, Dong; Fang, Shaohua; Yang, Li; Hirano, Shin-Ichi

    2017-07-17

    Although Li-rich layered oxides (LLOs) have the highest capacity of any cathodes used, the rate capability of LLOs falls short of meeting the requirements of electric vehicles and smart grids. Herein, a layered-spinel microsphere/reduced graphene oxide heterostructured cathode (LS@rGO) is prepared in situ. This cathode is composed of a spinel phase, two layered structures, and a small amount of reduced graphene oxide (1.08 wt % of carbon). The assembly delivers a considerable charge capacity (145 mA h g(-1) ) at an ultrahigh charge- discharge rate of 60 C (12 A g(-1) ). The rate capability of LS@rGO is influenced by the introduced spinel phase and rGO. X-ray absorption and X-ray photoelectron spectroscopy data indicate that Cr ions move from octahedral lattice sites to tetrahedral lattice sites, and that Mn ions do not participate in the oxidation reaction during the initial charge process. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Hierarchical surface atomic structure of a manganese-based spinel cathode for lithium-ion batteries.

    Science.gov (United States)

    Lee, Sanghan; Yoon, Gabin; Jeong, Minseul; Lee, Min-Joon; Kang, Kisuk; Cho, Jaephil

    2015-01-19

    The increasing use of lithium-ion batteries (LIBs) in high-power applications requires improvement of their high-temperature electrochemical performance, including their cyclability and rate capability. Spinel lithium manganese oxide (LiMn2O4) is a promising cathode material because of its high stability and abundance. However, it exhibits poor cycling performance at high temperatures owing to Mn dissolution. Herein we show that when stoichiometric lithium manganese oxide is coated with highly doped spinels, the resulting epitaxial coating has a hierarchical atomic structure consisting of cubic-spinel, tetragonal-spinel, and layered structures, and no interfacial phase is formed. In a practical application of the coating to doped spinel, the material retained 90% of its capacity after 800 cycles at 60 °C. Thus, the formation of an epitaxial coating with a hierarchical atomic structure could enhance the electrochemical performance of LIB cathode materials while preventing large losses in capacity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Prospects for spinel-stabilized, high-capacity lithium-ion battery cathodes

    Science.gov (United States)

    Croy, Jason R.; Park, Joong Sun; Shin, Youngho; Yonemoto, Bryan T.; Balasubramanian, Mahalingam; Long, Brandon R.; Ren, Yang; Thackeray, Michael M.

    2016-12-01

    Herein we report early results on efforts to optimize the electrochemical performance of a cathode composed of a lithium- and manganese-rich "layered-layered-spinel" (LLS) material for lithium-ion battery applications. Pre-pilot scale synthesis leads to improved particle properties compared with lab-scale efforts, resulting in high capacities (∼200 mAh g-1) and good energy densities (>700 Wh kgoxide-1) in tests with lithium-ion cells. Subsequent surface modifications give further improvements in rate capabilities and high-voltage stability. These results bode well for advances in the performance of this class of lithium- and manganese-rich cathode materials.

  8. A truncated octahedral spinel LiMn2O4 as high-performance cathode material for ultrafast and long-life lithium-ion batteries

    Science.gov (United States)

    Jiang, Caihua; Tang, Zilong; Wang, Shitong; Zhang, Zhongtai

    2017-07-01

    Spinel LiMn2O4 is a promising cathode candidate for lithium ion batteries whose electrochemical properties strongly depend on the surface orientation. In this work, we have successfully synthesized a high crystalline and well-defined truncated octahedral LiMn2O4 through the hydrothermal and heat treatment. The main {111} facets are aligned along the orientations mitigating Mn dissolution while the truncated {100} and {110} facets are along those facilitating Li+ diffusion. Benefiting from the unique structure, the octahedral LiMn2O4 delivers 143.4 mAh g-1 (close to the theoretical capacity of 148 mAh g-1) at 0.2 C and over 120 mAh g-1 at 30 C (discharged within 2 min) at 55 °C. Moreover, the fabricated LiMn2O4/Li4Ti5O12-TiO2 full cell demonstrates 121.6 mAh g-1 at 1 C and 56.0 mAh g-1 at 30 C with ∼81.2% capacity retention following 1000 cycles. The facilely synthesized truncated octahedral LiMn2O4 shows great potentials in practical applications for ultrafast and long-life lithium-ion batteries.

  9. High-Capacity Layered-Spinel Cathodes for Li-Ion Batteries.

    Science.gov (United States)

    Nayak, Prasant Kumar; Levi, Elena; Grinblat, Judith; Levi, Mikhael; Markovsky, Boris; Munichandraiah, N; Sun, Yang Kook; Aurbach, Doron

    2016-09-08

    Li and Mn-rich layered oxides with the general structure x Li2 MnO3 ⋅(1-x) LiMO2 (M=Ni, Mn, Co) are promising cathode materials for Li-ion batteries because of their high specific capacity, which may be greater than 250 mA h g(-1) . However, these materials suffer from high first-cycle irreversible capacity, gradual capacity fading, limited rate capability and discharge voltage decay upon cycling, which prevent their commercialization. The decrease in average discharge voltage is a major issue, which is ascribed to a structural layered-to-spinel transformation upon cycling of these oxide cathodes in wide potential ranges with an upper limit higher than 4.5 V and a lower limit below 3 V versus Li. By using four elements systems (Li, Mn, Ni, O) with appropriate stoichiometry, it is possible to prepare high capacity composite cathode materials that contain LiMn1.5 Ni0.5 O4 and Lix Mny Niz O2 components. The Li and Mn-rich layered-spinel cathode materials studied herein exhibit a high specific capacity (≥200 mA h g(-1) ) with good capacity retention upon cycling in a wide potential domain (2.4-4.9 V). The effect of constituent phases on their electrochemical performance, such as specific capacity, cycling stability, average discharge voltage, and rate capability, are explored here. This family of materials can provide high specific capacity, high rate capability, and promising cycle life. Using Co-free cathode materials is also an obvious advantage of these systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. An Integrated, Layered-Spinel Composite Cathode for Energy Storage Applications

    Science.gov (United States)

    Hagh, Nader; Skandan, Ganesh

    2012-01-01

    At low operating temperatures, commercially available electrode materials for lithium-ion batteries do not fully meet the energy and power requirements for NASA fs exploration activities. The composite cathode under development is projected to provide the required energy and power densities at low temperatures and its usage will considerably reduce the overall volume and weight of the battery pack. The newly developed composite electrode material can provide superior electrochemical performance relative to a commercially available lithium cobalt system. One advantage of using a composite cathode is its higher energy density, which can lead to smaller and lighter battery packs. In the current program, different series of layered-spinel composite materials with at least two different systems in an integrated structure were synthesized, and the volumetric and gravimetric energy densities were evaluated. In an integrated network of a composite electrode, the effect of the combined structures is to enhance the capacity and power capabilities of the material to levels greater than what is possible in current state-of-the-art cathode systems. The main objective of the current program is to implement a novel cathode material that meets NASA fs low temperature energy density requirements. An important feature of the composite cathode is that it has at least two components (e.g., layered and spinel) that are structurally integrated. The layered material by itself is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated, thereby delivering a large amount of energy with stable cycling. A key aspect of the innovation has been the development of a scalable process to produce submicronand micron-scale particles of these composite materials. An additional advantage of using such a composite electrode material is its low irreversible loss (.5%), which is primarily due to the unique activation

  11. Microwave-enhanced electrochemical cycling performance of the LiNi0.2Mn1.8O4 spinel cathode material at elevated temperature

    CSIR Research Space (South Africa)

    Raju, Kumar

    2016-04-01

    Full Text Available confirmed by XRD, XPS, (sup6)LiMAS-NMR and electrochemical studies including electrochemical impedance spectroscopy (EIS). The microwave-treated sample (LMNO(submic)) allowed for the clear exposure of the {111} facets of the spinel, optimized the Mn(sup3...

  12. Improvement of Capacity and Cycling Performance of Spinel LiMn2O4 Cathode Materials with TiO2-B Nanobelts

    DEFF Research Database (Denmark)

    Zhang, J.Y.; Shen, J.X.; Wang, T.L.

    2013-01-01

    The spinel LiMn2O4 was modified with TiO2-B nanobelts to improve its specific capacity and cycling performance. TiO2-B/LiMn2O4 composites were fabricated by a facile liquid phase mixing method. The morphology and structure of the samples were characterized by means of X-ray diffraction, scanning ...

  13. Enhanced electrochemical performance of Li-rich layered cathode materials via chemical activation of Li2MnO3 component and formation of spinel/carbon coating layer

    Science.gov (United States)

    Pang, Shengli; Xu, Kaijie; Wang, Yonggang; Shen, Xiangqian; Wang, Wenzhi; Su, Yanjing; Zhu, Meng; Xi, Xiaoming

    2017-10-01

    Li-rich layered oxides are promising cathode materials for advanced Li-ion batteries because of their high specific capacity and operating potential. In this work, the Li-rich layered oxide Li1·2Mn0·54Ni0·13Co0·13O2 (LMNC), is modified via a carbonization-reduction process (yielding the corresponding reduced compound denoted LMNC-R). Compared to the pristine oxide, LMNC-R delivers significantly enhanced initial discharge capacity/columbic efficiency, remarkably improved rate performance with an accelerated Li+ diffusion rate, and significantly increased capacity/voltage retention. The specific energy density and energy retention after 100 cycles increase from 378.2 Wh kg-1 and 47.7% for LMNC to 572.0 Wh kg-1 and 71.3%, respectively, for LMNC-R. The enhancement in the electrochemical performance of LMNC-R can be attributed to the synchronous formation of the oxygen non-stoichiometric Li2MnO3-δ component and to the carbon/spinel double coating layer in the material that resulted from the post-treatment process. Thus, the carbonization-reduction modification process can be used to tailor the structural evolution procedure and to suppress the metal ion dissolution of the Li-rich layered oxide during cycling.

  14. Suppressing Manganese Dissolution from Lithium Manganese Oxide Spinel Cathodes with Single-Layer Graphene

    Energy Technology Data Exchange (ETDEWEB)

    Jaber-Ansari, Laila; Puntambekar, Kanan P.; Kim, Soo; Aykol, Muratahan; Luo, Langli; Wu, Jinsong; Myers, Benjamin D.; Iddir, Hakim; Russell, John T.; Saldana, Spencer J.; Kumar, Rajan; Thackeray, Michael M.; Curtiss, Larry A.; Dravid, Vinayak P.; Wolverton, Christopher M.; Hersam, Mark C.

    2015-06-24

    Spinel-structured LiMn 2 O 4 (LMO) is a desirable cathode material for Li-ion batteries due to its low cost, abundance, and high power capability. However, LMO suffers from limited cycle life that is triggered by manganese dissolution into the electrolyte during electrochemical cycling. Here, it is shown that single-layer graphene coatings suppress manganese dissolution, thus enhancing the performance and lifetime of LMO cathodes. Relative to lithium cells with uncoated LMO cathodes, cells with graphene-coated LMO cathodes provide improved capacity retention with enhanced cycling stability. X-ray photoelectron spectroscopy reveals that graphene coatings inhibit manganese depletion from the LMO surface. Additionally, transmission electron microscopy demonstrates that a stable solid electrolyte interphase is formed on graphene, which screens the LMO from direct contact with the electrolyte. Density functional theory calculations provide two mechanisms for the role of graphene in the suppression of manganese dissolution. First, common defects in single-layer graphene are found to allow the transport of lithium while concurrently acting as barriers for manganese diffusion. Second, graphene can chemically interact with Mn 3+ at the LMO electrode surface, promoting an oxidation state change to Mn 4+ , which suppresses dissolution.

  15. Cathode material for lithium batteries

    Science.gov (United States)

    Park, Sang-Ho; Amine, Khalil

    2013-07-23

    A method of manufacture an article of a cathode (positive electrode) material for lithium batteries. The cathode material is a lithium molybdenum composite transition metal oxide material and is prepared by mixing in a solid state an intermediate molybdenum composite transition metal oxide and a lithium source. The mixture is thermally treated to obtain the lithium molybdenum composite transition metal oxide cathode material.

  16. Understanding the capacity fade mechanisms of spinel manganese oxide cathodes and improving their performance in lithium ion batteries

    Science.gov (United States)

    Choi, Won Chang

    Lithium ion batteries have been successful in portable electronics market due to their high energy density, adopting the layered LiCoO2 as the cathode material in commercial lithium ion cells. However, increasing interest in lithium ion batteries for electric vehicle and hybrid electric vehicle applications requires alternative cathode materials due to the high cost, toxicity, and limited power capability of the layered LiCoO2 cathode. In this regard, spinel LiMn2O4 has become appealing as manganese is inexpensive and environmentally benign, but LiMn2O 4 is plagued by severe capacity fade at elevated temperatures. This dissertation explores the factors that control and limit the electrochemical performance of spinel LiMn2O4 cathodes and focuses on improving the performance parameters such as the capacity, cyclability, and rate capability of various spinel cathodes derived from LiMn2O 4. From a systematic investigation of a number of cationic and anionic (fluorine) substituted spinel oxide compositions, the improvements in electrochemical properties and performances are found to be due to the reduced manganese dissolution and suppressed lattice parameter difference between the two cubic phases formed during the charge-discharge process. Investigations focused on fluorine substitution reveal that spinel LiMn 2-y-zLiyZnzO4-etaFeta oxyfluoride cathodes synthesized by solid-state reactions at 800°C employing ZnF2 as a raw material and spinel LiMn2-y-zLiy NizO4-etaFeta oxyfluoride cathodes synthesized by firing the cation-substituted LiMn2-y-zLiy NizO4 oxides with NH4HF2 at a moderate temperature of 450°C show superior cyclability, increased capacity, reduced Mn dissolution, and excellent storage performance compared to the corresponding oxide analogs and the conventional LiMn2O 4. Spinel-layered composite cathodes are found to exhibit better electrochemical performance with graphite anode when charged to 4.7 V in the first cycle followed by cycling at 4.3--3.5 V

  17. Investigation of spinel-related and orthorhombic LiMNO2 cathodes for rechargeable lithium batteries

    CSIR Research Space (South Africa)

    Gummow, RJ

    1994-05-01

    Full Text Available Cathode materials that have been synthesized by reduction of lithium-manganese- Cathode materials that have been synthesized by reduction of lithium-manganese-oxide and manganese-oxide precursors with hydrogen at 300 to 350-degrees...

  18. Effect of mulitivalent cation dopants on lithium manganese spinel cathodes

    CSIR Research Space (South Africa)

    De Kock, A

    1998-02-01

    Full Text Available Journal of Power Sources 70 (I 998) 247-252 The effect of multivalent cation dopants on lithium manganese spine1 cathodes A. de Kock, E. Ferg * , R.J. Gummow Dii,ision of Matericrls Scrence and Technoiog,v, CSIR. P.0. Bar ZY5... of multivalent cation dopants (Mg?+. Zn?+ and Al?+ ). Optimal dopant levelx to achieve maximum capacity and the greatest stability with repeated cycling have been determined. The effect of doping the oxygen-rich spine1 Li...

  19. Synthesis and electrochemical properties of Ni doped spinel LiNi (subx)Mn (sub2-x)O(sub)4 (0 ≤ x ≤ 0.5) cathode materials for Li-Ion battery

    CSIR Research Space (South Africa)

    Kebede, MA

    2012-10-01

    Full Text Available Spherical pristine LiMn(sub2)O(sub4) and Ni doped LiNixMn(sub2-x)O(sub)4 (x=0.1, 0.2, 0.3, 0.4, 0.5) cathode materials for lithium ion battery with high first cycle discharge capacity and excellent cycle performance were synthesized using...

  20. Synthesis and Electrochemical Properties of Ni Doped Spinel LiNixMn2-xO4 (0 ≤ x ≤ 0.5) Cathode Materials for Li-Ion Battery

    CSIR Research Space (South Africa)

    Kebede, M

    2013-11-01

    Full Text Available Spherical pristine LiMn2O4 and Ni doped LiNixMn2-xO4 (x=0.1, 0.2, 0.3, 0.4, 0.5) cathode materials for lithium ion battery with high first cycle discharge capacity and excellent cycle performance were synthesized using the solution...

  1. The role of particle size on the electrochemical properties at 25 and at 55 deg. C of the LiCr{sub 0.2}Ni{sub 0.4}Mn{sub 1.4}O{sub 4} spinel as 5 V-cathode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Aklalouch, Mohamed [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas (CSIC) c/Sor Juana Ines de la Cruz, 3 28049-Madrid (Spain); ECME, Faculte des Sciences et Techniques Marrakech, Universite Cadi Ayyad, Av. A. El Khattabi, B.P.549 Marrakech (Morocco); Rojas, Rosa M.; Rojo, Jose Maria [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas (CSIC) c/Sor Juana Ines de la Cruz, 3 28049-Madrid (Spain); Saadoune, Ismael [ECME, Faculte des Sciences et Techniques Marrakech, Universite Cadi Ayyad, Av. A. El Khattabi, B.P.549 Marrakech (Morocco); Amarilla, Jose Manuel, E-mail: amarilla@icmm.csic.e [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas (CSIC) c/Sor Juana Ines de la Cruz, 3 28049-Madrid (Spain)

    2009-12-01

    The role of the particle size on the electrochemical properties at 25 and at 55 deg. C of the LiCr{sub 0.2}Ni{sub 0.4}Mn{sub 1.4}O{sub 4} spinel synthesized by combustion method has been determined. Samples with different particle size were obtained by heating the raw spinel from 700 to 1100 deg. C, for 1 h in air. X-ray diffraction patterns revealed that all the prepared materials are single-phase spinels. The main effect of the thermal treatment is the remarkable increase of the particles size from approx60 to approx3000 nm as determined by transmission electron microscopy. The electrochemical properties were determined at high discharge currents (1C rate) in two-electrode Li-cells. At 25 and at 55 deg. C, in spite of the great differences in particle size, the discharge capacity drained by all samples is similar (Q{sub dch} approx 135 mAh g{sup -1}). Instead, the cycling performances strongly change with the particle size. The spinels with PHI > 500 nm show better cycling stability at 25 and at 55 deg. C than those with PHI < 500 nm. The samples heated at 1000 and 1100 deg. C, with high potential (E approx 4.7 V), elevate capacity (Q approx 135 mAh g{sup -1}), and remarkable cycling performances (capacity retention after 250 cycles >96%) are very attractive materials as 5V-cathodes for high-energy Li-ion batteries.

  2. Spinel LiMn 2 O 4 Nanorods as Lithium Ion Battery Cathodes

    KAUST Repository

    Kim, Do Kyung

    2008-11-12

    Spinel LiMn 2O 4 is a low-cost, environmentally friendly, and highly abundant material for Li-ion battery cathodes. Here, we report the hydrothermal synthesis of single-crystalline β-MnO 2 nanorods and their chemical conversion into free-standing single-crystalline LiMn 2O 4 nanorods using a simple solid-state reaction. The LiMn 2O 4 nanorods have an average diameter of 130 nm and length of 1.2 μm. Galvanostatic battery testing showed that LiMn 2O 4 nanorods have a high charge storage capacity at high power rates compared with commercially available powders. More than 85% of the initial charge storage capacity was maintained for over 100 cycles. The structural transformation studies showed that the Li ions intercalated into the cubic phase of the LiMn 2O 4 with a small change of lattice parameter, followed by the coexistence of two nearly identical cubic phases in the potential range of 3.5 to 4.3V. © 2008 American Chemical Society.

  3. Mitigation of chromium poisoning of cathodes in solid oxide fuel cells employing CuMn1.8O4 spinel coating on metallic interconnect

    Science.gov (United States)

    Wang, Ruofan; Sun, Zhihao; Pal, Uday B.; Gopalan, Srikanth; Basu, Soumendra N.

    2018-02-01

    Chromium poisoning is one of the major reasons for cathode performance degradation in solid oxide fuel cells (SOFCs). To mitigate the effect of Cr-poisoning, a protective coating on the surface of interconnect for suppressing Cr vaporization is necessary. Among the various coating materials, Cu-Mn spinel coating is considered to be a potential candidate due to their good thermal compatibility, high stability and good electronic conductivity at high temperature. In this study, Crofer 22 H meshes with no protective coating, those with commercial CuMn2O4 spinel coating and the ones with lab-developed CuMn1.8O4 spinel coating were investigated. The lab-developed CuMn1.8O4 spinel coating were deposited on Crofer 22 H mesh by electrophoretic deposition and densified by a reduction and re-oxidation process. With these different Crofer 22 H meshes (bare, CuMn2O4-coated, and CuMn1.8O4-coated), anode-supported SOFCs with Sr-doped LaMnO3-based cathode were electrochemically tested at 800 °C for total durations of up to 288 h. Comparing the mitigating effects of the two types of Cu-Mn spinel coatings on Cr-poisoning, it was found that the performance of the denser lab-developed CuMn1.8O4 spinel coating was distinctly better, showing no degradation in the cell electrochemical performance and significantly less Cr deposition near the cathode/electrolyte interface after the test.

  4. Experimental and ab initio investigations on textured Li–Mn–O spinel thin film cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, J., E-mail: Julian.Fischer@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Music, D. [RWTH Aachen University, Materials Chemistry, Kopernikusstrasse 10, 52074 Aachen (Germany); Bergfeldt, T.; Ziebert, C.; Ulrich, S.; Seifert, H.J. [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2014-12-01

    This paper describes the tailored preparation of nearly identical lithium–manganese–oxide thin film cathodes with different global grain orientations. The thin films were synthesized by rf magnetron sputtering from a LiMn{sub 2}O{sub 4}-target in a pure argon plasma. Under appropriate processing conditions, thin films with a cubic spinel structure and a nearly similar density and surface topography but different grain orientation, i.e. (111)- and (440)-textured films, were achieved. The chemical composition was determined by inductively coupled plasma optical emission spectroscopy and carrier gas hot extraction. The constitution- and microstructure were evaluated by X-ray diffraction and Raman spectroscopy. The surface morphology and roughness were investigated by scanning electron and atomic force microscopy. The differently textured films represent an ideal model system for studying potential effects of grain orientation on the lithium ion diffusion and electrochemical behavior in LiMn{sub 2}O{sub 4}-based thin films. They are nearly identical in their chemical composition, atomic bonding behavior, surface-roughness, morphology and thickness. Our initial ab initio molecular dynamics data indicate that Li ion transport is faster in (111)-textured structure than in (440)-textured one. - Highlights: • Thin film model system of differently textured cubic Li–Mn–O spinels. • Investigation of the Li–Mn–O thin film mass density by X-ray reflectivity. • Ab initio molecular dynamics simulation on Li ion diffusion in LiMn{sub 2}O{sub 4}.

  5. Power generation using spinel manganese-cobalt oxide as a cathode catalyst for microbial fuel cell applications.

    Science.gov (United States)

    Mahmoud, Mohamed; Gad-Allah, Tarek A; El-Khatib, K M; El-Gohary, Fatma

    2011-11-01

    This study focused on the use of spinel manganese-cobalt (Mn-Co) oxide, prepared by a solid state reaction, as a cathode catalyst to replace platinum in microbial fuel cells (MFCs) applications. Spinel Mn-Co oxides, with an Mn/Co atomic ratios of 0.5, 1, and 2, were prepared and examined in an air cathode MFCs which was fed with a molasses-laden synthetic wastewater and operated in batch mode. Among the three Mn-Co oxide cathodes and after 300 h of operation, the Mn-Co oxide catalyst with Mn/Co atomic ratio of 2 (MnCo-2) exhibited the highest power generation 113 mW/m2 at cell potential of 279 mV, which were lower than those for the Pt catalyst (148 mW/m2 and 325 mV, respectively). This study indicated that using spinel Mn-Co oxide to replace platinum as a cathodic catalyst enhances power generation, increases contaminant removal, and substantially reduces the cost of MFCs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Synthesis and characterization of advanced high capacity cathode active nanomaterials with three integrated spinel-layered phases for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Bulut, Emrah, E-mail: ebulut@sakarya.edu.tr [Department of Chemistry, Sakarya University, 54187 Serdivan, Sakarya (Turkey); Can, Mustafa, E-mail: mstfacan@gmail.com [Vocational School of Arifiye, Sakarya University, 54580 Arifiye, Sakarya (Turkey); Özacar, Mahmut, E-mail: nmozacart@hotmail.com [Department of Chemistry, Sakarya University, 54187 Serdivan, Sakarya (Turkey); Akbulut, Hatem, E-mail: akbulut@Sakarya.edu.tr [Department of Metallurgical and Materials Engineering, Sakarya University, 54187 Serdivan, Sakarya (Turkey)

    2016-06-15

    Mesoporous cathode active materials that included undoped and separated Cu{sup 2+} and Co{sup 3+} doped spinels were prepared. The “doped spinel-Layered-Li-rich spinel” composite nanoparticles within the three integrated phased (LiM{sub 0,02}Mn{sub 1,98}O{sub 4}–Li{sub 2}MnO{sub 3}–Li{sub 1,27}Mn{sub 1,73}O{sub 4}; where M is Cu{sup 2+} and Co{sup 3+}) were synthesized by a microwave assisted hydrothermal synthesis. These materials were investigated with X-Ray powder Diffraction spectroscopy (XRD), Scanning Electron Microscopy (SEM and FE-SEM), High Resolution Transmission Electron Microscopy (HR-TEM), galvanostatic cycling at 0.1C and 0.5C rates, Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS). The effects of the calcination temperature and the partial substitution of Mn{sup 3+} in the spinel by Cu{sup 2+} and Co{sup 3+}, and onto the spinel structure were investigated with XRD. The lattice parameters of the spinel structured compounds were calculated from the XRD data using the Williamson-Hall equation. However, the morphological changes, which depended on the calcination temperature, were examined by SEM, FE-SEM and HRTEM. Furthermore, the two other phases which were different from LiM{sub 0,02}Mn{sub 1,98}O{sub 4} had a great impact on the electrochemical performance over the potential range of the 3–5 V. At the 0.1C rate, the first discharge capacities of undoped and Cu{sup 2+}, Co{sup 3+} doped materials were 577, 285, 560 mAh/g respectively. After 50 cycles at 0.5C rate, we achieved 96.2%; 52.5%; 95.4% capacity retention for the undoped and Cu{sup 2+}, Co{sup 3+} doped materials respectively. - Highlights: • Mesoporous cathode active nanomaterials with three integrated phase were synthesized. • The materials were characterized structurally by XRD, FE-SEM, HR-TEM. • Integrated phases provide an additional 400 mAh/g discharge capacity at low rate. • Higher specific capacities than literature values were achieved at 0

  7. High-Capacity, High-Voltage Composite Oxide Cathode Materials

    Science.gov (United States)

    Hagh, Nader M.

    2015-01-01

    This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

  8. A truncated manganese spinel cathode for excellent power and lifetime in lithium-ion batteries.

    Science.gov (United States)

    Kim, Joo-Seong; Kim, Kyungsu; Cho, Woosuk; Shin, Weon Ho; Kanno, Ryoji; Choi, Jang Wook

    2012-12-12

    Spinel-structured lithium manganese oxide (LiMn(2)O(4)) cathodes have been successfully commercialized for various lithium battery applications and are among the strongest candidates for emerging large-scale applications. Despite its various advantages including high power capability, however, LiMn(2)O(4) chronically suffers from limited cycle life, originating from well-known Mn dissolution. An ironical feature with the Mn dissolution is that the surface orientations supporting Li diffusion and thus the power performance are especially vulnerable to the Mn dissolution, making both high power and long lifetime very difficult to achieve simultaneously. In this investigation, we address this contradictory issue of LiMn(2)O(4) by developing a truncated octahedral structure in which most surfaces are aligned to the crystalline orientations with minimal Mn dissolution, while a small portion of the structure is truncated along the orientations to support Li diffusion and thus facilitate high discharge rate capabilities. When compared to control structures with much smaller dimensions, the truncated octahedral structure as large as 500 nm exhibits better performance in both discharge rate performance and cycle life, thus resolving the previously conflicting aspects of LiMn(2)O(4).

  9. Cells having cathodes containing polycarbon disulfide materials

    Science.gov (United States)

    Okamoto, Yoshi; Skotheim, Terje A.; Lee, Hung S.

    1995-08-15

    The present invention relates to an electric current producing cell which contains an anode, a cathode having as a cathode-active material one or more carbon-sulfur compounds of the formula (CS.sub.x).sub.n, in which x takes values from 1.2 to 2.3 and n is greater or equal to 2, and where the redox process does not involve polymerization and de-polymerization by forming and breaking S--S bonds in the polymer backbone. The cell also contains an electrolyte which is chemically inert with respect to the anode and the cathode.

  10. Cells having cathodes containing polycarbon disulfide materials

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Y.; Skotheim, T.A.; Lee, H.S.

    1995-08-15

    The present invention relates to an electric current producing cell which contains an anode, a cathode having as a cathode-active material one or more carbon-sulfur compounds of the formula (CS{sub x}){sub n}, in which x takes values from 1.2 to 2.3 and n is greater or equal to 2, and where the redox process does not involve polymerization and de-polymerization by forming and breaking S--S bonds in the polymer backbone. The cell also contains an electrolyte which is chemically inert with respect to the anode and the cathode. 5 figs.

  11. Spinels as cathodes for the electrochemical reduction of O2 and NO

    DEFF Research Database (Denmark)

    Simonsen, Vibe Louise Ernlund; Find, D.; Lilliedal, M.

    2007-01-01

    Spinels were synthesised and investigated as electro-catalyst for the electrochemical reduction of oxygen and nitric oxide using cyclic voltammetry and cone shaped electrodes. The following four spinels were investigated; CoFe2O4, NiFe2O4, CuFe2O4 and Co3O4. The composition CuFe2O4 revealed the l...

  12. Introduction to porous spinel for refractory (high temp material

    Directory of Open Access Journals (Sweden)

    Kumar Saurav

    2016-09-01

    Full Text Available The paper examines thermal properties of materials. The transient pulse method was used for specific heat, thermal diffusivity and thermal conductivity determination. Porous MgO was synthesis by heating pellets at 1100 °C for 1 h. The resultant porous MgO was then immersed in 10 mol/L aluminum nitrate solution, dried, and reheated at 1300 °C for 2 h to convert it to spinel. The evaluation was performed with the help of mathematical apparatus used for study of fractal structures properties. The method results from generalized relations that were designed for study of physical properties of fractal structures. As it is shown these relations are in a good agreement with the equations used for the description of time responses of temperature for the pulse input of supplied heat.

  13. Improved cathode materials for microbial electrosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, T; Nie, HR; Bain, TS; Lu, HY; Cui, MM; Snoeyenbos-West, OL; Franks, AE; Nevin, KP; Russell, TP; Lovley, DR

    2013-01-01

    Microbial electrosynthesis is a promising strategy for the microbial conversion of carbon dioxide to transportation fuels and other organic commodities, but optimization of this process is required for commercialization. Cathodes which enhance electrode-microbe electron transfer might improve rates of product formation. To evaluate this possibility, biofilms of Sporomusa ovata, which are effective in acetate electrosynthesis, were grown on a range of cathode materials and acetate production was monitored over time. Modifications of carbon cloth that resulted in a positive-charge enhanced microbial electrosynthesis. Functionalization with chitosan or cyanuric chloride increased acetate production rates 6-7 fold and modification with 3-aminopropyltriethoxysilane gave rates 3-fold higher than untreated controls. A 3-fold increase in electrosynthesis over untreated carbon cloth cathodes was also achieved with polyaniline cathodes. However, not all strategies to provide positively charged surfaces were successful, as treatment of carbon cloth with melamine or ammonia gas did not stimulate acetate electrosynthesis. Treating carbon cloth with metal, in particular gold, palladium, or nickel nanoparticles, also promoted electrosynthesis, yielding electrosynthesis rates that were 6-,4.7- or 4.5-fold faster than the untreated control, respectively. Cathodes comprised of cotton or polyester fabric treated with carbon nanotubes yielded cathodes that supported acetate electrosynthesis rates that were similar to 3-fold higher than carbon cloth controls. Recovery of electrons consumed in acetate was similar to 80% for all materials. The results demonstrate that one approach to increase rates of carbon dioxide reduction in microbial electrosynthesis is to modify cathode surfaces to improve microbe-electrode interactions.

  14. Close cathode chamber: Low material budget MWPC

    Science.gov (United States)

    Varga, Dezső; Kiss, Gábor; Hamar, Gergő; Bencédi, Gyula

    2013-01-01

    Performance of asymmetric-type MWPC-s are presented. In this structure, referred to as Close Cathode Chamber in an earlier study, the material budget is significantly reduced on one hand by the elimination of external support frame, on the other hand by thin detector walls. In this paper it is demonstrated that the outline is compatible with large size detectors (1 m wire length), maintaining mechanical and operation stability, with total weight of 3 kg (including support structure) for a half square meter surface. The detection efficiency and response time is shown to be sufficient for L0 triggering in the ALICE VHMPID layout. Reduced sensitivity to cathode deformations (due to internal overpressure as mechanical strain) is directly demonstrated. On small sized chambers, improvement of position resolution with analog readout is evaluated, reaching 0.09 mm RMS with 2 mm wide cathode segments. Simulation results on signal time evolutions are presented. With the above studies, comparison of classical MWPC-s and the Close Cathode Chamber design is performed in all major aspects.

  15. Chemical, structural, and electrochemical characterization of 5 V spinel and complex layered oxide cathodes of lithium ion batteries

    Science.gov (United States)

    Tiruvannamalai Annamalai, Arun Kumar

    2007-12-01

    Lithium ion batteries have revolutionized the portable electronics market since their commercialization first by Sony Corporation in 1990. They are also being intensively pursued for electric and hybrid electric vehicle applications. Commercial lithium ion cells are currently made largely with the layered LiCoO 2 cathode. However, only 50% of the theoretical capacity of LiCoO 2 can be utilized in practical cells due to the chemical and structural instabilities at deep charge as well as safety concerns. These drawbacks together with the high cost and toxicity of Co have created enormous interest in alternative cathodes. In this regard, spinel LiMn2O4 has been investigated widely as Mn is inexpensive and environmentally benign. However, LiMn 2O4 exhibits severe capacity fade on cycling, particularly at elevated temperatures. With an aim to overcome the capacity fading problems, several cationic substitutions to give LiMn2-yMyO 4 (M = Cr, Fe, Co, Ni, and Cu) have been pursued in the literature. Among the cation-substituted systems, LiMn1.5Ni0.5O 4 has become attractive as it shows a high capacity of ˜ 130 mAh/g (theoretical capacity: 147 mAh/g) at around 4.7 V. With an aim to improve the electrochemical performance of the 5 V LiMn 1.5Ni0.5O4 spinel oxide, various cation-substituted LiMn1.5-yNi0.5-zMy+zO4 (M = Li, Mg, Fe, Co, and Zn) spinel oxides have been investigated by chemical lithium extraction. The cation-substituted LiMn1.5-yNi0.5-zM y+zO4 spinel oxides exhibit better cyclability and rate capability in the 5 V region compared to the unsubstituted LiMn1.5Ni 0.5O4 cathodes although the degree of manganese dissolution does not vary significantly. The better electrochemical properties of LiMn 1.5-yNi0.5-zMy+zO4 are found to be due to a smaller lattice parameter difference among the three cubic phases formed during the charge-discharge process. In addition, while the spinel Li1-xMn1.58Ni0.42O4 was chemically stable, the spinel Li1-xCo2O4 was found to exhibit both

  16. Free energy for protonation reaction in lithium-ion battery cathode materials.

    Energy Technology Data Exchange (ETDEWEB)

    Benedek, R.; Thackeray, M. M.; van de Walle, A.; Chemical Sciences and Engineering Division; California Inst. of Tech.

    2008-09-09

    Calculations are performed of free energies for proton-for-lithium-ion exchange reactions in lithium-ion battery cathode materials. First-principles calculations are employed for the solid phases and tabulated ionization potential and hydration energy data for aqueous ions. Layered structures, spinel LiMn{sub 2}O{sub 4}, and olivine LiFePO{sub 4} are considered. Protonation is most favorable energetically in layered systems, such as Li{sub 2} MnO{sub 3} and LiCoO{sub 2}. Less favorable are ion-exchange in spinel LiMn{sub 2}O{sub 4} and LiV{sub 3}O{sub 8}. Unfavorable is the substitution of protons for Li in olivine LiFePO{sub 4}, because of the large distortion of the Fe and P coordination polyhedra. The reaction free energy scales roughly linearly with the volume change in the reaction.

  17. Influence of annealing temperature on the electrochemical and surface properties of the 5-V spinel cathode material LiCr0.2Ni0.4Mn1.4O4 synthesized by a sol–gel technique

    DEFF Research Database (Denmark)

    Younesi, Reza; Malmgren, Sara; Edström, Kristina

    2014-01-01

    LiCr0.2Ni0.4Mn1.4O4 was synthesized by a sol–gel technique in which tartaric acid was used as oxide precursor. The synthesized powder was annealed at five different temperatures from 600 to 1,000 °C and tested as a 5-V cathode material in Li-ion batteries. The study shows that annealing at higher...

  18. Monitoring local redox processes in LiNi0.5Mn1.5O4 battery cathode material by in operando EPR spectroscopy.

    Science.gov (United States)

    Niemöller, Arvid; Jakes, Peter; Eurich, Svitlana; Paulus, Anja; Kungl, Hans; Eichel, Rüdiger-A; Granwehr, Josef

    2018-01-07

    Despite the multitude of analytical methods available to characterize battery cathode materials, identifying the factors responsible for material aging is still challenging. We present the first investigation of transient redox processes in a spinel cathode during electrochemical cycling of a lithium ion battery by in operando electron paramagnetic resonance (EPR). The battery contains a LiNi0.5Mn1.5O4 (LNMO) spinel cathode, which is a material whose magnetic interactions are well understood. The evolution of the EPR signal in combination with electrochemical measurements shows the impact of Mn3+ on the Li+ motion inside the spinel. Moreover, state of charge dependent linewidth variations confirm the formation of a solid solution for slow cycling, which is taken over by mixed models of solid solution and two-phase formation for fast cycling due to kinetic restrictions and overpotentials. Long-term measurements for 480 h showed the stability of the investigated LNMO, but also small amounts of cathode degradation products became visible. The results point out how local, exchange mediated magnetic interactions in cathode materials are linked with battery performance and can be used for material characterization.

  19. Intermetallics as advanced cathode materials in hydrogen production via electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Stojic, Dragica Lj.; Marceta Kaninski, Milica P.; Maksic, Aleksandar D.; Simic, Natasa D. [Laboratory of Physical Chemistry, Vinca Institute of Nuclear Sciences, P.O. Box 522, 11001-Belgrade (Serbia and Montenegro); Grozdic, Tomislav D. [Centre for Multidisciplinary Studies, University of Belgrade, 11030-Belgrade (Serbia and Montenegro)

    2006-06-15

    Intermetallics phases along Mo-Pt phase diagram have been investigated as cathode materials for the production of hydrogen by electrolysis from water KOH solutions, in an attempt to increase the electrolytic process efficiency. These materials were compared with conventional cathodes (Fe and Ni), often used in the alkaline electrolysis, and also with the intermetallic Ti-Pt. An significant upgrade of the electrolytic efficiency using intermetallics in pure KOH electrolyte was achieved in comparison with conventional cathode materials. The effects of those cathode materials on the process efficiency were discussed in the context of transition metal features that issue from their electronic configuration. (author)

  20. Development of cathode material for lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Rustam Mukhtaruly Turganaly

    2014-08-01

    Full Text Available The electrochemical characteristics of the cathode material coated with carbon layer has been developed. Various carbon coating methods. There  has been carried out a comparative electrochemical analysis of the coated and uncoated with carbon cathode material

  1. Iron phosphate materials as cathodes for lithium batteries

    CERN Document Server

    Prosini, Pier Paolo

    2011-01-01

    ""Iron Phosphate Materials as Cathodes for Lithium Batteries"" describes the synthesis and the chemical-physical characteristics of iron phosphates, and presents methods of making LiFePO4 a suitable cathode material for lithium-ion batteries. The author studies carbon's ability to increase conductivity and to decrease material grain size, as well as investigating the electrochemical behaviour of the materials obtained. ""Iron Phosphate Materials as Cathodes for Lithium Batteries"" also proposes a model to explain lithium insertion/extraction in LiFePO4 and to predict voltage profiles at variou

  2. Synthesis and characterization of inverse spinels, intercalation materials for Li-ion batteries

    NARCIS (Netherlands)

    Van Landschoot, N.

    2006-01-01

    Chapter 2 describes the solid-state synthesis of LiNiVO4 and LiCoVO4. The materials are prepared at 800C and are phase pure, as shown by X-ray diffraction and have the inverse spinel structure. Due to the solid-state synthesis the particle size is quite large and the particle size distribution is

  3. Layered Lithium-Rich Oxide Nanoparticles Doped with Spinel Phase: Acidic Sucrose-Assistant Synthesis and Excellent Performance as Cathode of Lithium Ion Battery.

    Science.gov (United States)

    Chen, Min; Chen, Dongrui; Liao, Youhao; Zhong, Xiaoxin; Li, Weishan; Zhang, Yuegang

    2016-02-01

    Nanolayered lithium-rich oxide doped with spinel phase is synthesized by acidic sucrose-assistant sol-gel combustion and evaluated as the cathode of a high-energy-density lithium ion battery. Physical characterizations indicate that the as-synthesized oxide (LR-SN) is composed of uniform and separated nanoparticles of about 200 nm, which are doped with about 7% spinel phase, compared to the large aggregated ones of the product (LR) synthesized under the same condition but without any assistance. Charge/discharge demonstrates that LR-SN exhibits excellent rate capability and cyclic stability: delivering an average discharge capacity of 246 mAh g(-1) at 0.2 C (1C = 250 mA g(-1)) and earning a capacity retention of 92% after 100 cycles at 4 C in the lithium anode-based half cell, compared to the 227 mA g(-1) and the 63% of LR, respectively. Even in the graphite anode-based full cell, LR-SN still delivers a capacity of as high as 253 mAh g(-1) at 0.1 C, corresponding to a specific energy density of 801 Wh kg(-1), which are the best among those that have been reported in the literature. The separated nanoparticles of the LR-SN provide large sites for charge transfer, while the spinel phase doped in the nanoparticles facilitates lithium ion diffusion and maintains the stability of the layered structure during cycling.

  4. Synthesis and electrochemical study of Mg{sub 1.5}MnO{sub 3}: A defect spinel cathode for rechargeable magnesium battery

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Partha [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Jampani, Prashanth H., E-mail: pjampani@pitt.edu [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Hong, DaeHo [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Gattu, Bharat [Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Poston, James A.; Manivannan, Ayyakkannu [US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Datta, Moni Kanchan [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); School of Dental Medicine, University of Pittsburgh, PA 15261 (United States); Center for Complex Engineered Multifunctional Materials, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

    2015-12-15

    Graphical abstract: Mg{sub 1.5}MnO{sub 3}, a defect oxide spinel derived by the Pechini route, was tested as cathode for rechargeable magnesium battery. TEM and XRD analyses of Mg{sub 1.5}MnO{sub 3} shows the formation of ∼100 nm sized nano particles in the cubic defect spinel structure (space group: Fd3m; unit cell: 0.833294 nm). Cyclic voltammetry illustrates a reversible reaction occurring between 0.3 and 1.5 V versus magnesium. Galvanostatic cycling of the Mg{sub 1.5}MnO{sub 3} cathode exhibits a low capacity of ∼12.4 mAh/g up to 20 cycle with ∼99.9% Coulombic efficiency when cycled at a current rate of ∼C/27. XPS (X-ray photoelectron spectroscopy) surface probe of magnesiated/de-magnesiated electrodes confirm a change in the redox center of Mn-ions during intercalation/de-intercalation of Mg-ion from the Mg{sub 1.5}MnO{sub 3} electrode. The low capacity of Mg{sub 1.5}MnO{sub 3} electrode mainly stem from the kinetic limitation of Mg-ion removal from the defect oxide spinel as the electrochemical impedance spectroscopy results of electrodes after 1st and 2nd cycle show that charge transfer resistance, R{sub e}, increases post charge state whereas interfacial resistance, R{sub i}, increases after discharge state, respectively. - Highlights: • Pechini process yields 100 nm sized particles of the defect cubic spinel Mg{sub 1.5}MnO{sub 3}. • Stable capacity of ∼12.4 mAh/g obtained at C/27 rate and 99.9% Coulombic efficiency. • XPS shows change in valence state of Mn{sup 3+}/Mn{sup 4+} center with cycling. • Low capacity stems from increase in charge-transfer and interfacial resistances with cycling. - Abstract: Mg{sub 1.5}MnO{sub 3}, a defect oxide spinel (space group: Fd3m; unit cell: 0.833294 nm) of particle size ∼100 nm derived by the Pechini route was tested as a cathode for rechargeable magnesium battery. Cyclic voltammetry illustrates a reversible reaction occurring in the 0.3–2.0 V potential window versus magnesium. The spinel however

  5. Battery designs with high capacity anode materials and cathode materials

    Science.gov (United States)

    Masarapu, Charan; Anguchamy, Yogesh Kumar; Han, Yongbong; Deng, Haixia; Kumar, Sujeet; Lopez, Herman A.

    2017-10-03

    Improved high energy capacity designs for lithium ion batteries are described that take advantage of the properties of high specific capacity anode active compositions and high specific capacity cathode active compositions. In particular, specific electrode designs provide for achieving very high energy densities. Furthermore, the complex behavior of the active materials is used advantageously in a radical electrode balancing design that significantly reduced wasted electrode capacity in either electrode when cycling under realistic conditions of moderate to high discharge rates and/or over a reduced depth of discharge.

  6. Chromium (V) compounds as cathode material in electrochemical power sources

    Science.gov (United States)

    Delnick, F.M.; Guidotti, R.A.; McCarthy, D.K.

    A cathode for use in a thermal battery, comprising a chromium (V) compound. The preferred materials for this use are Ca/sub 5/(CrO/sub 4/)/sub 3/Cl, Ca/sub 5/(CrO/sub 4/)OH, and Cr/sub 2/O/sub 5/. The chromium (V) compound can be employed as a cathode material in ambient temperature batteries when blended with a suitably conductive filler, preferably carbon black.

  7. Structural and electrochemical properties of aluminium doped LiMn2O4 cathode materials for Li battery: experimental and ab initio calculations

    CSIR Research Space (South Africa)

    Kebede, MA

    2014-03-01

    Full Text Available . Rajalakshmi, Cerium and zinc: Dual-doped LiMn2O4 spinels as cathode material for use in lithium rechargeable batteries, J. Power Sources 187 (2009) 565-574. [12] B. Hwang, R. Santhanam, D. Liu, Y. Tsai, Effect of Al-substitution on the stability of LiMn2O... properties of aluminium doped LiMn2O4 cathode materials for Li battery: experimental and ab initio calculations Mesfin A. Kebede1,a), Maje J. Phasha1, Niki Kunjuzwa1, Lukas J. le Roux1, Donald Mkhonto2, Kenneth I. Ozoemena1 and Mkhulu K. Mathe1 1...

  8. Reduced Graphene Oxide-Wrapped Nickel-Rich Cathode Materials for Lithium Ion Batteries.

    Science.gov (United States)

    Shim, Jae-Hyun; Kim, Young-Min; Park, Miji; Kim, Jongsik; Lee, Sanghun

    2017-06-07

    The encapsulation of Ni-rich cathode materials (LiNi0.6Co0.2Mn0.2O2) for lithium ion batteries in reduced graphene oxide (rGO) sheets is introduced to improve electrochemical performances. Using (3-aminopropyl)triethoxysilane, the active materials are completely wrapped with several rGO layers of ∼2 nm thickness. By virtue of the great electrical conductivity of graphene, the rGO-coated cathode materials exhibit much enhanced electrochemical performances of cycling property and rate capability. In addition, it is shown that the structural degradation of the active materials, which is from the rhombohedral layered structure (R3̅m) to the spinel (Fd3̅m) or rock-salt phase (Fm3̅m), is significantly reduced as well as delayed due to the protection of the active materials in the rGO layers from direct contact with electrolytes and the consequent suppression of side reactions.

  9. Odyssey of Multivalent Cathode Materials: Open Questions and Future Challenges.

    Science.gov (United States)

    Canepa, Pieremanuele; Sai Gautam, Gopalakrishnan; Hannah, Daniel C; Malik, Rahul; Liu, Miao; Gallagher, Kevin G; Persson, Kristin A; Ceder, Gerbrand

    2017-03-08

    The rapidly expanding field of nonaqueous multivalent intercalation batteries offers a promising way to overcome safety, cost, and energy density limitations of state-of-the-art Li-ion battery technology. We present a critical and rigorous analysis of the increasing volume of multivalent battery research, focusing on a wide range of intercalation cathode materials and the mechanisms of multivalent ion insertion and migration within those frameworks. The present analysis covers a wide variety of material chemistries, including chalcogenides, oxides, and polyanions, highlighting merits and challenges of each class of materials as multivalent cathodes. The review underscores the overlap of experiments and theory, ranging from charting the design metrics useful for developing the next generation of MV-cathodes to targeted in-depth studies rationalizing complex experimental results. On the basis of our critical review of the literature, we provide suggestions for future multivalent cathode studies, including a strong emphasis on the unambiguous characterization of the intercalation mechanisms.

  10. Intermetallics as cathode materials in the electrolytic hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Stojic, D.L.; Maksic, A.D.; Kaninski, M.P.M. [Vinca Inst. of Nuclear Sciences, Belgrade (Serbia and Montenegro). Lab. of Physical Chemistry; Cekic, B.D. [Vinca Inst. of Nuclear Sciences, Belgrade (Serbia and Montenegro). Lab. of Physics; Miljanic, S.S. [Belgrade Univ. (Serbia and Montenegro). Faculty of Physical Chemistry

    2005-01-01

    The intermetallics of transition metals have been investigated as cathode materials for the production of hydrogen by electrolysis from water-KOH solutions, in an attempt to increase the electrolytic process efficiency. We found that the best effect among all investigated cathodes (Hf{sub 2}Fe, Zr-Pt, Nb-Pd(I), Pd-Ta, Nb-Pd(II), Ti-Pt) exhibits the Hf{sub 2}Fe phase. These materials were compared with conventional cathodes (Fe and Ni), often used in the alkaline electrolysis. A significant upgrade of the electrolytic efficiency using intermetallics, either in pure KOH electrolyte or in combination with ionic activators added in situ, was achieved. The effects of these cathode materials on the process efficiency were discussed in the context of transition metal features that issue from their electronic configuration. (Author)

  11. Comprehensive Enhancement of Nanostructured Lithium-Ion Battery Cathode Materials via Conformal Graphene Dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kan-Sheng [Department of Materials; Xu, Rui [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States; Luu, Norman S. [Department of Materials; Secor, Ethan B. [Department of Materials; Hamamoto, Koichi [Department of Materials; Li, Qianqian [Department of Materials; Kim, Soo [Department of Materials; Sangwan, Vinod K. [Department of Materials; Balla, Itamar [Department of Materials; Guiney, Linda M. [Department of Materials; Seo, Jung-Woo T. [Department of Materials; Yu, Xiankai [Department of Materials; Liu, Weiwei [Department of Materials; Wu, Jinsong [Department of Materials; Wolverton, Chris [Department of Materials; Dravid, Vinayak P. [Department of Materials; Barnett, Scott A. [Department of Materials; Lu, Jun [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States; Amine, Khalil [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States; Hersam, Mark C. [Department of Materials

    2017-03-01

    Efficient energy storage systems based on lithium-ion batteries represent a critical technology across many sectors including consumer electronics, electrified transportation, and a smart grid accommodating intermittent renewable energy sources. Nanostructured electrode materials present compelling opportunities for high-performance lithium-ion batteries, but inherent problems related to the high surface area to volume ratios at the nanometer-scale have impeded their adoption for commercial applications. Here, we demonstrate a materials and processing platform that realizes high-performance nanostructured lithium manganese oxide (nano-LMO) spinel cathodes with conformal graphene coatings as a conductive additive. The resulting nanostructured composite cathodes concurrently resolve multiple problems that have plagued nanoparticle-based lithium-ion battery electrodes including low packing density, high additive content, and poor cycling stability. Moreover, this strategy enhances the intrinsic advantages of nano-LMO, resulting in extraordinary rate capability and low temperature performance. With 75% capacity retention at a 20C cycling rate at room temperature and nearly full capacity retention at -20 degrees C, this work advances lithium-ion battery technology into unprecedented regimes of operation.

  12. Comprehensive Enhancement of Nanostructured Lithium-Ion Battery Cathode Materials via Conformal Graphene Dispersion.

    Science.gov (United States)

    Chen, Kan-Sheng; Xu, Rui; Luu, Norman S; Secor, Ethan B; Hamamoto, Koichi; Li, Qianqian; Kim, Soo; Sangwan, Vinod K; Balla, Itamar; Guiney, Linda M; Seo, Jung-Woo T; Yu, Xiankai; Liu, Weiwei; Wu, Jinsong; Wolverton, Chris; Dravid, Vinayak P; Barnett, Scott A; Lu, Jun; Amine, Khalil; Hersam, Mark C

    2017-04-12

    Efficient energy storage systems based on lithium-ion batteries represent a critical technology across many sectors including consumer electronics, electrified transportation, and a smart grid accommodating intermittent renewable energy sources. Nanostructured electrode materials present compelling opportunities for high-performance lithium-ion batteries, but inherent problems related to the high surface area to volume ratios at the nanometer-scale have impeded their adoption for commercial applications. Here, we demonstrate a materials and processing platform that realizes high-performance nanostructured lithium manganese oxide (nano-LMO) spinel cathodes with conformal graphene coatings as a conductive additive. The resulting nanostructured composite cathodes concurrently resolve multiple problems that have plagued nanoparticle-based lithium-ion battery electrodes including low packing density, high additive content, and poor cycling stability. Moreover, this strategy enhances the intrinsic advantages of nano-LMO, resulting in extraordinary rate capability and low temperature performance. With 75% capacity retention at a 20C cycling rate at room temperature and nearly full capacity retention at -20 °C, this work advances lithium-ion battery technology into unprecedented regimes of operation.

  13. Effects of precursor treatment on the structure and electrochemical properties of spinel LiMn{sub 2}O{sub 4} cathode

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Hongwei [College of Chemistry and Environmental Science, Key Laboratory of Green Chemical Medium and Reaction of Ministry of Education, Henan Normal University, Xinxiang, Henan 453007 (China); Chang, Zhaorong, E-mail: czr_56@163.com [College of Chemistry and Environmental Science, Key Laboratory of Green Chemical Medium and Reaction of Ministry of Education, Henan Normal University, Xinxiang, Henan 453007 (China); Zhao, Haili [College of Chemistry and Environmental Science, Key Laboratory of Green Chemical Medium and Reaction of Ministry of Education, Henan Normal University, Xinxiang, Henan 453007 (China); Yuan, Xiao-Zi; Wang, Haijiang [National Research Council of Canada, Vancouver, BC, Canada V6T 1W5 (Canada); Gao, Shuyan, E-mail: shuyangao@htu.cn [College of Chemistry and Environmental Science, Key Laboratory of Green Chemical Medium and Reaction of Ministry of Education, Henan Normal University, Xinxiang, Henan 453007 (China)

    2013-07-25

    Highlights: •The Mn–Na oxide with high valence can be easily formed and result in impurity diffraction peaks for the LiMn{sub 2}O{sub 4}. •Feeding N{sub 2} and adding hydrazine could effectively prevent Mn{sup 2+} from being oxidized into the Mn–Na oxide. •LiMn{sub 2}O{sub 4} synthesized by our method delivers the excellent structural characteristics and electrochemical performances. -- Abstract: As a precursor of spinel LiMn{sub 2}O{sub 4} cathode, manganese oxide is prepared by co-precipitation via a two-step drying method. The effects of precursor treatment on the structure, morphology, and electrochemical performance of the synthesized spinel LiMn{sub 2}O{sub 4} are studied using contrasting experiments involving the addition of hydrazine, N{sub 2}, and H{sub 2}O{sub 2}. The tests show that different treatments have a great effect on the crystal structure, morphology, tap density, and electrochemical performance of LiMn{sub 2}O{sub 4}. When the precursor is treated by adding hydrazine and pure N{sub 2}, the synthesized LiMn{sub 2}O{sub 4} shows an integral lattice, uniform particle size, a pure spinel phase with an ordered octahedral crystal structure, and high tap density (2.23 g cm{sup −3}). The electrochemical results show that spinel LiMn{sub 2}O{sub 4} exhibits higher specific capacity and better cyclic stability than other samples, especially at an elevated temperature and high discharge current. The initial discharge capacity of the electrode is 110.8 mAh g{sup −1} at a rate of 3 °C, and exhibits a good capacity retention of 96.4% after 30 cycles; at a rate of 5 °C, the initial discharge capacity is 107.5 mAh g{sup −1}, with a capacity retention of 87.3% after 50 cycles.

  14. Spinel electrodes for lithium batteries - a review

    Energy Technology Data Exchange (ETDEWEB)

    Thackeray, M.M.; De Picciotto, L.A.; De Kock, A.; Johnson, P.J.; Nicholas, V.A.; Adendorff, K.T.

    1987-08-01

    This paper briefly reviews recent electrochemical data of several transition-metal oxide and sulphide spinel compounds of general formula A(B/sub 2/)X/sub 4/ that have been employed as cathode materials in both room-temperature and high-temperature (400/sup 0/C) lithium cels. Particular attention is given to the performance of the oxide spinels M/sub 3/O/sub 4/ (M = Fe, Co, Mn) that have like A- and B-type cations, the lithium spinels Li(M/sub 2/)O/sub 4/ (M = Ti, V, Mn) and LiFe/sub 5/O/sub 8/, and the thiospinels CuCo/sub 2/S/sub 4/ and CuTi/sub 2/S/sub 4/. Reaction processes and the structural characteristics of the reaction products are highlighted.

  15. Comparative Issues of Cathode Materials for Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Christian M. Julien

    2014-03-01

    Full Text Available After an introduction to lithium insertion compounds and the principles of Li-ion cells, we present a comparative study of the physical and electrochemical properties of positive electrodes used in lithium-ion batteries (LIBs. Electrode materials include three different classes of lattices according to the dimensionality of the Li+ ion motion in them: olivine, layered transition-metal oxides and spinel frameworks. Their advantages and disadvantages are compared with emphasis on synthesis difficulties, electrochemical stability, faradaic performance and security issues.

  16. Novel Composite Materials for SOFC Cathode-Interconnect Contact

    Energy Technology Data Exchange (ETDEWEB)

    J. H. Zhu

    2009-07-31

    This report summarized the research efforts and major conclusions of our University Coal Research Project, which focused on developing a new class of electrically-conductive, Cr-blocking, damage-tolerant Ag-perovksite composite materials for the cathode-interconnect contact of intermediate-temperature solid oxide fuel cell (SOFC) stacks. The Ag evaporation rate increased linearly with air flow rate initially and became constant for the air flow rate {ge} {approx} 1.0 cm {center_dot} s{sup -1}. An activation energy of 280 KJ.mol{sup -1} was obtained for Ag evaporation in both air and Ar+5%H{sub 2}+3%H{sub 2}O. The exposure environment had no measurable influence on the Ag evaporation rate as well as its dependence on the gas flow rate, while different surface morphological features were developed after thermal exposure in the oxidizing and reducing environments. Pure Ag is too volatile at the SOFC operating temperature and its evaporation rate needs to be reduced to facilitate its application as the cathode-interconnect contact. Based on extensive evaporation testing, it was found that none of the alloying additions reduced the evaporation rate of Ag over the long-term exposure, except the noble metals Au, Pt, and Pd; however, these noble elements are too expensive to justify their practical use in contact materials. Furthermore, the addition of La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSM) into Ag to form a composite material also did not significantly modify the Ag evaporation rate. The Ag-perovskite composites with the perovskite being either (La{sub 0.6}Sr{sub 0.4})(Co{sub 0.8}Fe{sub 0.2})O{sub 3} (LSCF) or LSM were systematically evaluated as the contact material between the ferritic interconnect alloy Crofer 22 APU and the LSM cathode. The area specific resistances (ASRs) of the test specimens were shown to be highly dependent on the volume percentage and the type of the perovskite present in the composite contact material as well as the amount of thermal cycling

  17. High voltage spinel oxides for Li-ion batteries: From the material research to the application

    Science.gov (United States)

    Patoux, Sébastien; Daniel, Lise; Bourbon, Carole; Lignier, Hélène; Pagano, Carole; Le Cras, Frédéric; Jouanneau, Séverine; Martinet, Sébastien

    Li-ion batteries are already used in many nomad applications, but improvement of this technology is still necessary to be durably introduced on new markets such as electric vehicles (EVs), hybrid electric vehicles (HEVs) or eventually photovoltaic solar cells. Modification of the nature of the active materials of electrodes is the most challenging and innovative aspect. High voltage spinel oxides for Li-ion batteries, with general composition LiMn 2- xM xO 4 (M a transition metal element), may be used to face increasing power source demand. It should be possible to obtain up to 240 Wh kg -1 at cell level when combining a nickel manganese spinel oxide with graphite (even more with silicon/carbon nanocomposites at the anode). Specific composition and material processing have to be selected with care, as discussed in this paper. It is demonstrated that 'LiNi 0.5Mn 1.5O 4' and LiNi 0.4Mn 1.6O 4 have remarkable properties such as high potential, high energy density, good cycle life and high rate capability. Choice of the electrolyte is also of primary importance in order to prevent its degradation at high voltage in contact with active surfaces. We showed that a few percents of additive in the electrolyte were suitable for protecting the positive electrode/electrolyte interface, and reducing the self-discharge. High voltage materials are also possibly interesting to be used in safe and high power Li-ion cells. In this case, the negative electrode may be made of Li 4Ti 5O 12 or TiO 2 to give a '3 V' system.

  18. Material and Energy Flows in the Production of Cathode and Anode Materials for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); James, Christine [Michigan State Univ., East Lansing, MI (United States); Gaines, Linda [Argonne National Lab. (ANL), Argonne, IL (United States); Gallagher, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Dai, Qiang [Argonne National Lab. (ANL), Argonne, IL (United States); Kelly, Jarod C. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    The Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model has been expanded to include four new cathode materials that can be used in the analysis of battery-powered vehicles: lithium nickel cobalt manganese oxide (LiNi0.4Co0.2Mn0.4O2 [NMC]), lithium iron phosphate (LiFePO4 [LFP]), lithium cobalt oxide (LiCoO2 [LCO]), and an advanced lithium cathode (0.5Li2MnO3∙0.5LiNi0.44Co0.25Mn0.31O2 [LMR-NMC]). In GREET, these cathode materials are incorporated into batteries with graphite anodes. In the case of the LMR-NMC cathode, the anode is either graphite or a graphite-silicon blend. Lithium metal is also an emerging anode material. This report documents the material and energy flows of producing each of these cathode and anode materials from raw material extraction through the preparation stage. For some cathode materials, we considered solid state and hydrothermal preparation methods. Further, we used Argonne National Laboratory’s Battery Performance and Cost (BatPaC) model to determine battery composition (e.g., masses of cathode, anode, electrolyte, housing materials) when different cathode materials were used in the battery. Our analysis concluded that cobalt- and nickel-containing compounds are the most energy intensive to produce.

  19. Material and Energy Flows in the Production of Cathode and Anode Materials for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; James, Christine [Michigan State Univ., East Lansing, MI (United States). Chemical Engineering and Materials Science Dept.; Gaines, Linda G. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Gallagher, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division

    2014-09-30

    The Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model has been expanded to include four new cathode materials that can be used in the analysis of battery-powered vehicles: lithium nickel cobalt manganese oxide (LiNi0.4Co0.2Mn0.4O2 [NMC]), lithium iron phosphate (LiFePO4 [LFP]), lithium cobalt oxide (LiCoO2 [LCO]), and an advanced lithium cathode (0.5Li2MnO3∙0.5LiNi0.44Co0.25Mn0.31O2 [LMR-NMC]). In GREET, these cathode materials are incorporated into batteries with graphite anodes. In the case of the LMR-NMC cathode, the anode is either graphite or a graphite-silicon blend. This report documents the material and energy flows of producing each of these cathode and anode materials from raw material extraction through the preparation stage. For some cathode materials, we considered solid state and hydrothermal preparation methods. Further, we used Argonne National Laboratory’s Battery Performance and Cost (BatPaC) model to determine battery composition (e.g., masses of cathode, anode, electrolyte, housing materials) when different cathode materials were used in the battery. Our analysis concluded that cobalt- and nickel-containing compounds are the most energy intensive to produce.

  20. High Capacity Cathode Materials for Next Generation Energy Storage

    Science.gov (United States)

    Papandrea, Benjamin John

    Energy storage devices are of increasing importance for applications in mobile electronics, hybrid electric vehicles, and can also play a critical role in renewable energy harvesting, conversion and storage. Since its commercial inception in the 1990's, the lithium-ion battery represents the dominant energy storage technology for mobile power supply today. However, the total capacity of lithium-ion batteries is largely limited by the theoretical capacities of the cathode materials such as LiCoO2 (272 mAh g-1), and LiFePO4 (170 mAh g-1), and cannot satisfy the increasing consumer demand, thus new cathode materials with higher capacities must be explored. Two of the most promising cathode materials with significantly larger theoretical capacities are sulfur (1675 mAh g-1) and air, specifically the oxygen (3840 mAh g-1). However, the usage of either of these cathodic materials is plagued with numerous issues that must be overcome before their commercialization. In the first part of my dissertation, we investigated the usage of a three-dimensional graphene membrane for a high energy density lithium-air (Li-Air) battery in ambient condition. One of the issues with Li-Air batteries is the many side reaction that can occur during discharge in ambient condition, especially with water vapor. Using a hydrophobic tortuous three-dimensional graphene membrane we are able to inhibit the diffusion of water vapor and create a lithium-air battery that cycles over 2000 times with a capacity limited at 140 mAh g-1, over 100 cycles with a capacity limited at 1425 mAh g-1, and over 20 cycles at the high capacity of 5700 mAh g-1. In the second part of my dissertation, we investigate the usage of a three-dimensional graphene aerogel to maximize the loading of sulfur to create a freestanding electrode with high capacity for a lithium-sulfur (Li-S) battery. We demonstrated that our three-dimensional graphene aerogel could sustain a loading of 95% by weight, and we achieved a capacity of

  1. Synthesis Of Fe Doped LiMn2O4 Cathode Materials For Li Battery By Solid State Reaction

    Directory of Open Access Journals (Sweden)

    Horata N.

    2015-06-01

    Full Text Available LiFe0.1Mn1.9O4 is expected as a cathode material for the rechargeable lithium-ion batteries. LiMn2O4 has been received attention because this has advantages such as low cost and low toxicity compared with other cathode materials of LiCoO2 and LiNiO2. However, LiMn2O4 has some problems such as small capacity and no long life. LiMn2O4 is phase transformation at around human life temperature. One of the methods to overcome this problem is to stabilize the spinel structure by substituting Mn site ion in LiMn2O4 with transition metals (Al, Mg, Ti, Ni, Fe, etc.. LiFe0.1Mn1.9O4 spinel was synthesized from Li2CO3, Fe2O3 and MnO2 powder. The purpose of this study is to report the optimal condition of Fe doped LiFe0.1Mn1.9O4. Li2CO3, Fe2O3, and MnO2 mixture powder was heated up to 1173 K by TG-DTA. Li2CO3 was thermal decomposed, and CO2 gas evolved, and formed Li2O at about 800 K. LiFe0.1Mn1.9O4 was synthesized from a consecutive reaction Li2O, Fe2O3 and MnO2 at 723 ~ 1023 K. Active energy is calculated to 178 kJmol−1 at 723 ~ 1023 K. The X-ray powder diffraction pattern of the LiFe0.1Mn1.9O4 heated mixture powder at 1023 K for 32 h in air flow was observed.

  2. Copper sulfates as cathode materials for Li batteries

    Science.gov (United States)

    Schwieger, Jonathan N.; Kraytsberg, Alexander; Ein-Eli, Yair

    As lithium battery technology sets out to bridge the gap between portable electronics and the electrical automotive industry, cathode materials still stand as the bottleneck regarding performances. In the realm of highly attractive polyanion-type structures as high-voltage cathode materials, the sulfate group (SO 4) 2- possesses an acknowledged superiority over other contenders in terms of open circuit voltage arising from the inductive effect of strong covalent S-O bonds. In parallel, novel lithium insertion mechanisms are providing alternatives to traditional intercalation, enabling reversible multi-electron processes securing high capacities. Combining both of these advantageous features, we report here the successful electrochemical reactivity of copper sulfate pentahydrate (CuSO 4·5H 2O) with respect to lithium insertion via a two-electron displacement reaction entailing the extrusion of metallic copper at a dual voltage of 3.2 V and 2.7 V followed by its reversible insertion at 3.5 V and 3.8 V. At this stage, cyclability was still shown to be limited due to the irreversible degradation to a monohydrate structure owing to constitutional water loss.

  3. Copper sulfates as cathode materials for Li batteries

    Energy Technology Data Exchange (ETDEWEB)

    Schwieger, Jonathan N.; Kraytsberg, Alexander; Ein-Eli, Yair [Technion Israel Institute of Technology, Department of Materials Engineering, Technion City, Haifa 32000 (Israel)

    2011-02-01

    As lithium battery technology sets out to bridge the gap between portable electronics and the electrical automotive industry, cathode materials still stand as the bottleneck regarding performances. In the realm of highly attractive polyanion-type structures as high-voltage cathode materials, the sulfate group (SO{sub 4}){sup 2-} possesses an acknowledged superiority over other contenders in terms of open circuit voltage arising from the inductive effect of strong covalent S-O bonds. In parallel, novel lithium insertion mechanisms are providing alternatives to traditional intercalation, enabling reversible multi-electron processes securing high capacities. Combining both of these advantageous features, we report here the successful electrochemical reactivity of copper sulfate pentahydrate (CuSO{sub 4}.5H{sub 2}O) with respect to lithium insertion via a two-electron displacement reaction entailing the extrusion of metallic copper at a dual voltage of 3.2 V and 2.7 V followed by its reversible insertion at 3.5 V and 3.8 V. At this stage, cyclability was still shown to be limited due to the irreversible degradation to a monohydrate structure owing to constitutional water loss. (author)

  4. Constructing Dense SiO x @Carbon Nanotubes versus Spinel Cathode for Advanced High-Energy Lithium-Ion Batteries

    KAUST Repository

    Ming, Hai

    2017-02-09

    A newly designed dense SiOx@carbon nanotubes (CNTs) composite with a high conductivity of 3.5 S cm−1 and tap density of 1.13 g cm−3 was prepared, in which the CNTs were stripped by physical energy crushing and then coated on SiOx nanoparticles. The composite exhibits high capacities of 835 and 687 mAh g−1 at current densities of 100 and 200 mA g−1, which can be finely persevered over 100 cycles. Benefiting from this promising anode, two new full cells of SiOx@CNTs/LiMn2O4 and SiOx@CNTs/LiNi0.5Mn1.5O4 with high energy densities of 2273 and 2747 Wh kganode−1 (i. e. 413 and 500 Wh kgcathode−1), respectively, were successfully assembled and can cycle more than 400 cycles. Even with further cycling at the elevated temperature of 45 °C, the cells can still deliver relatively high capacities of 568 and 465 mAh ganode−1, respectively, over 100 cycles. Such desired high-energy lithium-ion batteries with working voltages over 4.0 V can be widely developed for diverse applications (e. g. in handheld devices, electric vehicles, and hybrid electric vehicles). The easy extension of the presented synthetic strategy and the configuration of high-energy battery system would be significant in materials synthesis and energy-storage devices.

  5. New Cathode Materials for Intermediate Temperature Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Allan J. Jacobson

    2006-09-30

    Operation of SOFCs at intermediate temperatures (500-800 C) requires new combinations of electrolyte and electrode materials that will provide both rapid ion transport across the electrolyte and electrode-electrolyte interfaces and efficient electrocatalysis of the oxygen reduction and fuel oxidation reactions. This project concentrates on materials and issues associated with cathode performance that are known to become limiting factors as the operating temperature is reduced. The specific objectives of the proposed research are to develop cathode materials that meet the electrode performance targets of 1.0 W/cm{sup 2} at 0.7 V in combination with YSZ at 700 C and with GDC, LSGM or bismuth oxide based electrolytes at 600 C. The performance targets imply an area specific resistance of {approx}0.5 {Omega}cm{sup 2} for the total cell. The research strategy is to investigate both established classes of materials and new candidates as cathodes, to determine fundamental performance parameters such as bulk diffusion, surface reactivity and interfacial transfer, and to couple these parameters to performance in single cell tests. The initial choices for study were perovskite oxides based on substituted LaFeO{sub 3} (P1 compositions), where significant data in single cell tests exist at PNNL for example, for La{sub 0.8}Sr{sub 0.2}FeO{sub 3} cathodes on both YSZ and CSO/YSZ. The materials selection was then extended to La{sub 2}NiO{sub 4} compositions (K1 compositions), and then in a longer range task we evaluated the possibility of completely unexplored group of materials that are also perovskite related, the ABM{sub 2}O{sub 5+{delta}}. A key component of the research strategy was to evaluate for each cathode material composition, the key performance parameters, including ionic and electronic conductivity, surface exchange rates, stability with respect to the specific electrolyte choice, and thermal expansion coefficients. In the initial phase, we did this in parallel with

  6. Hydrogen Induced Stress Cracking of Materials Under Cathodic Protection

    Science.gov (United States)

    LaCoursiere, Marissa P.

    Hydrogen embrittlement of AISI 4340, InconelRTM 718, Alloy 686 and Alloy 59 was studied using slow strain rate tests of both smooth and notched cylindrical specimens. Two heat treatments of the AISI 4340 material were used as a standard for two levels of yield strength: 1479 MPa, and 1140 MPa. A subset of the 1140 MPa AISI 4340 material also underwent plasma nitriding. The InconelRTM 718 material was hardened following AMS 5663M to obtain a yield strength of 1091 MPa. The Alloy 686 material was obtained in the Grade 3 condition with a minimum yield strength of 1034 MPa. The Alloy 59 material was obtained with a cold worked condition similar to the Alloy 686 and with a minimum yield strength of 1034 MPa. Ninety-nine specimens were tested, including smooth cylindrical tensile test specimens and smooth and notched cylindrical slow strain rate tensile tests specimens. Testing included specimens that had been precharged with hydrogen in 3.5% NaCl at 50°C for 2 weeks (AISI 4340), 4 weeks (InconelRTM 718, Alloy 686, Alloy 59) and 16 weeks (InconelRTM 718, Alloy 686, Alloy 59) using a potentiostat to deliver a cathodic potential of -1100 mV vs. SCE. The strain rate over the gauge section for the smooth specimens and in the notch root for the notched specimens was 1 x 10-6 /s. It was found that the AISI 4340 was highly embrittled in simulated ocean water when compared to the nickel based superalloys. The higher strength AISI 4340 showed much more embrittlement, as expected. Testing of the AISI 4340 at both 20°C and 4°C showed that the temperature had no effect on the hydrogen embrittlement response. The InconelRTM 718 was highly embrittled when precharged, although it only showed low levels of embrittlement when unprecharged. Both the Alloy 686 and Alloy 59 showed minimal embrittlement in all conditions. Therefore, for the materials examined, the use of Alloy 686 and Alloy 59 for components in salt water environments when under a cathodic potential of -1100 mV vs. SCE is

  7. Direct regeneration of recycled cathode material mixture from scrapped LiFePO4 batteries

    Science.gov (United States)

    Li, Xuelei; Zhang, Jin; Song, Dawei; Song, Jishun; Zhang, Lianqi

    2017-03-01

    A new green recycling process (named as direct regeneration process) of cathode material mixture from scrapped LiFePO4 batteries is designed for the first time. Through this direct regeneration process, high purity cathode material mixture (LiFePO4 + acetylene black), anode material mixture (graphite + acetylene black) and other by-products (shell, Al foil, Cu foil and electrolyte solvent, etc.) are recycled from scrapped LiFePO4 batteries with high yield. Subsequently, recycled cathode material mixture without acid leaching is further directly regenerated with Li2CO3. Direct regeneration procedure of recycled cathode material mixture from 600 to 800 °C is investigated in detail. Cathode material mixture regenerated at 650 °C display excellent physical, chemical and electrochemical performances, which meet the reuse requirement for middle-end Li-ion batteries. The results indicate the green direct regeneration process with low-cost and high added-value is feasible.

  8. Lanthanides: new metallic cathode materials for organic photovoltaic cells.

    Science.gov (United States)

    Nikiforov, Maxim P; Strzalka, Joseph; Jiang, Zhang; Darling, Seth B

    2013-08-21

    Organic photovoltaics (OPVs) are compliant with inexpensive, scalable, and environmentally benign manufacturing technologies. While substantial attention has been focused on optimization of active layer chemistry, morphology, and processing, far less research has been directed to understanding charge transport at the interfaces between the electrodes and the active layer. Electrical properties of these interfaces not only impact efficiency, but also play a central role in stability of organic solar cells. Low work function metals are the most widely used materials for the electron transport layer with Ca being the most common material. In bulk heterojunction OPV devices, low work function metals are believed to mirror the role they play in OLEDs, where such metals are used to control carrier selectivity, transport, extraction, and blocking, as well as interface band bending. Despite their advantages, low work function materials are generally prone to reactions with water, oxygen, nitrogen, and carbon dioxide from air leading to rapid device degradation. Here we discuss the search for a new metallic cathode interlayer material that increases device stability and still provides device efficiency similar to that achieved with a Ca interlayer.

  9. Cobalt-manganese-based spinels as multifunctional materials that unify catalytic water oxidation and oxygen reduction reactions.

    Science.gov (United States)

    Menezes, Prashanth W; Indra, Arindam; Sahraie, Nastaran Ranjbar; Bergmann, Arno; Strasser, Peter; Driess, Matthias

    2015-01-01

    Recently, there has been much interest in the design and development of affordable and highly efficient oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts that can resolve the pivotal issues that concern solar fuels, fuel cells, and rechargeable metal-air batteries. Here we present the synthesis and application of porous CoMn2 O4 and MnCo2 O4 spinel microspheres as highly efficient multifunctional catalysts that unify the electrochemical OER with oxidant-driven and photocatalytic water oxidation as well as the ORR. The porous materials were prepared by the thermal degradation of the respective carbonate precursors at 400 °C. The as-prepared spinels display excellent performances in electrochemical OER for the cubic MnCo2 O4 phase in comparison to the tetragonal CoMn2 O4 material in an alkaline medium. Moreover, the oxidant-driven and photocatalytic water oxidations were performed and they exhibited a similar trend in activity to that of the electrochemical OER. Remarkably, the situation is reversed in ORR catalysis, that is, the oxygen reduction activity and stability of the tetragonal CoMn2 O4 catalyst outperformed that of cubic MnCo2 O4 and rivals that of benchmark Pt catalysts. The superior catalytic performance and the remarkable stability of the unifying materials are attributed to their unique porous and robust microspherical morphology and the intrinsic structural features of the spinels. Moreover, the facile access to these high-performance materials enables a reliable and cost-effective production on a large scale for industrial applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Particle size effect of Ni-rich cathode materials on lithium ion battery performance

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ilkyu [Green Chemistry Division, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-600 (Korea, Republic of); Department of Chemical Engineering, Kyungppok National University, Daegu 702-701 (Korea, Republic of); Lee, Chul Wee [Green Chemistry Division, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-600 (Korea, Republic of); Kim, Jae Chang [Department of Chemical Engineering, Kyungppok National University, Daegu 702-701 (Korea, Republic of); Yoon, Songhun, E-mail: yoonshun@krict.re.kr [Green Chemistry Division, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-600 (Korea, Republic of)

    2012-01-15

    Graphical abstract: The preparation condition of Ni-rich cathode materials was investigated. When the retention time was short, a poor cathode performance was observed. For long retention time condition, cathode performance displayed a best result at pH 12. Highlights: Black-Right-Pointing-Pointer Ni-rich cathode materials (LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}) were prepared by co-precipitation method using separate addition of Al salt. Black-Right-Pointing-Pointer Particle size of Ni-rich cathode materials became larger with increase of retention time and solution pH. Black-Right-Pointing-Pointer Cathode performance was poor for low retention time. Black-Right-Pointing-Pointer Optimal pH for co-precipitation was 12. -- Abstract: Herein, Ni-rich cathode materials (LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}) in lithium ion batteries are prepared by a separate addition of Ni/Co salt and Al sol solution using a continuously stirred tank reactor. Retention time and solution pH were controlled in order to obtain high performance cathode material. Particle size increase was observed with a higher retention time of the reactants. Also, primary and secondary particles became smaller according to an increase of solution pH, which was probably due to a decrease of growth rate. From the cathode application, a high discharge capacity (175 mAh g{sup -1}), a high initial efficiency (90%) and a good cycleability were observed in the cathode material prepared under pH 12 condition, which was attributed to its well-developed layered property and the optimal particle size. However, rate capability was inversely proportional to the particle size, which was clarified by a decrease of charge-transfer resistance measured in the electrochemical impedance spectroscopy.

  11. Optimization of Layered Cathode Materials for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Christian Julien

    2016-07-01

    Full Text Available This review presents a survey of the literature on recent progress in lithium-ion batteries, with the active sub-micron-sized particles of the positive electrode chosen in the family of lamellar compounds LiMO2, where M stands for a mixture of Ni, Mn, Co elements, and in the family of yLi2MnO3•(1 − yLiNi½Mn½O2 layered-layered integrated materials. The structural, physical, and chemical properties of these cathode elements are reported and discussed as a function of all the synthesis parameters, which include the choice of the precursors and of the chelating agent, and as a function of the relative concentrations of the M cations and composition y. Their electrochemical properties are also reported and discussed to determine the optimum compositions in order to obtain the best electrochemical performance while maintaining the structural integrity of the electrode lattice during cycling.

  12. The Impact of Cathode Material and Shape on Current Density in an Aluminum Electrolysis Cell

    Science.gov (United States)

    Song, Yang; Peng, Jianping; Di, Yuezhong; Wang, Yaowu; Li, Baokuan; Feng, Naixiang

    2016-02-01

    A finite element model was developed to determine the impact of cathode material and shape on current density in an aluminum electrolysis cell. For the cathode material, results show that increased electrical resistivity leads to a higher cathode voltage drop; however, the horizontal current is reduced in the metal. The horizontal current magnitude for six different cathode materials in decreasing order is graphitized, semi-graphitized, full graphitic, 50% anthracite (50% artificial graphite), 70% anthracite (30% artificial graphite), 100% anthracite. The modified cathode shapes with an inclined cathode surface, higher collector bar and cylindrical protrusions are intended to improve horizontal current and flow resistance. Compared to a traditional cathode, modified collector bar sizes of 70 mm × 230 mm and 80 mm × 270 mm can reduce horizontal current density component Jx by 10% and 19%, respectively, due to better conductivity of the steel. The horizontal current in the metal decreases with increase of cathode inclination. The peak value of Jx can be approximately reduced by 20% for a 2° change in inclination. Cylindrical protrusions lead to local horizontal current increase on their tops, but the average current is less affected and the molten metal is effectively slowed down.

  13. Structure and electrochemical performances of co-substituted LiCo(x)Li(x-y)Mn(2-x)O4 cathode materials for the rechargeable lithium ion batteries.

    Science.gov (United States)

    Mohan, P; Kalaignan, G Paruthimal

    2013-10-01

    Spinel LiMn2O4 and Co, Li co-substituted LiCo(x)Li(x-y)Mn(2-x)O4 (x = 0.20; y = 0.05, 0.10 and 0.15) cathode materials were synthesized by sol-gel technique using lithium acetate, manganese acetate, cobalt acetate and tartaric acid as the starting materials. The effect of Co, Li substitution on the structure and surface morphology of LiCo(x)Li(x-y)Mn(2-x)O4 has been examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The materials for all the compositions have exhibited a phase pure cubic spinel structures from the XRD analysis. The crystallinity and average particle size of the synthesized materials were decreased by the substitution of Co, Li. The electrochemical properties of the assembled LiCo(x)Li(x-y)Mn(2-x)O4/Li/LiPF6 cells were evaluated for charge/discharge studies at different rates and electrochemical impedance measurements. This co-substituted LiMn2O4 has improved specific capacity and capacity retention over pure spinel LiMn2O4. The co-substitution of LiMn2O4 cathode material has increases cyclability; however, the discharge capacity reduces. Among all the compositions, LiCo(0.10)Li(0.10-)Mn(1.80)O4 cathode has improved the structural stability and excellent electrochemical performances of the rechargeable lithium-ion batteries.

  14. Surface reconstruction and chemical evolution of stoichiometric layered cathode materials for lithium-ion batteries

    National Research Council Canada - National Science Library

    Lin, Feng; Markus, Isaac M; Nordlund, Dennis; Weng, Tsu-Chien; Asta, Mark D; Xin, Huolin L; Doeff, Marca M

    2014-01-01

    ...)O2 cathode materials for lithium-ion batteries. Using correlated ensemble-averaged high-throughput X-ray absorption spectroscopy and spatially resolved electron microscopy and spectroscopy, here we report structural reconstruction...

  15. Advanced Cathode Material For High Energy Density Lithium-Batteries Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced cathode materials having high red-ox potential and high specific capacity offer great promise to the development of high energy density lithium-based...

  16. Graphene-Based Composites as Cathode Materials for Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Libao Chen

    2013-01-01

    Full Text Available Owing to the superior mechanical, thermal, and electrical properties, graphene was a perfect candidate to improve the performance of lithium ion batteries. Herein, we review the recent advances in graphene-based composites and their application as cathode materials for lithium ion batteries. We focus on the synthesis methods of graphene-based composites and the superior electrochemical performance of graphene-based composites as cathode materials for lithium ion batteries.

  17. Graphene-Based Composites as Cathode Materials for Lithium Ion Batteries

    OpenAIRE

    Libao Chen; Ming Zhang; Weifeng Wei

    2013-01-01

    Owing to the superior mechanical, thermal, and electrical properties, graphene was a perfect candidate to improve the performance of lithium ion batteries. Herein, we review the recent advances in graphene-based composites and their application as cathode materials for lithium ion batteries. We focus on the synthesis methods of graphene-based composites and the superior electrochemical performance of graphene-based composites as cathode materials for lithium ion batteries.

  18. Improving the performance of high voltage LiMn1.5Ni0.5O4 cathode material by carbon coating

    Science.gov (United States)

    Niketic, Svetlana; Couillard, Martin; MacNeil, Dean; Abu-Lebdeh, Yaser

    2014-12-01

    In this work, the high voltage LiMn1.5Ni0.5O4 cathode material has been synthesized as octadecahedron crystals with a disordered spinel structure and has been coated with a carbon layer from two different precursors (sucrose and Xerogel carbon) to improve its performance in Li-ion batteries. The effect of carbon coating on the physical and electrochemical properties of the crystals has been evaluated using X-ray diffraction (XRD), Infrared (IR) and Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental and surface area (BET) analyses and battery cycling at different charge/discharge rates and temperatures. It was found that the amount of carbon, present as a thin layer (5-10 nm) and estimated at Xerogel carbon shows the highest capacity at 10 C rate and 60 °C.

  19. The Impact of Strong Cathodic Polarization on SOC Electrolyte Materials

    DEFF Research Database (Denmark)

    Kreka, Kosova; Hansen, Karin Vels; Jacobsen, Torben

    2016-01-01

    of impurities at the grain boundaries, electrode poisoning, delamination or cracks of the electrolyte etc., have been observed in cells operated at such conditions, lowering the lifetime of the cell1,2. High polarizations are observed at the electrolyte/cathode interface of an electrolysis cell operated at high...... current density. In case of a cell voltage above 1.6 V, p-type and n-type electronic conductivity are often observed at the anode and cathode respectively3. Hence, a considerable part of the current is lost as leakage through the electrolyte, thus lowering the efficiency of the cell considerably.......One of the most promising reversible energy conversion/storage technologies is that of Solid Oxide Fuel/Electrolysis Cells (SOFC/SOEC, collectively termed SOC). Long term durability is typically required for such devises to become economically feasible, hence considerable amount of work has...

  20. High insulation foam glass material from waste cathode ray tube panel glass

    DEFF Research Database (Denmark)

    König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

    Recycling of materials from obsolete equipment has become an important part of global waste management. With responsible collecting, dismantling and materials separation, majority of materials can be recycled. Cathode ray tube (CRT) glass represents as much as two-thirds of the weight of a TV...

  1. Characterization of Li4Ti5O12 and LiMn2O4 spinel materials treated with aqueous acidic solutions

    NARCIS (Netherlands)

    Simon, D.R.

    2007-01-01

    In this thesis an investigation of two spinel materials, Li4Ti5O12 and LiMn2O4 used for Li-ion battery applications is performed interms of formation and reactivity towards acidic solutions. Subsequent characterizations such as structural, magnetic, chemical, and electrochemical characterizations

  2. In Situ Carbon Coated LiNi0.5Mn1.5O4 Cathode Material Prepared by Prepolymer of Melamine Formaldehyde Resin Assisted Method

    Directory of Open Access Journals (Sweden)

    Wei Yang

    2016-01-01

    Full Text Available Carbon coated spinel LiNi0.5Mn1.5O4 were prepared by spray-drying using prepolymer of melamine formaldehyde resin (PMF as carbon source of carbon coating layer. The PMF carbon coated LiNi0.5Mn1.5O4 was characterized by XRD, SEM, and other electrochemical measurements. The as-prepared lithium nickel manganese oxide has the cubic face-centered spinel structure with a space group of Fd3m. It showed good electrochemical performance as a cathode material for lithium ion battery. After 100 discharge and charge cycles at 0.5 C rate, the specific discharge capacity of carbon coated LiNi0.5Mn1.5O4 was 130 mAh·g−1, and the corresponding capacity retention was 98.8%. The 100th cycle specific discharge capacity at 10 C rate of carbon coated LiNi0.5Mn1.5O4 was 105.4 mAh·g−1, and even the corresponding capacity retention was 95.2%.

  3. One-Pot Hydrothermal Synthesis of LiMn2O4 Cathode Material with Excellent High-Rate and Cycling Properties

    Science.gov (United States)

    Jiang, Qianqian; Wang, Xingyao; Zhang, Han

    2016-08-01

    The spinel LiMn2O4 was prepared by a one-step hydrothermal method using acetone as the reductant under different hydrothermal temperatures. X-ray diffraction and scanning electron microscopy analysis indicated that optimal LiMn2O4 particles (LMO-120) were synthesized at the temperature of 120°C and the particles were well distributed and about 410 nm in size. Electrochemical performance showed that the as-prepared LiMn2O4 particles exhibited a higher initial discharge capacity than commercial LiMn2O4 (131.5 mAh g-1 versus 115.6 mAh g-1 at 0.2 C). An excellent discharge capacity retention rate of 94.07% was observed after 60 charge-discharge cycles. On the other hand, when cycled at the high rate of 1 C, the optimal LiMn2O4 in this work showed a high discharge capacity of 107.5 mAh g-1 in contrast to only 92.3 mAh g-1 of the commercial LiMn2O4. These results indicate that LMO-120 showed excellent electrochemical performance, especially the prolonged cycling life and high-rate performance, which suggested that this spinel LiMn2O4 has promise for practical application as a high-rate cathode material for lithium ion batteries.

  4. Activated porous carbon wrapped sulfur sub-microparticles as cathode materials for lithium sulfur batteries

    Science.gov (United States)

    Wang, Y.; Yan, Y. L.; Ren, B.; Yang, R.; Zhang, W.; Xu, Y. H.

    2017-03-01

    The lithium-sulfur batteries holds a high theoretical capacity and specific energy, which is 4-5 times larger than that of today’s lithium-ion batteries, yet the low sulfur loading and large particles in the cathode greatly offset its advantage in high energy density. In the present paper, a liquid phase deposition method was introduced to synthesize sub-micro sulfur particles, which utilized as cathode materials after composed with activated porous carbon. Compared with common sublimed sulfur cathodes, as-obtained composite cathode shows an enhanced initial discharge capacity from 840.7 mAh/g to 1093 mAh/g at C/10. The reversible specific capacity after 50 cycles increased from 383 mAh/g to 504 mAh/g. The developed method has the advantages of simple process, convenient operation and low cost, and is suitable for the industrial preparation of lithium/sulfur batteries.

  5. Preparation and Characterization of Cathode Materials for Lithium-Oxygen Batteries

    DEFF Research Database (Denmark)

    Storm, Mie Møller

    A possible future battery type is the Li-air battery which theoretically has the potential of reaching gravimetric energy densities close to those of gasoline. The Li-airbattery is discharged by the reaction of Li-ions and oxygen, drawn from the air, reacting at the battery cathode to form Li2O2....... The type of cathode material affects the battery discharge capacity and charging potential and with a carbon based cathode many questions are still unanswered. The focus of this Ph.D. project has been the synthesis of reduced graphene oxide as well as the investigation of the effect of reduced graphene...... the discharge capacity of the battery as well as the charging potential. In situ X-ray diffraction studies on carbon black cathodes in a capillary battery showed the formation of crystalline Li2O2 on the first discharge cycle, the intensity of Li2O2 on the second discharge cycle was however diminished...

  6. Design of crossed cathode in TCO material electrochemical removal from computer displays' device

    Energy Technology Data Exchange (ETDEWEB)

    Pa, P.S. [National Taipei Univ. of Education, Taipei City, Taiwan (China). Dept. of Digital Content Design, Graduate School of Toy and Game Design

    2010-07-01

    This presentation reported on a study involving new transparent conductive oxide (TCO) materials and electronic and optoelectronic devices. In particular, it described a crossed cathode design system that can remove TCO electrochemically from a thin film transistor liquid crystal display (TFT-LCD) surface of a computer screen. The design etching processes requires only a short time to remove the TCO thin-films easily and cleanly. The defective TCO materials were removed using this precise process, and the defective colour filters were returned to the production line. A fifth generation TFT-LCD was used for the experiment. A thin thickness of the crossed cathode, or a small edge radius of the crossed cathode, corresponded to a higher etching rate for the TCO thin-films. A small distance between the crossed cathode and the cylinder anode, or a small gap width between the crossed cathode and the workpiece, also corresponded to a higher etching rate. A higher feed rate of the workpiece together with sufficient electric power resulted in electrochemical etching. It was concluded that the effects of dreg discharge could be improved by providing pulsed direct current or using a high rotational speed of the crossed cathode.

  7. Carbyne Polysulfide as a Novel Cathode Material for Rechargeable Magnesium Batteries

    Directory of Open Access Journals (Sweden)

    Yanna NuLi

    2014-01-01

    Full Text Available We report the formation of carbyne polysulfide by coheating carbon containing carbyne moieties and elemental sulfur. The product is proved to have a sp2 hybrid carbon skeleton with polysulfide attached on it. The electrochemical performance of carbyne polysulfide as a novel cathode material for rechargeable magnesium batteries is firstly investigated. The material exhibits a high discharge capacity of 327.7 mAh g−1 at 3.9 mA g−1. These studies show that carbyne polysulfide is a promising candidate as cathode material for rechargeable Mg batteries if the capacity retention can be significantly improved.

  8. Carbyne polysulfide as a novel cathode material for rechargeable magnesium batteries.

    Science.gov (United States)

    NuLi, Yanna; Chen, Qiang; Wang, Weikun; Wang, Ying; Yang, Jun; Wang, Jiulin

    2014-01-01

    We report the formation of carbyne polysulfide by coheating carbon containing carbyne moieties and elemental sulfur. The product is proved to have a sp2 hybrid carbon skeleton with polysulfide attached on it. The electrochemical performance of carbyne polysulfide as a novel cathode material for rechargeable magnesium batteries is firstly investigated. The material exhibits a high discharge capacity of 327.7 mAh g(-1) at 3.9 mA g(-1). These studies show that carbyne polysulfide is a promising candidate as cathode material for rechargeable Mg batteries if the capacity retention can be significantly improved.

  9. Cathode material for lithium ion accumulators prepared by screen printing for Smart Textile applications

    Science.gov (United States)

    Syrový, T.; Kazda, T.; Syrová, L.; Vondrák, J.; Kubáč, L.; Sedlaříková, M.

    2016-03-01

    The presented study is focused on the development of LiFePO4 based cathode for thin and flexible screen printed secondary lithium based accumulators. An ink formulation was developed for the screen printing technique, which enabled mass production of accumulator's cathode for Smart Label and Smart Textile applications. The screen printed cathode was compared with an electrode prepared by the bar coating technique using an ink formulation based on the standard approach of ink composition. Obtained LiFePO4 cathode layers were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and galvanostatic charge/discharge measurements at different loads. The discharge capacity, capacity retention and stability at a high C rate of the LiFePO4 cathode were improved when Super P and PVDF were replaced by conductive polymers PEDOT:PSS. The achieved capacity during cycling at various C rates was approximately the same at the beginning and at the end, and it was about 151 mAh/g for cycling under 1C. The obtained results of this novelty electrode layer exceed the parameters of several electrode layers based on LiFePO4 published in literature in terms of capacity, cycling stability and overcomes them in terms of simplicity/industrial process ability of cathode layer fabrication and electrode material preparation.

  10. A Vacuum Encapsulated Lateral FED with Various Cathode Materials

    Science.gov (United States)

    Park, Cheol-Min; Lim, Moo-Sup; Han, Min-Koo

    We have fabricated poly-Si, Si, and Ti-silicide field emitter arrays employing in-situ vacuum encapsulated lateral field emitter structures and investigated the field emission characteristics such as turn-on voltage, emission current density, and the stability of the emission current. Although poly-Si and Si emitter exhibit almost identical turn-on voltages, the Si emitter shows a sharp turn-on characteristic compared with the poly-Si emitter. It may be caused by the uniform surface of the Si emitter. The current densities of poly-Si, and Si emitter are 0.47, 0.43μA/tip respectively when the anode to cathode voltage is 90V. The turn-on voltage and current density of the Ti-silicide emitter are about 31V, and 1.81μA/tip at a VAK of 90V. The normalized current fluctuations shows that the Ti-silicide emitter exhibits the most stable current.

  11. Intercalation of Mg-ions in layered V2O5 cathode materials for rechargeable Mg-ion batteries

    DEFF Research Database (Denmark)

    Sørensen, Daniel Risskov; Johannesen, Pætur; Christensen, Christian Kolle

    The development of functioning rechargeable Mg-ion batteries is still in its early stage, and a coarse screening of suitable cathode materials is still on-going. Within the intercalation-type cathodes, layered crystalline materials are of high interest as they are known to perform well in Li...

  12. Submicron organic nanofiber devices with different anode-cathode materials: A simple approach

    DEFF Research Database (Denmark)

    Henrichsen, Henrik Hartmann; Sturm, Heinz; Bøggild, Peter

    2010-01-01

    The authors present a simple general method for simultaneously producing tens of submicron electrode gaps with different cathode and anode materials on top of nanofibers, nanowires, and nanotubes, with an optional gap size variation. Using this method, an ensemble of para-hexaphenylene (p6P...

  13. Cost and energy demand of producing nickel manganese cobalt cathode material for lithium ion batteries

    Science.gov (United States)

    Ahmed, Shabbir; Nelson, Paul A.; Gallagher, Kevin G.; Susarla, Naresh; Dees, Dennis W.

    2017-02-01

    The price of the cathode active materials in lithium ion batteries is a key cost driver and thus significantly impacts consumer adoption of devices that utilize large energy storage contents (e.g. electric vehicles). A process model has been developed and used to study the production process of a common lithium-ion cathode material, lithiated nickel manganese cobalt oxide, using the co-precipitation method. The process was simulated for a plant producing 6500 kg day-1. The results indicate that the process will consume approximately 4 kWh kgNMC-1 of energy, 15 L kgNMC-1 of process water, and cost 23 to produce a kg of Li-NMC333. The calculations were extended to compare the production cost using two co-precipitation reactions (with Na2CO3 and NaOH), and similar cathode active materials such as lithium manganese oxide and lithium nickel cobalt aluminum oxide. A combination of cost saving opportunities show the possibility to reduce the cost of the cathode material by 19%.

  14. Magnetostructural coupling in spinel oxides

    Science.gov (United States)

    Kemei, Moureen

    2015-03-01

    Spinels oxides are of great interest functionally as multiferroic, battery, and magnetic materials as well as fundamentally because they exhibit novel spin, structural, and orbital ground states. Competing interactions are at the heart of novel functional behavior in spinels. Here, we explore the intricate landscape of spin, lattice, and orbital interactions in magnetic spinels by employing variable-temperature high-resolution synchrotron x-ray powder diffraction, total neutron scattering, magnetic susceptibility, dielectric, and heat capacity measurements. We show that the onset of long-range magnetic interactions often gives rise to lattice distortions. Our work illustrates that the spinels NiCr2O4, CuCr2O4,andMn3O4, which are tetragonal at room temperature due to Jahn-Teller ordering, undergo further spin-driven structural distortions at the onset of long-range ferrimagnetic order. We have also studied the complete structural description of the ground states of several spinels including the geometrically frustrated spinels ZnCr2O4andMgCr2O4. The detailed spin-lattice studies of spinel oxides presented here illustrate the prevalence of structural phase coexistence when magnetostructural changes occur below 50 K. The new understanding of structural ground states in spinel oxides will guide the design of structure-property relationships in these materials. Broadly, this work highlights the importance of variable-temperature high-resolution synchrotron x-ray diffraction in understanding phase transitions in functional materials. Schlumberger Foundation Faculty for the Future fellowship, MRL Facilities funded by the NSF under Award No. DMR 1121053, and the Advanced Photon Source supported by the DOE, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

  15. Progress in High-Capacity Core-Shell Cathode Materials for Rechargeable Lithium Batteries.

    Science.gov (United States)

    Myung, Seung-Taek; Noh, Hyung-Joo; Yoon, Sung-June; Lee, Eung-Ju; Sun, Yang-Kook

    2014-02-20

    High-energy-density rechargeable batteries are needed to fulfill various demands such as self-monitoring analysis and reporting technology (SMART) devices, energy storage systems, and (hybrid) electric vehicles. As a result, high-energy electrode materials enabling a long cycle life and reliable safety need to be developed. To ensure these requirements, new material chemistries can be derived from combinations of at least two compounds in a secondary particle with varying chemical composition and primary particle morphologies having a core-shell structure and spherical cathode-active materials, specifically a nanoparticle core and shell, nanoparticle core and nanorod shell, and nanorod core and shell. To this end, several layer core-shell cathode materials were developed to ensure high capacity, reliability, and safety.

  16. Activated graphene as a cathode material for Li-ion hybrid supercapacitors.

    Science.gov (United States)

    Stoller, Meryl D; Murali, Shanthi; Quarles, Neil; Zhu, Yanwu; Potts, Jeffrey R; Zhu, Xianjun; Ha, Hyung-Wook; Ruoff, Rodney S

    2012-03-14

    Chemically activated graphene ('activated microwave expanded graphite oxide', a-MEGO) was used as a cathode material for Li-ion hybrid supercapacitors. The performance of a-MEGO was first verified with Li-ion electrolyte in a symmetrical supercapacitor cell. Hybrid supercapacitors were then constructed with a-MEGO as the cathode and with either graphite or Li(4)Ti(5)O(12) (LTO) for the anode materials. The results show that the activated graphene material works well in a symmetrical cell with the Li-ion electrolyte with specific capacitances as high as 182 F g(-1). In a full a-MEGO/graphite hybrid cell, specific capacitances as high as 266 F g(-1) for the active materials at operating potentials of 4 V yielded gravimetric energy densities for a packaged cell of 53.2 W h kg(-1).

  17. Cathode and insulator materials for a 30 kW arcjet thruster

    Science.gov (United States)

    Sokolowski, Witold; O'Donnell, Tim; Deininger, William

    1989-01-01

    This paper describes past experience with 30 kW arcjet engines, emphasizing the operational parameters pertinent to the selection of new/alternate erosion-resistant materials to enhance lifetime. Mechanisms of mass loss from the electrodes and insulators are suggested, and ways of identifying potential processes for controlling cathode erosion and insulator degradation are proposed. The limitations of present materials used in critical arcjet thruster components are described. An outline is given of the criteria and the figure of merit on which the selection of candidate materials can be based. Potentially useful new/alternate materials are listed based on available thermophysical and other material properties.

  18. Investigation of a Spinel-forming Cu-Mn Foam as an Oxygen Electrode Contact Material in a Solid Oxide Cell Single Repeating Unit

    DEFF Research Database (Denmark)

    Zielke, Philipp; Wulff, Anders Christian; Sun, Xiufu

    2017-01-01

    and steels. The consequence is a low layer and interface strength. A metallic copper manganese foam, which is oxidized under operation conditions into a conductive Cu1+xMn2–xO4 spinel, is presented in this work as a viable contact solution. The foam has been electrochemically tested in a single repeating...... unit setup for 350 hours of constant operation, followed by dynamic conditions with thermal cycles. After operation, a micro structural analysis using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction was carried out. It was confirmed that after oxidation....../operation the manganese solely formed a CuMn-spinel phase, mixed with a CuO phase. A separate Mn-oxide phase was not found. The conductivity and contacting of the foam was sufficient for > 350 h of SOFC operation. With an initial serial resistance comparable to single cell tests using gold foil as contact material...

  19. Spinel-structured surface layers for facile Li ion transport and improved chemical stability of lithium manganese oxide spinel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hae Ri [Center for Energy Convergence Research, Korea Institute of Science Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Department of Chemical and Biological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 136-701 (Korea, Republic of); Seo, Hyo Ree; Lee, Boeun; Cho, Byung Won [Center for Energy Convergence Research, Korea Institute of Science Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Kwan-Young [Department of Chemical and Biological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 136-701 (Korea, Republic of); Oh, Si Hyoung, E-mail: sho74@kist.re.kr [Center for Energy Convergence Research, Korea Institute of Science Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)

    2017-01-15

    Graphical abstract: Strategically-designed spinel-structured nano-scale surface layer, LiM{sub x}Mn{sup IV}{sub 1−x}O{sub 4}, featuring a high Li{sup +} ion conductivity and a good chemical stability was applied on Al-doped LiMn{sub 2}O{sub 4} spinel for the drastic improvement of the electrochemical performance at the elevated temperature as a promising cathode material for lithium rechargeable batteries. - Highlights: • Spinel-structured surface layer with a high Li-ion conductivity and a good chemical stability was prepared. • Simple wet process was developed to apply nano-scale surface layer on aluminum doped lithium manganese oxide spinel. • The properties of nano-scale surface layer were characterized by analytical tools including GITT, HR-TEM and XAS. • Materials with surface coating layer exhibit an excellent electrochemical performance at the elevated temperature. - Abstract: Li-ion conducting spinel-structured oxide layer with a manganese oxidation state close to being tetravalent was prepared on aluminum-doped lithium manganese oxide spinel for improving the electrochemical performances at the elevated temperatures. This nanoscale surface layer provides a good ionic conduction path for lithium ion transport to the core and also serves as an excellent chemical barrier for protecting the high-capacity core material from manganese dissolution into the electrolyte. In this work, a simple wet process was employed to prepare thin LiAlMnO{sub 4} and LiMg{sub 0.5}Mn{sub 1.5}O{sub 4} layers on the surface of LiAl{sub 0.1}Mn{sub 1.9}O{sub 4}. X-ray absorption studies revealed an oxidation state close to tetravalent manganese on the surface layer of coated materials. Materials with these surface coating layers exhibited excellent capacity retentions superior to the bare material, without undermining the lithium ion transport characteristics and the high rate performances.

  20. Vanadium oxide nanotubes as cathode material for Mg-ion batteries

    DEFF Research Database (Denmark)

    Christensen, Christian Kolle; Sørensen, Daniel Risskov; Bøjesen, Espen Drath

    Vanadium oxide compounds as cathode material for secondary Li-ion batteries gained interest in the 1970’s due to high specific capacity (>250mAh/g), but showed substantial capacity fading.1 Developments in the control of nanostructured morphologies have led to more advanced materials, and recently...... vanadium oxide nanotubes (VOx-NT) were shown to perform well as a cathode material for Mg-ion batteries.2 The VOx-NTs are easily prepared via a hydrothermal process to form multiwalled scrolls of VO layer with primary amines interlayer spacer molecules.3 The tunable and relative large layer spacing 1-3 nm...... synchrotron powder X-ray diffraction measured during battery operation. These results indicate Mg-intercalation in the multiwalled VOx-NTs occurs within the space between the individual vanadium oxide layers while the underlying VOx frameworks constructing the walls are affected only to a minor degree...

  1. Four-electron transfer tandem tetracyanoquinodimethane for cathode-active material in lithium secondary battery

    Science.gov (United States)

    Kurimoto, Naoya; Omoda, Ryo; Mizumo, Tomonobu; Ito, Seitaro; Aihara, Yuichi; Itoh, Takahito

    2018-02-01

    Quinoid compounds are important candidates of organic active materials for lithium-ion batteries. However, its high solubility to organic electrolyte solutions and low redox potential are known as their major drawbacks. To circumvent these issues, we have designed and synthesized a tandem-tetracyanoquinonedimethane type cathode-active material, 11,11,12,12,13,13,14,14-octacyano-1,4,5,8-anthradiquinotetramethane (OCNAQ), that has four redox sites per molecule, high redox potential and suppressed solubility to electrolyte solution. Synthesized OCNAQ has been found to have two-step redox reactions by cyclic voltammetry, and each step consists of two-electron reactions. During charge-discharge tests using selected organic cathode-active materials with a lithium metal anode, the cell voltages obtained from OCNAQ are higher than those for 11,11-dicyanoanthraquinone methide (AQM) as expected, due to the strong electron-withdrawing effect of the cyano groups. Unfortunately, even with the use of the organic active material, the issue of dissolution to the electrolyte solution cannot be suppressed completely; however, appropriate choice of the electrolyte solutions, glyme-based electrolyte solutions in this study, give considerable improvement of the cycle retention (98% and 56% at 10 and 100 cycles at 0.5C, respectively). The specific capacity and energy density obtained in this study are 206 mAh g-1 and 554 mWh g-1 with respect to the cathode active material.

  2. Innovative application of ionic liquid to separate Al and cathode materials from spent high-power lithium-ion batteries.

    Science.gov (United States)

    Zeng, Xianlai; Li, Jinhui

    2014-04-30

    Because of the increasing number of electric vehicles, there is an urgent need for effective recycling technologies to recapture the significant amount of valuable metals contained in spent lithium-ion batteries (LiBs). Previous studies have indicated, however, that Al and cathode materials were quite difficult to separate due to the strong binding force supplied by the polyvinylidene fluoride (PVDF), which was employed to bind cathode materials and Al foil. This research devoted to seek a new method of melting the PVDF binder with heated ionic liquid (IL) to separate Al foil and cathode materials from the spent high-power LiBs. Theoretical analysis based on Fourier's law was adopted to determine the heat transfer mechanism of cathode material and to examine the relationship between heating temperature and retention time. All the experimental and theoretic results show that peel-off rate of cathode materials from Al foil could reach 99% when major process parameters were controlled at 180°C heating temperature, 300 rpm agitator rotation, and 25 min retention time. The results further imply that the application of IL for recycling Al foil and cathode materials from spent high-power LiBs is highly efficient, regardless of the application source of the LiBs or the types of cathode material. This study endeavors to make a contribution to an environmentally sound and economically viable solution to the challenge of spent LiB recycling. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Synthesis and investigation of novel cathode materials for sodium ion batteries

    Science.gov (United States)

    Sawicki, Monica

    Environmental pollution and eventual depletion of fossil fuels and lithium has increased the need for research towards alternative electrical energy storage systems. In this context, research in sodium ion batteries (NIBs) has become more prevalent since the price in lithium has increased due to its demand and reserve location. Sodium is an abundant resource that is low cost, and safe; plus its chemical properties are similar to that of Li which makes the transition into using Na chemistry for ion battery systems feasible. In this study, we report the effects of processing conditions on the electrochemical properties of Na-ion batteries made of the NaCrO2 cathode. NaCrO2 is synthesized via solid state reactions. The as-synthesized powder is then subjected to high-energy ball milling under different conditions which reduces particle size drastically and causes significant degradation of the specific capacity for NaCrO2. X-ray diffraction reveals that lattice distortion has taken place during high-energy ball milling and in turn affects the electrochemical performance of the cathode material. This study shows that a balance between reducing particle size and maintaining the layered structure is essential to obtain high specific capacity for the NaCrO2 cathode. In light of the requirements for grid scale energy storage: ultra-long cycle life (> 20,000 cycles and calendar life of 15 to 20 years), high round trip efficiency (> 90%), low cost, sufficient power capability, and safety; the need for a suitable cathode materials with excellent capacity retention such as Na2MnFe(CN)6 and K2MnFe(CN)6 will be investigated. Prussian blue (A[FeIIIFeII (CN)6]•xH2O, A=Na+ or K+ ) and its analogues have been investigated as an alkali ion host for use as a cathode material. Their structure (FCC) provides large ionic channels along the direction enabling facile insertion and extraction of alkali ions. This material is also capable of more than one Na ion insertion per unit formula

  4. Improving the Performance of Lithium-Ion Batteries by Using Spinel Nanoparticles

    Directory of Open Access Journals (Sweden)

    J. C. Arrebola

    2008-01-01

    Full Text Available In this work, we examined the use of nanospinels to construct batttery electrodes. We chose two spinels suitable as cathode materials (LiMn2O4 and LiNi0.5Mn1.5O4, which are representative of 4 and 5 V versus Li metal, resp. and one providing good results as anode (Li4Ti5O12. In order to ensure good cell performance, nanometric particles must meet another requirement; thus they should contain few surface or bulk defects (i.e., they should be highly crystalline. Because the synthesis of such spinels usually requires a thermal treatment, ensuring that they will meet both requirements entails accuratly controlling in the synthesis conditions. Thermal decomposition of nanooxalate in the spinel-conaining elements obtained by mechanochenical activation in the presence of polymers provides a simple, effective route for this purpose. We prepared two types of hybrid lithium-ion batteries using LiMn2O4 and LiNi0.5Mn1.5O4 as cathode materials, and Li4Ti5O12 as anode material. The electrochemical properties of these cells were compared with those of a similar configuration made from micrometric particles. The nano-nano configuration exhibited higher reversibility and better performance than the micro-micro configuartion in both types of cells, possibly as a result of lithium ions in the former being able to migrate more easily into the electrode material.

  5. Designing and Thermal Analysis of Safe Lithium Ion Cathode Materials for High Energy Applications

    Science.gov (United States)

    Hu, Enyuan

    Safety is one of the most critical issues facing lithium-ion battery application in vehicles. Addressing this issue requires the integration of several aspects, especially the material chemistry and the battery thermal management. First, thermal stability investigation was carried out on an attractive high energy density material LiNi0.5Mn1.5O4. New findings on the thermal-stability and thermal-decomposition-pathways related to the oxygen-release are discovered for the high-voltage spinel Li xNi0.5Mn1.5O4 (LNMO) with ordered (o-) and disordered (d-) structures at fully delithiated (charged) state using a combination of in situ time-resolved x-ray diffraction (TR-XRD) coupled with mass spectroscopy (MS) and x-ray absorption spectroscopy (XAS). Both fully charged o--LixNi0.5Mn1.5O 4 and d-LixNi0.5Mn1.5O 4 start oxygen-releasing structural changes at temperatures below 300 °C, which is in sharp contrast to the good thermal stability of the 4V-spinel LixMn2O4 with no oxygen being released up to 375 °C. This is mainly caused by the presence of Ni4+ in LNMO, which undergoes dramatic reduction during the thermal decomposition. In addition, charged o-LNMO shows better thermal stability than the d-LNMO counterpart, due to the Ni/Mn ordering and smaller amount of the rock-salt impurity phase in o-LNMO. Newly identified two thermal-decomposition-pathways from the initial LixNi0.5Mn1.5O 4 spinel to the final NiMn2O4-type spinel structure with and without the intermediate phases (NiMnO3 and alpha-Mn 2O3) are found to play key roles in thermal stability and oxygen release of LNMO during thermal decomposition. In addressing the safety issue associated with LNMO, Fe is selected to partially substitute Ni and Mn simultaneously utilizing the electrochemical activity and structure-stabilizing high spin Fe3+. The synthesized LiNi1/3Mn4/3Fe1/3O4 showed superior thermal stability and satisfactory electrochemical performance. At charged state, it is able to withstand the temperature as

  6. Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

    Science.gov (United States)

    Doeff, Marca M.; Peng, Marcus Y.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard C.

    1996-01-01

    An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell.

  7. Design of fast ion conducting cathode materials for grid-scale sodium-ion batteries.

    Science.gov (United States)

    Wong, Lee Loong; Chen, Haomin; Adams, Stefan

    2017-03-15

    The obvious cost advantage as well as attractive electrochemical properties, including excellent cycling stability and the potential of high rate performance, make sodium-ion batteries prime candidates in the race to technically and commercially enable large-scale electrochemical energy storage. In this work, we apply our bond valence site energy modelling method to further the understanding of rate capabilities of a wide range of potential insertion-type sodium-ion battery cathode materials. We demonstrate how a stretched exponential function permits us to systematically quantify the rate performance, which in turn reveals guidelines for the design of novel sodium-ion battery chemistries suitable for high power, grid-scale applications. Starting from a diffusion relaxation model, we establish a semi-quantitative prediction of the rate-performance of half-cells from the structure of the cathode material that factors in dimensionality of Na(+) ion migration pathways, the height of the migration barriers and the crystallite size of the active material. With the help of selected examples, we also illustrate the respective roles of unoccupied low energy sites within the pathway and temperature towards the overall rate capability of insertion-type cathode materials.

  8. Commercial materials as cathode for hydrogen production in microbial electrolysis cell.

    Science.gov (United States)

    Farhangi, Sara; Ebrahimi, Sirous; Niasar, Mojtaba Shariati

    2014-10-01

    The use of commercial electrodes as cathodes in a single-chamber microbial electrolysis cell has been investigated. The cell was operated in sequencing batch mode and the performance of the electrodes was compared with carbon cloth containing 0.5 mg Pt cm(-2). Overall H2 recovery [Formula: see text] was 66.7 ± 1.4, 58.7 ± 1.1 and 55.5 ± 1.5 % for Pt/CC, Ni and Ti mesh electrodes, respectively. Columbic efficiencies of the three cathodes were in the same range (74.8 ± 1.5, 77.6 ± 1.7 and 75.7 ± 1.2 % for Pt/CC, Ni and Ti mesh electrodes, respectively). A similar performance for the three cathodes under near-neutral pH and ambient temperature was obtained. The commercial electrodes are much cheaper than carbon cloth containing Pt. Low cost and good performance of these electrodes suggest they are suitable cathode materials for large scale application.

  9. Microwave-assisted synthesis of high-voltage nanostructured LiMn1.5Ni0.5O4 spinel: tuning the Mn3+ content and electrochemical performance

    CSIR Research Space (South Africa)

    Jafta, CJ

    2013-08-01

    Full Text Available The LiMn1.5Ni0.5O4 spinel is an important lithium ion battery cathode material that has continued to receive major research attention because of its high operating voltage (∼4.8 V). This study interrogates the impact of microwave irradiation...

  10. Mesoporous nitrogen-rich carbon materials as cathode catalysts in microbial fuel cells

    KAUST Repository

    Ahn, Yongtae

    2014-12-01

    The high cost of the catalyst material used for the oxygen reduction reaction in microbial fuel cell (MFC) cathodes is one of the factors limiting practical applications of this technology. Mesoporous nitrogen-rich carbon (MNC), prepared at different temperatures, was examined as an oxygen reduction catalyst, and compared in performance to Pt in MFCs and electrochemical cells. MNC calcined at 800 °C produced a maximum power density of 979 ± 131 mW m-2 in MFCs, which was 37% higher than that produced using MNC calined at 600 °C (715 ± 152 mW m-2), and only 14% lower than that obtained with Pt (1143 ± 54 mW m-2). The extent of COD removal and coulombic efficiencies were the same for all cathode materials. These results show that MNC could be used as an alternative to Pt in MFCs. © 2014 Elsevier B.V. All rights reserved.

  11. Sulfurized carbon: a class of cathode materials for high performance lithium/sulfur batteries

    Directory of Open Access Journals (Sweden)

    Sheng S. Zhang

    2013-12-01

    Full Text Available Liquid electrolyte lithium/sulfur (Li/S batteries cannot come into practical applications because of many problems such as low energy efficiency, short cycle life, and fast self-discharge. All these problems are related to the dissolution of lithium polysulfide, a series of sulfur reduction intermediates, in the liquid electrolyte, and resulting parasitic reactions with the Li anode. Covalently binding sulfur onto carbon surface is a solution to completely eliminate the dissolution of lithium polysulfide and make the Li/S battery viable for practical applications. This can be achieved by replacing elemental sulfur with sulfurized carbon as the cathode material. This article reviews the current efforts on this subject and discusses the syntheses, electrochemical properties, and prospects of the sulfurized carbon as a cathode material in the rechargeable Li/S batteries.

  12. Chemical compatibility study of melilite-type gallate solid electrolyte with different cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Mancini, Alessandro [INSTM R.U. and Department of Chemistry–Physical Chemistry Division, University of Pavia, Pavia I-27100 (Italy); Felice, Valeria; Natali Sora, Isabella [INSTM R.U. and Department of Engineering, University of Bergamo, Dalmine, Bergamo I-24044 (Italy); Malavasi, Lorenzo [INSTM R.U. and Department of Chemistry–Physical Chemistry Division, University of Pavia, Pavia I-27100 (Italy); Tealdi, Cristina, E-mail: cristina.tealdi@unipv.it [INSTM R.U. and Department of Chemistry–Physical Chemistry Division, University of Pavia, Pavia I-27100 (Italy)

    2014-05-01

    Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25} has been extensively investigated by X-ray powder diffraction in a wide temperature range (up to 1573 K). Perovskite-type La{sub 0.8}Sr{sub 0.2}MnO{sub 3−d} and La{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−d} and K{sub 2}NiF{sub 4}-type La{sub 2}NiO{sub 4+d} were selected as cathode materials. The results of this study allow identifying the most suitable electrode material to be used in combination with the melilite-type gallate electrolyte and set the basis for future work on this novel system. - Graphical abstract: Chemical reactivity between cathodes and electrolytes is a crucial issue for long term SOFCs stability and performances. In this study, chemical reactivity between selected cathodic materials and the ionic conducting melilite La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25} has been extensively investigated by means of X-ray powder diffraction. - Highlights: • Chemical compatibility between melilite-type gallate and cathodes for SOFCs up to 1573 K. • No reactivity observed between La{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}Cu{sub 0.2}O{sub 3−d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}. • Reactivity observed between La{sub 0.80}Sr{sub 0.20}MnO{sub 3−d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}. • Significant reactivity observed between La{sub 2}NiO{sub 4+d} and La{sub 1.50}Sr{sub 0.50}Ga{sub 3}O{sub 7.25}.

  13. Layered cathode materials for lithium ion rechargeable batteries

    Science.gov (United States)

    Kang, Sun-Ho [Naperville, IL; Amine, Khalil [Downers Grove, IL

    2007-04-17

    A number of materials with the composition Li.sub.1+xNi.sub..alpha.Mn.sub..beta.Co.sub..gamma.M'.sub..delta.O.sub.2-- zF.sub.z (M'=Mg,Zn,Al,Ga,B,Zr,Ti) for use with rechargeable batteries, wherein x is between about 0 and 0.3, .alpha. is between about 0.2 and 0.6, .beta. is between about 0.2 and 0.6, .gamma. is between about 0 and 0.3, .delta. is between about 0 and 0.15, and z is between about 0 and 0.2. Adding the above metal and fluorine dopants affects capacity, impedance, and stability of the layered oxide structure during electrochemical cycling.

  14. Investigating the stability of cathode materials for rechargeable lithium ion batteries

    Science.gov (United States)

    Huang, Yiqing

    Lithium ion batteries are widely used in portable electronic devices and electric vehicles. However, safety is one of the most important issues for the Li-ion batteries' use. Some cathode materials, such as LiCoO 2, are thermally unstable in the charged state. Upon decomposition these cathode materials release O2, which could react with organic electrolyte, leading to a thermal runaway. Thus understanding the stability of the cathode materials is critical to the safety of lithium ion batteries. Olivine-type LiMnPO4 is a promising cathode material for lithium ion batteries because of its high energy density. We have revealed the critical role of carbon in the stability and thermal behaviour of olivine MnPO 4 obtained by chemical delithiation of LiMnPO4. (Li)MnPO 4 samples with various particle sizes and carbon contents were studied. Carbon-free LiMnPO4 obtained by solid state synthesis in O 2 becomes amorphous upon delithiation. Small amounts of carbon (0.3 wt.%) help to stabilize the olivine structure, so that completely delithiated crystalline olivine MnPO4 can be obtained. Larger amount of carbon (2 wt.%) prevents full delithiation. Heating in air, O2, or N 2 results in structural disorder (analysis. Safety of batteries not only depends on the stability of the active materials, but also the interactions between the active materials and electrolyte. Thus we study the stability between the cathode materials and the electrolyte. The thermal stability of electrochemically delithiated Li0.1N 0.8C0.15Al0.05O2 (NCA), FePO4 (FP), Mn0.8Fe0.2PO4 (MFP), hydrothermally synthesized VOPO4, LiVOPO4 and electrochemically lithiated Li2VOPO4 is investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis, coupled with mass spectrometry (TGA-MS). The thermal stability is found in the order: NCAperformance of the aerogel. In addition to fully reversible V reduction and oxidation due to the intercalation reaction, we observe the formation of LiOH species

  15. Sulfur-carbon nanocomposites and their application as cathode materials in lithium-sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chengdu; Dudney, Nancy J.; Howe, Jane Y.

    2017-08-01

    The invention is directed in a first aspect to a sulfur-carbon composite material comprising: (i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and (ii) elemental sulfur contained in at least a portion of said micropores. The invention is also directed to the aforesaid sulfur-carbon composite as a layer on a current collector material; a lithium ion battery containing the sulfur-carbon composite in a cathode therein; as well as a method for preparing the sulfur-composite material.

  16. Sulfur-carbon nanocomposites and their application as cathode materials in lithium-sulfur batteries

    Science.gov (United States)

    Liang, Chengdu; Dudney, Nancy J; Howe, Jane Y

    2015-05-05

    The invention is directed in a first aspect to a sulfur-carbon composite material comprising: (i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and (ii) elemental sulfur contained in at least a portion of said micropores. The invention is also directed to the aforesaid sulfur-carbon composite as a layer on a current collector material; a lithium ion battery containing the sulfur-carbon composite in a cathode therein; as well as a method for preparing the sulfur-composite material.

  17. Comparison of Nonprecious Metal Cathode Materials for Methane Production by Electromethanogenesis.

    KAUST Repository

    Siegert, Michael

    2014-02-18

    In methanogenic microbial electrolysis cells (MMCs), CO2 is reduced to methane using a methanogenic biofilm on the cathode by either direct electron transfer or evolved hydrogen. To optimize methane generation, we examined several cathode materials: plain graphite blocks, graphite blocks coated with carbon black or carbon black containing metals (platinum, stainless steel or nickel) or insoluble minerals (ferrihydrite, magnetite, iron sulfide, or molybdenum disulfide), and carbon fiber brushes. Assuming a stoichiometric ratio of hydrogen (abiotic):methane (biotic) of 4:1, methane production with platinum could be explained solely by hydrogen production. For most other materials, however, abiotic hydrogen production rates were insufficient to explain methane production. At -600 mV, platinum on carbon black had the highest abiotic hydrogen gas formation rate (1600 ± 200 nmol cm(-3) d(-1)) and the highest biotic methane production rate (250 ± 90 nmol cm(-3) d(-1)). At -550 mV, plain graphite (76 nmol cm(-3) d(-1)) performed similarly to platinum (73 nmol cm(-3) d(-1)). Coulombic recoveries, based on the measured current and evolved gas, were initially greater than 100% for all materials except platinum, suggesting that cathodic corrosion also contributed to electromethanogenic gas production.

  18. Intrinsic origin of intra-granular cracking in Ni-rich layered oxide cathode materials.

    Science.gov (United States)

    Min, Kyoungmin; Cho, Eunseog

    2018-01-08

    Mechanical degradation phenomena in layered oxide cathode materials during electrochemical cycling have limited their long-term usage because they deteriorate the structural stability and result in a poor capacity retention rate. Among them, intra-granular cracking inside primary particles progressively degrades the performance of the cathode but comprehensive understanding of its intrinsic origin is still lacking. In this study, the mechanical properties of the primary particle in a Ni-rich layered oxide cathode material (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ) are investigated under tensile and compressive deformation towards both in-plane and out-of-plane directions within the density functional theory framework. The Young's modulus and maximum strength values indicate that the pristine structure is more vulnerable to tensile deformation than compression. In addition, delithiation significantly deteriorates the mechanical properties regardless of the direction of deformation. In particular, a substantial degree of anisotropy is observed, indicating that the mechanical properties in the out-of-plane direction are much weaker than those in the in-plane direction. Particular weakness in that direction is further confirmed using heterogeneously delithiated structures as well as by calculating the accumulated mechanical stress values inside during delithiation. A comparison of the mechanical properties of the structure with a lower Ni content (Ni = 33%) demonstrates that the Ni-rich material is slightly weaker and hence its intra-granular cracking could become accelerated during cycling.

  19. Potassium nickel hexacyanoferrate as a high-voltage cathode material for nonaqueous magnesium-ion batteries

    Science.gov (United States)

    Chae, Munseok S.; Hyoung, Jooeun; Jang, Minchul; Lee, Hochun; Hong, Seung-Tae

    2017-09-01

    The magnesium insertion capability of Prussian blue (PB) analogue, potassium nickel hexacyanoferrate K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (KNF-086), is demonstrated as a cathode material for rechargeable magnesium-ion batteries using a conventional organic electrolyte. K1.51Ni[Fe(CN)6]0.954(H2O)0.766 is synthesized first, and potassium ions are electrochemically extracted to prepare the KNF-086 cathode. The electrochemical test cell is composed of KNF-086 as the working electrode, an activated carbon as the counter and reference electrode, and 0.5 M Mg(ClO4)2 in acetonitrile as the electrolyte. The cell shows a reversible magnesium insertion/extraction reaction with a discharge capacity of 48.3 mAh g-1 at a 0.2 C rate, and an average discharge voltage at 2.99 V (vs. Mg/Mg2+) that is the highest among the cathode materials ever reported for magnesium-ion batteries. Elemental analysis and Fourier electron-density map analysis from powder X-ray diffraction data confirm that the magnesium-inserted phase is Mg0.27K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (MKNF-086), and the magnesium ions in MKNF-086 are positioned at the center of the large interstitial cavities of cubic PB. Compared to KNF-086, MKNF-086 exhibits a decreased unit cell parameter (0.8%) and volume (2.4%). These results demonstrate that a PB analogue, potassium nickel hexacyanoferrate, could be utilized as a potential cathode material for conventional organic electrolyte-based magnesium-ion batteries.

  20. Triphenyl borate as a bi-functional additive to improve surface stability of Ni-rich cathode material

    Science.gov (United States)

    Yim, Taeeun; Jang, Seol Heui; Han, Young-Kyu

    2017-12-01

    Nickel-rich cathode material has received marked attention as an advanced cathode material, however, its inferior surface property limits the achievement of high performance in lithium-ion batteries. We propose the use of a bi-functional additive of triphenyl borate (TPB) for improvement of the safety and electrochemical performance of Ni-rich cathode materials. First, TPB removes residual lithium species from the Ni-rich cathode surface via chemical binding with anion part of residual lithium species, and effectively reduces swelling behavior of the cell. Second, TPB creates effective cathode-electrolyte interphase (CEI) layers on the electrode surface by an electrochemical reaction, and greatly enhances the surface stability of the nickel-rich cathode. This work demonstrate that a cell cycled with the TPB additive exhibits a remarkable retention of 88.6% at 60 °C after 100 cycles for an NCM721 cathode material. We suggest a working mechanism for TPB based on systematic analyses, including in-situ and ex-situ experiments.

  1. Evaluation of materials for bipolar plates in simulated PEM fuel-cell cathodic environments

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, S.V.; Belmonte, M.R.; Moron, L.E.; Torres, J.; Orozco, G. [Centro de Investigacion y Desarrollo Technologico en Electroquimica S.C. Parcque Sanfandila, Queretaro (Mexico); Perez-Quiroz, J.T. [Mexican Transport Inst., Queretaro (Mexico); Cortes, M. A. [Mexican Petroleum Inst., Mexico City (Mexico)

    2008-04-15

    The bipolar plates in proton exchange membrane fuel cells (PEMFC) are exposed to an oxidizing environment on the cathodic side, and therefore are susceptible to corrosion. Corrosion resistant materials are needed for the bipolar plates in order to improve the lifespan of fuel cells. This article described a study in which a molybdenum (Mo) coating was deposited over austenitic stainless steel 316 and carbon steel as substrates in order to evaluate the resulting surfaces with respect to their corrosion resistance in simulated anodic and cathodic PEMFC environments. The molybdenum oxide films were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. The article presented the experiment and discussed the results of the corrosion behaviour of coated stainless steel. In general, the electrochemical characterization of bare materials and coated steel consisted of slow potentiodynamic polarization curves followed by a constant potential polarization test. The test medium was 0.5M sulfuric acid with additional introduction of oxygen to simulate the cathodic environment. All tests were performed at ambient temperature and at 50 degrees Celsius. The potentiostat used was a Gamry instrument. It was concluded that it is possible to deposit Mo-oxides on steel without using another alloying metal. The preferred substrate for corrosion prevention was found to be an alloy with high chromium content. 24 refs., 4 figs.

  2. Ultrafast synthesis of Te nanorods as cathode materials for lithium-tellurium batteries

    Science.gov (United States)

    Huang, Dekang; Li, Shu; Xiao, Xin; Cao, Minglei; Gao, Lin; Xiang, Yong-Gang; Chen, Hao; Shen, Yan

    2017-12-01

    Recently, tellurium has been regarded as a promising cathode material for rechargeable lithium-ion batteries due to its high theoretical volumetric capacity. However, a plethora of research are focusing on impregnating the tellurium into porous carbon materials by the thermal-diffusion method, which would consume large amounts of energy and take prolonged time. Herein, a carbon and binder-free cathode with 100% Te is fabricated by a facile galvanic replacement method on a nickle foam. Driven by the large electrochemical potential difference between Ni and Te, desirable amounts of Te can be obtained in just 10 min with no need of energy input. Li-Te batteries constructed by the as-obtained cathode show relatively good performance in DMSO solvent. To further elevate the performance of this battery especially at low current density, commercial carbon cloth is added between the separator and Te electrode as an interlayer. The cell with interlayer delivers a gravimetric capacity of 116.2 mAh g-1 after 70 cycles at the current density of 100 mA g-1, which is 2.8 times as high as that of a cell without interlayer (40.4 mAh g-1).

  3. Synthesis and Electrochemical Properties of LiNi0.5Mn1.5O4 Cathode Materials with Cr(3+) and F(-) Composite Doping for Lithium-Ion Batteries.

    Science.gov (United States)

    Li, Jun; Li, Shaofang; Xu, Shuaijun; Huang, Si; Zhu, Jianxin

    2017-12-01

    A Cr(3+) and F(-) composite-doped LiNi0.5Mn1.5O4 cathode material was synthesized by the solid-state method, and the influence of the doping amount on the material's physical and electrochemical properties was investigated. The structure and morphology of the cathode material were characterized by XRD, SEM, TEM, and HRTEM, and the results revealed that the sample exhibited clear spinel features. No Cr(3+) and F(-) impurity phases were found, and the spinel structure became more stable. The results of the charge/discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) test results suggested that LiCr0.05Ni0.475Mn1.475O3.95F0.05 in which the Cr(3+) and F(-) doping amounts were both 0.05, had the optimal electrochemical properties, with discharge rates of 0.1, 0.5, 2, 5, and 10 C and specific capacities of 134.18, 128.70, 123.62, 119.63, and 97.68 mAh g(-1) , respectively. After 50 cycles at a rate of 2 C, LiCr0.05Ni0.475Mn1.475O3.95F0.05 showed extremely good cycling performance, with a discharge specific capacity of 121.02 mAh g(-1) and a capacity retention rate of 97.9%. EIS test revealed that the doping clearly decreased the charge-transfer resistance.

  4. Synthesis and Electrochemical Properties of LiNi0.5Mn1.5O4 Cathode Materials with Cr3+ and F- Composite Doping for Lithium-Ion Batteries

    Science.gov (United States)

    Li, Jun; Li, Shaofang; Xu, Shuaijun; Huang, Si; Zhu, Jianxin

    2017-06-01

    A Cr3+ and F- composite-doped LiNi0.5Mn1.5O4 cathode material was synthesized by the solid-state method, and the influence of the doping amount on the material's physical and electrochemical properties was investigated. The structure and morphology of the cathode material were characterized by XRD, SEM, TEM, and HRTEM, and the results revealed that the sample exhibited clear spinel features. No Cr3+ and F- impurity phases were found, and the spinel structure became more stable. The results of the charge/discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) test results suggested that LiCr0.05Ni0.475Mn1.475O3.95F0.05 in which the Cr3+ and F- doping amounts were both 0.05, had the optimal electrochemical properties, with discharge rates of 0.1, 0.5, 2, 5, and 10 C and specific capacities of 134.18, 128.70, 123.62, 119.63, and 97.68 mAh g-1 , respectively. After 50 cycles at a rate of 2 C, LiCr0.05Ni0.475Mn1.475O3.95F0.05 showed extremely good cycling performance, with a discharge specific capacity of 121.02 mAh g-1 and a capacity retention rate of 97.9%. EIS test revealed that the doping clearly decreased the charge-transfer resistance.

  5. Synthesis and characterization of LiMgyMn2–yO4 cathode materials ...

    Indian Academy of Sciences (India)

    Unknown

    pound begins to decompose at lower temperatures and the exothermic combustion of citric acid supplying ade- quate heat energy for initiating the crystallization of ... the spinel structure must be electrically compensated by oxidation of Mn3+ to Mn4+. This suggests that even for substituted spinel phases, only the amount of ...

  6. In situ wrapping of the cathode material in lithium-sulfur batteries.

    Science.gov (United States)

    Hu, Chenji; Chen, Hongwei; Shen, Yanbin; Lu, Di; Zhao, Yanfei; Lu, An-Hui; Wu, Xiaodong; Lu, Wei; Chen, Liwei

    2017-09-07

    While lithium-sulfur batteries are poised to be the next-generation high-density energy storage devices, the intrinsic polysulfide shuttle has limited their practical applications. Many recent investigations have focused on the development of methods to wrap the sulfur material with a diffusion barrier layer. However, there is a trade-off between a perfect preassembled wrapping layer and electrolyte infiltration into the wrapped sulfur cathode. Here, we demonstrate an in situ wrapping approach to construct a compact layer on carbon/sulfur composite particles with an imperfect wrapping layer. This special configuration suppresses the shuttle effect while allowing polysulfide diffusion within the interior of the wrapped composite particles. As a result, the wrapped cathode for lithium-sulfur batteries greatly improves the Coulombic efficiency and cycle life. Importantly, the capacity decay of the cell at 1000 cycles is as small as 0.03% per cycle at 1672 mA g-1.To suppress the polysulfide shuttling effect in Li-S batteries, here the authors report a carbon/sulfur composite cathode with a wrapping layer that overcomes the trade-off between limiting polysulfide diffusion and allowing electrolyte infiltration, and affords extraordinary cycling stability.

  7. Elastomeric Cathode Binder

    Science.gov (United States)

    Yen, S. P. S.; Shen, D. S.; Somoano, R. B.

    1985-01-01

    Soluble copolymer binder mixed with cathode material and solvent forms flexible porous cathode used in lithium and Ni/Cd batteries. Cathodes prepared by this process have lower density due to expanding rubbery binder and greater flexibility than conventional cathodes. Fabrication procedure readily adaptable to scaled-up processes.

  8. Mesoscale Evaluation of Titanium Silicide Monolayer as a Cathode Host Material in Lithium-Sulfur Batteries

    Science.gov (United States)

    Liu, Zhixiao; Balbuena, Perla B.; Mukherjee, Partha P.

    2017-09-01

    Two-dimensional materials are competitive candidates as cathode materials in lithium-sulfur batteries for immobilizing soluble polysulfides and mitigating the shuttle effect. In this study, a mesoscale modeling approach, which combines first-principles simulation and kinetic Monte Carlo simulation, is employed to evaluate titanium silicide (Ti2Si and TiSi2) monolayers as potential host materials in lithium-sulfur batteries. It is found that the Ti2Si monolayer has much stronger affinities to Li2S x ( x = 1, 2, 4) molecules than does the TiSi2 monolayer. Also, Ti2Si can facilitate the dissociation of long-chain Li2S4 to LiS2. On the other hand, TiSi2 can only provide a weak chemical interaction for trapping soluble Li2S4. Therefore, the Ti2Si monolayer can be considered to be the next-generation cathode material for lithium-sulfur batteries. Nevertheless, the strong interaction between Ti2Si and Li2S also causes fast surface passivation. How to control the Li2S precipitation on Ti2Si should be answered by future studies.

  9. High-Capacity Cathode Material with High Voltage for Li-Ion Batteries.

    Science.gov (United States)

    Shi, Ji-Lei; Xiao, Dong-Dong; Ge, Mingyuan; Yu, Xiqian; Chu, Yong; Huang, Xiaojing; Zhang, Xu-Dong; Yin, Ya-Xia; Yang, Xiao-Qing; Guo, Yu-Guo; Gu, Lin; Wan, Li-Jun

    2018-01-15

    Electrochemical energy storage devices with a high energy density are an important technology in modern society, especially for electric vehicles. The most effective approach to improve the energy density of batteries is to search for high-capacity electrode materials. According to the concept of energy quality, a high-voltage battery delivers a highly useful energy, thus providing a new insight to improve energy density. Based on this concept, a novel and successful strategy to increase the energy density and energy quality by increasing the discharge voltage of cathode materials and preserving high capacity is proposed. The proposal is realized in high-capacity Li-rich cathode materials. The average discharge voltage is increased from 3.5 to 3.8 V by increasing the nickel content and applying a simple after-treatment, and the specific energy is improved from 912 to 1033 Wh kg-1 . The current work provides an insightful universal principle for developing, designing, and screening electrode materials for high energy density and energy quality. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Polyimide encapsulated lithium-rich cathode material for high voltage lithium-ion battery.

    Science.gov (United States)

    Zhang, Jie; Lu, Qingwen; Fang, Jianhua; Wang, Jiulin; Yang, Jun; NuLi, Yanna

    2014-10-22

    Lithium-rich materials represented by xLi2MnO3·(1 - x)LiMO2 (M = Mn, Co, Ni) are attractive cathode materials for lithium-ion battery due to their high specific energy and low cost. However, some drawbacks of these materials such as poor cycle and rate capability remain to be addressed before applications. In this study, a thin polyimide (PI) layer is coated on the surface of Li1.2Ni0.13Mn0.54Co0.13O2 (LNMCO) by a polyamic acid (PAA) precursor with subsequently thermal imidization process. X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HR-TEM) results confirm the successful formation of a PI layer (∼3 nm) on the surface of LNMCO without destruction of its main structure. X-ray photoelectron spectroscopy (XPS) spectra show a slight shift of the Mn valence state from Mn(IV) to Mn(III) in the PI-LNMCO treated at 450 °C, elucidating that charge transfer takes place between the PI layer and LNMCO surface. Electrochemical performances of LNMCO including cyclic stability and rate capability are evidently improved by coating a PI nanolayer, which effectively separates the cathode material from the electrolyte and stabilizes their interface at high voltage.

  11. Structural and vibrational studies of LiNi{sub 1-y}Co{sub y}VO{sub 4} (0{<=}y{<=}1) cathodes materials for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Julien, C.; Massot, M. [Univ. Pierre et Marie Curie, Paris (France). Lab. des Milieux Desordonnes et Heterogenes; Perez-Vicente, C. [Laboratoire des Agregats Moleculaires et Materiaux Inorganiques, CC-015, Universite de Montpellier II, place Eugene-Bataillon, 34095, Montpellier (France)

    2000-05-15

    The structure and vibrational properties of high voltage cathode materials, namely LiNi{sub 1-y}CO{sub y}VO{sub 4} solid solution with (0{<=}y{<=}1), have been studied using X-ray diffraction, Raman scattering and FTIR measurements. Rietveld refinements show that LiNi{sub 1-y}Co{sub y}VO{sub 4} vanadates belong to the inverse spinel structure with Fd3m(O{sup 7}{sub h}) space group. Analysis of Raman spectra has been carried out in the molecular approximation using a local environment model including VO{sub 4} tetrahedra, (Ni, Co)O{sub 6} and LiO{sub 6} octahedra as vibrational local units. (orig.)

  12. Surface structure evolution of cathode materials for Li-ion batteries

    Science.gov (United States)

    Yingchun, Lyu; Yali, Liu; Lin, Gu

    2016-01-01

    Lithium ion batteries are important electrochemical energy storage devices for consumer electronics and the most promising candidates for electrical/hybrid vehicles. The surface chemistry influences the performance of the batteries significantly. In this short review, the evolution of the surface structure of the cathode materials at different states of the pristine, storage and electrochemical reactions are summarized. The main methods for the surface modification are also introduced. Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB07030200) and the National Basic Research Program of China (Grant Nos. 2014CB921002 and 2012CB921702).

  13. Evaluating the economic viability of a material recovery system: the case of cathode ray tube glass.

    Science.gov (United States)

    Gregory, Jeremy R; Nadeau, Marie-Claude; Kirchain, Randolph E

    2009-12-15

    This paper presents an analysis of the material recovery system for leaded glass from cathode ray tubes (CRTs) using a dynamic material flow analysis. In particular, the global mass flow of primary and secondary CRT glass and the theoretical capacities for using secondary CRT glass to make new CRT glass are analyzed. The global mass flow analysis indicates that the amount of new glass required is decreasing, but is much greater than the amount of secondary glass collected, which is increasing. The comparison of the ratio of secondary glass collected to the amount of new glass required from the mass flow analysis indicates that the material recovery system is sustainable for the foreseeable future. However, a prediction of the time at which the market for secondary glass will collapse due to excess capacity is not possible at the moment due to several sources of uncertainty.

  14. Preparation and performances of Co-Mn spinel coating on a ferritic stainless steel interconnect material for solid oxide fuel cell application

    Science.gov (United States)

    Zhang, H. H.; Zeng, C. L.

    2014-04-01

    Ferritic stainless steels have become the candidate materials for interconnects of intermediate temperature solid oxide fuel cell (SOFC). The present issues to be solved urgently for the application of ferritic stainless steel interconnects are their rapid increase in contact resistance and Cr poisoning. In the present study, a chloride electrolyte suspension has been developed to electro-deposit a Co-Mn alloy on a type 430 stainless steel, followed by heat treatment at 750 °C in argon and at 800 °C in air to obtain Co-Mn spinel coatings. The experimental results indicate that an adhesive and compact Co-Mn alloy layer can be deposited in the chloride solution. After heat treatment, a complex coating composed of an external MnCo2O4 layer and an inner Cr-rich oxide layer has been formed on 430SS. The coating improves the oxidation resistance of the steel at 800 °C in air, especially in wet air, and inhibits the outward diffusion of Cr from the Cr-rich scale. Moreover, a low contact resistance has been achieved with the application of the spinel coatings.

  15. Nanocrystalline and long cycling LiMn2O4 cathode material derived by a solution combustion method for lithium ion batteries

    Science.gov (United States)

    Lu, Cheng-Zhang; Fey, George Ting-Kuo

    2006-04-01

    A nanostructured LiMn2O4 spinel phase is used as a cathode for 4 V lithium batteries and is prepared by solution combustion synthesis using urea as a fuel. Lithium manganese oxides have received more increasing attention in recent years as high-capacity intercalation cathodes for rechargeable lithium-ion batteries. Nanostructured electrodes have been shown to enhance the cell cyclability. For optimum synthesis, the spinel LiMn2O4 showed that the optimal heat treatment protocol was a 10 h calcination at 700 °C, which sustained 229 cycles between 3.0 and 4.3 V at a charge discharge rate of 0.1 °C before reaching an 80% charge retention cut-off value. X-ray diffraction and electron diffraction pattern investigations demonstrate that all the LiMn2O4 products are a spinel phase crystal. TEM micrographs show the prepared products were highly crystalline with an average particle size of 20 50 nm. Cyclic voltammetry shows the absence of phase transitions in the samples ensures negligible strain, resulting in a longer cycle life. This work shows the feasibility of the solution combustion method for obtaining manganese oxides with nano-architecture and high cyclability, and suggests it is a promising method for providing small diffusion pathways that improve lithium-ion intercalation kinetics and minimize surface distortions during cycling.

  16. Surface element segregation and electrical conductivity of lithium layered transition-metal oxide cathode materials

    Science.gov (United States)

    Li, Guohua; Li, Qi; Li, Liping; Fan, Jianming; Ge, Qingqin; Xie, Dongjiu; Zheng, Jing; Li, Guangshe

    2018-01-01

    Surface element segregation and electric conductivity are critical in determining lithium storage ability of given cathode materials, which are poorly understood and not correlated with the structure and overall performance. Here, layered lithium transition-metal oxides, one of the state-of-the-art cathode materials for lithium ion batteries are chosen to study. A serial of LiNixCo1-2xMnxO2 samples were prepared via a solid state reaction and subsequently characterized by XRD in conjunction with structural refinement, XPS depth profiling, and AC impedance spectroscopy. Slightly different expansion rates are observed for lattice parameters (a and c/3) with varying of Ni content, which is attributed to the increase of average metal-ion radius and an increase of eg electron that enhances the columbic repulsion between transition metal and oxygen atoms. XPS depth profiling results show that surface composition is significantly deviated from bulk, in which Ni and Mn atoms tend to enrich in the surface region, while Co element is relatively deficient. Further, surface element segregation is alleviated by the increase of Ni/Mn content. Moreover, increasing the Ni/Mn content also raises the activation energy of bulk conduction.

  17. A mesoporous carbon–sulfur composite as cathode material for high rate lithium sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyunji; Zhao, Xiaohui; Kim, Dul-Sun [Department of Chemical and Biological Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of); Ahn, Hyo-Jun; Kim, Ki-Won [Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of); Cho, Kwon-Koo, E-mail: kkcho66@gnu.ac.kr [Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of); Ahn, Jou-Hyeon, E-mail: jhahn@gnu.ac.kr [Department of Chemical and Biological Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of); Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of)

    2014-10-15

    Highlights: • CMK-3 mesoporous carbon was synthesized as conducting reservoir for housing sulfur. • Sulfur/CMK-3 composites were prepared by two-stage thermal treatment. • The composite at 300 °C for 20 h shows improved electrochemical properties. - Abstract: Sulfur composite was prepared by encapsulating sulfur into CMK-3 mesoporous carbon with different heating times and then used as the cathode material for lithium sulfur batteries. Thermal treatment at 300 °C plays an important role in the sulfur encapsulation process. With 20 h of heating time, a portion of sulfur remained on the surface of carbon, whereas with 60 h of heating time, sulfur is confined deeply in the small pores of carbon that cannot be fully exploited in the redox reaction, thus causing low capacity. The S/CMK-3 composite with thermal treatment for 40 h at 300 °C contained 51.3 wt.% sulfur and delivered a high initial capacity of 1375 mA h g{sup −1} at 0.1 C. Moreover, it showed good capacity retention of 704 mA h g{sup −1} at 0.1 C and 578 mA h g{sup −1} at 2 C even after 100 cycles, which proves its potential as a cathode material for high capability lithium sulfur batteries.

  18. Synthesis of Co-Al-Cl LDH by cathodic material reprocessing from cellular phone batteries

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Fabio Augusto do; Machado, Erica Oliveira; Freitas, Leonardo Luis de; Santana, Laiane Kalita; Canobre, Sheila Cristina, E-mail: fabioamaral@yahoo.com.br, E-mail: fabioamaral@iqufu.ufu.br [Universidade Federal de Uberlandia (UFU/LAETE), (Brazil). Inst. de Quimica. Lab. de Armazenamento de Energia e Tratamento de Efluente

    2014-08-15

    The aim of this paper was the recovering of the cathodic material from discarded lithium ion batteries for obtainment of the lamellar double hydroxides (LDHs) by the co-precipitation method at variable pH in HCl and H{sub 2}O{sub 2} 1:1 (v/v) acid solution containing Co and Al (extracted from cathodic material composed of LiCoO{sub 2} and aluminum foil). These metals were precipitated in LiOH at pH 9 or 11, or NH{sub 4}OH at pH 9 and submitted to the hydrothermal treatment (HT) to improve the structural organization of the LDHs lamellae. After precipitation, the resulting solids were structurally characterized by XRD for phase identification and calculation of the unit cell parameter, thermally by TGA for the identification of the mass loss and morphologically by SEM. The sample obtained by precipitation with LiOH at pH 11 / hydrothermal treatment showed diffraction peaks similar to hydrotalcite, morphological and thermal characteristics similar to the pattern Co-Al-Cl LDH obtained by co-precipitation at constant pH 8. (author)

  19. Accelerated discovery of cathode materials with prolonged cycle life for lithium-ion battery.

    Science.gov (United States)

    Nishijima, Motoaki; Ootani, Takuya; Kamimura, Yuichi; Sueki, Toshitsugu; Esaki, Shogo; Murai, Shunsuke; Fujita, Koji; Tanaka, Katsuhisa; Ohira, Koji; Koyama, Yukinori; Tanaka, Isao

    2014-08-01

    Large-scale battery systems are essential for efficiently utilizing renewable energy power sources from solar and wind, which can generate electricity only intermittently. The use of lithium-ion batteries to store the generated energy is one solution. A long cycle life is critical for lithium-ion battery when used in these applications; this is different from portable devices which require 1,000 cycles at most. Here we demonstrate a novel co-substituted lithium iron phosphate cathode with estimated 70%-capacity retention of 25,000 cycles. This is found by exploring a wide chemical compositional space using density functional theory calculations. Relative volume change of a compound between fully lithiated and delithiated conditions is used as the descriptor for the cycle life. On the basis of the results of the screening, synthesis of selected materials is targeted. Single-phase samples with the required chemical composition are successfully made by an epoxide-mediated sol-gel method. The optimized materials show excellent cycle-life performance as lithium-ion battery cathodes.

  20. Kinetic modelling of molten carbonate fuel cells: Effects of cathode water and electrode materials

    Science.gov (United States)

    Arato, E.; Audasso, E.; Barelli, L.; Bosio, B.; Discepoli, G.

    2016-10-01

    Through previous campaigns the authors developed a semi-empirical kinetic model to describe MCFC performance for industrial and laboratory simulation. Although effective in a wide range of operating conditions, the model was validated for specific electrode materials and dry feeding cathode compositions. The new aim is to prove that with appropriate improvements it is possible to apply the model to MCFC provided by different suppliers and to new sets of reactant gases. Specifically, this paper describes the procedures to modify the model to switch among different materials and identify a new parameter taking into account the effects of cathode water vapour. The new equation is integrated as the kinetic core within the SIMFC (SIMulation of Fuel Cells) code, an MCFC 3D model set up by the PERT group of the University of Genova, for reliability test. Validation is performed using data collected through tests carried out at the University of Perugia using single cells. The results are discussed giving examples of the simulated performance with varying operating conditions. The final formulation average percentage error obtained for all the simulated cases with respect to experimental results is maintained around 1%, despite the difference between the basic and the new conditions and facilities.

  1. Energy storage in hybrid organic-inorganic materials hexacyanoferrate-doped polypyrrole as cathode in reversible lithium cells

    DEFF Research Database (Denmark)

    Torres-Gomez, G,; Skaarup, Steen; West, Keld

    2000-01-01

    A study of the hybrid oganic-inorganic hexacyanoferrate-polypyrrole material as a cathode in rechargeable lithium cells is reported as part of a series of functional hybrid materials that represent a new concept in energy storage. The effect of synthesis temperatures of the hybrid in the specific...

  2. Metal Nanoparticles and Carbon-Based Nanostructures as Advanced Materials for Cathode Application in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Pietro Calandra

    2010-01-01

    Full Text Available We review the most advanced methods for the fabrication of cathodes for dye-sensitized solar cells employing nanostructured materials. The attention is focused on metal nanoparticles and nanostructured carbon, among which nanotubes and graphene, whose good catalytic properties make them ideal for the development of counter electrode substrates, transparent conducting oxide, and advanced catalyst materials.

  3. Novel Carbon Materials in the Cathode Formulation for High Rate Rechargeable Hybrid Aqueous Batteries

    Directory of Open Access Journals (Sweden)

    Xiao Zhu

    2017-11-01

    Full Text Available Novel carbon materials, carbon nanotubes (CNTs and porous graphene (PG, were exploited and used as conductive additives to improve the rate performance of LiMn2O4 cathode for the rechargeable aqueous Zn/LiMn2O4 battery, namely the rechargeable hybrid aqueous battery (ReHAB. Thanks to the long-range conductivity and stable conductive network provided by CNTs, the rate and cycling performances of LiMn2O4 cathode in ReHAB are highly improved—up to about 100 mAh·g−1 capacity is observed at 10 C (1 C = 120 mAh·g−1. Except for CNTs, porous graphene (PG with a high surface area, an abundant porous structure, and an excellent electrical conductivity facilitates the transportation of Li ions and electrons, which can also obviously enhance the rate capability of the ReHAB. This is important because the ReHAB could be charged/discharged in a few minutes, and this leads to potential application of the ReHAB in automobile industry.

  4. New Redox Polymers that Exhibit Reversible Cleavage of Sulfur Bonds as Cathode Materials.

    Science.gov (United States)

    Baloch, Marya; Ben Youcef, Hicham; Li, Chunmei; Garcia-Calvo, Oihane; Rodriguez, Lide M; Shanmukaraj, Devaraj; Rojo, Teofilo; Armand, Michel

    2016-11-23

    Two new cathode materials based on redox organosulfur polymers were synthesized and investigated for rechargeable lithium batteries as a proof-of-concept study. These cathodes offered good cycling performance owing to the absence of polysulfide solubility, which plagues Li/S systems. Herein, an aliphatic polyamine or a conjugated polyazomethine was used as the base to tether the redox-active species. The activity comes from the cleavage and formation of S-S or N-S bonds, which is made possible by the rigid conjugated backbone. The synthesized polymers were characterized through FTIR spectroscopy and thermogravimetric analysis (TGA). Galvanostatic measurements were performed to evaluate the discharge/charge cycles and characterize the performance of the lithium-based cells, which displayed initial discharge capacities of approximately 300 mA h g(-1) at C/5 over 100 cycles with approximately 98 % Coulombic efficiency. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Two-Electron Reaction without Structural Phase Transition in Nanoporous Cathode Material

    Directory of Open Access Journals (Sweden)

    Tomoyuki Matsuda

    2012-01-01

    Full Text Available We investigated the charge/discharge properties, valence states, and structural properties of a nanoporous cathode material LixMn[Fe(CN6]0.83·3.5H2O. The film-type electrode of LixMn[Fe(CN6]0.83·3.5H2O exhibited a high charge capacity (=128 mAh g-1 and a good cyclability (87% of the initial value after 100 cycles and is one of the promising candidates for Li-ion battery cathode. X-ray absorption spectra near the Fe and Mn K-edges revealed that the charge/discharge process is a two-electron reaction; that is, MnII–NC–FeII, MnII–NC–FeIII, and MnIII–NC–FeIII. We further found that the crystal structure remains cubic throughout the charge/discharge process. The lattice constant slightly increased during the [FeII(CN6]4-/[FeIII(CN6]3- oxidization reaction while decreased during the MnII/MnIII oxidization reaction. The two-electron reaction without structural phase transition is responsible for the high charge capacity and the good cyclability.

  6. Recent advances in first principles computational research of cathode materials for lithium-ion batteries.

    Science.gov (United States)

    Meng, Ying Shirley; Arroyo-de Dompablo, M Elena

    2013-05-21

    To meet the increasing demands of energy storage, particularly for transportation applications such as plug-in hybrid electric vehicles, researchers will need to develop improved lithium-ion battery electrode materials that exhibit high energy density, high power, better safety, and longer cycle life. The acceleration of materials discovery, synthesis, and optimization will benefit from the combination of both experimental and computational methods. First principles (ab Initio) computational methods have been widely used in materials science and can play an important role in accelerating the development and optimization of new energy storage materials. These methods can prescreen previously unknown compounds and can explain complex phenomena observed with these compounds. Intercalation compounds, where Li(+) ions insert into the host structure without causing significant rearrangement of the original structure, have served as the workhorse for lithium ion rechargeable battery electrodes. Intercalation compounds will also facilitate the development of new battery chemistries such as sodium-ion batteries. During the electrochemical discharge reaction process, the intercalating species travel from the negative to the positive electrode, driving the transition metal ion in the positive electrode to a lower oxidation state, which delivers useful current. Many materials properties change as a function of the intercalating species concentrations (at different state of charge). Therefore, researchers will need to understand and control these dynamic changes to optimize the electrochemical performance of the cell. In this Account, we focus on first-principles computational investigations toward understanding, controlling, and improving the intrinsic properties of five well known high energy density Li intercalation electrode materials: layered oxides (LiMO2), spinel oxides (LiM2O4), olivine phosphates (LiMPO4), silicates-Li2MSiO4, and the tavorite-LiM(XO4)F (M = 3d

  7. Recycling of spent lithium-ion battery cathode materials by ammoniacal leaching

    Energy Technology Data Exchange (ETDEWEB)

    Ku, Heesuk; Jung, Yeojin; Jo, Minsang; Park, Sanghyuk [Department of Energy & Mineral Resources Engineering, Sejong University, Seoul 05006 (Korea, Republic of); Kim, Sookyung [Urban Mine Department, Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong-gu, Daejeon (Korea, Republic of); Yang, Donghyo, E-mail: ydh@kigam.re.kr [Urban Mine Department, Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong-gu, Daejeon (Korea, Republic of); Rhee, Kangin; An, Eung-Mo; Sohn, Jeongsoo [Urban Mine Department, Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong-gu, Daejeon (Korea, Republic of); Kwon, Kyungjung, E-mail: kfromberk@gmail.com [Department of Energy & Mineral Resources Engineering, Sejong University, Seoul 05006 (Korea, Republic of)

    2016-08-05

    Highlights: • Ammoniacal leaching is used to recover spent Li-ion battery cathode materials. • Leaching agents consist of ammonia, ammonium sulfite and ammonium carbonate. • Ammonium sulfite is a reductant and ammonium carbonate acts as pH buffer. • Co and Cu can be fully leached while Mn and Al are not leached. • Co recovery via ammoniacal leaching is economical compared to acid leaching. - Abstract: As the production and consumption of lithium ion batteries (LIBs) increase, the recycling of spent LIBs appears inevitable from an environmental, economic and health viewpoint. The leaching behavior of Ni, Mn, Co, Al and Cu from treated cathode active materials, which are separated from a commercial LIB pack in hybrid electric vehicles, is investigated with ammoniacal leaching agents based on ammonia, ammonium carbonate and ammonium sulfite. Ammonium sulfite as a reductant is necessary to enhance leaching kinetics particularly in the ammoniacal leaching of Ni and Co. Ammonium carbonate can act as a pH buffer so that the pH of leaching solution changes little during leaching. Co and Cu can be fully leached out whereas Mn and Al are hardly leached and Ni shows a moderate leaching efficiency. It is confirmed that the cathode active materials are a composite of LiMn{sub 2}O{sub 4}, LiCo{sub x}Mn{sub y}Ni{sub z}O{sub 2,} Al{sub 2}O{sub 3} and C while the leach residue is composed of LiNi{sub x}Mn{sub y}Co{sub z}O{sub 2}, LiMn{sub 2}O{sub 4}, Al{sub 2}O{sub 3}, MnCO{sub 3} and Mn oxides. Co recovery via the ammoniacal leaching is believed to gain a competitive edge on convenitonal acid leaching both by reducing the sodium hydroxide expense for increasing the pH of leaching solution and by removing the separation steps of Mn and Al.

  8. Advanced carbon materials/olivine LiFePO4 composites cathode for lithium ion batteries

    Science.gov (United States)

    Gong, Chunli; Xue, Zhigang; Wen, Sheng; Ye, Yunsheng; Xie, Xiaolin

    2016-06-01

    In the past two decades, LiFePO4 has undoubtly become a competitive candidate for the cathode material of the next-generation LIBs due to its abundant resources, low toxicity and excellent thermal stability, etc. However, the poor electronic conductivity as well as low lithium ion diffusion rate are the two major drawbacks for the commercial applications of LiFePO4 especially in the power energy field. The introduction of highly graphitized advanced carbon materials, which also possess high electronic conductivity, superior specific surface area and excellent structural stability, into LiFePO4 offers a better way to resolve the issue of limited rate performance caused by the two obstacles when compared with traditional carbon materials. In this review, we focus on advanced carbon materials such as one-dimensional (1D) carbon (carbon nanotubes and carbon fibers), two-dimensional (2D) carbon (graphene, graphene oxide and reduced graphene oxide) and three-dimensional (3D) carbon (carbon nanotubes array and 3D graphene skeleton), modified LiFePO4 for high power lithium ion batteries. The preparation strategies, structure, and electrochemical performance of advanced carbon/LiFePO4 composite are summarized and discussed in detail. The problems encountered in its application and the future development of this composite are also discussed.

  9. Cathode materials produced by spray flame synthesis for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hamid, NoorAshrina Binti A.

    2013-07-03

    Lithium ion batteries are one of the most enthralling rechargeable energy storage systems for portable application due to their high energy density. Nevertheless, with respect to electromobility innovation towards better electrochemical properties such as higher energy and power density is required. Altering the cathode material used in Li-ion batteries is favorable since the mass- and volume performance is closely related to the cathode electrode mass. Instead of using LiCoO{sub 2} as cathode electrode, LiFePO{sub 4} has gained serious attention as this material owns a high theoretical capacity of 170 mAh g{sup -1}. It is non-toxic, cheap and consists of abundant materials but suffers from low electronic and ionic conductivity. Utilization of nanotechnology methods in combination with composite formation is known to cure this problem effectively. In this work, a new combination of techniques using highly scalable gas-phase synthesis namely spray-flame synthesis and subsequent solid-state reaction has been used to synthesize nanocomposite LiFePO{sub 4}/C. At first this work deals with the formation and characterization of nanosize FePO{sub 4} from a solution of iron(III)acetylacetonate and tributyl phosphate in toluene using spray-flame synthesis. It was shown that a subsequent solid state reaction with Li{sub 2}CO{sub 3} and glucose yielded a LiFePO{sub 4}/C nanocomposite with very promising electrochemical properties. Based on these initial findings the influence of two synthesis parameter - carbon content and annealing temperature - was investigated towards the physicochemical properties of LiFePO{sub 4}/C. It was shown that an annealing temperature of 700 C leads to high purity composite materials consisting of crystalline LiFePO{sub 4} with crystallite sizes well below 100 nm and amorphous carbon consisting of disordered and graphite-like carbon. Variation of glucose amount between 10 and 30 wt% resulted in carbon contents between 2.1 and 7.3 wt%. In parallel

  10. Understanding the Enhanced Kinetics of Gradient-Chemical-Doped Lithium-Rich Cathode Material.

    Science.gov (United States)

    Ding, Zhengping; Xu, Mingquan; Liu, Jiatu; Huang, Qun; Chen, Libao; Wang, Peng; Ivey, Douglas G; Wei, Weifeng

    2017-06-21

    Although chemical doping has been extensively employed to improve the electrochemical performance of Li-rich layered oxide (LLO) cathodes for Li ion batteries, the correlation between the electrochemical kinetics and local structure and chemistry of these materials after chemical doping is still not fully understood. Herein, gradient surface Si/Sn-doped LLOs with improved kinetics are demonstrated. The atomic local structure and surface chemistry are determined using electron microscopy and spectroscopy techniques, and remarkably, the correlation of local structure-enhanced kinetics is clearly described in this work. The experimental results suggest that Si/Sn substitution decreases the TMO2 slab thickness and enlarges the interslab spacing, and the concentration gradient of Si/Sn affects the magnitude of these structural changes. The expanded interslab spacing accounts for the enhanced Li(+) diffusivity and rate performance observed in Si/Sn-doped materials. The improved understanding of the local structure-enhanced kinetic relationship for doped LLOs demonstrates the potential for the design and development of other high-rate intercalated electrode materials.

  11. Characterization and electrochemical activities of nanostructured transition metal nitrides as cathode materials for lithium sulfur batteries

    Science.gov (United States)

    Mosavati, Negar; Salley, Steven O.; Ng, K. Y. Simon

    2017-02-01

    The Lithium Sulfur (Li-S) battery system is one of the most promising candidates for electric vehicle applications due to its higher energy density when compared to conventional lithium ion batteries. However, there are some challenges facing Li-S battery commercialization, such as: low active material utilization, high self-discharge rate, and high rate of capacity fade. In this work, a series of transition metal nitrides: Tungsten nitride (WN), Molybdenum Nitride (Mo2N), and Vanadium Nitride (VN) was investigated as cathode materials for lithium polysulfide conversion reactions. Capacities of 697, 569, and 264 mAh g-1 were observed for WN, Mo2N, VN, respectively, with 8 mg cm-2 loading, after 100 cycles at a 0.1 C rate. WN higher electrochemical performance may be attributed to a strong reversible reaction between nitrides and polysulfide, which retains the sulfur species on the electrode surface, and minimizes the active material and surface area loss. X-ray photoelectron spectroscopy (XPS) analysis was performed to gain a better understanding of the mechanism underlying each metal nitride redox reactions.

  12. Two-Dimensional Vanadium Carbide (MXene) as a High-Capacity Cathode Material for Rechargeable Aluminum Batteries.

    Science.gov (United States)

    VahidMohammadi, Armin; Hadjikhani, Ali; Shahbazmohamadi, Sina; Beidaghi, Majid

    2017-11-28

    Rechargeable aluminum batteries (Al batteries) can potentially be safer, cheaper, and deliver higher energy densities than those of commercial Li-ion batteries (LIBs). However, due to the very high charge density of Al3+ cations and their strong interactions with the host lattice, very few cathode materials are known to be able to reversibly intercalate these ions. Herein, a rechargeable Al battery based on a two-dimensional (2D) vanadium carbide (V2CTx) MXene cathode is reported. The reversible intercalation of Al3+ cations between the MXene layers is suggested to be the mechanism for charge storage. It was found that the electrochemical performance could be significantly improved by converting multilayered V2CTx particles to few-layer sheets. With specific capacities of more than 300 mAh g-1 at high discharge rates and relatively high discharge potentials, V2CTx MXene electrodes show one of the best performances among the reported cathode materials for Al batteries. This study can lead to foundations for the development of high-capacity and high energy density rechargeable Al batteries by showcasing the potential of a large family of intercalation-type cathode materials based on MXenes.

  13. Preparation of mesohollow and microporous carbon nanofiber and its application in cathode material for lithium–sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yuanhe; Gao, Mingxia, E-mail: gaomx@zju.edu.cn; Li, Xiang; Liu, Yongfeng; Pan, Hongge, E-mail: hgpan@zju.edu.cn

    2014-09-01

    Highlights: • Mesohollow and microporous carbon fibers were prepared via electrospinning and carbonization. • Sulfur (S) incorporated into the porous fibers by thermal heating in 60 wt.%, forming composite. • S fills fully in the micropores and partially in the mesohollows of the carbon fibers. • The composite shows high capacity and capacity retention as cathode material for Li–S batteries. • Mesohollow and microporous structure is effective in improving the property of S cathode. - Abstract: Mesohollow and microporous carbon nanofibers (MhMpCFs) were prepared by a coaxial electrospinning with polyacrylonitrile (PAN) and polymethylmethacrylate (PMMA) as outer and inner spinning solutions followed by a carbonization. The carbon fibers were thermal treated with sublimed sulfur to form S/MhMpCFs composite, which was used as cathode material for lithium–sulfur batteries. Electrochemical study shows that the S/MhMpCFs cathode material provides a maximum capacity of 815 mA h/g after several cycles of activation, and the capacity retains 715 mA h/g after 70 cycles, corresponding to a retention of 88%. The electrochemical property of the S/MhMpCFs composite is much superior than the S-incorporated solid carbon fibers prepared from electrospinning of single PAN. The mechanism of the enhanced electrochemical property of the S/MhMpCFs composite is discussed.

  14. Materials Characteristics and Surface Morphology of a Cesium Iodide Coated Carbon Velvet Cathode (POSTPRINT)

    Science.gov (United States)

    2009-03-31

    cathodes consist of an array of carbon fibers pyrolytically bonded to a carbon substrate. The fibers then receive a CsI coating using either a...vapor deposition technique or an aerosol spray technique. The cathodes discussed in this article have been coated using the vapor deposition technique

  15. Exploring Lithium Deficiency in Layered Oxide Cathode for Li-Ion Battery

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sung-Jin [Joint School of Nanoscience and Nanoengineering, North Carolina Agricultural and Technical State University, Greensboro NC 27401 USA; Uddin, Md-Jamal [Joint School of Nanoscience and Nanoengineering, North Carolina Agricultural and Technical State University, Greensboro NC 27401 USA; Alaboina, Pankaj K. [Joint School of Nanoscience and Nanoengineering, North Carolina Agricultural and Technical State University, Greensboro NC 27401 USA; Han, Sang Sub [Department of Materials Science Engineering, Seoul National University, Seoul 08826 Republic of Korea; Nandasiri, Manjula I. [Imaging and Chemical Analysis Laboratory, Department of Physics, Montana State University, Bozeman MT 59718 USA; Choi, Yong Seok [Department of Materials Science Engineering, Seoul National University, Seoul 08826 Republic of Korea; Hu, Enyuan [Chemistry Division, Brookhaven National Laboratory, Upton NY 11973 USA; Nam, Kyung-Wan [Department of Energy Materials Engineering, Dongguk University, Seoul 04620 Republic of Korea; Schwarz, Ashleigh M. [Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99352 USA; Nune, Satish K. [Energy and Environmental Division, Pacific Northwest National Laboratory, Richland WA 99352 USA; Cho, Jong Soo [Joint School of Nanoscience and Nanoengineering, North Carolina Agricultural and Technical State University, Greensboro NC 27401 USA; Oh, Kyu Hwan [Department of Materials Science Engineering, Seoul National University, Seoul 08826 Republic of Korea; Choi, Daiwon [Energy and Environmental Division, Pacific Northwest National Laboratory, Richland WA 99352 USA

    2017-06-23

    Abstract or short description: The ever-growing demand for high capacity cathode materials is on the rise since the futuristic applications are knocking on the door. Conventional approach to developing such cathode relies on the lithium-excess materials to operate the cathode at high voltage and extract more lithium-ion. Yet, they fail to satiate the needs because of their unresolved issues upon cycling such as, for lithium manganese-rich layered oxides – their voltage fading, and for as nickel-based layered oxides – the structural transition. Here, in contrast, lithium-deficient ratio is demonstrated as a new approach to attain high capacity at high voltage for layered oxide cathodes. Rapid and cost effective lithiation of a porous hydroxide precursor with lithium deficient ratio acted as a driving force to partially convert the layered material to spinel phase yielding in a multiphase structure (MPS) cathode material. Upon cycling, MPS revealed structural stability at high voltage and high temperature and resulted in fast lithium-ion diffusion by providing a distinctive SEI chemistry – MPS displayed minimum lithium loss in SEI and formed a thinner SEI. MPS thus offer high energy and high power applications and provides a new perspective compared to the conventional layered cathode materials denying the focus for lithium excess material.

  16. High sulfur-containing carbon polysulfide polymer as a novel cathode material for lithium-sulfur battery.

    Science.gov (United States)

    Zhang, Yiyong; Peng, Yueying; Wang, Yunhui; Li, Jiyang; Li, He; Zeng, Jing; Wang, Jing; Hwang, Bing Joe; Zhao, Jinbao

    2017-09-12

    The lithium-sulfur battery, which offers a high energy density and is environmental friendly, is a promising next generation of rechargeable energy storage system. However, despite these attractive attributes, the commercialization of lithium-sulfur battery is primarily hindered by the parasitic reactions between the Li metal anode and dissolved polysulfide species from the cathode during the cycling process. Herein, we synthesize the sulfur-rich carbon polysulfide polymer and demonstrate that it is a promising cathode material for high performance lithium-sulfur battery. The electrochemical studies reveal that the carbon polysulfide polymer exhibits superb reversibility and cycle stability. This is due to that the well-designed structure of the carbon polysulfide polymer has several advantages, especially, the strong chemical interaction between sulfur and the carbon framework (C-S bonds) inhibits the shuttle effect and the π electrons of the carbon polysulfide compound enhance the transfer of electrons and Li+. Furthermore, as-prepared carbon polysulfide polymer-graphene hybrid cathode achieves outstanding cycle stability and relatively high capacity. This work highlights the potential promise of the carbon polysulfide polymer as the cathode material for high performance lithium-sulfur battery.

  17. A core-shell structured LiNi0.5Mn1.5O4@LiCoO2 cathode material with superior rate capability and cycling performance.

    Science.gov (United States)

    Deng, Yunlong; Mou, Jirong; He, Lihua; Xie, Fengyu; Zheng, Qiaoji; Xu, Chenggang; Lin, Dunmin

    2018-01-02

    A core-shell structured LiNi0.5Mn1.5O4@LiCoO2 cathode material has been successfully synthesized by the combination of sol-gel and solid state methods. The coating of LiCoO2 has a significant effect on the electrochemical performance of the spinel LiNi0.5Mn1.5O4-based cathode material, especially the cycling stability at high temperature and rate capability. After modification, the ionic conductivity of the material is greatly improved due to the high ion conductivity of LiCoO2. The LiNi0.5Mn1.5O4@LiCoO2 with 1% LiCoO2 presents the optimal rate capability and delivers a relatively high discharge capacity of 122 mA h g-1 at 10C. On the other hand, the surface coating of LiCoO2 can effectively facilitate Li+ interfacial diffusion, and alleviate the side reactions between the active material and the electrolyte; as a result, the capacity retention of 96.17% for the LiNi0.5Mn1.5O4@LiCoO2 electrode with 1% LiCoO2 is much higher than that for the bare LiNi0.5Mn1.5O4 (74.93%) after 100 cycles at elevated temperature. Our study confirms that the core-shell structure construction caused by the coating of LiCoO2 plays a critical role in the improvement of the electrochemical cycling stability at elevated temperatures and rate capability.

  18. Facile synthesis and characterization of a SnO2-modified LiNi0.5Mn1.5O4 high-voltage cathode material with superior electrochemical performance for lithium ion batteries.

    Science.gov (United States)

    Ma, Feng; Geng, Fushan; Yuan, Anbao; Xu, Jiaqiang

    2017-04-12

    A thin-layer-SnO2 modified LiNi0.5Mn1.5O4@SnO2 material is synthesized via a facile synthetic approach. It is physically and electrochemically characterized as a high-voltage lithium ion battery cathode and compared to the pristine LiNi0.5Mn1.5O4 material prepared under similar conditions. The two materials are proved to be crystals of a well-defined disordered spinel phase with the morphology of aggregates of micron/submicron polyhedral particles. The Mn(3+) ions and the inactive NixLiyO phase in the LiNi0.5Mn1.5O4@SnO2 is less than those in the LiNi0.5Mn1.5O4 due to incorporation of a very small amount of Sn(2+) into the spinel structure upon high-temperature calcination of the precursor. Besides, the mean particle size of the LiNi0.5Mn1.5O4@SnO2 is obviously smaller than that of the LiNi0.5Mn1.5O4. The LiNi0.5Mn1.5O4@SnO2 demonstrates much superior electrochemical performance over the LiNi0.5Mn1.5O4 in terms of specific capacity, rate capability and cyclability. For example, the discharge capacities at current rates of 0.2C, 2C and 20C are 145.4, 139.9 and 112.2 mA h g(-1), respectively. A capacity retention rate of ca. 75% is obtained after 500 cycles at 2C rate. The improved electrochemical performance is attributed to the positive effect of the surface protective SnO2 coating layer as well as the structural and morphological modifications of the spinel.

  19. Determination of the mechanism and extent of surface degradation in Ni-based cathode materials after repeated electrochemical cycling

    Directory of Open Access Journals (Sweden)

    Sooyeon Hwang

    2016-09-01

    Full Text Available We take advantage of scanning transmission electron microscopy and electron energy loss spectroscopy to investigate the changes in near-surface electronic structure and quantify the degree of local degradation of Ni-based cathode materials with the layered structure (LiNi0.8Mn0.1Co0.1O2 and LiNi0.4Mn0.3Co0.3O2 after 20 cycles of delithiation and lithiation. Reduction of transition metals occurs in the near-surface region of cathode materials: Mn is the major element to be reduced in the case of relatively Mn-rich composition, while reduction of Ni ions is dominant in Ni-rich materials. The valences of Ni and Mn ions are complementary, i.e., when one is reduced, the other is oxidized in order to maintain charge neutrality. The depth of degradation zone is found to be much deeper in Ni-rich materials. This comparative analysis provides important insights needed for the devising of new cathode materials with high capacity as well as long lifetime.

  20. Electroluminescence and impedance analyses of organic light emitting diodes using anhydride materials as cathode interfacial layers

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Eunkyoung [Department of Physics, Brain Korea 21 Physics Research Division, Institute of Basic Science, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Park, Hyungjun [School of Information and Communication Engineering, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Park, Keunhee; Moon, Mi Ran [Department of Physics, Brain Korea 21 Physics Research Division, Institute of Basic Science, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Sohn, Sunyoung [Korea Basic Science Institute, Dukjin Dong 664-14, Jeonju 561-756 (Korea, Republic of); Jung, Donggeun [Department of Physics, Brain Korea 21 Physics Research Division, Institute of Basic Science, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Yi, Junsin [School of Information and Communication Engineering, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Chae, Heeyeop [Department of Chemical Engineering, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Kim, Hyoungsub, E-mail: hsubkim@skku.ed [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of)

    2009-05-29

    Pyromellitic dianhydride (PMDA) and trimellitic anhydride (TMA) were tried as cathode interfacial layers between tris-(8-hydroxyquinoline) aluminum (Alq{sub 3}) and Al in organic light emitting diodes (OLEDs). Both ultra-thin anhydride cathode interfacial layers improved the electroluminescence characteristics of OLEDs compared to those without any interfacial layer, and the PMDA interfacial layer showed the most significant enhancement of the device performance. According to impedance measurements and equivalent circuit analysis, the PMDA interfacial layer decreased the impedance, probably due to the increase in the injection efficiency of electrons from the Al cathode.

  1. Nondestructive Thickness Quantification for Nanoscale Coatings on Li-Ion Battery Cathode Material.

    Science.gov (United States)

    Ouyang, Wuye; Todd, Clifford S

    2017-03-07

    Nickel manganese cobalt oxide (NMC) is a high energy capacity cathode material that attracts the interest of many research groups. Coating a protection layer on the NMC surface is one approach to improve its cycling and safety performance. However, there is no standard and consistent way to characterize the coating performance (thickness) of this protection layer, especially due to the nanoscale of primary particle and spherical morphology of the secondary particle. In this paper, a novel empirical method based on energy dispersive X-ray spectroscopy (EDX) analysis at low accelerating voltage is proposed to evaluate the protection layer thickness on the scale of tens of nanometers. The layer thickness is characterized by measuring the intensity decrease of a substrate element due to absorption by overlying coating layers. An internal standard coating (metal layer) is applied to mimic the morphology influence and improve the accuracy of thickness quantitation. For the model sample evaluation, carbon layer coatings of 1 to 10 nm thickness were successfully quantified by this method.

  2. Carbon black as an alternative cathode material for electrical energy recovery and transfer in a microbial battery.

    Science.gov (United States)

    Zhang, Xueqin; Guo, Kun; Shen, Dongsheng; Feng, Huajun; Wang, Meizhen; Zhou, Yuyang; Jia, Yufeng; Liang, Yuxiang; Zhou, Mengjiao

    2017-08-01

    Rather than the conventional concept of viewing conductive carbon black (CB) to be chemically inert in microbial electrochemical cells (MECs), here we confirmed the redox activity of CB for its feasibility as an electron sink in the microbial battery (MB). Acting as the cathode of a MB, the solid-state CB electrode showed the highest electron capacity equivalent of 18.58 ± 0.46 C/g for the unsintered one and the lowest capacity of 2.29 ± 0.48 C/g for the one sintered under 100% N2 atmosphere. The capacity vibrations of CBs were strongly in coincidence with the abundances of C=O moiety caused by different pretreatments and it implied one plausible mechanism based on CB's surface functionality for its electron capturing. Once subjected to electron saturation, CB could be completely regenerated by different strategies in terms of electrochemical discharging or donating electrons to biologically-catalyzed nitrate reduction. Surface characterization also revealed that CB's regeneration fully depended on the reversible shift of C=O moiety, further confirming the functionality-based mechanism for CB's feasibility as the role of MB's cathode. Moreover, resilience tests demonstrated that CB cathode was robust for the multi-cycles charging-discharging operations. These results imply that CB is a promising alternative material for the solid-state cathode in MBs.

  3. Microstructure control of SOFC cathodes using the self-organizing behavior of LSM/ScSZ composite powder material prepared by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Hagiwara, Akifusa; Hobara, Natsuro; Takizawa, Koichi [R and D Center, Engineering R and D Division, Tokyo Electric Power Company, 4-1, Egasaki-cho, Tsurumi-ku, Yokohama, 230-8510 (Japan); Sato, Kazuyoshi; Abe, Hiroya; Naito, Makio [Joining and Welding Research Institute(JWRI), Osaka University, 11-1 Mihogaoka, Ibaragi, Osaka 567-0047 (Japan)

    2007-06-15

    Composite particles for SOFC cathodes were synthesized by a spray pyrolysis method. The constituent materials for the cathode are provided in the form of a metal ion solution with the addition of an electrolyte sol solution, and sprayed droplets of the solution undergo pyrolysis to form composite LSM/ScSZ particles. The resultant particles have been shown to possess a structure on a nano-order with a well-controlled particle size and material composition. Also, the cathode using the composite particles has demonstrated a significant reduction in the interfacial area specific resistance by 30-50% when compared to those for conventional cathode materials. This paper describes the processes for cathode fabrication in order to understand how such a finely controlled cathode microstructure is realized. In particular, the self-organizing behavior during the course of crystal growth within the cathode is carefully observed. The present results encourage further optimization of the composite particle design in order to further improve the cathode performance. (author)

  4. The impact of new cathode materials relative to baseline performance of microbial fuel cells all with the same architecture and solution chemistry

    KAUST Repository

    Yang, Wulin

    2017-04-21

    Differences in microbial fuel cell (MFC) architectures, materials, and solution chemistries, have previously hindered direct comparisons of improvements in power production due to new cathode materials. However, one common reactor design has now been used in many different laboratories around the world under similar operating conditions based on using: a graphite fiber brush anode, a platinum cathode catalyst, a single-chamber cube-shaped (4-cm) MFC with a 3-cm diameter anolyte chamber, 50 mM phosphate buffer, and an acetate fuel. Analysis of several publications over 10 years from a single laboratory showed that even under such identical operational conditions, maximum power densities varied by 15%, with an average of 1.36 ± 0.20 W m–2 (n=24), normalized to cathode projected area (34 W m–3 liquid volume). In other laboratories, maximum power was significantly less, with an average of 1.03 ± 0.46 W m–2 (n=11), despite identical conditions. One likely reason for the differences in power is cathode age. Power production with Pt catalyst cathodes significantly declined after one month of operation or more to 0.87 ± 0.31 W m–2 (n=18) based on studies where cathode aging was examined, while in many studies the age of the cathode was not reported. Using these studies as a performance baseline, we review the claims of improvements in power generation due to new anode or cathode materials, or changes in solution conductivities and substrates.

  5. Functionally Graded Cathodes for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Harry Abernathy; Meilin Liu

    2006-12-31

    One primary suspected cause of long-term performance degradation of solid oxide fuels (SOFCs) is the accumulation of chromium (Cr) species at or near the cathode/electrolyte interface due to reactive Cr molecules originating from Cr-containing components (such as the interconnect) in fuel cell stacks. To date, considerable efforts have been devoted to the characterization of cathodes exposed to Cr sources; however, little progress has been made because a detailed understanding of the chemistry and electrochemistry relevant to the Cr-poisoning processes is still lacking. This project applied multiple characterization methods - including various Raman spectroscopic techniques and various electrochemical performance measurement techniques - to elucidate and quantify the effect of Cr-related electrochemical degradation at the cathode/electrolyte interface. Using Raman microspectroscopy the identity and location of Cr contaminants (SrCrO{sub 4}, (Mn/Cr){sub 3}O{sub 4} spinel) have been observed in situ on an LSM cathode. These Cr contaminants were shown to form chemically (in the absence of current flowing through the cell) at temperatures as low as 625 C. While SrCrO{sub 4} and (Mn/Cr){sub 3}O{sub 4} spinel must preferentially form on LSM, since the LSM supplies the Sr and Mn cations necessary for these compounds, LSM was also shown to be an active site for the deposition of Ag{sub 2}CrO{sub 4} for samples that also contained silver. In contrast, Pt and YSZ do not appear to be active for formation of Cr-containing phases. The work presented here supports the theory that Cr contamination is predominantly chemically-driven and that in order to minimize the effect, cathode materials should be chosen that are free of cations/elements that could preferentially react with chromium, including silver, strontium, and manganese.

  6. Characterization of tantalum doped lanthanum strontium ferrite as cathode materials for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Natali Sora, Isabella, E-mail: isabella.natali-sora@unibg.it [INSTM R.U. Bergamo and Department of Engineering and Applied Sciences, University of Bergamo, Viale Marconi 5, Dalmine, BG 24044 (Italy); Felice, Valeria [INSTM R.U. Bergamo and Department of Engineering and Applied Sciences, University of Bergamo, Viale Marconi 5, Dalmine, BG 24044 (Italy); Zurlo, Francesca; Licoccia, Silvia; Di Bartolomeo, Elisabetta [Department of Chemical Science and Technologies & NAST Center University of Rome “Tor Vergata”, Via della Ricerca Scientifica, 00133 (Italy)

    2015-11-05

    The phase relations and crystal structures of La{sub 1−x}Sr{sub x}Fe{sub 1−y}Ta{sub y}O{sub 3} in the compositional range x = 0–0.60, y = 0–0.20 were investigated by powder X-ray diffraction (XRD). The formal concentration of Fe{sup 4+} in the La{sub 1−x}Sr{sub x}Fe{sub 1−y}Ta{sub y}O{sub 3±w} (LSFT) system was calculated and related to the electrical/electrochemical properties. To investigate the electrochemical behaviour as cathode material for SOFCs, impedance measurements were performed on LSFT/electrolyte/LSFT symmetrical cells by using La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.2}O{sub 3}, (LSGM) as electrolyte material. The lowest area specific resistance (ASR), derived from the polarization resistance (R{sub p}), 1 Ω cm{sup 2} at 750 °C, was measured for the LSFT compound doped with x = 0.40 and y = 0.05. - Highlights: • The lowest area specific resistance was obtained with Sr = 0.40 and Ta = 0.05. • The activation energies E{sub a} are in the range of 1.3–1.6 eV. • The samples were single phase when Sr = 0, 0.20, 0.40, and 0.6 and Ta = 0.05. • A predictive trend of the electric conductivity is proposed.

  7. Evaluation of several electrolyte mixture-cathode material combinations in electrodeposition of americium radioisotopes for alpha-spectrometric measurements.

    Science.gov (United States)

    Krmpotić, Matea; Rožmarić, Martina; Benedik, Ljudmila

    2017-10-01

    Three different types of electrolytes, subsequently modified and adjusted, in combination with three cathode materials used as source backings were analysed for electrodeposition of americium isotopes for alpha-spectrometric measurements. The obtained results are discussed in terms of electrodeposition yield and source quality (source homogeneity and spectral resolution, FWHM). The optimal conditions for source preparation are provided. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Cathode material and pulsed plasma treatment influence on the microstructure and microhardness of high-chromium cast iron surface

    Directory of Open Access Journals (Sweden)

    Юлія Геннадіївна Чабак

    2016-11-01

    Full Text Available The article presents an analysis of the cathode material and the pulse plasma treatment mode influence on the surface microstructure and microhardness of high chrome (15% Cr cast iron. The methods of metallographic analysis and microhardness measurements were used. It has been shown that pulsed plasma treatment at 4 kV voltage with the use of the electro-axial thermal accelerator results in surface modification with high microhardness 950-1050 HV50, and in the formation of the coating due to the transfer of the electrodes material. The specific features of using different cathode materials have been systematized. It has been found that graphite electrodes are not recommended to be used due to their low strength and fracture under plasma pulses. In case of using tungsten cathode a coating of small thickness (20-30 microns and having cracks has been formed on the specimen surface. The most expedient is to apply the electrodes with low melting point (such as killed St.3, which provides a high-quality state of treated surface and formation the protective crack-free coating of 80-100 microns thick. It has been found that as a result of the plasma pulsed treatment the enrichment of coating with carbon is likely to occur that results in microhardness increase. The prospects of this technology as well as its shortcomings have been described

  9. Quantifying the environmental impact of a Li-rich high-capacity cathode material in electric vehicles via life cycle assessment.

    Science.gov (United States)

    Wang, Yuqi; Yu, Yajuan; Huang, Kai; Chen, Bo; Deng, Wensheng; Yao, Ying

    2017-01-01

    A promising Li-rich high-capacity cathode material (xLi2MnO3·(1-x)LiMn0.5Ni0.5O2) has received much attention with regard to improving the performance of lithium-ion batteries in electric vehicles. This study presents an environmental impact evaluation of a lithium-ion battery with Li-rich materials used in an electric vehicle throughout the life cycle of the battery. A comparison between this cathode material and a Li-ion cathode material containing cobalt was compiled in this study. The battery use stage was found to play a large role in the total environmental impact and high greenhouse gas emissions. During battery production, cathode material manufacturing has the highest environmental impact due to its complex processing and variety of raw materials. Compared to the cathode with cobalt, the Li-rich material generates fewer impacts in terms of human health and ecosystem quality. Through the life cycle assessment (LCA) results and sensitivity analysis, we found that the electricity mix and energy efficiency significantly influence the environmental impacts of both battery production and battery use. This paper also provides a detailed life cycle inventory, including firsthand data on lithium-ion batteries with Li-rich cathode materials.

  10. High-Capacity Micrometer-Sized Li 2 S Particles as Cathode Materials for Advanced Rechargeable Lithium-Ion Batteries

    KAUST Repository

    Yang, Yuan

    2012-09-19

    Li 2S is a high-capacity cathode material for lithium metal-free rechargeable batteries. It has a theoretical capacity of 1166 mAh/g, which is nearly 1 order of magnitude higher than traditional metal oxides/phosphates cathodes. However, Li 2S is usually considered to be electrochemically inactive due to its high electronic resistivity and low lithium-ion diffusivity. In this paper, we discover that a large potential barrier (∼1 V) exists at the beginning of charging for Li 2S. By applying a higher voltage cutoff, this barrier can be overcome and Li 2S becomes active. Moreover, this barrier does not appear again in the following cycling. Subsequent cycling shows that the material behaves similar to common sulfur cathodes with high energy efficiency. The initial discharge capacity is greater than 800 mAh/g for even 10 μm Li 2S particles. Moreover, after 10 cycles, the capacity is stabilized around 500-550 mAh/g with a capacity decay rate of only ∼0.25% per cycle. The origin of the initial barrier is found to be the phase nucleation of polysulfides, but the amplitude of barrier is mainly due to two factors: (a) charge transfer directly between Li 2S and electrolyte without polysulfide and (b) lithium-ion diffusion in Li 2S. These results demonstrate a simple and scalable approach to utilizing Li 2S as the cathode material for rechargeable lithium-ion batteries with high specific energy. © 2012 American Chemical Society.

  11. Ba1-xSrxCoyFe1-yO3-delta SOFC cathode materials : bulk properties, kinetics and mechanism of oxygen reduction

    OpenAIRE

    Wang, Lei

    2009-01-01

    This work is mainly concerned with the mixed conducting perovskite solid solution materials family Ba1-xSrxCoyFe1-yO3-delta (BSCF) which is discussed as solid oxide fuel cell (SOFC) cathode material. The aim is to get an improved understanding of the complex oxygen reduction reaction on such oxides in general, and in particular for the application as catalytically active cathode in SOFC. As a SOFC cathode candidate, the stability of BSCFs with regard to the application was first studied o...

  12. Facile electrochemical polymerization of polypyrrole film applied as cathode material in dual rotating disk photo fuel cell

    Science.gov (United States)

    Li, Kan; Zhang, Hongbo; Tang, Tiantian; Tang, Yanping; Wang, Yalin; Jia, Jinping

    2016-08-01

    Polypyrrole (PPy) film is synthesized on Ti substrate through electrochemical polymerization method and is applied as cathode material in a TiO2 NTs-PPy dual rotating disk photo fuel cell (PFC). The optimized PPy electrochemical polymerization is carried out using linear sweep voltammetry from 0 V to 1.2 V (vs. SCE) with scan rate of 0.1 V s-1, 100 circles. Sixty milliliter real textile wastewater with the initial COD and conductivity of 408 ± 6 mgO2 L-1 and 20180 μS cm-1 is treated in this PFC under UV irradiation. About 0.46 V open-circuit voltage (VOC) and 1.8-2.2 mA short-circuit current (JSC) are obtained. Due to the effective electron-hole separation effect, the COD removal rate is as high as 0.0055 min-1. Stable current and COD removal can be obtained at different output voltage. Two influence factors including rotating speed and pH are investigated. Better electricity generation performance and COD removal activity are achieved at high rotating speed and in acidic condition. In comparison with platinized cathode, though VOC is lower, similar JSC is measured. Considering the high cost of Pt, PPy is a promising alternative cathode material in PFC that can also generate electricity efficiently and stably.

  13. Fe-N-C catalyst modified graphene sponge as a cathode material for lithium-oxygen battery

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Ling, E-mail: yulingcug@126.com; Shen, Yue, E-mail: shenyue1213@mail.hust.edu.cn; Huang, Yunhui, E-mail: huangyh@mail.hust.edu.cn

    2014-05-15

    Highlights: • Hydrothermally-synthesized graphene sponge is excellent skeleton of Li-O{sub 2} cathode. • Fe-N-C catalyst loaded on GS was attained via pyrolysis of FePc and GS composites. • High capacity and good cyclability were achieved with Fe-N-GS air electrode. • The synergy of porous structure and catalytic activity leads to the high performance. - Abstract: The cathode of a lithium-oxygen battery needs the synergism of a porous conducting material and a catalyst to facilitate the formation and decomposition of lithium peroxide. Here we introduce a graphene sponge (GS) modified with Fe-N-C catalyst for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). The porous, 3-dimensional conductive and free standing nature of the graphene sponge makes it become excellent skeleton of cathode for lithium-oxygen battery. The Fe-N-C catalyst nanoparticles dispersed uniformly on the graphene sheets show excellent catalytic reactivity in both discharge and charge processes. This kind of composite material greatly improves the capacity and cyclability of the lithium-oxygen battery. With dimethyl sulphoxide as electrolyte, the capacity reaches 6762 mAh g{sup −1} which is twice of the pure graphene sponge. In addition, the cell containing Fe-N-GS air electrode exhibits stable cyclic performance and effective reduction of charge potential plateau, indicating that Fe-N-GS is promising as an OER catalyst in rechargeable lithium-air batteries.

  14. Inverse vulcanization of sulfur with divinylbenzene: Stable and easy processable cathode material for lithium-sulfur batteries

    Science.gov (United States)

    Gomez, Iñaki; Mecerreyes, David; Blazquez, J. Alberto; Leonet, Olatz; Ben Youcef, Hicham; Li, Chunmei; Gómez-Cámer, Juan Luis; Bondarchuk, Oleksandr; Rodriguez-Martinez, Lide

    2016-10-01

    Lithium-Sulfur (Li-S) battery technology is one of the promising candidates for next generation energy storage systems. Many studies have focused on the cathode materials to improve the cell performance. In this work we present a series of poly (S-DVB) copolymers synthesised by inverse vulcanization of sulfur with divinylbenzene (DVB). The poly (S-DVB) cathode shows excellent cycling performances at C/2 and C/4 current rates, respectively. It was demonstrated poly (S-DVB) copolymer containing 20% DVB did not influence the electrochemical performance of the sulfur material, compared to elemental sulfur as high specific capacities over ∼700 mAh g-1 at 500 cycles were achieved at C/4 current rate, comparable to conventional carbon-based S cathodes. However, the use of copolymer network is assumed to act firstly as sulfur reservoir and secondly as mechanical stabilizer, enhancing significantly the cycling lifetime. The Li-poly (S-DVB) cell demonstrated an extremely low degradation rate of 0.04% per cycle achieving over 1600 cycles at C/2 current rate.

  15. One-step synthesis of graphene/polypyrrole nanofiber composites as cathode material for a biocompatible zinc/polymer battery.

    Science.gov (United States)

    Li, Sha; Shu, Kewei; Zhao, Chen; Wang, Caiyun; Guo, Zaiping; Wallace, Gordon; Liu, Hua Kun

    2014-10-08

    The significance of developing implantable, biocompatible, miniature power sources operated in a low current range has become manifest in recent years to meet the demands of the fast-growing market for biomedical microdevices. In this work, we focus on developing high-performance cathode material for biocompatible zinc/polymer batteries utilizing biofluids as electrolyte. Conductive polymers and graphene are generally considered to be biocompatible and suitable for bioengineering applications. To harness the high electrical conductivity of graphene and the redox capability of polypyrrole (PPy), a polypyrrole fiber/graphene composite has been synthesized via a simple one-step route. This composite is highly conductive (141 S cm(-1)) and has a large specific surface area (561 m(2) g(-1)). It performs more effectively as the cathode material than pure polypyrrole fibers. The battery constructed with PPy fiber/reduced graphene oxide cathode and Zn anode delivered an energy density of 264 mWh g(-1) in 0.1 M phosphate-buffer saline.

  16. Suppressing the chromium disproportionation reaction in O3-type layered cathode materials for high capacity sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Ming-Hui; Wang, Yong; Shadike, Zulipiya; Yue, Ji-Li; Hu, Enyuan; Bak, Seong-Min; Zhou, Yong-Ning; Yang, Xiao-Qing; Fu, Zheng-Wen

    2017-01-01

    Chromium-based layered cathode materials suffer from the irreversible disproportionation reaction of Cr4+ to Cr3+ and Cr6+, which hinders the reversible multi-electron redox of Cr ions in layered cathodes, and limits their capacity and reversibility. To address this problem, a novel O3-type layer-structured transition metal oxide of NaCr1/3Fe1/3Mn1/3O2 (NCFM) was designed and studied as a cathode material. A high reversible capacity of 186 mA h g-1 was achieved at a current rate of 0.05C in a voltage range of 1.5 to 4.2 V. X-ray diffraction revealed an O3 → (O3 + P3) → (P3 + O3'') → O3'' phase-transition pathway for NCFM during charge. X-ray absorption, X-ray photoelectron and electron energy-loss spectroscopy measurements revealed the electronic structure changes of NCFM during Na+ deintercalation/intercalation processes. It is confirmed that the disproportionation reaction of Cr4+ to Cr3+ and Cr6+ can be effectively suppressed by Fe3+ and Mn4+ substitution. These results demonstrated that the reversible multi-electron oxidation/reduction of Cr ions can be achieved in NCFM during charge and discharge accompanied by CrO6 octahedral distortion and recovery.

  17. Metalized, three-dimensional structured oxygen cathode materials for lithium/air batteries and method for making and using the same

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Weibing; Buettner-Garrett, Josh

    2017-04-18

    This disclosure relates generally to cathode materials for electrochemical energy cells, more particularly to metal/air electrochemical energy cell cathode materials containing silver vanadium oxide and methods of making and using the same. The metal/air electrochemical energy cell can be a lithium/air electrochemical energy cell. Moreover the silver vanadium oxide can be a catalyst for one or more of oxidation and reduction processes of the electrochemical energy cell.

  18. Current characteristics of quasi-planar vacuum diodes with explosive-emission cathodes made of various materials at a high-voltage pulse duration of a few nanoseconds

    Science.gov (United States)

    Afanas'ev, K. V.; Vagner, M. I.; Kutenkov, O. P.; Pegel, I. V.; Pribytkov, G. A.; Rostov, V. V.; Tarakanov, V. P.

    2012-12-01

    The currents of 5-ns pulsed high-current electron beams produced in a planar vacuum diode with explosive-emission cathodes made of various materials with no external magnetic field at an average electric field strength in the gap of about 300 kV/cm have been measured and time-integrated observation of the optical luminescence of the cathode surface have been performed. Cathodes with a ceramic bushing and spring metal contacts, with ceramic plates set in a magnetic iron matrix, with blades made of stamped exfoliated graphite (Graflex), with blades made of foil fiberglass plastic, and a composite cathode made of crystalline boron and copper powders were tested. The current carried by one emission center has been estimated to range between 5 and 20 A for various cathodes. For the metal-dielectric cathode, the velocity of expansion of the cathode plasma over the ceramic surface has been estimated as 2·107 cm/s. The lifetimes of the cathodes at a pulse repetition rate of 50 Hz have been investigated.

  19. Development of Graphene-based novel cathode material in MES system

    DEFF Research Database (Denmark)

    Chen, Leifeng; Aryal, Nabin; Ammam, Fariza

    2014-01-01

    It has been reported that physical contact between unique nanostructures of electrode and bacteria isimportant for microbial electrosynthesis. The higher specific surface area of cathode can increase contact interface area with bacteria and enhance electron-exchange at the electrode surface.The g...

  20. A New CuO-Fe2 O3 -Mesocarbon Microbeads Conversion Anode in a High-Performance Lithium-Ion Battery with a Li1.35 Ni0.48 Fe0.1 Mn1.72 O4 Spinel Cathode.

    Science.gov (United States)

    Di Lecce, Daniele; Verrelli, Roberta; Campanella, Daniele; Marangon, Vittorio; Hassoun, Jusef

    2017-04-10

    A ternary CuO-Fe2 O3 -mesocarbon microbeads (MCMB) conversion anode was characterized and combined with a high-voltage Li1.35 Ni0.48 Fe0.1 Mn1.72 O4 spinel cathode in a lithium-ion battery of relevant performance in terms of cycling stability and rate capability. The CuO-Fe2 O3 -MCMB composite was prepared by using high-energy milling, a low-cost pathway that leads to a crystalline structure and homogeneous submicrometrical morphology as revealed by XRD and electron microscopy. The anode reversibly exchanges lithium ions through the conversion reactions of CuO and Fe2 O3 and by insertion into the MCMB carbon. Electrochemical tests, including impedance spectroscopy, revealed a conductive electrode/electrolyte interface that enabled the anode to achieve a reversible capacity value higher than 500 mAh g-1 when cycled at a current of 120 mA g-1 . The remarkable stability of the CuO-Fe2 O3 -MCMB electrode and the suitable characteristics in terms of delivered capacity and voltage-profile retention allowed its use in an efficient full lithium-ion cell with a high-voltage Li1.35 Ni0.48 Fe0.1 Mn1.72 O4 cathode. The cell had a working voltage of 3.6 V and delivered a capacity of 110 mAh gcathode-1 with a Coulombic efficiency above 99 % after 100 cycles at 148 mA gcathode-1 . This relevant performances, rarely achieved by lithium-ion systems that use the conversion reaction, are the result of an excellent cell balance in terms of negative-to-positive ratio, favored by the anode composition and electrochemical features. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Sea urchin-like mesoporous carbon material grown with carbon nanotubes as a cathode catalyst support for fuel cells

    Science.gov (United States)

    Kuo, Ping-Lin; Hsu, Chun-Han; Li, Wan-Ting; Jhan, Jing-Yi; Chen, Wei-Fu

    A sea urchin-like carbon (UC) material with high surface area (416 m 2 g -1), adequate electrical conductivity (59.6 S cm -1) and good chemical stability was prepared by growing carbon nanotubes onto mesoporous carbon hollow spheres. A uniform dispersion of Pt nanoparticles was then anchored on the UC, where the Pt nanoparticles were prepared using benzylamine as the stabilizer. For this Pt loaded carbon, cyclic voltammogram measurements showed an exceptionally high electrochemically active surface area (EAS) (114.8 m 2 g -1) compared to the commonly used commercial E-TEK catalyst (65.2 m 2 g -1). The durability test demonstrates that the carbon used as a support exhibited minor loss in EAS of Pt. Compared to the E-TEK (20 wt%) cathode catalyst, this Pt loaded UC catalyst has greatly enhanced catalytic activity toward the oxygen reduction reaction, less cathode flooding and considerably improved performance, resulting in an enhancement of ca. 37% in power density compared with that of E-TEK. Based on the results obtained, the UC is an excellent support for Pt nanoparticles used as cathode catalysts in proton exchange membrane fuel cells.

  2. Sea urchin-like mesoporous carbon material grown with carbon nanotubes as a cathode catalyst support for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Ping-Lin; Hsu, Chun-Han; Li, Wan-Ting; Jhan, Jing-Yi; Chen, Wei-Fu [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101 (China)

    2010-12-15

    A sea urchin-like carbon (UC) material with high surface area (416 m{sup 2} g{sup -1}), adequate electrical conductivity (59.6 S cm{sup -1}) and good chemical stability was prepared by growing carbon nanotubes onto mesoporous carbon hollow spheres. A uniform dispersion of Pt nanoparticles was then anchored on the UC, where the Pt nanoparticles were prepared using benzylamine as the stabilizer. For this Pt loaded carbon, cyclic voltammogram measurements showed an exceptionally high electrochemically active surface area (EAS) (114.8 m{sup 2} g{sup -1}) compared to the commonly used commercial E-TEK catalyst (65.2 m{sup 2} g{sup -1}). The durability test demonstrates that the carbon used as a support exhibited minor loss in EAS of Pt. Compared to the E-TEK (20 wt%) cathode catalyst, this Pt loaded UC catalyst has greatly enhanced catalytic activity toward the oxygen reduction reaction, less cathode flooding and considerably improved performance, resulting in an enhancement of ca. 37% in power density compared with that of E-TEK. Based on the results obtained, the UC is an excellent support for Pt nanoparticles used as cathode catalysts in proton exchange membrane fuel cells. (author)

  3. H2V3O8 Nanowires as High-Capacity Cathode Materials for Magnesium-Based Battery.

    Science.gov (United States)

    Tang, Han; Xu, Nuo; Pei, Cunyuan; Xiong, Fangyu; Tan, Shuangshuang; Luo, Wen; An, Qinyou; Mai, Liqiang

    2017-08-30

    Magnesium-based batteries have received much attention as promising candidates to next-generation batteries because of high volumetric capacity, low price, and dendrite-free property of Mg metal. Herein, we reported H2V3O8 nanowire cathode with excellent electrochemical property in magnesium-based batteries. First, it shows a satisfactory magnesium storage ability with 304.2 mA h g(-1) capacity at 50 mA g(-1). Second, it possesses a high-voltage platform of ∼2.0 V vs Mg/Mg(2+). Furthermore, when evaluated as a cathode material for magnesium-based hybrid Mg(2+)/Li(+) battery, it exhibits a high specific capacity of 305.4 mA h g(-1) at 25 mA g(-1) and can be performed in a wide working temperature range (-20 to 55 °C). Notably, the insertion-type ion storage mechanism of H2V3O8 nanowires in hybrid Mg(2+)/Li(+) batteries are investigated by ex situ X-ray diffraction and Fourier transform infrared. This research demonstrates that the H2V3O8 nanowire cathode is a potential candidate for high-performance magnesium-based batteries.

  4. Synthesis of Cation and Water Free Cryptomelane Type OMS-2 Cathode Materials: The Impact of Tunnel Water on Electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Poyraz, Altug S.; Huang, Jianping; Zhang, Bingjie; Marschilok, Amy C.; Takeuchi, Kenneth J.; Takeuchi, Esther S.

    2017-01-01

    Cryptomelane type manganese dioxides (α-MnO2, OMS-2) are interesting potential cathode materials due to the ability of their one dimensional (1D) tunnels to reversibly host various cations including Li+and an accessible stable 3+/4+ redox couple. Here, we synthesized metal cation free OMS-2 materials where the tunnels were occupied by only water and hydronium ions. Water was subsequently removed from the tunnels. Cation free OMS-2 and Dry-OMS-2 were used as cathodes in Li based batteries to investigate the role of tunnel water on their electrochemistry. The initial discharge capacity was higher for Dry-OMS-2 (252 mAh/g) compared to OMS-2 (194 mAh/g), however, after 100 cycles Dry-OMS-2 and OMS-2 delivered 137 mAh/g and 134 mAh/g, respectively. Li+ion diffusion was more facile for Dry-OMS as evidenced by rate capability, at 400 mA/g. Dry-OMS-2 delivered 135mAh/g whereas OMS-2 delivered ~115 mAh/g. This first report of the impact of tunnel water on the electrochemistry of OMS-2 type materials demonstrates that the presence of tunnel water in OMS-2 type materials negatively impacts the electrochemistry.

  5. Electroconductive properties in doped spinel oxides

    Science.gov (United States)

    Dwivedi, Shalini; Sharma, Ramesh; Sharma, Yamini

    2014-11-01

    The application of spinel oxides as transparent conducting oxides (TCOs) in optoelectronic devices as a substitute for ZnO is attracting attention in the recent years. Despite attractive photo-luminescence properties of zinc aluminate and zinc gallate, relatively little work has been done to interpret the optical response of spinel oxides on the basis of energy band structures. We present the electronic properties of ZnX2O4 (X = Al, Ga, In) calculated by the full potential linearized augmented plane wave method. Optical properties such as absorption coefficient and reflectivity are calculated and interpreted in terms of energy bands and density of states. Enhancement in optical properties was studied for Li and Mn ions doped in the ZnGa2O4 matrix. The main features in the experimentally observed photoluminescence spectra for doped and undoped ZnGa2O4 have been verified through the optical parameters. The transparence of spinel oxides to UV radiations is also clearly illustrated in the reflectivity vs. energy curves. At very small wavelengths the oxides may be used as reflective coating materials. Transport properties of the zinc spinel oxides have been investigated for the first time, and are found to have high Seebeck coefficients, high electrical conductivity and low thermal conductivity, with high value of figure of merit ZT ∼ 0.8. The study of vibrational and thermodynamic properties by the projector augmented wave method confirms the dynamic stability of the doped and undoped spinel oxides. Zinc spinel oxides are found to be p-type semiconductors with an optimum value of band gap ∼2-3 eV and appear to meet the conditions of low resistivity and high transparency (>80%) for state-of-art TCOs.

  6. Construction of tubular polypyrrole-wrapped biomass-derived carbon nanospheres as cathode materials for lithium-sulfur batteries

    Science.gov (United States)

    Yu, Qiuhong; Lu, Yang; Peng, Tao; Hou, Xiaoyi; Luo, Rongjie; Wang, Yange; Yan, Hailong; Liu, Xianming; Kim, Jang-Kyo; Luo, Yongsong

    2017-03-01

    A promising hybrid material composed of tubular polypyrrole (T-PPy)-wrapped monodisperse biomass-derived carbon nanospheres (BCSs) was first synthesized successfully via a simple hydrothermal approach by using watermelon juice as the carbon source, and further used as an anchoring object for sulfur (S) of lithium-sulfur (Li-S) batteries. The use of BCSs with hydrophilic nature as a framework could provide large interface areas between the active materials and electrolyte, and improve the dispersion of T-PPy, which could help in the active material utilization. As a result, BCS@T-PPy/S as a cathode material exhibited a high capacity of 1143.6 mA h g-1 and delivered a stable capacity up to 685.8 mA h g-1 after 500 cycles at 0.5 C, demonstrating its promising application for rechargeable Li-S batteries.

  7. Reactivity between carbon cathode materials and electrolyte based on industrial and laboratory data

    CSIR Research Space (South Africa)

    Chauke, L

    2013-07-01

    Full Text Available similar: all contained Na(sub3)AlF(sub6), NaF, CaF(sub2) and NaAl(sub11)O(sub17). Al(sub4)C(sub3), AlN and NaCN were only detected in the spent industrial cathodes. The inability to locate Al(sub4)C(sub3) in the laboratory scale samples could be due...

  8. Advanced Mg-Mn-Ca sacrificial anode materials for cathodic protection

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.G.; Kim, Y.W. [Sungkyunkwan Univ. (Korea). Dept. of Metallurgical Engineering

    2001-02-01

    Addition of calcium to the Mg-Mn sacrificial anodes enhanced the anode efficiency by promoting the uniformly distributed corrosion along the grain boundaries and increased the driving potential by intrinsic electronegative potential of {alpha}-Mg. The reason for the uniform intergranular corrosion is that Mg{sub 2}Ca precipitate (cathode) at grain boundaries is galvanically coupled to {alpha}-Mg matrix (anode). Larger anodic area limits the localized nature of the intergranular attack. (orig.)

  9. Research Progress in Improving the Cycling Stability of High-Voltage LiNi0.5Mn1.5O4 Cathode in Lithium-Ion Battery

    Science.gov (United States)

    Xu, XiaoLong; Deng, SiXu; Wang, Hao; Liu, JingBing; Yan, Hui

    2017-04-01

    High-voltage lithium-ion batteries (HVLIBs) are considered as promising devices of energy storage for electric vehicle, hybrid electric vehicle, and other high-power equipment. HVLIBs require their own platform voltages to be higher than 4.5 V on charge. Lithium nickel manganese spinel LiNi0.5Mn1.5O4 (LNMO) cathode is the most promising candidate among the 5 V cathode materials for HVLIBs due to its flat plateau at 4.7 V. However, the degradation of cyclic performance is very serious when LNMO cathode operates over 4.2 V. In this review, we summarize some methods for enhancing the cycling stability of LNMO cathodes in lithium-ion batteries, including doping, cathode surface coating, electrolyte modifying, and other methods. We also discuss the advantages and disadvantages of different methods.

  10. Preparation and electrochemical properties of cathode materials for lithium ion battery by aerosol process

    Energy Technology Data Exchange (ETDEWEB)

    Ogihara, Takashi [Department of Fiber Amenity Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui-shi, Fukui 910-8507 (Japan)], E-mail: ogihara@matse.u-fukui.ac.jp; Kodera, Takayuki; Myoujin, Kenichi; Motohira, Shigeru [Department of Fiber Amenity Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui-shi, Fukui 910-8507 (Japan)

    2009-04-15

    Lithium transition metal oxide powders such as LiMn{sub 2}O{sub 4}, LiNi{sub 0.5}Mn{sub 1.5}O{sub 4}, LiCo{sub 1/3}Ni{sub 1/3}Mn{sub 1/3}O{sub 2} and LiFePO{sub 4} were prepared by spray pyrolysis. The particle characteristics of them were determined by SEM, XRD, BET and AAS. Lithium transition metal oxide powders had spherical morphology of 1-2 {mu}m with narrow size distribution and homogeneous chemical composition. The electrochemical properties of cathode were also estimated by rechargeable capacity, cycle performance, thermal stability and high rate charging. The cathodes obtained by spray pyrolysis exhibited that the discharge capacity of LiMn{sub 2}O{sub 4}, LiNi{sub 0.5}Mn{sub 1.5}O{sub 4}, LiCo{sub 1/3}Ni{sub 1/3}Mn{sub 1/3}O{sub 2} and LiFePO{sub 4} was 120, 130, 170 and 150 mAh/g, respectively and stable up to 500 cycles at a rate of 1 C. Mass production of lithium transition metal oxide powders was carried out by using internal combustion type of spray pyrolysis. The electrochemical properties of cathode obtained by internal combustion type spray pyrolysis were comparable with those obtained by spray pyrolysis.

  11. Tuning charge-discharge induced unit cell breathing in layer-structured cathode materials for lithium-ion batteries

    Science.gov (United States)

    Zhou, Yong-Ning; Ma, Jun; Hu, Enyuan; Yu, Xiqian; Gu, Lin; Nam, Kyung-Wan; Chen, Liquan; Wang, Zhaoxiang; Yang, Xiao-Qing

    2014-11-01

    For LiMO2 (M=Co, Ni, Mn) cathode materials, lattice parameters, a(b), contract during charge. Here we report such changes in opposite directions for lithium molybdenum trioxide (Li2MoO3). A ‘unit cell breathing’ mechanism is proposed based on crystal and electronic structural changes of transition metal oxides during charge-discharge. Metal-metal bonding is used to explain such ‘abnormal’ behaviour and a generalized hypothesis is developed. The expansion of the metal-metal bond becomes the controlling factor for a(b) evolution during charge, in contrast to the shrinking metal-oxygen bond as controlling factor in ‘normal’ materials. The cation mixing caused by migration of molybdenum ions at higher oxidation state provides the benefits of reducing the c expansion range in the early stage of charging and suppressing the structure collapse at high voltage charge. These results may open a new strategy for designing layered cathode materials for high energy density lithium-ion batteries.

  12. Cathode material comparison of thermal runaway behavior of Li-ion cells at different state of charges including over charge

    Science.gov (United States)

    Mendoza-Hernandez, Omar Samuel; Ishikawa, Hiroaki; Nishikawa, Yuuki; Maruyama, Yuki; Umeda, Minoru

    2015-04-01

    The analysis of Li-ion secondary cells under outstanding conditions, as overcharge and high temperatures, is important to determine thermal abuse characteristics of electroactive materials and precise risk assessments on Li-ion cells. In this work, the thermal runaway behavior of LiCoO2 and LiMn2O4 cathode materials were compared at different state of charges (SOCs), including overcharge, by carrying out accelerating rate calorimetry (ARC) measurements using 18650 Li-ion cells. Onset temperatures of self-heating reactions and thermal runaway behavior were identified, and by using these onset points thermal mapping plots were made. We were able to identify non-self-heating, self-heating and thermal runaway regions as a function of state of charge and temperature. The cell using LiMn2O4 cathode material was found to be more thermally stable than the cell using LiCoO2. In parallel with the ARC measurements, the electrochemical behavior of the cells was monitored by measuring the OCV and internal resistance of the cells. The electrochemical behavior of the cells showed a slightly dependency on SOC.

  13. Dual-phase spinel MnCo2O4 and spinel MnCo2O4/nanocarbon hybrids for electrocatalytic oxygen reduction and evolution.

    Science.gov (United States)

    Ge, Xiaoming; Liu, Yayuan; Goh, F W Thomas; Hor, T S Andy; Zong, Yun; Xiao, Peng; Zhang, Zheng; Lim, Suo Hon; Li, Bing; Wang, Xin; Liu, Zhaolin

    2014-08-13

    Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential reactions for energy-storage and -conversion devices relying on oxygen electrochemistry. High-performance, nonprecious metal-based hybrid catalysts are developed from postsynthesis integration of dual-phase spinel MnCo2O4 (dp-MnCo2O4) nanocrystals with nanocarbon materials, e.g., carbon nanotube (CNT) and nitrogen-doped reduced graphene oxide (N-rGO). The synergic covalent coupling between dp-MnCo2O4 and nanocarbons effectively enhances both the bifunctional ORR and OER activities of the spinel/nanocarbon hybrid catalysts. The dp-MnCo2O4/N-rGO hybrid catalysts exhibited comparable ORR activity and superior OER activity compared to commercial 30 wt % platinum supported on carbon black (Pt/C). An electrically rechargeable zinc-air battery using dp-MnCo2O4/CNT hybrid catalysts on the cathode was successfully operated for 64 discharge-charge cycles (or 768 h equivalent), significantly outperforming the Pt/C counterpart, which could only survive up to 108 h under similar conditions.

  14. Naphthalene Diimide Based n-Type Conjugated Polymers as Efficient Cathode Interfacial Materials for Polymer and Perovskite Solar Cells.

    Science.gov (United States)

    Jia, Tao; Sun, Chen; Xu, Rongguo; Chen, Zhiming; Yin, Qingwu; Jin, Yaocheng; Yip, Hin-Lap; Huang, Fei; Cao, Yong

    2017-10-18

    A series of naphthalene diimide (NDI) based n-type conjugated polymers with amino-functionalized side groups and backbones were synthesized and used as cathode interlayers (CILs) in polymer and perovskite solar cells. Because of controllable amine side groups, all the resulting polymers exhibited distinct electronic properties such as oxidation potential of side chains, charge carrier mobilities, self-doping behaviors, and interfacial dipoles. The influences of the chemical variation of amine groups on the cathode interfacial effects were further investigated in both polymer and perovskite solar cells. We found that the decreased electron-donating property and enhanced steric hindrance of amine side groups substantially weaken the capacities of altering the work function of the cathode and trap passivation of the perovskite film, which induced ineffective interfacial modifications and declining device performance. Moreover, with further improvement of the backbone design through the incorporation of a rigid acetylene spacer, the resulting polymers substantially exhibited an enhanced electron-transporting property. Upon use as CILs, high power conversion efficiencies (PCEs) of 10.1% and 15.2% were, respectively, achieved in polymer and perovskite solar cells. Importantly, these newly developed n-type polymers were allowed to be processed over a broad thickness range of CILs in photovoltaic devices, and a prominent PCE of over 8% for polymer solar cells and 13.5% for perovskite solar cells can be achieved with the thick interlayers over 100 nm, which is beneficial for roll-to-roll coating processes. Our findings contribute toward a better understanding of the structure-performance relationship between CIL material design and solar cell performance, and provide important insights and guidelines for the design of high-performance n-type CIL materials for organic and perovskite optoelectronic devices.

  15. Preparation for CeO2/Nanographite Composite Materials and Electrochemical Degradation of Phenol by CeO2/Nanographite Cathodes.

    Science.gov (United States)

    Yu, Li; Yu, Xiujuan; Sun, Tianyi; Wang, Na

    2015-07-01

    CeO2/nanographite (CeO2/nano-G) composite materials were got by chemical precipitation method with nanographite (nano-G) and cerous nitrate hexahydrate as raw materials. The microstructures of CeO2/nano-G composite materials were characterized by means of SEM, XRD, XPS and Raman. The cathodes were made by nano-G and CeO2/nano-G composite materials, respectively. The electrolysis phenol was conducted by the diaphragm cell prepared cathode and the Ti/RuO2 anode. The results indicated that the Cerium oxide is mainly in nanoscale spherical state, uniformly dispersed in the nanographite sheet surface, and there are two different oxidation states for elemental Ce, namely, Ce(III) and Ce(IV). In the diaphragm electrolysis system with the aeration conditions, the degradation rate of phenol reached 93.9% under 120 min's electrolysis. Ceria in the cathode materials might lead to an increase in the local oxygen concentration, which accelerated the two-electron reduction of O2 to hydrogen peroxide (H2O2). The removal efficiency of phenol by using the CeO2/nano-G composite cathode was better than that of the nano-G cathode.

  16. Optimization of a microbial fuel cell for wastewater treatment using recycled scrap metals as a cost-effective cathode material.

    Science.gov (United States)

    Lefebvre, Olivier; Tan, Zi; Shen, Yujia; Ng, How Y

    2013-01-01

    Microbial fuel cell (MFC) for wastewater treatment is still hindered by the prohibitive cost of cathode material, especially when platinum is used to catalyze oxygen reduction. In this study, recycled scrap metals could be used efficiently as cathode material in a specially-designed MFC. In terms of raw power, the scrap metals ranked as follows: W/Co > Cu/Ni > Inconel 718 > carpenter alloy; however, in terms of cost and long term stability, Inconel 718 was the preferred choice. Treatment performance--assessed on real and synthetic wastewater--was considerably improved either by filling the anode compartment with carbon granules or by operating the MFC in full-loop mode. The latter option allowed reaching 99.7% acetate removal while generating a maximum power of 36 W m(-3) at an acetate concentration of 2535 mg L(-1). Under these conditions, the energy produced by the system averaged 0.1 kWh m(-3) of wastewater treated. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. The influence of reduced graphene oxide on electrical conductivity of LiFePO4-based composite as cathode material

    Science.gov (United States)

    Arifin, Muhammad; Aimon, Akfiny Hasdi; Winata, Toto; Abdullah, Mikrajuddin; Iskandar, Ferry

    2016-02-01

    LiFePO4 is fascinating cathode active materials for Li-ion batteries application because of their high electrochemical performance such as a stable voltage at 3.45 V and high specific capacity at 170 mAh.g-1. However, their low intrinsic electronic conductivity and low ionic diffusion are still the hindrance for their further application on Li-ion batteries. Therefore, the efforts to improve their conductivity are very important to elevate their prospecting application as cathode materials. Herein, we reported preparation of additional of reduced Graphene Oxide (rGO) into LiFePO4-based composite via hydrothermal method and the influence of rGO on electrical conductivity of LiFePO4-based composite by varying mass of rGO in composition. Vibration of LiFePO4-based composite was detected on Fourier Transform Infrared Spectroscopy (FTIR) spectra, while single phase of LiFePO4 nanocrystal was observed on X-Ray Diffraction (XRD) pattern, it furthermore, Scanning Electron Microscopy (SEM) images showed that rGO was distributed around LiFePO4-based composite. Finally, the 4-point probe measurement result confirmed that the optimum electrical conductivity is in additional 2 wt% rGO for range 1 to 2 wt% rGO.

  18. Deep Discharge Characteristics of LiMn2O4-dCld Cathode Material

    Science.gov (United States)

    2014-06-12

    the thermodynamic and kinetic properties of the Li//LixMn2O4-dXd electrochemical systems. The glass cell consisted of two machined pistons that are...was synthesized and evaluated as a cathode for lithium and lithium-ion electrochemical systems. The reversible region for the Li//LixMn2O4-dCld... electrochemical couple was found to be on the order of 0.05 < x < 1.75 in a two step thermodynamic charge- discharge profile. The high voltage twin

  19. Nitrogen--sulfur--carbon nanocomposites and their application as cathode materials in lithium--sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Sheng; Sun, Xiao-Guang; Guo, Bingkun; Wang, Xiqing; Mayes, Richard T.; Ben, Teng; Qiu, Shilun

    2016-09-27

    The invention is directed in a first aspect to electron-conducting porous compositions comprising an organic polymer matrix doped with nitrogen atoms and having elemental sulfur dispersed therein, particularly such compositions having an ordered framework structure. The invention is also directed to composites of such S/N-doped electron-conducting porous aromatic framework (PAF) compositions, or composites of an S/N-doped mesoporous carbon composition, which includes the S/N-doped composition in admixture with a binder, and optionally, conductive carbon. The invention is further directed to cathodes for a lithium-sulfur battery in which such composites are incorporated.

  20. Energetics of perovskite-type materials applied in solid oxide fuel cells (SOFCs): Electrolytes, cathodes and interconnects

    Science.gov (United States)

    Cheng, Jihong

    Perovskite-type oxides (ABO3) find a great variety of applications in solid oxide fuel cells (SOFCs), including solid electrolytes, cathodes and interconnects, which are closely related to the defect chemistry involved. Thermodynamic studies are needed to systematically understand the nature of the structure-property relations and provide guidance to predict and/or select proper materials. High temperature solution calorimetry in molten oxide solvents is a powerful tool and has been applied for several perovskite systems that have simple (undoped) and complex (doped) compositions. LaBO3 perovskites (B = Al, Ga, Sc, In, Cr, Fe, Co, Ni) represent a group of excellent parent materials for electrolytes, cathodes, and interconnects in SOFCs. Their enthalpies of formation from oxides generally exhibit a relationship between stability and the major structural parameter for perovskites, the tolerance factor. As the tolerance factor deviates more from unity, the enthalpy of formation from oxides becomes less exothermic. This work verifies this general trend for A3+B3+O3 type perovskites, joining other two types, i.e., A1+B5+O 3 and A2+B4+O3. In alkaline earth doped perovskites, though structural parameters are likely to continue affecting stability, defects, which are introduced upon doping, actually play a more profound role in defining energetic trends. In the newly developed electrolyte materials, Mg, Sr, and Ba-doped LaGaO 3 perovskites, oxygen vacancies are created to compensate the charge imbalance between dopant and host ions. Oxygen vacancies have a destabilization effect on the structure due to the partial disconnection of the corner-shared BO6 octahedral framework. On the other hand, they tend to order at the short-range scale, forming vacancy-dopant clusters, as evidenced by neutron diffraction. In alkaline earth doped perovskites that contain transition metals, two charge compensation scenarios are possible: oxidation of the transition metal or creation of

  1. Large-Scale Production of V6O13 Cathode Materials Assisted by Thermal Gravimetric Analysis-Infrared Spectroscopy Technology.

    Science.gov (United States)

    Liang, Han-Pu; Du, Jian; Jones, Timothy G J; Lawrence, Nathan S; Meredith, Andrew W

    2016-10-05

    The kilogram-scale fabrication of V6O13 cathode materials has been notably assisted by in situ thermal gravimetric analysis (TGA)-infrared spectroscopy (IR) technology. This technology successfully identified a residue of ammonium metavanadate in commercial V6O13, which is consistent with the X-ray photoelectron spectroscopy result. Samples of V6O13 materials have been fabricated and characterized by TGA-IR, scanning electron microscopy, and X-ray diffraction. The initial testing results at 125 °C have shown that test cells containing the sample prepared at 500 °C show up to a 10% increase in the initial specific capacity in comparison with commercial V6O13.

  2. Electrochemical Characteristics of Layered Transition Metal Oxide Cathode Materials for Lithium Ion Batteries: Surface, Bulk Behavior, and Thermal Properties.

    Science.gov (United States)

    Tian, Chixia; Lin, Feng; Doeff, Marca M

    2018-01-16

    Layered lithium transition metal oxides, in particular, NMCs (LiNi x Co y Mn z O 2 ) represent a family of prominent lithium ion battery cathode materials with the potential to increase energy densities and lifetime, reduce costs, and improve safety for electric vehicles and grid storage. Our work has focused on various strategies to improve performance and to understand the limitations to these strategies, which include altering compositions, utilizing cation substitutions, and charging to higher than usual potentials in cells. Understanding the effects of these strategies on surface and bulk behavior and correlating structure-performance relationships advance our understanding of NMC materials. This also provides information relevant to the efficacy of various approaches toward ensuring reliable operation of these materials in batteries intended for demanding traction and grid storage applications. In this Account, we start by comparing NMCs to the isostructural LiCoO 2 cathode, which is widely used in consumer batteries. Effects of changing the metal content (Ni, Mn, Co) upon structure and performance of NMCs are briefly discussed. Our early work on the effects of partial substitution of Al, Fe, and Ti for Co on the electrochemical and bulk structural properties is then covered. The original aim of this work was to reduce the Co content (and thus the raw materials cost) and to determine the effect of the substitutions on the electrochemical and bulk structural properties. More recently, we have turned to the application of synchrotron and advanced microscopy techniques to understand both bulk and surface characteristics of the NMCs. Via nanoscale-to-macroscale spectroscopy and atomically resolved imaging techniques, we were able to determine that the surfaces of NMC undergo heterogeneous reconstruction from a layered structure to rock salt under a variety of conditions. Interestingly, formation of rock salt also occurs under abuse conditions. The surface

  3. Crystallography and Growth of Epitaxial Oxide Films for Fundamental Studies of Cathode Materials Used in Advanced Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Leonid A. Bendersky

    2017-05-01

    Full Text Available Li-ion battery systems, synthesized as epitaxial thin films, can provide powerful insights into their electrochemical processes. Crystallographic analysis shows that many important cathode oxides have an underlying similarity: their structures can be considered as different ordering schemes of Li and transition metal ions within a pseudo-cubic sublattice of oxygen anions arranged in a face-center cubic (FCC fashion. This oxygen sublattice is compatible with SrTiO3 and similar perovskite oxides, thus perovskites can be used as supporting substrates for growing epitaxial cathode films. The predicted epitaxial growth and crystallographic relations were experimentally verified for different oxide films deposited by pulsed laser deposition (PLD on SrTiO3 or SrRuO3/SrTiO3 of different orientations. The results based on cross-sectional high-resolution TEM of the following films are presented in the paper: (a trigonal LiCoO2; (b orthorhombic LiMnO2; (c monoclinic Li2MnO3; (d compositionally-complex monoclinic Li1.2Mn0.55Ni0.15Co0.1O2. All results demonstrated the feasibility of epitaxial growth for these materials, with the growth following the predicted cube-on-cube orientation relationship between the cubic and pseudo-cubic oxygen sublattices of a substrate and a film, respectively.

  4. Designing Air-Stable O3-Type Cathode Materials by Combined Structure Modulation for Na-Ion Batteries.

    Science.gov (United States)

    Yao, Hu-Rong; Wang, Peng-Fei; Gong, Yue; Zhang, Jienan; Yu, Xiqian; Gu, Lin; OuYang, Chuying; Yin, Ya-Xia; Hu, Enyuan; Yang, Xiao-Qing; Stavitski, Eli; Guo, Yu-Guo; Wan, Li-Jun

    2017-06-28

    As promising high-capacity cathode materials for Na-ion batteries, O3-type Na-based metal oxides always suffer from their poor air stability originating from the spontaneous extraction of Na and oxidation of transition metals when exposed to air. Herein, a combined structure modulation is proposed to tackle concurrently the two handicaps via reducing Na layers spacing and simultaneously increasing valence state of transition metals. Guided by density functional theory calculations, we demonstrate such a modulation can be subtly realized through cosubstitution of one kind of heteroatom with comparable electronegativity and another one with substantially different Fermi level, by adjusting the structure of NaNi0.5Mn0.5O2 via Cu/Ti codoping. The as-obtained NaNi0.45Cu0.05Mn0.4Ti0.1O2 exhibits an increase of 20 times in stable air-exposure period and 9 times in capacity retention after 500 cycles, and even retains its structure and capacity after being soaked in water. Such a simple and effective structure modulation reveals a new avenue for high-performance O3-type cathodes and pushes the large-scale industrialization of Na-ion batteries a decisive step forward.

  5. New lithium iron pyrophosphate as 3.5 V class cathode material for lithium ion battery.

    Science.gov (United States)

    Nishimura, Shin-ichi; Nakamura, Megumi; Natsui, Ryuichi; Yamada, Atsuo

    2010-10-06

    A new pyrophosphate compound Li(2)FeP(2)O(7) was synthesized by a conventional solid-state reaction, and its crystal structure was determined. Its reversible electrode operation at ca. 3.5 V vs Li was identified with the capacity of a one-electron theoretical value of 110 mAh g(-1) even for ca. 1 μm particles without any special efforts such as nanosizing or carbon coating. Li(2)FeP(2)O(7) and its derivatives should provide a new platform for related lithium battery electrode research and could be potential competitors to commercial olivine LiFePO(4), which has been recognized as the most promising positive cathode for a lithium-ion battery system for large-scale applications, such as plug-in hybrid electric vehicles.

  6. Iron (III) nanocomposites for enzyme-less biomimetic cathode. A promising material for use in biofuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Marccus Victor Almeida; Bonfim, Clarissa [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Santo Andre (Brazil); Silva, Welter Cantanhede da [Departamento de Quimica, CCN, Universidade Federal do Piaui, Teresina (Brazil); Crespilho, Frank Nelson

    2010-11-15

    In this paper, we discuss the synthesis and electrochemical properties of a new material based on iron oxide nanoparticles stabilized with poly(diallyldimethylammonium chloride) (PDAC); this material can be used as a biomimetic cathode material for the reduction of H{sub 2}O{sub 2} in biofuel cells. A metastable phase of iron oxide and iron hydroxide nanoparticles (PDAC-FeOOH/Fe{sub 2}O{sub 3}-NPs) was synthesized through a single procedure. On the basis of the Stokes-Einstein equation, colloidal particles (diameter: 20 nm) diffused at a considerably slow rate (D = 0.9 x 10{sup -} {sup 11} m s{sup -} {sup 1}) as compared to conventional molecular redox systems. The quasi-reversible electrochemical process was attributed to the oxidation and reduction of Fe{sup 3+}/Fe{sup 2+} from PDAC-FeOOH/Fe{sub 2}O{sub 3}-NPs; in a manner similar to redox enzymes, it acted as a pseudo-prosthetic group. Further, PDAC-FeOOH/Fe{sub 2}O{sub 3}-NPs was observed to have high electrocatalytic activity for H{sub 2}O{sub 2} reduction along with a significant overpotential shift, {delta}E = 0.68 V from - 0.29 to 0.39 V, in the presence and absence of PDAC-FeOOH/Fe{sub 2}O{sub 3}-NPs. The abovementioned iron oxide nanoparticles are very promising as candidates for further research on biomimetic biofuel cells, suggesting two applications: the preparation of modified electrodes for direct use as cathodes and use as a supporting electrolyte together with H{sub 2}O{sub 2}. (author)

  7. Building Honeycomb-Like Hollow Microsphere Architecture in a Bubble Template Reaction for High-Performance Lithium-Rich Layered Oxide Cathode Materials.

    Science.gov (United States)

    Chen, Zhaoyong; Yan, Xiaoyan; Xu, Ming; Cao, Kaifeng; Zhu, Huali; Li, Lingjun; Duan, Junfei

    2017-09-13

    In the family of high-performance cathode materials for lithium-ion batteries, lithium-rich layered oxides come out in front because of a high reversible capacity exceeding 250 mAh g -1 . However, the long-term energy retention and high energy densities for lithium-rich layered oxide cathode materials require a stable structure with large surface areas. Here we propose a "bubble template" reaction to build "honeycomb-like" hollow microsphere architecture for a Li 1.2 Mn 0.52 Ni 0.2 Co 0.08 O 2 cathode material. Our material is designed with ca. 8-μm-sized secondary particles with hollow and highly exposed porous structures that promise a large flexible volume to achieve superior structure stability and high rate capability. Our preliminary electrochemical experiments show a high capacity of 287 mAh g -1 at 0.1 C and a capacity retention of 96% after 100 cycles at 1.0 C. Furthermore, the rate capability is superior without any other modifications, reaching 197 mAh g -1 at 3.0 C with a capacity retention of 94% after 100 cycles. This approach may shed light on a new material engineering for high-performance cathode materials.

  8. Turning Waste Chemicals into Wealth—A New Approach To Synthesize Efficient Cathode Material for an Li–O 2 Battery

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Ying [Beijing Key Laboratory of Environmental Science and Engineering,; amp, Engineering, Beijing Institute of Technology, Beijing 100081, China; Wu, Feng [Beijing Key Laboratory of Environmental Science and Engineering,; amp, Engineering, Beijing Institute of Technology, Beijing 100081, China

    2017-03-20

    An Li–O2 battery requires the oxygen-breathing cathode to be highly electronically conductive, rapidly oxygen diffusive, structurally stable, and often times electrocatalytically active. Catalyst-decorated porous carbonaceous materials are the chosen air cathode in this regard. Alternatively, biomass-derived carbonaceous materials possess great ability to remove heavy and toxic metal ions from waste, forming a metal-adsorbed porous carbonaceous material. The similar structure between the air cathode and the metal-adsorbed biomass-derived carbon nicely bridges these two irrelevant areas. In this study, we investigated the electrochemical activity of a biochar material Ag-ESB directly synthesized from ethanol sludge residue in a rechargeable aprotic Li–O2 battery. Ag ions were adsorbed from sewage and became Ag nanoparticles with uniform coverage on the biochar surface. The as-prepared material exhibits good electrochemical behavior in battery testing, especially toward the battery efficiency and cyclability. This study provides the possibility of synthetically efficient cathode material by reusing “waste” such as biofuel sludge residue. It is an economically and environmentally friendly approach both for an energy-storage system and for waste recycling.

  9. Enhanced electrochemical properties of LiNiO{sub 2}-based cathode materials by nanoscale manganese carbonate treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Junkai; Wang, Zhixing, E-mail: zxwang.csu@hotmail.com; Guo, Huajun; Li, Xinhai

    2017-05-01

    Highlights: • Li residuals are consumed during the process of modification. • MnO{sub 2} coating layer can protect bulk material from the erosion of electrolyte. • The electrochemical performance is enhanced by the nanosacle MnCO{sub 3} treatment. • The enhancement of coating can be strengthened by the removal of lithium impurities. - Abstract: LiNiO{sub 2}-based layered oxides are of great importance as cathode materials for rechargeable batteries. In this paper, illustrating LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} as an example, the effect of nanoscale MnCO{sub 3} treatment on LiNiO{sub 2}-based materials is investigated for the first time. The structures of materials and the properties about the object surface are characterized by XRD, SEM, TEM, EDAX and XPS. The results demonstrate that a part of MnCO{sub 3} is able to react with lithium impurities to form nonstoichiometric Li{sub x}Mn{sub y}O{sub 4} and the rest of MnCO{sub 3} is converted to MnO{sub 2} coating on the surface of the material in situ. After 100 repeated cycles at 1C, the modified material exhibits a capacity retention rate of 91.2%, while the bare material only remains 84.8%. And the modified material exhibits more significantly improved cycling stability when cycling at 60 °C, maintaining 85.7% of its initial capacity at 1C after 100th cycles. The consumption of Li impurities can decelerate the decomposition of electrolyte during cycling, thus result in less resistive byproducts. Moreover, the obtained MnO{sub 2} coating layer acts as an isolating layer to suppress the drastic reaction between active material and electrolyte. This synergistic effect is responsible for the excellent properties of MnCO{sub 3}-modified material.

  10. Magnetic properties of nanostructured spinel ferrites and ...

    Indian Academy of Sciences (India)

    structured spinel ferrites such as Ni0.5Zn0.5Fe2O4 and Mn0.67Zn0.33Fe2O4 and also that of the nanocomposite Nd2Fe14B/-Fe permanent magnetic material. The increase in the magnetic transition temperature of Ni-Zn ferrite from 538 K in the ...

  11. Synergetic effects of Al3+ doping and graphene modification on the electrochemical performance of V2O5 cathode materials.

    Science.gov (United States)

    Zhu, Kai; Qiu, Hailong; Zhang, Yongquan; Zhang, Dong; Chen, Gang; Wei, Yingjin

    2015-03-01

    A series of V2O5-based cathode materials that include V2O5 and Al0.14 V2O5 nanoparticles, V2O5/reduced graphene oxide (RGO), and Al0.16 V2O5/RGO nanocomposites are prepared by a simple soft chemical method. XRD and Raman scattering show that the Al ions reside in the interlayer space of the materials. These doping ions strengthen the V−O bonds of the [VO5] unit and enhance the linkage of the [VO5] layers, which thus increases the structural stability of V2O5. SEM and TEM images show that the V2O5 nanoparticles construct a hybrid structure with RGO that enables fast electron transport in the electrode matrix. The electrochemical properties of the materials are studied by charge-discharge cycling, cyclic voltammetry, and electrochemical impedance spectroscopy. Of all the materials tested, the one that contained both Al ions and RGO (Al0.16 V2O5/RGO) exhibited the highest discharge capacity, the best rate capability, and excellent capacity retention. The superior electrochemical performance is attributed to the synergetic effects of Al(3+) doping and RGO modification, which not only increase the structural stability of the V2O5 lattice but also improve the electrochemical kinetics of the material. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Electrochemical characterization of nano-sized Pd-based catalysts as cathode materials in direct methanol fuel cells.

    Science.gov (United States)

    Choi, M; Han, C; Kim, I T; An, J C; Lee, J J; Lee, H K; Shim, J

    2011-01-01

    To improve the catalytic activity of palladium (Pd) as a cathode catalyst in direct methanol fuel cells (DMFCs), we prepared palladium-titanium oxide (Pd-TiO2) catalysts which the Pd and TiO2 nanoparticles were simultaneously impregnated on carbon. We selected Pd and TiO2 as catalytic materials because of their electrochemical stability in acid solution. The crystal structure and the loading amount of Pd and TiO2 on carbon were characterized by X-ray diffraction (XRD) and energy dispersive X-ray microanalysis (EDX). The electrochemical characterization of Pd-TiO2/C catalysts for the oxygen reduction reaction was carried out in half and single cell systems. The catalytic activities of the Pd-TiO2 catalysts were strongly influenced by the TiO2 content. In the single cell test, the Pd-TiO2 catalysts showed very comparable performance to the Pt catalyst.

  13. Cu- and Fe-hexacyanoferrate as cathode materials for Potassium ion battery: A First-principles study

    Science.gov (United States)

    Targholi, Ehsan; Mousavi-Khoshdel, S. Morteza; Rahmanifara, Mohmmadsafi; Yahya, M. Z. A.

    2017-11-01

    In this paper, the efficiency of Iron-Hexacyanoferrate (FeHCF) and Copper-Hexacyanoferrate (CuHCF) as the cathode materials for using in the energy storage application have been investigated using Density Functional Theory. The changes of their lattice parameters due to the insertion of K+ cation were explored. It was found that these changes for CuHCF are less than FeHCF. FeHCF, KFHCF, CuHCF, KCuHCF, and K2CuHCF are found to have a half-metallic nature. In contrast, K2FeHCF is found to be a diamagnetic insulator. K+ diffusion through the FeHCF and CuHCF frameworks have the energy barrier of 1.46 eV and 1.00 eV, respectively.

  14. Effect of microstructure on low temperature electrochemical properties of LiFePO{sub 4}/C cathode material

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Nannan; Zhi, Xiaoke; Wang, Li; Liu, Yanhui; Liang, Guangchuan, E-mail: liangguangchuan@hebut.edu.cn

    2015-10-05

    Graphical abstract: The low temperature performance of Li-ion batteries and LiFePO{sub 4}/C composites was discussed. A conclusion that cathode material is the main limitation for the low temperature performance was come up, by comparing the low temperature performance of 18650 Li-ion batteries with LiMn{sub 2}O{sub 4}, LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} and LiFePO{sub 4}/C as cathode materials. The low temperature performance results indicate the LiFePO{sub 4}/C microstructure is the main factor influencing the low temperature performance of LiFePO{sub 4}. A new LiFePO{sub 4}/C with pomegranate-like spherical structure was proposed in this paper, which shows superior low temperature performance, which can be attributed to its uniform fine primary particles and smaller primary particles. - Highlights: • Low temperature performance of Li-ion battery and LiFePO{sub 4}/C composite was discussed. • Cathode material mainly decided the low temperature performance of Li-ion battery. • LiFePO{sub 4}/C microstructure mainly affects its low temperature performance. • Pomegranate-like spherical structure LiFePO{sub 4}/C has good low temperature performance. - Abstract: The low-temperature electrochemical performance of Li-ion batteries is mainly determined by the choice of cathode material, as evident from a comparison of the low-temperature electrochemical performance of the 18650 batteries with the LiMn{sub 2}O{sub 4}, LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2}, and LiFePO{sub 4}/C as the cathode, respectively, at −20 °C. LiFePO{sub 4}/C materials with different morphologies and microstructures were prepared by different methods. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), galvanostatic charge–discharge measurements and EIS. The low-temperature performance of the samples and those of the coin cells utilizing the materials as cathodes were measured. The results

  15. Conducting Polymers Crosslinked with Sulfur as Cathode Materials for High-Rate, Ultralong-Life Lithium-Sulfur Batteries.

    Science.gov (United States)

    Zeng, Shuaibo; Li, Ligui; Xie, Lihong; Zhao, Dengke; Wang, Nan; Chen, Shaowei

    2017-09-11

    Low electrical conductivity and a lack of chemical confinement are two major factors that limit the rate performances and cycling stabilities of cathode materials in lithium-sulfur (Li-S) batteries. Herein, sulfur is copolymerized with poly(m-aminothiophenol) (PMAT) nanoplates through inverse vulcanization to form the highly crosslinked copolymer cp(S-PMAT) in which approximately 80 wt % of the feed sulfur is bonded chemically to the thiol groups of PMAT. A cp(S-PMAT)/C-based cathode exhibits a high discharge capacity of 1240 mAh g-1 at 0.1 C and remarkable rate capacities of 880 mAh g-1 at 1 C and 600 mAh g-1 at 5 C. Moreover, it can retain a capacity of 495 mAh g-1 after 1000 deep discharge-charge cycles at 2 C; this corresponds to a retention of 66.9 % and a decay rate of only 0.040 % per cycle. Such a remarkable rate performance is attributed to the highly conductive pathways of PMAT nanoplates, and the excellent cycling stability is ascribed mainly to the chemical confinement of sulfur through a large number of stable covalent bonds between sulfur and the thiol groups of PMAT. The results suggest that this strategy is a viable paradigm for the design and engineering of conducting polymers with reactive functional groups as effective electrode materials for high-performance Li-S batteries. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Metallurgically prepared NiCu alloys as cathode materials for hydrogen evolution reaction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Kunchan; Xia, Ming [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Xiao, Tao [2nd Xiangya Hospital, Central South University, Changsha 410011 (China); Lei, Ting, E-mail: tlei@mail.csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Yan, Weishan [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)

    2017-01-15

    Ni−Cu bimetallic alloys with Cu content of 5, 10, 20, 30 and 50 wt% are prepared by powder metallurgy method, which consisted of powder mixing, pressing and sintering processes. The X-ray diffraction (XRD) measurement confirms that all the five Ni−Cu alloys possess the f.c.c. structure. The hydrogen evolution reaction (HER) activity of the prepared Ni−Cu alloy electrodes was studied in 6 M KOH solution by cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that the electrocatalytic activity for the HER depended on the composition of Ni−Cu alloys, where Ni−10Cu alloy exhibited considerably higher HER activity than Ni plate and other Ni−Cu alloys, indicative of its chemical composition related intrinsic activity. - Highlights: • Ni−Cu alloys with various Cu contents were prepared by powder metallurgy method. • Ni−Cu alloy exhibits chemical composition related synergistic effect for HER activity. • Ni−10Cu alloy electrode presents a most efficient activity for HER. • Two time constants are observed in Nyquist curve and both of them related to the kinetics of HER.

  17. Magnetostructural and magnetodielectric coupling in spinel oxides

    Science.gov (United States)

    Kemei, Moureen Chemurgor

    Spinels oxides are of great interest functionally as multiferroic, battery, and magnetic materials as well as fundamentally because they exhibit novel spin, structural, and orbital ground states. Competing interactions are at the heart of novel functional behavior in spinels. Here, we explore the intricate landscape of spin, lattice, and orbital interactions in magnetic spinels by employing variable-temperature high-resolution synchrotron x-ray powder diffraction, total neutron scattering, magnetic susceptibility, dielectric, and heat capacity measurements. We show that the onset of long-range magnetic interactions often gives rise to lattice distortions. We present the complete crystallographic descriptions of the ground state structures of several spinels, thereby paving the way for accurate modeling and design of structure-property relationships in these materials. We also report the emergence of magnetodielectric coupling in the magnetostructural phases of some of the studied spinels. We begin by examining spin-lattice coupling in the Jahn-Teller active systems NiCr2O4 and CuCr2O4. Orbital ordering yields a cubic to tetragonal lattice distortion in these materials above their magnetic ordering temperatures, however, we find that magnetic ordering also drives structural distortions in these spinels through exchange striction. We provide the first orthorhombic structural descriptions of NiCr 2O4 and CuCr2O4. Our observation of strong spin-lattice coupling in NiCr2O4 and CuCr 2O4 inspired the study of magnetodielectric coupling in these spinels. Magnetocapacitance measurements of NiCr2O4 reveal multiferroic behavior and new magnetostructural distortions below the Neel temperature. This observation illustrates the sensitivity of dielectric measurements to magnetostructural transitions in spinel materials. Finally, in the examination of NiCr2O4 we show that magnetodielectric coupling is well described by Ginzburg-Landau theory. In addition to exchange striction

  18. Molten salt-directed synthesis method for LiMn2O4 nanorods as a cathode material for a lithium-ion battery with superior cyclability

    CSIR Research Space (South Africa)

    Kebede, Mesfin A

    2017-02-01

    Full Text Available A molten salt synthesis technique has been used to prepare nanorods of Mn2O3 and single-crystal LiMn2O4 nanorods cathode material with superior capacity retention. The molten salt-directed synthesis involved the use of NaCl as the eutectic melt...

  19. Miniaturized cathodic arc plasma source

    Science.gov (United States)

    Anders, Andre; MacGill, Robert A.

    2003-04-15

    A cathodic arc plasma source has an anode formed of a plurality of spaced baffles which extend beyond the active cathode surface of the cathode. With the open baffle structure of the anode, most macroparticles pass through the gaps between the baffles and reflect off the baffles out of the plasma stream that enters a filter. Thus the anode not only has an electrical function but serves as a prefilter. The cathode has a small diameter, e.g. a rod of about 1/4 inch (6.25 mm) diameter. Thus the plasma source output is well localized, even with cathode spot movement which is limited in area, so that it effectively couples into a miniaturized filter. With a small area cathode, the material eroded from the cathode needs to be replaced to maintain plasma production. Therefore, the source includes a cathode advancement or feed mechanism coupled to cathode rod. The cathode also requires a cooling mechanism. The movable cathode rod is housed in a cooled metal shield or tube which serves as both a current conductor, thus reducing ohmic heat produced in the cathode, and as the heat sink for heat generated at or near the cathode. Cooling of the cathode housing tube is done by contact with coolant at a place remote from the active cathode surface. The source is operated in pulsed mode at relatively high currents, about 1 kA. The high arc current can also be used to operate the magnetic filter. A cathodic arc plasma deposition system using this source can be used for the deposition of ultrathin amorphous hard carbon (a-C) films for the magnetic storage industry.

  20. Flakelike LiCoO2 with Exposed {010} Facets As a Stable Cathode Material for Highly Reversible Lithium Storage.

    Science.gov (United States)

    Wu, Naiteng; Zhang, Yun; Guo, Yi; Liu, Shengjie; Liu, Heng; Wu, Hao

    2016-02-03

    A thick and dense flakelike LiCoO2 with exposed {010} active facets is synthesized using Co(OH)2 nanoflake as a self-sacrificial template obtained from a simple coprecipitation method, and served as a cathode material for lithium ion batteries. When operated at a high cutoff voltage up to 4.5 V, the resultant LiCoO2 exhibits an outstanding rate capability, delivering a reversible discharge capacity as high as 179, 176, 168, 116, and 96 mA h g(-1) at 25 °C under the current rate of 0.1, 0.5, 1, 5, and 10 C, respectively. When charge/discharge cycling at 55 °C, a high specific capacity of 148 mA h g(-1) (∼88% retention) can be retained after 100 cycles under 1 C, demonstrating excellent cycling and thermal stability. Besides, the flakelike LiCoO2 also shows an impressive low-temperature electrochemical activity with specific capacities of 175 (0.1 C) and 154 mA h g(-1) (1 C) at -10 °C, being the highest ever reported for a subzero-temperature lithium storage capability, as well as 52% capacity retention even after 80 cycles under 1 C. Such superior high-voltage electrochemical performances of the flakelike LiCoO2 operated at a wide temperature range are mainly attributed to its unique hierarchical structure with specifically exposed facets. The exposed {010} active facets provide a preferential crystallographic orientation for Li-ion migration, while the micrometer-sized secondary particles agglomerated by submicron primary LiCoO2 flakes endow the electrode with better structural integrity, both of which ensure the LiCoO2 cathode to manifest remarkably enhanced reversible lithium storage properties.

  1. Binder-free cobalt phosphate one-dimensional nanograsses as ultrahigh-performance cathode material for hybrid supercapacitor applications

    Science.gov (United States)

    Sankar, K. Vijaya; Lee, S. C.; Seo, Y.; Ray, C.; Liu, S.; Kundu, A.; Jun, S. C.

    2018-01-01

    One-dimensional (1D) nanostructure exhibits excellent electrochemical performance because of their unique physico-chemical properties like fast electron transfer, good rate capability, and cyclic stability. In the present study, Co3(PO4)2 1D nanograsses are grown on Ni foam using a simple and eco-friendly hydrothermal technique with different reaction times. The open space with uniform nanograsses displays a high areal capacitance, rate capability, energy density, and cyclic stability due to the nanostructure enhancing fast ion and material interactions. Ex-situ microscope images confirm the dependence of structural stability on the reaction time, and the nanograsses promoted ion interaction through material. Further, the reproducibility of the electrochemical performance confirms the binder-free Co3(PO4)2 1D nanograsses to be a suitable high-performance cathode material for application to hybrid supercapacitor. Finally, the assembled hybrid supercapacitor exhibits a high energy density (26.66 Wh kg-1 at 750 W kg-1) and longer lifetimes (80% retained capacitance after 6000 cycles). Our results suggests that the Co3(PO4)2 1D nanograss design have a great promise for application to hybrid supercapacitor.

  2. Lithium-Excess Research of Cathode Material Li2MnTiO4 for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Xinyi Zhang

    2015-11-01

    Full Text Available Lithium-excess and nano-sized Li2+xMn1−x/2TiO4 (x = 0, 0.2, 0.4 cathode materials were synthesized via a sol-gel method. The X-ray diffraction (XRD experiments indicate that the obtained main phases of Li2.0MnTiO4 and the lithium-excess materials are monoclinic and cubic, respectively. The scanning electron microscope (SEM images show that the as-prepared particles are well distributed and the primary particles have an average size of about 20–30 nm. The further electrochemical tests reveal that the charge-discharge performance of the material improves remarkably with the lithium content increasing. Particularly, the first discharging capacity at the current of 30 mA g−1 increases from 112.2 mAh g−1 of Li2.0MnTiO4 to 187.5 mAh g−1 of Li2.4Mn0.8TiO4. In addition, the ex situ XRD experiments indicate that the monoclinic Li2MnTiO4 tends to transform to an amorphous state with the extraction of lithium ions, while the cubic Li2MnTiO4 phase shows better structural reversibility and stability.

  3. Scale-up of Metal Hexacyanoferrate Cathode Material for Sodium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dzwiniel, Trevor L. [Argonne National Lab. (ANL), Argonne, IL (United States); Pupek, Krzysztof Z. [Argonne National Lab. (ANL), Argonne, IL (United States); Krumdick, Gregory K. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-10-04

    Sharp Laboratories of America (SLA) approached Argonne National Laboratory with a bench-scale process to produce material for a sodium-ion battery, referred to as Prussian Blue, and a request to produce 1 kg of material for their ARPA-E program. The target performance criteria was an average capacity of >150 mAh/g.

  4. AS Spinel toodab ja ehitab

    Index Scriptorium Estoniae

    1998-01-01

    1990. aastast tegutseb Eestis majade, suvilate, aiamajade, saunade jt. hoonete elementide komplektide valmistamisega AS Spinel. Märjamaal toodetakse freespuidust hoonete komplekte, Kõrvetagusel valmivad soojustatud puitkarkassil elemendid monteeritavate majade jaoks

  5. Synthesis and characterization of Co-doped lanthanum nickelate perovskites for solid oxide fuel cell cathode material

    Energy Technology Data Exchange (ETDEWEB)

    Chavez G, L.; Hinojosa R, M. [Universidad Autonoma de Nuevo Leon, Ciudad Universitaria, San Nicolas de los Garza, 66450 Nuevo Leon (Mexico); Medina L, B.; Ringuede, A.; Cassir, M. [Institut de Recherche de Chimie Paris, CNRS-Chimie ParisTech, 11 rue Pierre et Marie Curie, 75005 Paris (France); Vannier, R. N., E-mail: leonardo.chavezgr@uanl.edu.mx [Unite de Catalyse et de Chimie du Solide, UMR 8181 CNRS, 59655, Villeneuve d Ascq Cedex (France)

    2017-11-01

    In the perovskite structures widely investigated and used as solid oxide fuel cells cathodes, oxygen reduction is mainly limited to the triple phase boundary (TPB), where oxygen (air), electrode and electrolyte are in contact. It is possible via the sol-gel modified Pechini method to: 1) control the material grain size, which can increase TPBs, 2) produce a homogenous material and 3) obtain a cathode material in a faster way compared with the solid state route. LaNi{sub x}Co{sub 1-x}O{sub 3} (x = 0.3, 0.5, 0.7) were synthesized by the modified Pechini method. The perovskite phase formation began at 350 degrees Celsius and the presence of pure LaNi{sub 0.7}Co{sub 0.3}O{sub 3}, LaNi{sub 0.5}Co{sub 0.5}O{sub 3} and LaNi{sub 0.3}Co{sub 0.7}O{sub 3} structures was evidenced by high temperature X-ray diffraction (Ht-XRD) measurements. Scanning electron microscopy (Sem) micrographs showed that the microstructure evolves with the amount of cobalt from a coalesced to an open structure. Electrochemical impedance spectroscopy (EIS) on symmetrical cells LaNi{sub x}Co{sub 1-x}O{sub 3}/YSZ (Yttria-stabilized zirconia)/LaNi{sub x}Co{sub 1-x}O{sub 3} showed that the highest ASR (area specific resistance) is obtained with x = 0.3, whereas ASR values are similar for x = 0.5 and 0.7 at temperatures higher than 600 degrees Celsius. At temperatures lower than 600 degrees Celsius, ASR is the lowest for LaNi{sub 0.5}Co{sub 0.5}O{sub 3}, showing that this composition with intermediate porosity appears as a good choice for and intermediate-temperature solid oxid fuel cell. (Author)

  6. Microwave-assisted optimization of the manganese redox states for enhanced capacity and capacity retention of LiAl(subx)Mn(sub2-x)O(sub4) (x = 0 and 0.3) spinel materials

    CSIR Research Space (South Africa)

    Nkosi, FP

    2015-03-01

    Full Text Available -microwaved samples. Note that the nMn values for LMO-a and LMO-comm are less than 3.5+, contradicting the general notion that LMO powders should be nMn ≈ 3.5+.Perhaps, more interesting is that when the LMO-a was subjected to microwave irradiation to obtain...-assisted optimization of the manganese redox states for enhanced capacity and capacity retention of LiAlxMn2-xO4 (x = 0 and 0.3) spinel materials Funeka P. Nkosi1,2, Charl J. Jafta2, Mesfin Kebede2, Lukas le Roux2, Mkhulu K. Mathe2, and Kenneth I. Ozoemena,1...

  7. All solid-state lithium polymer secondary batteries using spinel Li{sub 4/3}Ti{sub 5/3}O{sub 4} as an active material

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Chie [Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama Meguro-ku, Tokyo 152-8552 (Japan); R and D Division, World Intec Co., Ltd., 6F Kyobashi K-1 bldg., 2-7-12 Yaesu, Chuo-ku, Tokyo 104-0028 (Japan); Wada, Shinta [Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama Meguro-ku, Tokyo 152-8552 (Japan); Nakayama, Masanobu, E-mail: masanobu@nitech.ac.j [Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama Meguro-ku, Tokyo 152-8552 (Japan); Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya city, Aichi 466-8555 (Japan)

    2010-02-28

    Present paper describes electrochemical performance of the all solid-state lithium polymer battery (LBP) using spinel-type Li{sub 4/3}Ti{sub 5/3}O{sub 4} which has been known as the potential candidate of anode materials. The assembled LPB with Li|solid polymer electrolyte(SPE)|Li{sub 4/3}Ti{sub 5/3}O{sub 4} construction showed stable charge-discharge cycles more than 300 times at 1 C condition. On the other hand, strong charge-discharge rate dependence for the specific capacity and initial capacity loss was indicated. Such a poor rate performance stemmed from low diffusivity of Li{sup +} ion in the by-products produced by the decomposition of SPE components at the SPE|Li{sub 4/3}Ti{sub 5/3}O{sub 4} interface.

  8. Electrochemical performance of co-doped Li1.2Mn0.6Ni0.2O2 cathode materials

    CSIR Research Space (South Africa)

    David, K

    2013-04-01

    Full Text Available The composite material has a xLi2MnO3·(1-x)LiMO2 (M = Mn, Co, Ni) structure has been considered as one of the most promising cathode materials for advanced lithium-ion batteries due to their low-cost and high capacity (> 200 mAh g−1) between 4.8 V...

  9. Multifunctional semi-interpenetrating polymer network-nanoencapsulated cathode materials for high-performance lithium-ion batteries.

    Science.gov (United States)

    Kim, Ju-Myung; Park, Jang-Hoon; Lee, Chang Kee; Lee, Sang-Young

    2014-04-08

    As a promising power source to boost up advent of next-generation ubiquitous era, high-energy density lithium-ion batteries with reliable electrochemical properties are urgently requested. Development of the advanced lithium ion-batteries, however, is staggering with thorny problems of performance deterioration and safety failures. This formidable challenge is highly concerned with electrochemical/thermal instability at electrode material-liquid electrolyte interface, in addition to structural/chemical deficiency of major cell components. Herein, as a new concept of surface engineering to address the abovementioned interfacial issue, multifunctional conformal nanoencapsulating layer based on semi-interpenetrating polymer network (semi-IPN) is presented. This unusual semi-IPN nanoencapsulating layer is composed of thermally-cured polyimide (PI) and polyvinyl pyrrolidone (PVP) bearing Lewis basic site. Owing to the combined effects of morphological uniqueness and chemical functionality (scavenging hydrofluoric acid that poses as a critical threat to trigger unwanted side reactions), the PI/PVP semi-IPN nanoencapsulated-cathode materials enable significant improvement in electrochemical performance and thermal stability of lithium-ion batteries.

  10. Bio-cathode materials evaluation and configuration optimization for power output of vertical subsurface flow constructed wetland - microbial fuel cell systems.

    Science.gov (United States)

    Liu, Shentan; Song, Hailiang; Wei, Size; Yang, Fei; Li, Xianning

    2014-08-01

    To optimize the performance of a vertical subsurface flow constructed wetland-microbial fuel cell (CW-MFC), studies of bio-cathode materials and reactor configurations were carried out. Three commonly used bio-cathode materials including stainless steel mesh (SSM), carbon cloth (CC) and granular activated carbon (GAC) were compared and evaluated. GAC-SSM bio-cathode achieved the highest maximum power density of 55.05 mWm(-2), and it was most suitable for CW-MFCs application because of its large surface area and helpful capillary water absorption. Two types of CW-MFCs with roots were constructed, one was placed in the anode and the other was placed in the cathode. Both planted CW-MFCs obtained higher power output than non-planted CW-MFC. Periodic voltage fluctuations of planted CW-MFCs were caused by light/dark cycles, and the influent substrate concentration significantly affected the amplitude of oscillation. The coulombic efficiencies of CW-MFCs decreased greatly with the increase of the influent substrate concentration. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Nitrate-Melt Synthesized HT-LiCoO2 as a Superior Cathode-Material for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Mariyappan Sathiya

    2009-07-01

    Full Text Available An electrochemically-active high-temperature form of LiCoO2 (HT-LiCoO2is prepared by thermally decomposing its constituent metal-nitrates at 700 ºC. The synthetic conditions have been optimized to achieve improved performance with the HT-LiCoO2cathode in Li-ion batteries. For this purpose, the synthesized materials have been characterized by powder X-ray diffraction, scanning electron microscopy, and galvanostatic charge-discharge cycling. Cathodes comprising HT-LiCoO2 exhibit a specific capacity of 140 mAhg-1 with good capacity-retention over several charge-discharge cycles in the voltage range between 3.5 V and 4.2 V, and can sustain improved rate capability in contrast to a cathode constituting LiCoO2 prepared by conventional ceramic method. The nitrate-melt-decomposition method is also found effective for synthesizing Mg-/Al- doped HT-LiCoO2; these also are investigated as cathode materials for Li-ion batteries.

  12. Powder Characterization and Electrochemical Properties of LiNi0.5Mn1.5O4 Cathode Materials Produced by Large Spray Pyrolysis Using Flame Combustion

    Directory of Open Access Journals (Sweden)

    Shinsuke Akao

    2011-01-01

    Full Text Available LiNi0.5Mn1.5O4 cathode materials were produced by spray pyrolysis apparatus using the flame combustion. SEM revealed that as-prepared powders had spherical morphology with porous microstructure which had an average diameter of about 2 μm with broad size distribution. After the calcination, LiNi0.5Mn1.5O4 powders with polygonal morphology and narrow particle size distribution were obtained. XRD showed that LiNi0.5Mn1.5O4 was well crystallized after the calcination at 900°C. Rechargeable measurement of LiNi0.5Mn1.5O4 cathode showed that the long plateau was observed at 4.7 V in discharge curve of LiNi0.5Mn1.5O4 cathode and its discharge capacity was 145 mAh/g at 1 C. The capacity retention of LiNi0.5Mn1.5O4 cathode were 95% at 1 C after 100 cycles. The discharge capacity and capacity retention of LiNi0.5Mn1.5O4 cathode were 125 mAh/g and 88% at 20 C. LiNi0.5Mn1.5O4 cathode exhibited also stable cycle performance at 50∘C.

  13. History of development of polycrystalline optical spinel in the U.S.

    Science.gov (United States)

    Harris, Daniel C.

    2005-05-01

    Optical quality polycrystalline spinel (MgAl2O4) has been sought as a visible- and infrared-transmitting material since the 1960s because of its potential for transparent armor and durable sensor windows. Its physical properties were known from synthetic crystals available since ~1950 from Linde Air Products. In the late 1960s, methods to process powder into transparent, polycrystalline spinel were investigated at North Carolina State University, General Electric Co., AVCO, and Westinghouse, mainly with Government support. The leading figure in the development of polycrystalline spinel was Don Roy, who began work on spinel at Coors Ceramics around 1970, initially for transparent armor. In the late 1970s, both Coors Ceramics and Raytheon Research Division were funded to make spinel for the infrared dome of the Advanced Short-Range Air-to-Air Missile, an application that disappeared by 1980. In the late 1980s, there was another burst of activity when spinel was a candidate for the Stinger Missile. By 1990, Raytheon had dropped spinel and the material was spun off by Coors Ceramics to Alpha Optical Systems, whose technical effort was led by Don Roy. With low commercial sales potential for spinel, Alpha was dissolved in 1993. RCS Technologies took over a Government contract seeking 200-mm spinel domes for the Harrier aircraft, but this effort ended in 1996 and RCS was dissolved. In 1998, the Army enlisted TA&T to make spinel for transparent armor. Other potential applications appeared and TA&T received numerous Government development contracts. Demand for the still-unavailable spinel drew Surmet to begin development in 2002. In early 2005, spinel is under active development at TA&T and Surmet.

  14. High rate performance of LiFePO4 cathode materials co-doped with ...

    Indian Academy of Sciences (India)

    The microstructures and morphologies of the synthesized materials were investigated by X-ray diffraction and scanning electron microscope while the electrochemical performances were ... Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072, China ...

  15. KINETIC TRANSFORMATION OF SPINEL TYPE LiMnLiMn2O4 INTO TUNNEL TYPE MnO2

    Directory of Open Access Journals (Sweden)

    Daud K Walanda

    2010-06-01

    Full Text Available Lithiated phase LiMn2O4 is a potential cathode material for high-energy batteries because it can be used in conjunction with suitable carbon anode materials to produce so-called lithium ion cells. The kinetic transformation of LiMn2O4 into manganese dioxide (MnO2 in sulphuric acid has been studied. It is assumed that the conversion of LiMn2O4 into R-MnO2 is a first order autocatalytic reaction. The transformation actually proceeds through the spinel l-MnO2 as an intermediate species which is then converted into gamma phase of manganese dioxide. In this reaction LiMn2O4 whose structure spinel type, which is packing between tetrahedral coordination and octahedral coordination, is converted to form octahedral tunnel structure of manganese dioxide, which is probably regarded as a reconstructive octahedral-coordination transformation. Therefore, it is a desire to investigate the transformation of manganese oxides in solid state chemistry by analysing XRD powder patterns. Due to the reactions involving solids, concentrations of reactant and product are approached with the expression of peak areas.   Keywords: high-energy battery, lithium ion cells, kinetic transformation

  16. Synthesis of LiFePO4/Pani/C composite as a cathode material for lithium ion battery

    Science.gov (United States)

    Rahayu, Iman; Hidayat, Sahrul; Aryadi, Lutfi

    2016-02-01

    In recent years, LiFePO4 studied intensively as a cathode material for Li-ion batteries because of high theoretical capacity, stability, and environmental friendly. However, its low intrinsic electronic conductivity. One way to improve its conductivity is addition of conductive material. Polyaniline (PANI) is one of the conductive polymer materials that widely studied because its unique physical and chemical properties which can be an insulator and conductor by doping-dedoping processes and has large potential application. The purpose of this research is to improve the conductivity of LiFePO4 with conductive polymer PANI. The method is performed by the addition of LiFePO4 during the polymerization process to form LiFePO4 polyaniline then added to the C-PANI with the addition of mass percent variation of 5%, 10%, 15%, 20% form-LiFePO4 composite PANI-C. In LiFePO4 added during polymerization PANI provide a smooth surface profile after composited with the carbon to LiFePO4-PANI-C compared to LiFePO4-C. LiFePO4-PANI-C composite provided higher conductivity is 18.45×10-4 S/cm compared to LiFePO4-C is 10.48×10-4 S/cm at 20% addition of carbon. This is due to PANI in LiFePO4 is added to the polyaniline polymerization process can act as a conductive adhesive to glue between carbon and LiFePO4.

  17. Synthesis of Nanoscale Lithium-Ion Battery Cathode Materials Using a Porous Polymer Precursor Method

    KAUST Repository

    Deshazer, H.D.

    2011-01-01

    Fine particles of metal oxides with carefully controlled compositions can be easily prepared by the thermal decomposition of porous polymers, such as cellulose, into which solutions containing salts of the desired cations have been dissolved. This is a simple and versatile method that can be used to produce a wide variety of materials with a range of particle sizes and carefully controlled chemical compositions. Examples of the use of this method to produce fine particles of LiCoO2 and Li(NiMnCo)1/3O2, which are used in the positive electrodes of lithium-ion batteries, are shown. Experiments have demonstrated that materials made using this method can have electrochemical properties comparable to those typically produced by more elaborate procedures. © 2011 The Electrochemical Society.

  18. Vanadium Pentoxide-Based Composite Synthesized Using Microwave Water Plasma for Cathode Material in Rechargeable Magnesium Batteries

    Directory of Open Access Journals (Sweden)

    Tatsuhiko Yajima

    2013-10-01

    Full Text Available Multivalent cation rechargeable batteries are expected to perform well as high-capacity storage devices. Rechargeable magnesium batteries have an advantage in terms of resource utilization and safety. Here, we report on sulfur-doped vanadium pentoxide (S-V2O5 as a potential material for the cathodes of such a battery; S-V2O5 showed a specific capacity of 300 mAh·g−1. S-V2O5 was prepared by a method using a low-temperature plasma generated by carbon felt and a 2.45 GHz microwave generator. This study investigates the ability of S-V2O5 to achieve high capacity when added to metal oxide. The highest recorded capacity (420 mAh·g−1 was reached with MnO2 added to composite SMn-V2O5, which has a higher proportion of included sulfur than found in S-V2O5. Results from transmission electron microscopy, energy-dispersive X-ray spectroscopy, Micro-Raman spectroscopy, and X-ray photoelectron spectroscopy show that the bulk of the SMn-V2O5 was the orthorhombic V2O5 structure; the surface was a xerogel-like V2O5 and a solid solution of MnO2 and sulfur.

  19. LiFePO4 - 3D carbon nanofiber composites as cathode materials for Li-ions batteries

    Science.gov (United States)

    Dimesso, L.; Spanheimer, C.; Jaegermann, W.; Zhang, Y.; Yarin, A. L.

    2012-03-01

    The characterization of carbon nanofiber 3D nonwovens, prepared by electrospinning process, coated with olivine structured lithium iron phosphate is reported. The LiFePO4 as cathode material for lithium ion batteries was prepared by a Pechini-assisted reversed polyol process. The coating has been successfully performed on carbon nanofiber 3D nonwovens by soaking in aqueous solution containing lithium, iron salts and phosphates at 70 °C for 2-4 h. After drying-out, the composites were annealed at 600 °C for 5 h under nitrogen. The surface investigation of the prepared composites showed a uniform coating of the carbon nonwoven nanofibers as well as the formation of cauliflower-like crystalline structures which are uniformly distributed all over the surface area of the carbon nanofibers. The electrochemical measurements on the composites showed good performances delivering a discharge specific capacity of 156 mAhg- 1 at a discharging rate of C/25 and 152 mAhg- 1 at a discharging rate of C/10 at room temperature.

  20. Recovery of valuable metals from waste cathode materials of spent lithium-ion batteries using mild phosphoric acid.

    Science.gov (United States)

    Chen, Xiangping; Ma, Hongrui; Luo, Chuanbao; Zhou, Tao

    2017-03-15

    Sustainable recycling of valuable metals from spent lithium-ion batteries (LIBs) may be necessary to alleviate the depletion of strategic metal resources and potential risk of environmental pollution. Herein a hydrometallurgical process was proposed to explore the possibility for the recovery of valuable metals from the cathode materials (LiCoO2) of spent LIBs using phosphoric acid as both leaching and precipitating agent under mild leaching conditions. According to the leaching results, over 99% Co can be separated and recovered as Co3(PO4)2 in a short-cut process involved merely with leaching and filtrating, under the optimized leaching conditions of 40°C (T), 60min (t), 4 vol.% H2O2, 20mLg-1 (L/S) and 0.7mol/L H3PO4. Then leaching kinetics was investigated based on the logarithmic rate kinetics model and the obtained results indicate that the leaching of Co and Li fits well with this model and the activation energies (Ea) for Co and Li are 7.3 and 10.2kJ/mol, respectively. Finally, it can be discovered from characterization results that the obtained product is 97.1% pure cobalt phosphate (Co3(PO4)2). Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Hydrometallurgical process for recovery of cobalt from waste cathodic active material generated during manufacturing of lithium ion batteries

    Science.gov (United States)

    Swain, Basudev; Jeong, Jinki; Lee, Jae-chun; Lee, Gae-Ho; Sohn, Jeong-Soo

    The paper presents a new leaching-solvent extraction hydrometallurgical process for the recovery of a pure and marketable form of cobalt sulfate solution from waste cathodic active material generated during manufacturing of lithium ion batteries (LIBs). Leaching of the waste was carried out as a function of the leachant H 2SO 4 concentration, temperature, pulp density and reductant H 2O 2 concentration. The 93% of cobalt and 94% of lithium were leached at suitable optimum conditions of pulp density: 100 g L -1, 2 M H 2SO 4, 5 vol.% of H 2O 2, with a leaching time 30 min and a temperature 75 °C. In subsequent the solvent extraction study, 85.42% of the cobalt was recovered using 1.5 M Cyanex 272 as an extractant at an O/A ratio of 1.6 from the leach liquor at pH 5.00. The rest of the cobalt was totally recovered from the raffinate using 0.5 M of Cyanex 272 and an O/A ratio of 1, and a feed pH of 5.35. Then the co-extracted lithium was scrubbed from the cobalt-loaded organic using 0.1 M Na 2CO 3. Finally, the cobalt sulfate solution with a purity 99.99% was obtained from the cobalt-loaded organic by stripping with H 2SO 4.

  2. Synthesis and Electrochemical Properties of Fe-doped V6O13 as Cathode Material for Lithium-ion Battery

    Directory of Open Access Journals (Sweden)

    YUAN Qi

    2018-01-01

    Full Text Available Fe-doped V6O13 was synthesized via a facile hydrothermal method after preparing precursor in order to improve the discharge capacity and cycle performance of V6O13 cathode material at high-lithium state. XRD, SEM and XPS were employed to characterize the phase, morphology and valence of the Fe-doped V6O13. Meanwhile, the electrochemical performance was analyzed and researched. Different morphologies and electrochemical performances of Fe-doped V6O13 were obtained via doping different contents of Fe3+ ion. The sample 0.02 presented the largest thickness of nanosheets (the thickness of 600-900nm and clearance between layers. The Fe-doped V6O13 has a better electrochemical performance than that of pure V6O13. The sample 0.02 exhibits the best electrochemical performance, the initial discharge specific capacity is 433mAh·g-1 and the capacity retention is 47.1% after 100 cycles.

  3. Three-dimensional interconnected cobalt oxide-carbon hollow spheres arrays as cathode materials for hybrid batteries

    Directory of Open Access Journals (Sweden)

    Jiye Zhan

    2016-06-01

    Full Text Available Hierarchical porous metal oxides arrays is critical for development of advanced energy storage devices. Herein, we report a facile template-assisted electro-deposition plus glucose decomposition method for synthesis of multilayer CoO/C hollow spheres arrays. The CoO/C arrays consist of multilayer interconnected hollow composite spheres with diameters of ∼350 nm as well as thin walls of ∼20 nm. Hierarchical hollow spheres architecture with 3D porous networks are achieved. As cathode of high-rate hybrid batteries, the multilayer CoO/C hollow sphere arrays exhibit impressive enhanced performances with a high capacity (73.5 mAh g−1 at 2 A g−1, and stable high-rate cycling life (70 mAh g−1 after 12,500 cycles at 2 A g−1. The improved electrochemical performance is owing to the composite hollow-sphere architecture with high contact area between the active materials and electrolyte as well as fast ion/electron transportation path.

  4. Synthesis and characterization of LiFePo4/C cathode material by freeze drying method with PVP

    Directory of Open Access Journals (Sweden)

    Kuzmanović Maja D.

    2014-01-01

    Full Text Available Lithium iron phosphate is a promising cathode material for lithium ion battery application thanks to its good characteristics. Here is presented the freeze drying method for the preparation of carbon coated LiFePO4, where PVP is used as a carbon source. The main advantage of this method is mixing at the atomic level and introducing the carbon source into the precursor solution. The synthesis process can be divided into three stages: freezing of a precursor solution, drying under vacuum until water evaporates and calicination of as-dried powder at slightly reductive atmosphere. Powder X-ray diffraction measurement demonstrated single phase LiFePO4 with crystallite size of 45.8 nm. Morphology and particle size was revealed with scanning electron microscopy and particle size analyzer. Galvanostatic cycling from 2.3 to 4.1 V vs. Li/Li+, shows typical LiFePO4 redox behavior with plateau at 3.4 V. The discharge capacity value obtained at C/10 rate was 154 mAh- 1, with decrease on greater C-rates.

  5. Recent Development of Graphene-Based Cathode Materials for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Man-Ning Lu

    2016-01-01

    Full Text Available Dye-sensitized solar cells (DSSCs have attracted extensive attention for serving as potential low-cost alternatives to silicon-based solar cells. As a vital role of a typical DSSC, the counter electrode (CE is generally employed to collect electrons via the external circuit and speed up the reduction reaction of I3- to I- in the redox electrolyte. The noble Pt is usually deposited on a conductive glass substrate as CE material due to its excellent electrical conductivity, electrocatalytic activity, and electrochemical stability. To achieve cost-efficient DSSCs, reasonable efforts have been made to explore Pt-free alternatives. Recently, the graphene-based CEs have been intensively investigated to replace the high-cost noble Pt CE. In this paper, we provided an overview of studies on the electrochemical and photovoltaic characteristics of graphene-based CEs, including graphene, graphene/Pt, graphene/carbon materials, graphene/conducting polymers, and graphene/inorganic compounds. We also summarize the design and advantages of each graphene-based material and provide the possible directions for designing new graphene-based catalysts in future research for high-performance and low-cost DSSCs.

  6. Recycling Spent Primary Cells for the Synthesis of Spinel ZnMn2O4 ...

    African Journals Online (AJOL)

    Michael

    2015-06-01

    Jun 1, 2015 ... corresponding to spinel ZnMn2O4. Synthesis of spinel ZnMn2O4 provides yet another avenue for recycling postconsumer plastics and spent primary cells. Acknowledgements. Part of the analyses for this work was done at the. School of Materials Science and Engineering and the Analytical Centre, UNSW, ...

  7. Lithium recycling and cathode material regeneration from acid leach liquor of spent lithium-ion battery via facile co-extraction and co-precipitation processes.

    Science.gov (United States)

    Yang, Yue; Xu, Shengming; He, Yinghe

    2017-06-01

    A novel process for extracting transition metals, recovering lithium and regenerating cathode materials based on facile co-extraction and co-precipitation processes has been developed. 100% manganese, 99% cobalt and 85% nickel are co-extracted and separated from lithium by D2EHPA in kerosene. Then, Li is recovered from the raffinate as Li2CO3 with the purity of 99.2% by precipitation method. Finally, organic load phase is stripped with 0.5M H2SO4, and the cathode material LiNi1/3Co1/3Mn1/3O2 is directly regenerated from stripping liquor without separating metal individually by co-precipitation method. The regenerative cathode material LiNi1/3Co1/3Mn1/3O2 is miro spherical morphology without any impurities, which can meet with LiNi1/3Co1/3Mn1/3O2 production standard of China and exhibits good electrochemical performance. Moreover, a waste battery management model is introduced to guarantee the material supply for spent battery recycling. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Amorphous MoS3as the sulfur-equivalent cathode material for room-temperature Li-S and Na-S batteries.

    Science.gov (United States)

    Ye, Hualin; Ma, Lu; Zhou, Yu; Wang, Lu; Han, Na; Zhao, Feipeng; Deng, Jun; Wu, Tianpin; Li, Yanguang; Lu, Jun

    2017-12-12

    Many problems associated with Li-S and Na-S batteries essentially root in the generation of their soluble polysulfide intermediates. While conventional wisdom mainly focuses on trapping polysulfides at the cathode using various functional materials, few strategies are available at present to fully resolve or circumvent this long-standing issue. In this study, we propose the concept of sulfur-equivalent cathode materials, and demonstrate the great potential of amorphous MoS 3 as such a material for room-temperature Li-S and Na-S batteries. In Li-S batteries, MoS 3 exhibits sulfur-like behavior with large reversible specific capacity, excellent cycle life, and the possibility to achieve high areal capacity. Most remarkably, it is also fully cyclable in the carbonate electrolyte under a relatively high temperature of 55 °C. MoS 3 can also be used as the cathode material of even more challenging Na-S batteries to enable decent capacity and good cycle life. Operando X-ray absorption spectroscopy (XAS) experiments are carried out to track the structural evolution of MoS 3 It largely preserves its chain-like structure during repetitive battery cycling without generating any free polysulfide intermediates.

  9. NiCr (x) Fe2-x O-4 as cathode materials for electrochemical reduction of NO (x)

    DEFF Research Database (Denmark)

    Bræstrup, Frantz Radzik; Kammer Hansen, Kent

    2010-01-01

    Solid solutions of spinel-type oxides with the composition NiCr x Fe2-x O4 (x = 0.0, 0.5, 1.0, 1.5, 2.0) were prepared with the glycine–nitrate combustion synthesis. Four-point DC resistivity measurements show an increase in the conductivity as more Cr is introduced into the structure, whereas...

  10. Comparison of LiV3O8 cathode materials prepared by different methods

    DEFF Research Database (Denmark)

    West, Keld; Zachau-Christiansen, Birgit; Skaarup, Steen

    1996-01-01

    Lithium trivanadate, LiV3O8, can be prepared in a finely dispersed form by dehydration of aqueous lithium vanadate gels. Two methods of dehydration, both easily adaptable to large-scale production, are described in this work: freeze drying and spray drying. After heat-treatment of the dried gels...... (xerogels) to remove loosely bound water they show a high capacity for lithium insertion, approaching four additional lithium per formula unit, and good reversibility as electrode materials for high energy density lithium cells. How the heat-treatment temperature influences the crystal structure...

  11. Morphological Control for Highly Efficient Inverted Polymer Solar Cells Via the Backbone Design of Cathode Interlayer Materials

    OpenAIRE

    Zhang, Wenjun; Wu, Yulei; Bao, Qinye; Gao, Feng; Fang, Junfeng

    2014-01-01

    Two alcohol-soluble organic molecules are synthesized and introduced into inverted organic solar cells as the cathode interlayer. A power conversion efficiency as high as 9.22% is obtained by using the more hydrophobic molecule FTBTF-N as the cathode interlayer. Morphological studies suggest that design of the backbone can help to enhance short-circuit current density and fill factor. Funding Agencies|National Natural Science Foundation of China [51273208]; China Postdoctoral Science Foun...

  12. Sucrose-aided combustion synthesis of nanosized LiMn{sub 1.99-y}Li{sub y}M{sub 0.01}O{sub 4} (M = Al{sup 3+}, Ni{sup 2+}, Cr{sup 3+}, Co{sup 3+}, y = 0.01 and 0.06) spinels. Characterization and electrochemical behavior at 25 and at 55 C in rechargeable lithium cells

    Energy Technology Data Exchange (ETDEWEB)

    Amarilla, J.M.; Pico, F.; Rojo, J.M.; Rojas, R.M. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas (CSIC), Sor Juana Ines de la Cruz no. 3, Cantoblanco, 28049 Madrid (Spain); Petrov, K.; Avdeev, G. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2009-06-15

    Doubly doped LiMn{sub 1.99-y}Li{sub y}M{sub 0.01}O{sub 4} (M = Al{sup 3+}, Ni{sup 2+}, Cr{sup 3+}, Co{sup 3+}; y = 0.01 and 0.06) spinels have been synthesized by the sucrose-aided combustion method. Combined TG/DTA and XRD studies have shown that stoichiometric single-phase spinels are formed after annealing of the samples at 700 C for 1 h. The samples obtained are nanocrystalline materials having a narrow size-distribution and a coherent domain size between 40 and 60 nm, depending on the amount of fuel (sucrose) used in the synthesis. The influence of the Li-excess, the type of M{sup n+}-dopant cation and the amount of fuel used in the synthesis on the electrochemical behavior of the spinels in a Li-cell at room and at elevated temperature (55 C) has been studied. At 25 C all the spinels synthesized have a good capacity retention after 100 cycles, QRt-100 > 92%. At 55 C the increase of the Li-excess improves the cycling performances. Rate capability studies show that the spinels retain >90% of their capacity even at 5C rate. The synergic effect of the Li-excess and the particle size on the electrochemical properties of the spinels as cathode material has been settled. The LiMn{sub 1.93}Li{sub 0.06}M{sub 0.01}O{sub 4}, (M = Al{sup 3+}, Ni{sup 2+}) spinels, with cyclabilities >99.9% by cycle at both 25 and 55 C, and high rate capabilities, are the ones that show the best electrochemical properties. (author)

  13. Synthesis, characterization and formation mechanism of SiC/spinel nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Tavangarian, Fariborz [Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States); Li, Guoqiang, E-mail: lguoqi1@lsu.edu [Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States); Department of Mechanical Engineering, Southern University, Baton Rouge, LA 70813 (United States)

    2014-06-15

    Highlights: • SiC/spinel nanocomposite was synthesized from talc, aluminum and graphite powders. • A mechanism was suggested for the SiC/spinel nanocomposite formation. • The SiC/spinel nanocomposite powder had a mean crystallite size of about 9 nm. • During the formation of nanocomposite some intermediate compounds were formed. - Abstract: This paper reports the successful synthesis of SiC/spinel (MgAl{sub 2}O{sub 4}) nanocomposite from talc, aluminum and graphite powders. The initial powders were mixed to obtain stoichiometric spinel containing 27.26 wt.% SiC. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques were utilized to characterize the synthesized powders. SiC/spinel nanocomposite was obtained after 6 h ball milling of initial materials in argon atmosphere with subsequent annealing at 1200 °C for 1 h in vacuum. The obtained nanocomposite had crystallites size between 1 and 15 nm with the mean diameter of 9 nm. The SiC/spinel composite formation mechanism was scrutinized. The results showed that SiC/spinel nanocomposite was not produced directly and the formation of some intermediate compounds is unavoidable during the synthesis procedure. The SiC/spinel nanocomposite powder may be a potential nanocomposite for high temperature applications with self-crack-healing capability.

  14. Jeffamine® based polymers as highly conductive polymer electrolytes and cathode binder materials for battery application

    Science.gov (United States)

    Aldalur, Itziar; Zhang, Heng; Piszcz, Michał; Oteo, Uxue; Rodriguez-Martinez, Lide M.; Shanmukaraj, Devaraj; Rojo, Teofilo; Armand, Michel

    2017-04-01

    We report a simple synthesis route towards a new type of comb polymer material based on polyether amines oligomer side chains (i.e., Jeffamine® compounds) and a poly(ethylene-alt-maleic anhydride) backbone. Reaction proceeds by imide ring formation through the NH2 group allowing for attachment of side chains. By taking advantage of the high configurational freedoms and flexibility of propylene oxide/ethylene oxide units (PO/EO) in Jeffamine® compounds, novel polymer matrices were obtained with good elastomeric properties. Fully amorphous solid polymer electrolytes (SPEs) based on lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and Jeffamine®-based polymer matrices show low glass transition temperatures around -40 °C, high ionic conductivities and good electrochemical stabilities. The ionic conductivities of Jeffamine-based SPEs (5.3 × 10-4 S cm-1 at 70 °C and 4.5 × 10-5 S cm-1 at room temperature) are higher than those of the conventional SPEs comprising of LiTFSI and linear poly(ethylene oxide) (PEO), due to the amorphous nature and the high concentration of mobile end-groups of the Jeffamine-based polymer matrices rather than the semi-crystalline PEO The feasibility of Jeffamine-based compounds in lithium metal batteries is further demonstrated by the implementation of Jeffamine®-based polymer as a binder for cathode materials, and the stable cycling of Li|SPE|LiFePO4 and Li|SPE|S cells using Jeffamine-based SPEs.

  15. Hierarchical sulfur-based cathode materials with long cycle life for rechargeable lithium batteries.

    Science.gov (United States)

    Wang, Jiulin; Yin, Lichao; Jia, Hao; Yu, Haitao; He, Yushi; Yang, Jun; Monroe, Charles W

    2014-02-01

    Composite materials of porous pyrolyzed polyacrylonitrile-sulfur@graphene nanosheet (pPAN-S@GNS) are fabricated through a bottom-up strategy. Microspherical particles are formed by spray drying of a mixed aqueous colloid of PAN nanoparticles and graphene nanosheets, followed by a simple heat treatment with elemental sulfur. The pPAN-S primary nanoparticles are wrapped homogeneously and loosely within a three-dimensional network of graphene nanosheets (GNS). The hierarchical pPAN-S@GNS composite shows a high reversible capacity of 1449.3 mAh g(-1) sulfur or 681.2 mAh g(-1) composite in the second cycle; after 300 cycles at a 0.2 C charge/discharge rate the capacity retention is 88.8 % of its initial reversible value. Additionally, the coulombic efficiency (CE) during cycling is near 100 %, apart from in the first cycle, in which CE is 81.1 %. A remarkable capacity of near 700 mAh g(-1) sulfur is obtained, even at a high discharge rate of 10 C. The superior performance of pPAN-S@GNS is ascribed to the spherical secondary GNS structure that creates an electronically conductive 3D framework and also reinforces structural stability. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Infiltrating sulfur into a highly porous carbon sphere as cathode material for lithium–sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xiaohui; Kim, Dul-Sun [Department of Chemical and Biological Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Ahn, Hyo-Jun; Kim, Ki-Won [Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Cho, Kwon-Koo, E-mail: kkcho66@gnu.ac.kr [Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Ahn, Jou-Hyeon, E-mail: jhahn@gnu.ac.kr [Department of Chemical and Biological Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of)

    2014-10-15

    Highlights: • A highly porous carbon (HPC) with regular spherical morphology was synthesized. • Sulfur/HPC composites were prepared by melt–diffusion method. • Sulfur/HPC composites showed improved cyclablity and long-term cycle life. - Abstract: Sulfur composite material with a highly porous carbon sphere as the conducting container was prepared. The highly porous carbon sphere was easily synthesized with resorcinol–formaldehyde precursor as the carbon source. The morphology of the carbon was observed with field emission scanning electron microscope and transmission electron microscope, which showed a well-defined spherical shape. Brunauer–Emmett–Teller analysis indicated that it possesses a high specific surface area of 1563 m{sup 2} g{sup −1} and a total pore volume of 2.66 cm{sup 3} g{sup −1} with a bimodal pore size distribution, which allow high sulfur loading and easy transportation of lithium ions. Sulfur carbon composites with varied sulfur contents were prepared by melt–diffusion method and lithium sulfur cells with the sulfur composites showed improved cyclablity and long-term cycle life.

  17. Developments in the Material Fabrication and Performance of LiMn2O4 dCld Cathode Material

    Science.gov (United States)

    2016-06-13

    lithium and lithium-ion electrochemical systems. An inherent disadvantage is their limited cyclability as a result of the energy barriers for...that can meet the demands of current and future portable electronic systems. In the U.S. Army, many of these systems are utilized in a Command...Degradation of the active material can be due to loss of crystallinity, alternative phase formations, or potential side reactions.1-4 Methods to eliminate or

  18. An efficient electrocatalyst as cathode material for solid oxide fuel cells: BaFe0·95Sn0·05O3-δ

    Science.gov (United States)

    Dong, Feifei; Ni, Meng; He, Wei; Chen, Yubo; Yang, Guangming; Chen, Dengjie; Shao, Zongping

    2016-09-01

    The B-site substitution with the minor amount of tin in BaFeO3-δ parent oxide is expected to stabilize a single perovskite lattice structure. In this study, a composition of BaFe0·95Sn0·05O3-δ (BFS) as a new cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) is synthesized and characterized. Special attention is paid to the exploration of some basic properties including phase structure, oxygen non-stoichiometry, electrical conductivity, oxygen bulk diffusion coefficient, and surface exchange coefficient, which are of significant importance to the electrochemical activity of cathode materials. BFS holds a single cubic perovskite structure over temperature range of cell operation, determined by in-situ X-ray diffraction and scanning transmission electron microscope. A high oxygen vacancy concentration at cell operating temperatures is observed by combining thermo-gravimetric data and iodometric titration result. Furthermore, electrical conductivity relaxation measurement illustrates the fast oxygen bulk diffusion and surface exchange kinetics. Accordingly, testing cells based on BFS cathode material demonstrate the low polarization resistance of 0.033 Ω cm2 and high peak power density of 1033 mW cm-2 at 700 °C, as well as a relatively stable long-term operation for ∼300 h. The results obtained suggest that BFS perovskite oxide holds a great promise as an oxygen reduction electrocatalyst for IT-SOFCs.

  19. Discharge/charge reaction mechanisms of FeS2 cathode material for aluminum rechargeable batteries at 55°C

    Science.gov (United States)

    Mori, Takuya; Orikasa, Yuki; Nakanishi, Koji; Kezheng, Chen; Hattori, Masashi; Ohta, Toshiaki; Uchimoto, Yoshiharu

    2016-05-01

    The aluminum rechargeable battery is a desirable device for large-scale energy storage owing to the high capacity derived from the properties of the aluminum metal anode. The development of cathode materials is needed to compose battery systems. However, the design principles of the cathode materials have not been determined. We focus on the high capacity FeS2 cathode materials and investigate the discharge/charge reaction mechanisms in chloroaluminate ionic liquids as the electrolyte at 55°C. X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) measurements are performed for the discharged and charged samples. S 3p-orbitals are shown to play an important role in the redox reactions from the results of the S and Fe K-edge XANES spectra. As a result of the redox reaction, FeS2 is transformed into low crystalline FeS and amorphous Al2S3, as shown by the XRD and S, Al, and Fe K-edge XANES spectra. This reaction mechanism is different from the reaction observed with lithium ion.

  20. Cathodic arcs

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre

    2003-10-29

    Cathodic arc plasma deposition has become the technology of choice for hard, wear and corrosion resistant coatings for a variety of applications. The history, basic physics of cathodic arc operation, the infamous macroparticle problem and common filter solutions, and emerging high-tech applications are briefly reviewed. Cathodic arc plasmas standout due to their high degree of ionization, with important consequences for film nucleation, growth, and efficient utilization of substrate bias. Industrial processes often use cathodic arc plasma in reactive mode. In contrast, the science of arcs has focused on the case of vacuum arcs. Future research directions include closing the knowledge gap for reactive mode, large area coating, linear sources and filters, metal plasma immersion process, with application in high-tech and biomedical fields.

  1. Hydrothermal synthesis of morphology-controlled LiFePO4 cathode material for lithium-ion batteries

    Science.gov (United States)

    Pei, Bo; Yao, Hongxu; Zhang, Weixin; Yang, Zeheng

    2012-12-01

    A simple sodium dodecyl benzene sulfonate (SDBS) mediated hydrothermal method has been described in this paper to prepare morphology-controlled LiFePO4, cathode material such as nanoparticles, nanorods and nanoplates with controllable b-axis thickness. When used in lithium-ion batteries, the LiFePO4/C nanoparticles (200 nm in size) and nanorods (90 nm in diameter along b-axis and 200 nm-1 μm in length) display initial discharge capacities of 145.3 and 149.0 mAh g-1 at 0.1 C rate, 33.9 and 61.3 mAh g-1 at 10 C rate, respectively. The LiFePO4/C nanoplates (20 nm thickness along b-axis and 50 nm width) deliver a discharge capacity of 162.9 mAh g-1 at 0.1 C rate and 107.9 mAh g-1 at 10 C rate. The Li-ion diffusion coefficients of the LiFePO4/C nanoparticles, nanorods and nanoplates are calculated to be 1.66 × 10-12, 2.99 × 10-12 and 1.64 × 10-11 cm2 s-1, respectively. In general, the discharge capacity and rate performance have been found to increase with the decreasing thickness of the b-axis. The experimental results demonstrate that decreasing the crystallite size in the b-axis and increasing the surface area of (010) plane can shorten Li-ion diffusion path and increase the electrode reaction, which significantly improve electrochemical performance of the LiFePO4/C nanocomposites.

  2. LiV3O8/Polytriphenylamine Composites with Enhanced Electrochemical Performances as Cathode Materials for Rechargeable Lithium Batteries

    Science.gov (United States)

    Li, Wenjuan; Zhu, Limin; Yu, Ziheng; Xie, Lingling; Cao, Xiaoyu

    2017-01-01

    LiV3O8/polytriphenylamine composites are synthesized by a chemical oxidative polymerization process and applied as cathode materials for rechargeable lithium batteries (RLB). The structure, morphology, and electrochemical performances of the composites are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, galvanostatic discharge/charge tests, and electrochemical impedance spectroscopy. It was found that the polytriphenylamine particles were composited with LiV3O8 nanorods which acted as a protective barrier against the side reaction of LiV3O8, as well as a conductive network to reduce the reaction resistance among the LiV3O8 particles. Among the LiV3O8/polytriphenylamine composites, the 17 wt % LVO/PTPAn composite showed the largest d100 spacing. The electrochemical results showed that the 17 wt % LVO/PTPAn composite maintained a discharge capacity of 271 mAh·g−1 at a current density of 60 mA·g−1, as well as maintaining 236 mAh·g−1 at 240 mA·g−1 after 50 cycles, while the bare LiV3O8 sample retained only 169 and 148 mAh·g−1, respectively. Electrochemical impedance spectra (EIS) results implied that the 17 wt % LVO/PTPAn composite demonstrated a decreased charge transfer resistance and increased Li+ ion diffusion ability, therefore manifesting better rate capability and cycling performance compared to the bare LiV3O8 sample. PMID:28772705

  3. Diagnosing, Optimizing and Designing Ni & Mn based Layered Oxides as Cathode Materials for Next Generation Li-ion Batteries and Na-ion Batteries

    Science.gov (United States)

    Liu, Haodong

    The progressive advancements in communication and transportation has changed human daily life to a great extent. While important advancements in battery technology has come since its first demonstration, the high energy demands needed to electrify the automotive industry have not yet been met with the current technology. One considerable bottleneck is the cathode energy density, the Li-rich layered oxide compounds xLi2MnO3.(1-x)LiMO 2 (M= Ni, Mn, Co) (0.5= Co) (0.5=discharge capacities greater than 280 mAh g-1 (almost twice the practical capacity of LiCoO 2). In this work, neutron diffraction under operando battery cycling is developed to study the lithium and oxygen dynamics of Li-rich compounds that exhibits oxygen activation at high voltage. The measured lattice parameter changes and oxygen position show movement of oxygen and lattice contractions during the high voltage plateau until the end of charge. Lithium migration kinetics for the Li-rich material is observed under operando conditions for the first time to reveal the rate of lithium extraction from the lithium layer and transition metal layer are related to the different charge and discharge characteristics. In the second part, a combination of multi-modality surface sensitive tools was applied in an attempt to obtain a complete picture to understand the role of NH4F and Al2O3 surface co-modification on Li-rich. The enhanced discharge capacity of the modified material can be primary assigned to three aspects: decreased irreversible oxygen loss, the activation of cathode material was facilitated with pre-activated Mn3+ on the surface, and stabilization of the Ni redox pair. These insights will provide guidance for the surface modification in high voltage cathode battery materials of the future. In the last part, the idea of Li-rich has transferred to the Na-ion battery cathode. A new O3 - Na0.78Li0.18Ni0.25Mn 0.583Ow is prepared as the cathode material for Na-ion batteries, delivering exceptionally high

  4. Nanotube cathodes.

    Energy Technology Data Exchange (ETDEWEB)

    Overmyer, Donald L.; Lockner, Thomas Ramsbeck; Siegal, Michael P.; Miller, Paul Albert

    2006-11-01

    Carbon nanotubes have shown promise for applications in many diverse areas of technology. In this report we describe our efforts to develop high-current cathodes from a variety of nanotubes deposited under a variety of conditions. Our goal was to develop a one-inch-diameter cathode capable of emitting 10 amperes of electron current for one second with an applied potential of 50 kV. This combination of current and pulse duration significantly exceeds previously reported nanotube-cathode performance. This project was planned for two years duration. In the first year, we tested the electron-emission characteristics of nanotube arrays fabricated under a variety of conditions. In the second year, we planned to select the best processing conditions, to fabricate larger cathode samples, and to test them on a high-power relativistic electron beam generator. In the first year, much effort was made to control nanotube arrays in terms of nanotube diameter and average spacing apart. When the project began, we believed that nanotubes approximately 10 nm in diameter would yield sufficient electron emission properties, based on the work of others in the field. Therefore, much of our focus was placed on measured field emission from such nanotubes grown on a variety of metallized surfaces and with varying average spacing between individual nanotubes. We easily reproduced the field emission properties typically measured by others from multi-wall carbon nanotube arrays. Interestingly, we did this without having the helpful vertical alignment to enhance emission; our nanotubes were randomly oriented. The good emission was most likely possible due to the improved crystallinity, and therefore, electrical conductivity, of our nanotubes compared to those in the literature. However, toward the end of the project, we learned that while these 10-nm-diameter CNTs had superior crystalline structure to the work of others studying field emission from multi-wall CNT arrays, these nanotubes still

  5. Measured cathode fall characteristics depending on the diameter of a hydrogen hollow cathode discharge

    Science.gov (United States)

    Gonzalez-Fernandez, V.; Grützmacher, K.; Steiger, A.; Pérez, C.; de la Rosa, M. I.

    2017-10-01

    In this work, Doppler-free two photon optogalvanic spectroscopy is used to measure the electric field strength in the cathode fall region of a hollow cathode discharge, operated in pure hydrogen, via the Stark splitting of the 2S level of atomic hydrogen. The cathode fall characteristics are analysed for various pressures and in a wide range of discharge currents. Tungsten is used as the cathode material, because it allows for reliable measurements in a fairly wide range of discharge conditions and because of its minimal sputtering. Two cathode diameters (10 mm and 15 mm) are used to study the dependence of the cathode fall on discharge geometry. The measurements reveal that the cathode fall characteristics are quite independent on the cathode diameter for equal cathode current density; hence the measurements can be used to test one dimensional modelling of the cathode fall region for low pressure hydrogen discharges using e.g. plane parallel electrodes.

  6. Origin of the low compressibility in hard nitride spinels

    DEFF Research Database (Denmark)

    Mori-Sánchez, P.; Marqués, M.; Beltrán, A.

    2003-01-01

    A microscopic investigation of first-principles electron densities of gamma-A(3)N(4) (A:C,Si,Ge) spinels reveals a clear relationship between the compressibility and the chemical bonding of these materials. Three striking findings emanate from this analysis: (i) the chemical graph is governed by ...

  7. Assessment of four different cathode materials at different initial pHs using unbuffered catholytes in microbial electrolysis cells

    KAUST Repository

    Ribot-Llobet, Edgar

    2013-03-01

    Nickel foam (NF), stainless steel wool (SSW), platinum coated stainless steel mesh (Pt), and molybdenum disulfide coated stainless steel mesh (MoS 2) electrodes have been proposed as catalysts for hydrogen gas production, but previous tests have primarily examined their performance in well buffered solutions. These materials were compared using two-chamber microbial electrolysis cells (MECs), and linear sweep voltammetry (LSV) in unbuffered saline solutions at two different initial pHs (7 and 12). There was generally no appreciable effect of initial pH on production rates or total gas production. NF produced hydrogen gas at a rate of 1.1 m3 H2/m 3·d, which was only slightly less than that using Pt (1.4 m3 H2/m3·d), but larger than that obtained with SSW (0.52 m3 H2/m3·d) or MoS2 (0.67 m3 H2/m3·d). Overall hydrogen gas recoveries with SSW (29.7 ± 0.5 mL), MoS2 (28.6 ± 1.3 mL) and NF (32.4 ± 2 mL) were only slightly less than that of Pt (37.9 ± 0.5 mL). Total energy recoveries, based on the gas produced versus electrical energy input, ranged from 0.75 ± 0.02 for Pt, to 0.55 ± 0.02 for SSW. An LSV analysis showed no effect of pH for NF and Pt, but overpotentials were reduced for MoS2 and SSW by using an initial lower pH. At cathode potentials more negative than -0.85 V (vs Ag/AgCl), NF had lower overpotentials than the MoS2. These results provide the first assessment of these materials under practical conditions of high pH in unbuffered saline catholytes, and position NF as the most promising inexpensive alternative to Pt.

  8. A Study of the Thermodynamics and Kinetics of Lithium Iron Phosphate as a Cathode Material for Lithium Batteries

    Science.gov (United States)

    Tan, Hongjin

    Olivine-type LiFePO4 has been recognized as one of the most promising cathode materials for rechargeable Li batteries. Its advantages include high capacity, high stability, nontoxicity, and low cost. Our methods for synthesizing nanocrystalline LixFePO 4 with the olivine structure are described. Solid-state reactions and precipitation reactions were both successful, and ball milling was especially effective at reducing crystallite sizes. Diffractometry and microscopy were used to characterize these materials, and results of impurity phases, excess Fe3+, and internal stresses are reported for the different types of synthesis. Applications of lithium-ion batteries, including automotive applications, require fast kinetics and high conductivity of ions and electrons. Unfortunately, LixFePO4 has the electronic structure of an insulator, an entirely unsatisfactory situation if it is to be used as a battery electrode. Electrical conductivity in LixFePO 4 occurs by the motion of small polarons, which are valence electrons at Fe atoms plus their distorted local environments. Electrical conductivity of LixFePO4 is interpreted in terms of small polaron hopping. There are other factors of importance in these measurements, such as impurities or defects that block the one-dimensional conduction channels of the olivine structure of LixFePO4. We studied the polaron hopping directly, which allows us to understand the intrinsic electrical conductivity, and how it depends on microstructure and composition of LixFePO4. The experimental technique was Mossbauer spectrometry, which has been used for many years as a means for determining the fractions of Fe2+ and Fe 3+ in a material. Usually the spectral signatures of Fe2+ and Fe3+ are distinct. When valence electrons hop between Fe 2+ and Fe3+ at a frequency of 108 Hz or higher, however, the valence changes during the timescale of the Mossbauer measurement and the spectrum is blurred. By measuring Mossbauer spectra at elevated

  9. Structural and magnetic properties of the iron substituted lithium-manganese spinel oxides

    Energy Technology Data Exchange (ETDEWEB)

    Wolska, E.; Nowicki, W.; Darul, J.; Piszora, P. [Adam Mickiewicz Univ., Lab. of Magnetochemistry, Faculty of Chemistry, Poznan (Poland); Tovar, M. [Hahn Meitner Institute, Berlin (Germany); Andrzejewski, B. [Institute of Molecular Physics, Polish Academy of Sciences, Poznan (Poland); Knapp, M. [Darmstadt University of Technology, Institute of Materials Science (Germany)

    2006-07-01

    Most studies on the lithium-manganese oxide as a cathode material have concentrated on the stabilization of the cubic spinel structure, mainly by doping other transition metal ions into LiMn{sub 2}O{sub 4} lattice. Partial substitution of Fe{sup 3+} ions for Mn{sup 3+} restrains the Jahn-Teller effect, owing to the reduction of Mn{sup 3+}/Mn{sup 4+} ratio. In LiFe{sub 0.1}Mn{sub 1.9}O{sub 4} spinel oxide the phase transitions from cubic to orthorhombic and/or tetragonal structure, appearing for LiMn{sub 2}O{sub 4} below the room temperature, may be totally suppressed. The changes in stoichiometry of LiFe{sub x}Mn{sub 2-x}O{sub 4} system, modify the sequence of phase transitions and lower the transition temperature. A superexchange magnetic interaction between the Mn ions via oxygen atoms alters, with the Fe{sup 3+} - content in Li{sub x}Mn{sub 3-x}O{sub 4} increasing from x = 0.0-0.1, showing the antiferromagnetic ordering at very low temperature. The Neel point increases from 7 to 27 K. Effect of Fe{sup 3+} ions substitution in the LiFe{sub x}Mn{sub 2-x}O{sub 4} system on its low-temperature structural phase transitions, have been investigated using high-resolution synchrotron X-ray powder diffraction, neutron powder diffraction and the magnetic susceptibility measurements. Divergences appear in the interpretation of magnetic structure on the basis of experimental results, acquired from neutron diffraction data, and obtained from the direct current susceptibility measurements. (authors)

  10. Evaluation of low cost cathode materials for treatment of industrial and food processing wastewater using microbial electrolysis cells

    KAUST Repository

    Tenca, Alberto

    2013-02-01

    Microbial electrolysis cells (MECs) can be used to treat wastewater and produce hydrogen gas, but low cost cathode catalysts are needed to make this approach economical. Molybdenum disulfide (MoS2) and stainless steel (SS) were evaluated as alternative cathode catalysts to platinum (Pt) in terms of treatment efficiency and energy recovery using actual wastewaters. Two different types of wastewaters were examined, a methanol-rich industrial (IN) wastewater and a food processing (FP) wastewater. The use of the MoS2 catalyst generally resulted in better performance than the SS cathodes for both wastewaters, although the use of the Pt catalyst provided the best performance in terms of biogas production, current density, and TCOD removal. Overall, the wastewater composition was more of a factor than catalyst type for accomplishing overall treatment. The IN wastewater had higher biogas production rates (0.8-1.8 m3/m3-d), and COD removal rates (1.8-2.8 kg-COD/m3-d) than the FP wastewater. The overall energy recoveries were positive for the IN wastewater (3.1-3.8 kWh/kg-COD removed), while the FP wastewater required a net energy input of -0.7 - 1.2 kWh/kg-COD using MoS 2 or Pt cathodes, and -3.1 kWh/kg-COD with SS. These results suggest that MoS2 is the most suitable alternative to Pt as a cathode catalyst for wastewater treatment using MECs, but that net energy recovery will be highly dependent on the specific wastewater. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  11. Electrochemical properties of graphene flakes as an air cathode material for Li-O2 batteries in an ether-based electrolyte.

    Science.gov (United States)

    Kim, Se Young; Lee, Ho-Taek; Kim, Kwang-Bum

    2013-12-14

    We employed graphene flakes as an air-cathode material for Li-O2 batteries and investigated their electrochemical properties in the dimethyl ether electrolyte. Graphene flakes were prepared by microwave-assisted reduction of graphene oxide, and their electrochemical properties were compared with those of Ketjen Black and carbon nanotubes. The catalytic effect of the prepared graphene flake-air cathode was demonstrated using cyclic voltammetry and discharge-charge testing performed under a limited discharge capacity. The catalytic effect of graphene flakes was also supported by morphological and spectroscopic analysis of the discharge-charge products formed on the graphene surface. Scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy revealed that Li2O2, Li2O, and Li2CO3 were the main discharge products on all carbon-air cathode surfaces. Raman spectroscopy revealed that LiRCO3 was additionally formed on Ketjen Black and carbon nanotubes during the first discharge; however, its formation was not observed on the graphene flakes. The catalytic effect of the graphene flakes and the absence of LiRCO3 in the discharge product could explain the higher Coulombic efficiency in the discharge-charge tests.

  12. Recovery of valuable metals from waste cathode materials of spent lithium-ion batteries using mild phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiangping, E-mail: chenxiangping101@163.com [School of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi’an 710021 (China); College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Ma, Hongrui, E-mail: mahr@sust.edu.cn [School of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi’an 710021 (China); Luo, Chuanbao; Zhou, Tao [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)

    2017-03-15

    Graphical abstract: Cobalt can be directly recovered as Co{sub 3}(PO{sub 4}){sub 2} from waste LiCoO{sub 2} using H{sub 3}PO{sub 4} as leaching and precipitating agent. - Highlights: • Phosphoric acid was innovatively used as leaching and precipitating agent. • Over 99% Co and Li can be separated and recovered in a single leaching step. • Co and Li can be separated under mild conditions of 40 °C and 0.7 M H{sub 3}PO{sub 4}. • Activation energy values for Co and Li are 7.3 and 10.168 kJ/mol. • Cobalt phosphate (97.1% in purity) can be obtained as the leaching product. - Abstract: Sustainable recycling of valuable metals from spent lithium-ion batteries (LIBs) may be necessary to alleviate the depletion of strategic metal resources and potential risk of environmental pollution. Herein a hydrometallurgical process was proposed to explore the possibility for the recovery of valuable metals from the cathode materials (LiCoO{sub 2}) of spent LIBs using phosphoric acid as both leaching and precipitating agent under mild leaching conditions. According to the leaching results, over 99% Co can be separated and recovered as Co{sub 3}(PO{sub 4}){sub 2} in a short-cut process involved merely with leaching and filtrating, under the optimized leaching conditions of 40 °C (T), 60 min (t), 4 vol.% H{sub 2}O{sub 2}, 20 mL g{sup −1} (L/S) and 0.7 mol/L H{sub 3}PO{sub 4}. Then leaching kinetics was investigated based on the logarithmic rate kinetics model and the obtained results indicate that the leaching of Co and Li fits well with this model and the activation energies (Ea) for Co and Li are 7.3 and 10.2 kJ/mol, respectively. Finally, it can be discovered from characterization results that the obtained product is 97.1% pure cobalt phosphate (Co{sub 3}(PO{sub 4}){sub 2}).

  13. Evidence of the current collector effect: study of the SOFC cathode material Ca{sub 3}Co{sub 4}O{sub 9+{delta}}

    Energy Technology Data Exchange (ETDEWEB)

    Rolle, A.; Thoreton, V.; Capoen, E.; Mentre, O.; Daviero-Minaud, S. [Univ. Lille Nord de France, Lille (France); CNRS UMR 8181-Unite de Catalyse et de Chimie du Solide - UCCS, ENSC, USTL Villeneuve d' Ascq (France); Rozier, P. [Centre d' Elaboration de Materiaux et d' Etudes Structurales, UPR CNRS 8011, Toulouse (France); Boukamp, B. [Faculty of Science and Technology and MESA+, Institute for Nanotechnology, University of Twente, Enschede (Netherlands)

    2012-04-15

    In the study of the performance of solid oxide fuel cell (SOFC) electrodes, the possible influence of the applied current collector is often not mentioned or recognized. In this article, as part of an optimization study of the potentially attractive Ca{sub 3}Co{sub 4}O{sub 9+{delta}} cathode material (Ca349), special attention is paid to the choice of current collector. The influence of both gold and platinum paste or grid current collectors on pure and composite (Ca349 + 30 wt.% Gd-doped ceria) is studied, using electrochemical impedance spectroscopy (EIS). Although, platinum is catalytically active in the oxygen reduction reaction and then is often considered as current collector for SOFC cathodes, in combination with Ca349 cathodes, additional low frequency dispersion is observed, leading to a larger polarization resistance than found in the case of gold current collectors. A subsequent experiment revealed that Pt reacts with Ca349, forming undesirable phases: CaPt{sub 2}O{sub 4}, Ca{sub 4}PtO{sub 6}, Ca{sub 3}Co{sub 2}O{sub 6}, and Co{sub 3}O{sub 4}. The impedance spectra were analyzed with ZView 3.3a and with EqCwin v1.2. One series equivalent circuit was deduced using ZView, whereas, two possible equivalent circuits (series and nested), leading to the same quality of fits, were evidenced in EqCwin. The circuits are closely related to interactions of the current collector and layer thickness effects of the cathodes. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Preparation of cathode materials for solid oxide solid fuel (SOFC) using gelatin; Preparacao de materiais catodicos para celulas a combustivel de oxido solido (SOFC) atraves do uso de gelatina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O., E-mail: rinaldo_mendesa@hotmail.com [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)

    2016-07-01

    Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca{sub 3}Co{sub 4}O{sub 9}, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)

  15. Controlled synthesis of LiNi0.5Mn1.5O4 cathode materials with superior electrochemical performance through urea-based solution combustion synthesis

    OpenAIRE

    Zhu, Chunyu; Han, Cheng-gong; Akiyama, Tomohiro

    2015-01-01

    High-voltage LiNi0.5Mn1.5O4 cathode materials were synthesized using urea-based solution combustion synthesis combined with a calcination treatment. The morphology and particle size distribution of the products were considerably dependent on the amount of urea fuel. The electrochemical characterization illustrated that the sample that was produced with a fuel ratio of phi = 0.5 had a homogenous particle size distribution of approximately 8 mu m, and showed the best cycling and rate performanc...

  16. Studies on bare and Mg-doped LiCoO2 as a cathode material for lithium ion batteries

    CSIR Research Space (South Africa)

    Reddy, MV

    2014-05-01

    Full Text Available cathodic and anodic redox peaks at 3.9 V and4.0 V, respectively. Galvanostatic cycling of Li(Mg(subx)Co(sub1-x)O(sub2) (x = 0, 0.03, 0.05) showed reversible charge capacity values at the 60th cycle to be: 147 (±3) mAh(sup g-1) (x = 0), 127 (±3) mAh(sup g-1...

  17. Co/Ti co-substituted layered LiNiO2 prepared using a concentration gradient method as an effective cathode material for Li-ion batteries

    Science.gov (United States)

    Ko, Hyoung Shin; Kim, Jea Han; Wang, Juan; Lee, Jong Dae

    2017-12-01

    The design of Li-ion batteries with high energy storage capacities and efficiencies is a subject of increased research interest, being of key importance for their large-scale applications and further commercialization. However, conventional Li-ion batteries are expensive and have stability-related concerns, which limit their practical applications. In our search for cheaper and safer Li-ion batteries, we use a concentration gradient method to prepare LiNi0.9Co0.1-xTixO2 (0.02 ≤ x ≤ 0.05) cathode materials surface-enriched with Co and Ti that exhibit decreased oxygen loss and improved structural stability. The corresponding crystal structures and morphologies are analyzed by X-ray diffraction and field emission scanning electron microscopy, with the Ni, Co, and Ti concentration distributions determined by energy-dispersive X-ray spectroscopy. The material with the best performance (x = 0.04) exhibits a discharge capacity of 214 mAh g-1 in a charge/discharge voltage range of 3.0-4.3 V (vs. Li/Li+), and possesses an excellent 50-cycle capacity retention of 98.7%. Thermogravimetric analysis shows that partial substitution of Ni with the strongly oxophilic Ti solves the problem of oxygen loss observed in Ni-rich cathode materials such as LiNiO2.

  18. Room temperature large-scale synthesis of layered frameworks as low-cost 4 V cathode materials for lithium ion batteries.

    Science.gov (United States)

    Hameed, A Shahul; Reddy, M V; Nagarathinam, M; Runčevski, Tomče; Dinnebier, Robert E; Adams, Stefan; Chowdari, B V R; Vittal, Jagadese J

    2015-11-23

    Li-ion batteries (LIBs) are considered as the best available technology to push forward the production of eco-friendly electric vehicles (EVs) and for the efficient utilization of renewable energy sources. Transformation from conventional vehicles to EVs are hindered by the high upfront price of the EVs and are mainly due to the high cost of LIBs. Hence, cost reduction of LIBs is one of the major strategies to bring forth the EVs to compete in the market with their gasoline counterparts. In our attempt to produce cheaper high-performance cathode materials for LIBs, an rGO/MOPOF (reduced graphene oxide/Metal-Organic Phosphate Open Framework) nanocomposite with ~4 V of operation has been developed by a cost effective room temperature synthesis that eliminates any expensive post-synthetic treatments at high temperature under Ar/Ar-H2. Firstly, an hydrated nanocomposite, rGO/K2[(VO)2(HPO4)2(C2O4)]·4.5H2O has been prepared by simple magnetic stirring at room temperature which releases water to form the anhydrous cathode material while drying at 90 °C during routine electrode fabrication procedure. The pristine MOPOF material undergoes highly reversible lithium storage, however with capacity fading. Enhanced lithium cycling has been witnessed with rGO/MOPOF nanocomposite which exhibits minimal capacity fading thanks to increased electronic conductivity and enhanced Li diffusivity.

  19. Room temperature large-scale synthesis of layered frameworks as low-cost 4 V cathode materials for lithium ion batteries

    Science.gov (United States)

    Hameed, A. Shahul; Reddy, M. V.; Nagarathinam, M.; Runčevski, Tomče; Dinnebier, Robert E.; Adams, Stefan; Chowdari, B. V. R.; Vittal, Jagadese J.

    2015-11-01

    Li-ion batteries (LIBs) are considered as the best available technology to push forward the production of eco-friendly electric vehicles (EVs) and for the efficient utilization of renewable energy sources. Transformation from conventional vehicles to EVs are hindered by the high upfront price of the EVs and are mainly due to the high cost of LIBs. Hence, cost reduction of LIBs is one of the major strategies to bring forth the EVs to compete in the market with their gasoline counterparts. In our attempt to produce cheaper high-performance cathode materials for LIBs, an rGO/MOPOF (reduced graphene oxide/Metal-Organic Phosphate Open Framework) nanocomposite with ~4 V of operation has been developed by a cost effective room temperature synthesis that eliminates any expensive post-synthetic treatments at high temperature under Ar/Ar-H2. Firstly, an hydrated nanocomposite, rGO/K2[(VO)2(HPO4)2(C2O4)]·4.5H2O has been prepared by simple magnetic stirring at room temperature which releases water to form the anhydrous cathode material while drying at 90 °C during routine electrode fabrication procedure. The pristine MOPOF material undergoes highly reversible lithium storage, however with capacity fading. Enhanced lithium cycling has been witnessed with rGO/MOPOF nanocomposite which exhibits minimal capacity fading thanks to increased electronic conductivity and enhanced Li diffusivity.

  20. Evaluation of Ca3(Co,M2O6 (M=Co, Fe, Mn, Ni as new cathode materials for solid-oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Fushao Li

    2015-10-01

    Full Text Available Series compounds Ca3(Co0.9M0.12O6 (M=Co, Fe, Mn, Ni with hexagonal crystal structure were prepared by sol–gel route as the cathode materials for solid oxide fuel cells (SOFCs. Effects of the varied atomic compositions on the structure, electrical conductivity, thermal expansion and electrochemical performance were systematically evaluated. Experimental results showed that the lattice parameters of Ca3(Co0.9Fe0.12O6 and Ca3(Co0.9Mn0.12O6 were both expanded to certain degree. Electron-doping and hole-doping effects were expected in Ca3(Co0.9Mn0.12O6 and Ca3(Co0.9Ni0.12O6 respectively according to the chemical states of constituent elements and thermal-activated behavior of electrical conductivity. Thermal expansion coefficients (TEC of Ca3(Co0.9M0.12O6 were measured to be distributed around 16×10−6 K−1, and compositional elements of Fe, Mn, and Ni were especially beneficial for alleviation of the thermal expansion problem of cathode materials. By using Ca3(Co0.9M0.12O6 as the cathodes operated at 800 °C, the interfacial area-specific resistance varied in the order of M=Cocathode materials for SOFCs.

  1. Polyaniline/multi-walled carbon nanotubes composite with core-shell structures as a cathode material for rechargeable lithium-polymer cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pan [School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209 (China); Han, Jia-Jun, E-mail: hanjiajunhitweihai@163.com [School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209 (China); Jiang, Li-Feng [Dalian Chemical Institute of Chinese Academy of Sciences, Dalian 116011 (China); Li, Zhao-Yu; Cheng, Jin-Ning [School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209 (China)

    2017-04-01

    Highlights: • The polyaniline multi-walled carbon nanotubes composite with core-shell structures was synthetized via in situ chemical oxidative polymerization, and the materials were characterized by physical and chemical methods. • The PANI/WMCNTs was synthetized via in situ chemical oxidative polymerization with core-shell structures. • The WMCNTs highly enhanced the conductivity of composites. • The comopsites were more conducive to the intercalation and deintercalation of anions and cations. • The much better performance as the cathode for lithium-ion cells was acquired for the composites. • The composites are low cost and eco-friendly which have a good prospect in future. - Abstract: The aniline was polymerized onto functionalized multi-walled carbon nanotubes in order to obtain a cathode material with core-shell structures for lithium batteries. The structure and morphology of the samples were investigated by Fourier transform infrared spectroscopy analysis, scanning electron microscope, transmission electron microscope and X-ray diffraction. The electrochemical properties of the composite were characterized by the cyclic voltammetry, the charge/discharge property, coulombic efficiency, and ac impedance spectroscopy in detail. At a constant current density of 0.2 C, the first specific discharge capacity of the reduced and oxidized PANI/WMCNTs were 181.8 mAh/g and 135.1 mAh/g separately, and the capacity retention rates were corresponding to 76.75% and 86.04% for 100 cycles with 99% coulombic efficiency. It was confirmed that the CNTs obviously enhanced the conductivity and electrochemical performance of polyaniline, and compared with the pure PANI, the reduced composite possessed a quite good performance for the cathode of lithium batteries.

  2. A facile method of preparing LiMnPO4/reduced graphene oxide aerogel as cathodic material for aqueous lithium-ion hybrid supercapacitors

    Science.gov (United States)

    Xu, Lin; Wang, Senlin; Zhang, Xiao; He, Taobin; Lu, Fengxia; Li, Huichang; Ye, Junhui

    2018-01-01

    A facile method of preparing LiMnPO4/reduced graphene oxide aerogel (LMP/rGO) as cathodic material was reported here. LiMnPO4 nano-particles were prepared using a facile polyvinyl pyrrolidone-assisted solvothermal route. Then LMP/rGO aerogel was prepared using the accessible restacking method. The influence of the cathodic electrode composition (ratio of rGO to LiMnPO4) on the performance of the LMP/rGO was evaluated by constant-current discharge tests. When compared with 217C g-1 for the pristine LMP, the best LMP/rGO (the content of rGO is 27.3 wt%) exhibits a higher capacity of 464.5C g-1 (at 0.5 A g-1), which presenting the capacity enhance of 114%. Moreover, a lithium-ion hybrid supercapacitor (LIHS) was successfully assembled by using LMP/rGO aerogel as the cathodic electrode and rGO aerogel as the anodic electrode. The LMP/rGO//rGO device achieves excellent specific energy of 16.46 W h kg-1 at a power density of 0.38 kW kg-1, even under the higher specific power of 4.52 kW kg-1, there still holds the specific energy of 11.79 W h kg-1. The LMP/rGO//rGO device maintains 91.2% of the initial capacity after 10,000 cycles (at 2 A g-1), which displays high rate performance and long cycle life. The 3D LMP/rGO aerogel could be a promising candidate material for the lithium-ion hybrid supercapacitors.

  3. Charge-discharge mechanisms of Li3V2(PO4)3 cathode materials in Li-batteries - studied by operando PXD

    DEFF Research Database (Denmark)

    Sørensen, Daniel Risskov; Mathiesen, Jette Katja; Henriksen, Christian

    potential and high theoretical capacity (197 mAh g-1) . The material exhibits distinct potential plateaus during Li-extraction for the crystallographic distinct lithium ions, which is typically a sign of a multiphase system where each phase determines the potential2. In this work, we wished to explore......Rechargeable Li-ion batteries are widely recognized as an enabling technology for electrochemical energy storage in applications ranging from small portable electronics over electric vehicles to grid-scale electricity storage1. However, Li-ion batteries still face challenges in terms...... of their safety, cost, energy density and rate performance. Herein lie the demand for new electrode materials that can provide the required battery properties. Monoclinic Li3V2(PO4)3 (LVP) is a well-known candidate as a cathode material in rechargeable Li-batteries, showing good cyclic stability, high operating...

  4. Influence of acids in the Ppy/V{sub 2}O{sub 5} hybrid synthesis and performance as a cathode material

    Energy Technology Data Exchange (ETDEWEB)

    Boyano, I.; Bengoechea, M.; de Meatza, I.; Miguel, O.; Ochoteco, E.; Grande, H. [CIDETEC, Energy Department, Paseo Miramon 196, Parque Tecnologico de San Sebastian, 20009 San Sebastian, Guipuzcoa (Spain); Cantero, I. [CEGASA, C/Artapadura, 11, 01013 Vitoria-Gasteiz, Alava (Spain); Lira-Cantu, M.; Gomez-Romero, P. [Instituto de Ciencia de Materiales de Barcelona (CSIC) Campus UAB, 08193 Bellaterra, Barcelona (Spain)

    2007-12-06

    Vanadium oxide (V{sub 2}O{sub 5}) is a candidate as cathodic material for lithium ion batteries. With the aim of improving the electrode performance, Polypyrrole (Ppy) has been proposed as binder and conducting element in the oxide structure. The hybrid synthesis has been carried out in the literature by chemical polymerization of Pyrrole in the host inorganic matrix, in some cases using the V{sub 2}O{sub 5} dispersed in an acidic solution as an oxidizing agent. The hybrid material can be prepared using different acidic solutions that can influence the polymerization process affecting the electrochemical properties of the final hybrid material. The reasons and consequences for this influence are discussed and analyzed using different experimental techniques. (author)

  5. The effect of Y2O3 addition on thermal shock behavior of magnesium aluminate spinel

    Directory of Open Access Journals (Sweden)

    Pošarac Milica

    2009-01-01

    Full Text Available The effect of yttria additive on the thermal shock behavior of magnesium aluminate spinel has been investigated. As a starting material we used spinel (MgAl2O4 obtained by the modified glycine nitrate procedure (MGNP. Sintered products were characterized in terms of phase analysis, densities, thermal shock, monitoring the damaged surface area in the refractory specimen during thermal shock and ultrasonic determination of the Dynamic Young modulus of elasticity. It was found that a new phase between yttria and alumina is formed, which improved thermal shock properties of the spinel refractories. Also densification of samples is enhanced by yttria addition.

  6. A strategy of constructing spherical core-shell structure of Li1.2Ni0.2Mn0.6O2@Li1.2Ni0.4Mn0.4O2 cathode material for high-performance lithium-ion batteries

    Science.gov (United States)

    Chong, Shaokun; Wu, Yifang; Chen, Yuanzhen; Shu, Chengyong; Liu, Yongning

    2017-07-01

    Serious decay of capacity and voltage for Li-rich layered cathode materials restrict their commercial application for Li-ion batteries. In this paper, a spherical core-shell structure, Li1.2Ni0.2Mn0.6O2@Li1.2Ni0.4Mn0.4O2 was in-situ prepared using hydrothermal method. SEM images as well as the analysis with XPS and EDS verified that the core-shell structure grows well. Electrochemical properties showed that the merits of the both materials have been preserved for high capacity of core material and high voltage as well as superior cycling stability of shell material. C/S-1/1 sample, whose mass proportion of core to shell is 1:1, exhibits the initial discharge capacity of 218 mAh·g-1 with the highest operating voltage of 3.763 V at 0.1C between 2.0 and 4.8 V, splendid cycling stability with the capacity retention of 93.1% and high voltage retention value of 3.335 V after 100 cycles. The improvement of electrochemical performances are attributed to the stable Li1.2Ni0.4Mn0.4O2 protective shell, which is beneficial to improve the electrochemical kinetics, mitigate the morphology evolution and retard the layered-spinel phase transition by restraining the release of O2 and weakening the electrode-electrolyte interfacial reaction.

  7. Quantitative structure-property relationship study of cathode volume changes in lithium ion batteries using ab-initio and partial least squares analysis

    Directory of Open Access Journals (Sweden)

    Xuelong Wang

    2017-09-01

    Full Text Available In this paper, we report a method through the combination of ab-initio calculations and partial least squares (PLS analysis to develop the Quantitative Structure –Activity Relationship (QSAR formulations of cathode volume changes in lithium ion batteries. The PLS analysis is based on ab-initio calculation data of 14 oxide cathodes with spinel structure LiX2O4 and 14 oxide cathodes with layered-structure LiXO2 (X = Ti, V, Cr, Mn, Fe, Co, Ni, Nb, Mo, Ru, Rh, Pd, Ta, Ir. Five types of descriptors, describing the characteristics of each compound from crystal structure, element, composition, local distortion and electronic level, with 34 factors in total, are adopted to obtain the QSAR formulation. According to the variable importance in projection analysis, the radius of X4+ ion, and the X octahedron descriptors make major contributions to the volume change of cathode during delithiation. The analysis is hopefully applied to the virtual screening and combinatorial design of low-strain cathode materials for lithium ion batteries.

  8. Position Assignment and Oxidation State Recognition of Fe and Co Centers in Heterometallic Mixed-Valent Molecular Precursors for the Low-Temperature Preparation of Target Spinel Oxide Materials

    Energy Technology Data Exchange (ETDEWEB)

    Lieberman, Craig M. [Department of Chemistry, University at Albany, Albany, New York 12222, United States; Barry, Matthew C. [Department of Chemistry, University at Albany, Albany, New York 12222, United States; Wei, Zheng [Department of Chemistry, University at Albany, Albany, New York 12222, United States; Rogachev, Andrey Yu. [Department; Wang, Xiaoping [Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States; Liu, Jun-Liang [CNRS, CRPP, UPR 8641, F-33600 Pessac, France; Univ. Bordeaux, UPR 8641, F-33600 Pessac, France; MOE Key Lab of Bioinorganic and Synthetic Chemistry,; Clérac, Rodolphe [CNRS, CRPP, UPR 8641, F-33600 Pessac, France; Univ. Bordeaux, UPR 8641, F-33600 Pessac, France; Chen, Yu-Sheng [ChemMatCARS, Center for Advanced Radiation; Filatov, Alexander S. [Department; Dikarev, Evgeny V. [Department of Chemistry, University at Albany, Albany, New York 12222, United States

    2017-07-31

    A series of mixed-valent, heterometallic (mixed-transition metal) diketonates that can be utilized as prospective volatile single-source precursors for the low-temperature preparation of MxM'3–xO4 spinel oxide materials is reported. Three iron–cobalt complexes with Fe/Co ratios of 1:1, 1:2, and 2:1 were synthesized by several methods using both solid-state and solution reactions. On the basis of nearly quantitative reaction yields, elemental analyses, and comparison of metal–oxygen bonds with those in homometallic analogues, heterometallic compounds were formulated as [FeIII(acac)3][CoII(hfac)2] (1), [CoII(hfac)2][FeIII(acac)3][CoII(hfac)2] (2), and [FeII(hfac)2][FeIII(acac)3][CoII(hfac)2] (3). In the above heteroleptic complexes, the Lewis acidic, coordinatively unsaturated CoII/FeII centers chelated by two hexafluoroacetylacetonate (hfac) ligands maintain bridging interactions with oxygen atoms of acetylacetonate (acac) groups that chelate the neighboring FeIII metal ion. Preliminary assignment of Fe and Co positions/oxidation states in 1–3 drawn from X-ray structural investigation was corroborated by a number of complementary techniques. Single-crystal resonant synchrotron diffraction and neutron diffraction experiments unambiguously confirmed the location of Fe and Co sites in the molecules of dinuclear (1) and trinuclear (2) complexes, respectively. Direct analysis in real time mass spectrometry revealed the presence of FeIII- and CoII-based fragments in the gas phase upon evaporation of precursors 1 and 2 as well as of FeIII, FeII, and CoII species for complex 3. Theoretical investigation of two possible “valent isomers”, [FeIII(acac)3

  9. Improvement in the Ppy/V{sub 2}O{sub 5} hybrid as a cathode material for Li ion batteries using PSA as an organic additive

    Energy Technology Data Exchange (ETDEWEB)

    Boyano, I.; Bengoechea, M.; de Meatza, I.; Miguel, O.; Ochoteco, E.; Rodriguez, J. [CIDETEC, Energy Department, Paseo Miramon 196, Parque Tecnologico de San Sebastian, 20009 Donostia-San Sebastian (Spain); Cantero, I. [CEGASA, C/Artapadura, 11, 01013 Vitoria-Gasteiz (Spain); Lira-Cantu, M.; Gomez-Romero, P. [Instituto de Ciencia de Materiales de Barcelona (CSIC), Campus UAB, 08193 Bellaterra, Barcelona (Spain)

    2007-04-15

    With the aim of improving the electrochemical properties of this candidate cathodic material for lithium ion batteries, a vanadium oxide (V{sub 2}O{sub 5}) and polypyrrole (Ppy) hybrid was prepared using pyridinesulfonic acid (PSA) as additive. The hybrid synthesis has been carried out in the literature by chemical polymerization of pyrrole in the host inorganic matrix, using the V{sub 2}O{sub 5} dispersed in an acidic solution as an oxidizing agent. In this work the hybrid has been synthesised with PSA giving good results compared to other samples of the pristine V{sub 2}O{sub 5} and to the Ppy/V{sub 2}O{sub 5} hybrid without additive. An improvement of about 20% in the charge storage capacity has been achieved. The reasons for this improvement are discussed and analyzed using different experimental techniques. The hybrid material has the added advantage of an improved performance without the addition of any binder or conducting element as a cathode in a lithium ion battery. (author)

  10. Synthesis of three-dimensionally interconnected sulfur-rich polymers for cathode materials of high-rate lithium–sulfur batteries

    Science.gov (United States)

    Kim, Hoon; Lee, Joungphil; Ahn, Hyungmin; Kim, Onnuri; Park, Moon Jeong

    2015-01-01

    Elemental sulfur is one of the most attractive cathode active materials in lithium batteries because of its high theoretical specific capacity. Despite the positive aspect, lithium–sulfur batteries have suffered from severe capacity fading and limited rate capability. Here we report facile large-scale synthesis of a class of organosulfur compounds that could open a new chapter in designing cathode materials to advance lithium–sulfur battery technologies. Porous trithiocyanuric acid crystals are synthesized for use as a soft template, where the ring-opening polymerization of elemental sulfur takes place along the thiol surfaces to create three-dimensionally interconnected sulfur-rich phases. Our lithium–sulfur cells display discharge capacity of 945 mAh g−1 after 100 cycles at 0.2 C with high-capacity retention of 92%, as well as lifetimes of 450 cycles. Particularly, the organized amine groups in the crystals increase Li+-ion transfer rate, affording a rate performance of 1210, mAh g−1 at 0.1 C and 730 mAh g−1 at 5 C. PMID:26065407

  11. Synthesis, characterization and rate capability performance of the micro-porous MnO{sub 2} nanowires as cathode material in lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    R, Ranjusha; S, Sonia T.; S, Roshny; V, Lakshmi [Nano Solar Division, Amrita Centre for Nanosciences, Kochi 682 041 (India); Kalluri, Sujith [Institute for Superconducting and Electronic Materials, University of Wollongong, New South Wales 2500 (Australia); Kim, Taik Nam [Department of Materials Engineering, Paichai University, Daejeon 302-735 (Korea, Republic of); Nair, Shantikumar V. [Nano Solar Division, Amrita Centre for Nanosciences, Kochi 682 041 (India); Balakrishnan, A., E-mail: avinash.balakrishnan@gmail.com [Nano Solar Division, Amrita Centre for Nanosciences, Kochi 682 041 (India)

    2015-10-15

    Graphical abstract: Translating MnO{sub 2} nanowires as cathode materials in coin cell and studying their discharge behavior and cycling stability at different C-rates. - Highlights: • MnO{sub 2} nanowires have been synthesized via hydrothermal route. • The nanowires were employed as cathode materials in Li-batteries. • Discharge and cycling stability were studied at different C-rates. • Specific capacity and power density of 251 mAh g{sup −1} and 200 W kg{sup −1} were attained. - Abstract: A peculiar architecture of one-dimensional MnO{sub 2} nanowires was synthesized by an optimized hydrothermal route and has been lucratively exploited to fabricate highly efficient microporous electrode overlays for lithium batteries. These fabricated electrodes comprised of interconnected nanoscale units with wire-shaped profile which exhibits high aspect ratio in the order of 10{sup 2}. Their outstanding intercalation/de-intercalation prerogatives have also been studied to fabricate lithium coin cells which revealed a significant specific capacity and power density of 251 mAh g{sup −1} and 200 W kg{sup −1}, respectively. A detailed electrochemical study was performed to elucidate how surface morphology and redox reaction behaviors underlying these electrodes influence the cyclic behavior of the electrode. Rate capability tests at different C-rates were performed to evaluate the capacity and cycling performance of these coin cells.

  12. Synthesis of LiFePO4/Graphene Nanocomposite and Its Electrochemical Properties as Cathode Material for Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Xiaoling Ma

    2015-01-01

    Full Text Available LiFePO4/graphene nanocomposite was successfully synthesized by rheological phase method and its electrochemical properties as the cathode materials for lithium ion batteries were measured. As the iron source in the synthesis, FeOOH nanorods anchored on graphene were first synthesized. The FeOOH nanorods precursors and the final LiFePO4/graphene nanocomposite products were characterized by XRD, SEM, and TEM. While the FeOOH precursors were nanorods with 5–10 nm in diameter and 10–50 nm in length, the LiFePO4 were nanoparticles with 20–100 nm in size. Compared with the electrochemical properties of LiFePO4 particles without graphene nanosheets, it is clear that the graphene nanosheets can improve the performances of LiFePO4 as the cathode material for lithium ion batteries. The as-synthesized LiFePO4/graphene nanocomposite showed high capacities and good cyclabilities. When measured at room temperature and at the rate of 0.1C (1C = 170 mA g−1, the composite showed a discharge capacity of 156 mA h g−1 in the first cycle and a capacity retention of 96% after 15 cycles. The improved performances of the composite are believed to be the result of the three-dimensional conducting network formed by the flexible and planar graphene nanosheets.

  13. Synthesis of three-dimensionally interconnected sulfur-rich polymers for cathode materials of high-rate lithium-sulfur batteries.

    Science.gov (United States)

    Kim, Hoon; Lee, Joungphil; Ahn, Hyungmin; Kim, Onnuri; Park, Moon Jeong

    2015-06-12

    Elemental sulfur is one of the most attractive cathode active materials in lithium batteries because of its high theoretical specific capacity. Despite the positive aspect, lithium-sulfur batteries have suffered from severe capacity fading and limited rate capability. Here we report facile large-scale synthesis of a class of organosulfur compounds that could open a new chapter in designing cathode materials to advance lithium-sulfur battery technologies. Porous trithiocyanuric acid crystals are synthesized for use as a soft template, where the ring-opening polymerization of elemental sulfur takes place along the thiol surfaces to create three-dimensionally interconnected sulfur-rich phases. Our lithium-sulfur cells display discharge capacity of 945 mAh g(-1) after 100 cycles at 0.2 C with high-capacity retention of 92%, as well as lifetimes of 450 cycles. Particularly, the organized amine groups in the crystals increase Li(+)-ion transfer rate, affording a rate performance of 1210, mAh g(-1) at 0.1 C and 730 mAh g(-1) at 5 C.

  14. Influence of thermal-decomposition temperatures on structures and properties of V2O5 as cathode materials for lithium ion battery

    Directory of Open Access Journals (Sweden)

    Yu Chen

    2015-02-01

    Full Text Available Submicron spherical V2O5 particles with a uniform size and a lower crystallinity were successfully synthesized by a chemical precipitation-thermal decomposition technique using the commercial V2O5 powders as starting material. The crystal structure and grain morphology of samples were characterized by X-ray diffraction (XRD and scanning electron microscopy (SEM, respectively. Electrochemical testing such as discharge–charge cycling (CD and cyclic voltammetry (CV were employed in evaluating their electrochemical properties as cathode materials for lithium ion battery. Results reveal that the crystallinity and crystalline size of V2O5 particles increased when the thermal-decomposition temperature increased from 400 °C to 500 °C, and their adhesiveness was also synchronously increased. This indicate that the thermal-decomposition temperature palyed a significant influence on electrochemical properties of V2O5 cathodes. The V2O5 sample obtained at 400 °C delivered not only a high initial discharge capacity of 330 mA h g−1 and also the good cycle stability during 50 cycles due to its higher values of α in crystal structure and better dispersity in grain morphology.

  15. Recent Progress in the Design of Advanced Cathode Materials and Battery Models for High-Performance Lithium-X (X = O2 , S, Se, Te, I2 , Br2 ) Batteries.

    Science.gov (United States)

    Xu, Jiantie; Ma, Jianmin; Fan, Qinghua; Guo, Shaojun; Dou, Shixue

    2017-07-01

    Recent advances and achievements in emerging Li-X (X = O2 , S, Se, Te, I2 , Br2 ) batteries with promising cathode materials open up new opportunities for the development of high-performance lithium-ion battery alternatives. In this review, we focus on an overview of recent important progress in the design of advanced cathode materials and battery models for developing high-performance Li-X (X = O2 , S, Se, Te, I2 , Br2 ) batteries. We start with a brief introduction to explain why Li-X batteries are important for future renewable energy devices. Then, we summarize the existing drawbacks, major progress and emerging challenges in the development of cathode materials for Li-O2 (S) batteries. In terms of the emerging Li-X (Se, Te, I2 , Br2 ) batteries, we systematically summarize their advantages/disadvantages and recent progress. Specifically, we review the electrochemical performance of Li-Se (Te) batteries using carbonate-/ether-based electrolytes, made with different electrode fabrication techniques, and of Li-I2 (Br2 ) batteries with various cell designs (e.g., dual electrolyte, all-organic electrolyte, with/without cathode-flow mode, and fuel cell/solar cell integration). Finally, the perspective on and challenges for the development of cathode materials for the promising Li-X (X = O2 , S, Se, Te, I2 , Br2 ) batteries is presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Structural characterization of layered Na0.5Co0.5Mn0.5O2 material as a promising cathode for sodium-ion batteries

    Science.gov (United States)

    Manikandan, Palanisamy; Heo, Seongwoo; Kim, Hyun Woo; Jeong, Hu Young; Lee, Eungje; Kim, Youngsik

    2017-09-01

    Layered Na0.5Co0.5Mn0.5O2 material is synthesized through a facile mixed hydroxy-carbonate route using (Co0.5Mn0.5)2(OH)2CO3 precursor and well characterized as a hexagonal layered structure under P63/mmc space group. The lattice parameters and unit cell volume (a = 2.8363 Å, c = 11.3152 Å and V = 78.83 Å3) are calculated by Rietveld refinement analysis. A flaky-bundle morphology is obtained to the layered Na0.5Co0.5Mn0.5O2 material with the hexagonal flake size ∼30 nm. Advanced transmission electron microscopic images are revealed the local structure of the layered Na0.5Co0.5Mn0.5O2 material with contrasting bright dots and faint dark dots corresponding to the Co/Mn and Na atoms. Two oxidation and reduction peaks are occurred in a cyclic voltammetric analysis corresponding to Co3+/Co4+ and Mn3+/Mn4+ redox processes. These reversible processes are attributed to the intercalation/de-intercalation of Na+ ions into the host structure of layered Na0.5Co0.5Mn0.5O2 material. Accordingly, the sodium cell is delivered the initial charge-discharge capacity 53/144 mAh g-1 at 0.5 C, which cycling studies are extended to rate capability test at 1 C, 3 C and 5C. Eventually, the Na-ion full-cell is yielded cathode charge-discharge capacity 55/52 mAh g-1 at 0.212 mA and exhibited as a high voltage cathode for Na-ion batteries.

  17. A Dual-Function Na2 SO4 Template Directed Formation of Cathode Materials with a High Content of Sulfur Nanodots for Lithium-Sulfur Batteries.

    Science.gov (United States)

    Luo, Chong; Lv, Wei; Deng, Yaqian; Zhou, Guangmin; Pan, Zheng-Ze; Niu, Shuzhang; Li, Baohua; Kang, Feiyu; Yang, Quan-Hong

    2017-07-01

    The sulfur content in carbon-sulfur hybrid using the melt-diffusion method is normally lower than 70 wt%, which greatly decreases the energy density of the cathode in lithium-sulfur (Li-S) batteries. Here, a scalable method inspired by the commercialized production of Na2 S is used to prepare a hierarchical porous carbon-sulfur hybrid (denoted HPC-S) with high sulfur content (≈85 wt%). The HPC-S is characterized by the structure of sulfur nanodots naturally embedded in a 3D carbon network. The strategy uses Na2 SO4 as the starting material, which serves not only as the sulfur precursor but also as a salt template for the formation of the 3D carbon network. The HPC-S cathode with such a high sulfur content shows excellent rate performance and cycling stability in Li-S batteries because of the sulfur nanoparticles, the unique carbon framework, and the strong interaction between them. The production method can also be readily scaled up and used in practical Li-S battery applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Polyaniline/multi-walled carbon nanotubes composite with core-shell structures as a cathode material for rechargeable lithium-polymer cells

    Science.gov (United States)

    Liu, Pan; Han, Jia-Jun; Jiang, Li-Feng; Li, Zhao-Yu; Cheng, Jin-Ning

    2017-04-01

    The aniline was polymerized onto functionalized multi-walled carbon nanotubes in order to obtain a cathode material with core-shell structures for lithium batteries. The structure and morphology of the samples were investigated by Fourier transform infrared spectroscopy analysis, scanning electron microscope, transmission electron microscope and X-ray diffraction. The electrochemical properties of the composite were characterized by the cyclic voltammetry, the charge/discharge property, coulombic efficiency, and ac impedance spectroscopy in detail. At a constant current density of 0.2 C, the first specific discharge capacity of the reduced and oxidized PANI/WMCNTs were 181.8 mAh/g and 135.1 mAh/g separately, and the capacity retention rates were corresponding to 76.75% and 86.04% for 100 cycles with 99% coulombic efficiency. It was confirmed that the CNTs obviously enhanced the conductivity and electrochemical performance of polyaniline, and compared with the pure PANI, the reduced composite possessed a quite good performance for the cathode of lithium batteries.

  19. On the Defect Chemistry, Electrical Properties and Electrochemical Performances As Solid Oxide Fuel Cell Cathode Materials of New La-(Sr/Vac)-Co-Ti-O Perovskites

    DEFF Research Database (Denmark)

    García-Alvarado, Flaviano; Gómez-Pérez, Alejandro; Pérez-Flores, Juan Carlos

    2015-01-01

    Perovskite-type oxides are well known materials that have been proposed as electrodes and electrolytes for solid oxide fuel cells (SOFCs). The structure, which is referred to the ABO3 stoichiometry, can accommodate many different transition metal ions in the B-site; its electronic conductivity...... conductivity in the pO2 range analyzed. The preliminary evaluation of the electrodes performance reveals polarization resistances in the 0.6-0.9 Ωcm2 range at 1073 K in oxygen for La2-xSrxCoTiO6-δ, which is fairly similar to the values obtained for LSM-based cathodes. However much higher polarization...... resistances are found for the La2-xCoTiO6-δ with values between 2.6-9.6 Ωcm2 in air at 1073 K. Additional electrochemical experiments to determine performances of planar (1-2 cm2) single SOFC bearing La2-xSrxCoTiO6-δ as the cathode are now in progress....

  20. (Bi,Sr (Fe1−x,MxO3−δ (M = Co, Ni and Mn Cathode Materials with Mixed Electro-Ionic Conductivity

    Directory of Open Access Journals (Sweden)

    Wen-Cheng J. Wei

    2016-11-01

    Full Text Available (Bi,SrFeO3−δ (BSF cathode materials doped with either Co, Ni or Mn are synthesized by an ethylene diamine tetra-acetic acid (EDTA-citrate complexing method, and the effects of the doping level on the mixed electronic-ionic conductivity at various temperatures are studied up to 800 °C. The phase purity and solid solution limit are investigated by X-ray diffraction (XRD. The ionic conductivity is measured by the four-probe direct current (DC method, the valence state of Fe and Mn by X-ray photoelectron spectroscopy (XPS, and the oxygen non-stoichiometry by differential thermo-gravimetric analysis (TGA. The doped ferrites show interesting electronic conductivity dependent on the testing temperature, implying two conductive mechanisms, either controlled by double exchange at lower temperatures or small polaron (electron-oxygen vacancy conduction at temperatures greater than 400 °C. The results of Co-doped BSF (S50C20 show the best mixed conductivity among the ferrites, and this is used to assemble cells. The cell with a S50C20 cathode in the region of 600–800 °C is improved by 15% in maximum power density greater than the cell with La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF due to the balanced contribution from oxygen ions, vacancies and electrons.

  1. Synthesis and structural stability of Cr-doped Li2MnSiO4/C cathode materials by solid-state method

    Science.gov (United States)

    Cheng, Hong-Mei; Zhao, Shi-Xi; Wu, Xia; Zhao, Jian-Wei; Wei, Lei; Nan, Ce-Wen

    2018-03-01

    The crystal structure of the Li2MnSiO4 cathode material would collapse during the charge and discharge process because of that the Mn-O coordination polyhedron changed from [MnO4] into [MnO6] in the process of Mn+2 to Mn+4, but the Cr element could remain [CrO4] crystal ligand from Cr+2 to Cr+4, so Cr element substitution was used to improve the structural stability of the Li2MnSiO4 cathode material. In this work, Li2Mn1-xCrxSiO4/C nanocomposites were synthesized by solid-state method. XRD, SEM and TEM observations show that the as-prepared Li2Mn1-xCrxSiO4/C materials presents an orthorhombic crystal structure (S.G. Pmn21), the particle size of Li2Mn1-xCrxSiO4/C powder ranges from 50 to 100 nm. The XRD and XPS results indicate that Cr+2 is successfully doped into Li2MnSiO4 lattice and has well compatibility with Li2MnSiO4. The electrochemical results display that Li2Mn92.5%Cr7.5%SiO4/C exhibits significantly enhanced cycle stability and discharge capability. The initial discharge capacity of the Li2Mn92.5%Cr7.5%SiO4/C sample is 255 mAh g-1, and the discharge capacity was still about 60 mAh g-1 after 50 cycles. Furthermore, the XRD patterns, TEM images and Raman analysis reveal that the Cr doping enhances the structural stability of Li2Mn1-xCrxSiO4/C and improves the electrochemical activity of the cathode. Thus, the Li2Mn92.5%Cr7.5%SiO4/C have shown potential applications for lithium ion batteries.

  2. The preparation and graphene surface coating NaTi{sub 2}(PO{sub 4}){sub 3} as cathode material for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Na; Wang, Yanping; Rao, Richuan; Dong, Xiongzi [Department of Chemical and Chemical Engineering, Hefei normal University, Hefei, Anhui 230601 (China); Zhang, Xianwen, E-mail: 18326056237@163.com [Institute of Advanced Energy Technology & Equipment, Hefei University of Technology, 193 Tunxi Road, Hefei, Anhui 230009 (China); Zhu, Sane, E-mail: sdjnlina@163.com [Department of Chemistry and Materials Engineering, Hefei University, Hefei, Anhui 230601 (China)

    2017-03-31

    Graphical abstract: The NaTi{sub 2}(PO{sub 4}){sub 3}/graphene composite is used directly as cathode electrode material for lithium-ion battery by using metal lithium as an anode electrode. Meanwhile, the electrochemical properties of the composite in this system is firstly studied in detail. The NaTi{sub 2}(PO{sub 4}){sub 3}/graphene composite exhibits the better rate and cyclic performance than NaTi{sub 2}(PO{sub 4}){sub 3}, which is ascribed to its stable 3-D framework and the enhanced electronic conduction resulting from the graphene sheets surface modification. - Highlights: • The graphene coated NaTi{sub 2}(PO{sub 4}){sub 3} was prepared by a simple sol-gel method followed by calcination. • The electrochemical properties of the NaTi{sub 2}(PO{sub 4}){sub 3}/graphene composite was firstly studied in detail when used as cathode electrode material for lithium-ion batteries. • The electrochemical reaction mechanism of NaTi{sub 2}(PO{sub 4}){sub 3}/graphene composite was investigated by ex situ XRD. - Abstract: The graphene coated NaTi{sub 2}(PO{sub 4}){sub 3} has been fabricated via a simple sol-gel process followed by calcination. The NaTi{sub 2}(PO{sub 4}){sub 3}/graphene (NTP/G) composite is used directly as cathode electrode material for lithium-ion battery and the electrochemical properties of the composite in this system is firstly studied in detail. In the charge-discharge process, two Li{sup +} can occupy octahedral M (2) site and be reversibly intercalated into the 3D framework of NTP through the ion conduction channel where almost all of Na{sup +} are immobilized to sustain the framework. At 5C rate, the capacity retention of the NTP/G composite after 800 cycles is still up to 82.7%. The superior electrochemical properties of NTP/G is ascribed to its stable 3-D framework and the enhanced electronic conduction resulting from the graphene sheets surface modification.

  3. The bearing of spinel cataclasites on the crust-mantle structure of the moon

    Science.gov (United States)

    Herzberg, C. T.

    1978-01-01

    Subsolidus thermodynamic calculations have been made to define the temperature and pressure conditions required to equilibrate lunar spinel cataclasites (olivine + high alumina orthopyroxene + pleonaste spinel + plagioclase + or - cordierite) that occur as clasts in 15445, 73263, and 72435. The results, which are subject to modification by improved thermodynamic data and experiment, indicate that those samples that are cordierite-free and of high Mg/(Mg + Fe) were derived from the lower crust and possibly from a high-velocity zone of the uppermost mantle. However, the cordierite-bearing type in 72435,8 /low Mg/(Mg + Fe)/ resided in the upper levels of the crust prior to excavation by impact. Consideration of the relevant supersolidus phase equilibria indicates that the whole-rock chemistry of all spinel cataclasites can only be explained by pleonaste spinel accumulation. These materials are interpreted to be primordial cumulate rocks formed during the differentiation of the lunar magma ocean.

  4. Sulfonate-immobilized artificial cathode electrolyte interphases layer on Ni-rich cathode

    Science.gov (United States)

    Chae, Bum-Jin; Yim, Taeeun

    2017-08-01

    Although lithium nickel cobalt manganese layered oxides with a high nickel composition have gained great attention due to increased overall energy density for energy conversion/storage systems, poor interfacial stability is considered a critical bottleneck impeding its widespread adoption. We propose a new approach based on immobilizing the artificial cathode-electrolyte interphase layer, which effectively reduces undesired surface reactions, leading to high interfacial stability of cathode material. For installation of artificial cathode-electrolyte interphases, a sulfonate-based amphiphilic organic precursor, which effectively suppresses electrolyte decomposition, is synthesized and subjected to immobilization on cathode material via simple wet-coating, followed by heat treatment at low temperature. The sulfonate-based artificial cathode-electrolyte interphase layer is well-developed on the cathode surface, and the cell controlled by the sulfonate-immobilized cathode exhibits remarkable electrochemical performance, including a high average Coulombic efficiency (99.8%) and cycling retention (97.4%) compared with pristine cathode material. The spectroscopic analyses of the cycled cathode show that the sulfonate-based artificial cathode-electrolyte interphase layer effectively mitigates electrolyte decomposition on the cathode surface, resulting in decreased interfacial resistance between electrode and electrolyte.

  5. Redox-Reversible Iron Orthovanadate Cathode for Solid Oxide Steam Electrolyzer.

    Science.gov (United States)

    Gan, Lizhen; Ye, Lingting; Ruan, Cong; Chen, Shigang; Xie, Kui

    2016-02-01

    A redox-reversible iron orthovanadate cathode is demonstrated for a solid oxide electrolyser with up to 100% current efficiency for steam electrolysis. The iron catalyst is grown on spinel-type electronic conductor FeV2O4 by in situ tailoring the reversible phase change of FeVO4 to Fe+FeV2O4 in a reducing atmosphere. Promising electrode performances have been obtained for a solid oxide steam electrolyser based on this composite cathode.

  6. Study of the Durability of Doped Lanthanum Manganite and Cobaltite Cathode Materials under ''Real World'' Air Exposure Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Prabhakar [Univ. of Connecticut, Storrs, CT (United States); Mahapatra, Manoj [Univ. of Connecticut, Storrs, CT (United States); Ramprasad, Rampi [Univ. of Connecticut, Storrs, CT (United States); Minh, Nguyen [Univ. of California, San Diego, CA (United States); Misture, Scott [Alfred Univ., NY (United States)

    2014-11-30

    The overall objective of the program is to develop and validate mechanisms responsible for the overall structural and chemical degradation of lanthanum manganite as well as lanthanum ferrite cobaltite based cathode when exposed to “real world” air atmosphere exposure conditions during SOFC systems operation. Of particular interest are the evaluation and analysis of degradation phenomena related to and responsible for (a) products formation and interactions with air contaminants, (b) dopant segregation and oxide exolution at free surfaces, (c) cation interdiffusion and reaction products formation at the buried interfaces, (d) interface morphology changes, lattice transformation and the development of interfacial porosity and (e) micro-cracking and delamination from the stack repeat units. Reaction processes have been studied using electrochemical and high temperature materials compatibility tests followed by structural and chemical characterization. Degradation hypothesis has been proposed and validated through further experimentation and computational simulation.

  7. Polymer-Templated LiFePO4/C Nanonetworks as High-Performance Cathode Materials for Lithium-Ion Batteries.

    Science.gov (United States)

    Fischer, Michael G; Hua, Xiao; Wilts, Bodo D; Castillo-Martínez, Elizabeth; Steiner, Ullrich

    2018-01-17

    Lithium iron phosphate (LFP) is currently one of the main cathode materials used in lithium-ion batteries due to its safety, relatively low cost, and exceptional cycle life. To overcome its poor ionic and electrical conductivities, LFP is often nanostructured, and its surface is coated with conductive carbon (LFP/C). Here, we demonstrate a sol-gel based synthesis procedure that utilizes a block copolymer (BCP) as a templating agent and a homopolymer as an additional carbon source. The high-molecular-weight BCP produces self-assembled aggregates with the precursor-sol on the 10 nm scale, stabilizing the LFP structure during crystallization at high temperatures. This results in a LFP nanonetwork consisting of interconnected ∼10 nm-sized particles covered by a uniform carbon coating that displays a high rate performance and an excellent cycle life. Our "one-pot" method is facile and scalable for use in established battery production methodologies.

  8. Template-Engaged Synthesis of 1D Hierarchical Chainlike LiCoO2 Cathode Materials with Enhanced High-Voltage Lithium Storage Capabilities.

    Science.gov (United States)

    Wu, Naiteng; Zhang, Yun; Wei, Yunhong; Liu, Heng; Wu, Hao

    2016-09-28

    A novel 1D hierarchical chainlike LiCoO2 organized by flake-shaped primary particles is synthesized via a facile template-engaged strategy by using CoC2O4·2H2O as a self-sacrificial template obtained from a simple coprecipitation method. The resultant LiCoO2 has a well-built hierarchical structure, consisting of secondary micrometer-sized chains and sub-micrometer-sized primary flakes, while these primary LiCoO2 flakes have specifically exposed fast-Li(+)-diffused active {010} facets. Owing to this unique hierarchical structure, the chainlike LiCoO2 serves as a stable cathode material for lithium-ion batteries (LIBs) operated at a high cutoff voltage up to 4.5 V, enabling highly reversible capacity, remarkable rate performance, and long-term cycle life. Specifically, the chainlike LiCoO2 can deliver a reversible discharge capacity as high as 168, 156, 150, and 120 mAh g(-1) under the current density of 0.1, 0.5, 1, and 5 C, respectively, while about 85% retention of the initial capacity can be retained after 200 cycles under 1 C at room temperature. Moreover, the chainlike LiCoO2 also shows an excellent cycling stability at a wide operating temperature range, showing the capacity retention of ∼73% after 200 cycles at 55 °C and of ∼68% after 50 cycles at -10 °C, respectively. The work described here suggests the great potential of the hierarchical chainlike LiCoO2 as high-voltage cathode materials aimed toward developing advanced LIBs with high energy density and power density.

  9. High Rate and Stable Li-Ion Insertion in Oxygen-Deficient LiV3O8 Nanosheets as a Cathode Material for Lithium-Ion Battery.

    Science.gov (United States)

    Song, Huanqiao; Luo, Mingsheng; Wang, Aimei

    2017-01-25

    Low performance of cathode materials has become one of the major obstacles to the application of lithium-ion battery (LIB) in advanced portable electronic devices, hybrid electric vehicles, and electric vehicles. The present work reports a versatile oxygen-deficient LiV3O8 (D-LVO) nanosheet that was synthesized successfully via a facile oxygen-deficient hydrothermal reaction followed by thermal annealing in Ar. When used as a cathode material for LIB, the prepared D-LVO nanosheets display remarkable capacity properties at various current densities (a capacity of 335, 317, 278, 246, 209, 167, and 133 mA h g-1 at 50, 100, 200, 500, 1000, 2000, and 4000 mA g-1, respectively) and excellent lithium-ion storage stability, maintaining more than 88% of the initial reversible capacity after 200 cycles at 1000 mA g-1. The outstanding electrochemical properties are believed to arise largely from the introduction of tetravalent V (∼15% V4+) and the attendant oxygen vacancies into LiV3O8 nanosheets, leading to intrinsic electrical conductivity more than 1 order of magnitude higher and lithium-ion diffusion coefficient nearly 2 orders of magnitude higher than those of LiV3O8 without detectable V4+ (N-LVO) and thus contributing to the easy lithium-ion diffusion, rapid phase transition, and the excellent electrochemical reversibility. Furthermore, the more uniform nanostructure, as well as the larger specific surface area of D-LVO than N-LVO nanosheets may also improve the electrolyte penetration and provide more reaction sites for fast lithium-ion diffusion during the discharge/charge processes.

  10. Raman spectroscopic studies of lithium manganates with spinel structure

    CERN Document Server

    Julien, C M

    2003-01-01

    Raman scattering spectra of a set of lithium manganospinels Li sub 1 sub - sub x sub + sub z Mn sub 2 sub - sub z O sub 4 with 0 sup<= x sup<= 1 and 0 sup<= z sup<= 0.33 are reported and analysed. Structural changes have been investigated following the evolution of Raman spectra with the concentration of lithium cations. The local structure was characterized as a function of the mean oxidation state of manganese cations. The trigonal distortion of MnO sub 6 octahedra is evidenced by insertion of lithium ions into the [B sub 2]O sub 4 spinel framework. A comparison with tetragonal Mn sub 3 O sub 4 and Fe sub 3 O sub 4 spinels shows the influence of the Jahn-Teller effect on the Raman features for this class of materials.

  11. Determination of ferrous and total iron in refractory spinels

    Energy Technology Data Exchange (ETDEWEB)

    Amonette, James E.; Matyas, Josef

    2015-12-30

    Accurate and precise determination of the redox state of iron (Fe) in spinels presents a significant challenge due to their refractory nature. The resultant extreme conditions needed to obtain complete dissolution generally oxidize some of the Fe(II) initially present and thus prevent the use of colorimetric methods for Fe(II) measurements. To overcome this challenge we developed a hybrid oxidimetric/colorimetric approach, using Ag(I) as the oxidimetric reagent for determination of Fe(II) and 1,10-phenanthroline as the colorimetric reagent for determination of total Fe. This approach, which allows determination of Fe(II) and total Fe on the same sample, was tested on a series of four geochemical reference materials and then applied to the analysis of Fe(Ni) spinel crystals isolated from simulated high-level-waste (HLW) glass and of several reagent magnetites. Results for the reference materials were in excellent agreement with published values, with the exception of USGS BIR-1, for which higher Fe(II) values and lower total Fe values were obtained. The Fe(Ni) spinels showed Fe(II) values at the detection limit (ca. 0.05 wt% Fe) and total Fe values slightly higher than obtained by total elemental analysis. For the magnetite samples, total Fe values were in agreement with reference results, but a wide range in Fe(II) values was obtained indicating various degrees of conversion to maghemite.

  12. Investigation of Lunar Spinels at Sinus Aestuum

    Science.gov (United States)

    Weitz, Catherine M.; Staid, Matthew I.; Gaddis, Lisa R.; Besse, Sebastian; Sunshine, Jessica M.

    2017-10-01

    Sinus Aestuum is the only known location on the Moon where orbital data have detected Fe-and/or Cr-spinel. We analyzed Moon Mineralogy Mapper (M3) visible to near-infrared data of the largest and strongest spinel signatures and determined that these locations always correspond to impact craters. M3 spectra show that at least three types of spinels may be present, all of which exhibit a strong and broad absorption at 2100 nm, and also one of the following: (1) a narrow 700-750 nm absorption, (2) a broad 600-900 nm absorption, or (3) both a weaker 700 nm and stronger 1000 nm absorption. All the spinel detections occur on either larger highland massifs that make up Sinus Aestuum east and west or smaller highland kīpukas and buried highlands within the mare. Almost all of the spinel signatures occur within the mapped pyroclastic dark mantle deposit (DMD). The strong correlation between spinel and DMD distribution on the highlands at Sinus Aestuum is best explained if the spinels were emplaced during the same explosive eruption(s) that deposited the pyroclastics in the Sinus Aestuum DMD. Our observations are most consistent with models of melt-rock reactions in the anorthositic lunar crust that produce contaminated (high-Al) regions within a volcanic dike or magmatic reservoir that was capable of erupting pyroclastic glass beads containing pleonaste spinel [Mg,Fe]Al2O4. Over billions of years, this surface layer of spinels and pyroclastics became heterogeneously mixed into and partially buried within the highland regolith where younger impact craters may sometimes expose it.

  13. Evolution of an alumina-magnesia/self-forming spinel castable. Part II: physico-chemical and mechanical properties

    Directory of Open Access Journals (Sweden)

    Gutiérrez-Campos D.

    1999-01-01

    Full Text Available This study was carried out in conjunction with the investigation, reported in Part I, on the microstructural characteristics of an alumina-spinel castable with several percentages of MgO content. Bulk density and cold crushing strength of samples were evaluated dried and at three fired states (1000, 1200, 1400 °C. Results indicate little influence of MgO additions on physico-chemical properties of the alumina-magnesia/self-forming spinel castable. Characteristics compared with those reported for conventional alumina-spinel castables did not show large difference in values. Therefore, the alumina-magnesia/self-forming spinel castable could be a possible material for substitution of the conventional alumina-spinel castable.

  14. High Cycling Performance Cathode Material: Interconnected LiFePO4/Carbon Nanoparticles Fabricated by Sol-Gel Method

    Directory of Open Access Journals (Sweden)

    Zhigao Yang

    2014-01-01

    Full Text Available Interconnected LiFePO4/carbon nanoparticles for Li-ion battery cathode have been fabricated by sol-gel method followed by a carbon coating process involving redox reactions. The carbon layers coated on the LiFePO4 nanoparticles not only served as a protection layer but also supplied fast electrons by building a 3D conductive network. As a cooperation, LiFePO4 nanoparticles encapsulated in interconnected conductive carbon layers provided the electrode reactions with fast lithium ions by offering the lithium ions shortening and unobstructed pathways. Field emission scanning electron microscopy (FESEM and X-ray diffraction (XRD tests showed optimized morphology. Electrochemical characterizations including galvanostatic charge/discharge, cyclic voltammetry (CV, and electrochemical impedance spectroscopy (EIS tests, together with impedance parameters calculated, all indicated better electrochemical performance and excellent cycling performance at high rate (with less than 9.5% discharge capacity loss over 2000 cycles, the coulombic efficiency maintained about 100%.

  15. Highly Efficient Retention of Polysulfides in "Sea Urchin"-Like Carbon Nanotube/Nanopolyhedra Superstructures as Cathode Material for Ultralong-Life Lithium-Sulfur Batteries.

    Science.gov (United States)

    Chen, Tao; Cheng, Baorui; Zhu, Guoyin; Chen, Renpeng; Hu, Yi; Ma, Lianbo; Lv, Hongling; Wang, Yanrong; Liang, Jia; Tie, Zuoxiu; Jin, Zhong; Liu, Jie

    2017-01-11

    Despite high theoretical energy density, the practical deployment of lithium-sulfur (Li-S) batteries is still not implemented because of the severe capacity decay caused by polysulfide shuttling and the poor rate capability induced by low electrical conductivity of sulfur. Herein, we report a novel sulfur host material based on "sea urchin"-like cobalt nanoparticle embedded and nitrogen-doped carbon nanotube/nanopolyhedra (Co-NCNT/NP) superstructures for Li-S batteries. The hierarchical micromesopores in Co-NCNT/NP can allow efficient impregnation of sulfur and block diffusion of soluble polysulfides by physical confinement, and the incorporation of embedded Co nanoparticles and nitrogen doping (∼4.6 at. %) can synergistically improve the adsorption of polysulfides, as evidenced by beaker cell tests. Moreover, the conductive networks of Co-NCNT/NP interconnected by nitrogen-doped carbon nanotubes (NCNTs) can facilitate electron transport and electrolyte infiltration. Therefore, the specific capacity, rate capability, and cycle stability of Li-S batteries are significantly enhanced. As a result, the Co-NCNT/NP based cathode (loaded with 80 wt % sulfur) delivers a high discharge capacity of 1240 mAh g-1 after 100 cycles at 0.1 C (based on the weight of sulfur), high rate capacity (755 mAh g-1 at 2.0 C), and ultralong cycling life (a very low capacity decay of 0.026% per cycle over 1500 cycles at 1.0 C). Remarkably, the composite cathode with high areal sulfur loading of 3.2 mg cm-2 shows high rate capacities and stable cycling performance over 200 cycles.

  16. SrCo{sub 1-x}Sb{sub x}O{sub 3-{delta}} perovskite oxides as cathode materials in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Aguadero, A.; Perez-Coll, D.; Escudero, M.J. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); de la Calle, C.; Alonso, J.A. [Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid (Spain); Daza, L. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain)

    2009-07-01

    The SrCo{sub 1-x}Sb{sub x}O{sub 3-{delta}} (x = 0.05, 0.1, 0.15 and 0.2) system was tested as possible cathode for solid oxide fuel cells (SOFCs). X-ray diffraction results show the stabilization of a tetragonal P4/mmm structure with Sb contents between x = 0.05 and x = 0.15. At x = 0.2 a phase transition takes place and the material is defined in the cubic Pm-3m space group. In comparison with the undoped hexagonal SrCoO{sub 3} phase, the obtained compounds present high thermal stability without abrupt changes in the expansion coefficient. In addition, a great enhancement of the electrical conductivity was observed at low and intermediate temperatures (T {<=} 800 C). The sample with x = 0.05 displays the highest conductivity value that reaches 500 S cm{sup -1} at 400 C and is over 160 S cm{sup -1} in the usual working conditions of a cathode in SOFC (650-900 C). Moreover, the impedance spectra of the SrCo{sub 1-x}Sb{sub x}O{sub 3-{delta}}/Ce{sub 0.8}Nd{sub 0.2}O{sub 2-{delta}}/SrCo{sub 1-x}Sb{sub x}O{sub 3-(delta)} (x {>=} 0.05) symmetrical cells reveal polarization resistances below 0.09 {omega} cm{sup 2} at 750 C which are much smaller than that displayed by the pristine SrCoO{sub 3-{delta}} sample. The composition with x = 0.05 shows the lowest ASR values ranging from 0.009 to 0.23 {omega} cm{sup 2} in the 900-600 C temperature interval with an activation energy of 0.82 eV. (author)

  17. Synthesis, Structure, and Sodium Mobility of Sodium Vanadium Nitridophosphate: A Zero-Strain and Safe High Voltage Cathode Material for Sodium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Huang Zhang

    2017-06-01

    Full Text Available Herein, the nitridophosphate Na3V(PO33N is synthesized by solid state method. X-ray diffraction (XRD and Rietveld refinement confirm the cubic symmetry with P213 space group. The material exhibits very good thermal stability and high operating voltage of 4.0 V vs. Na/Na+ due to V3+/V4+ redox couple. In situ X-ray diffraction studies confirm the two-phase (de-sodiation process to occur with very low volume changes. The refinement of the sodium occupancies reveal the low accessibility of sodium cations in the Na2 and Na3 sites as the main origin for the lower experimental capacity (0.38 eq. Na+, 28 mAh g−1 versus the theoretical one (1.0 eq. Na+, 74 mAh g−1. These observations provide valuable information for the further optimization of this materials class in order to access their theoretical electrochemical performance as a potentially interesting zero-strain and safe high-voltage cathode material for sodium-ion batteries.

  18. Doping Li-rich cathode material Li2MnO3 : Interplay between lattice site preference, electronic structure, and delithiation mechanism

    Science.gov (United States)

    Hoang, Khang

    2017-12-01

    We report a detailed first-principles study of doping in Li2MnO3 , in both the dilute doping limit and heavy doping, using hybrid density-functional calculations. We find that Al, Fe, Mo, and Ru impurities are energetically most favorable when incorporated into Li2MnO3 at the Mn site, whereas Mg is most favorable when doped at the Li sites. Nickel, on the other hand, can be incorporated at the Li site and/or the Mn site, and the distribution of Ni over the lattice sites can be tuned by tuning the material preparation conditions. There is a strong interplay among the lattice site preference and charge and spin states of the dopant, the electronic structure of the doped material, and the delithiation mechanism. The calculated electronic structure and voltage profile indicate that in Ni-, Mo-, or Ru-doped Li2MnO3 , oxidation occurs on the electrochemically active transition-metal ion(s) before it does on oxygen during the delithiation process. The role of the dopants is to provide charge compensation and bulk electronic conduction mechanisms in the initial stages of delithiation, hence enabling the oxidation of the lattice oxygen in the later stages. This work thus illustrates how the oxygen-oxidation mechanism can be used in combination with the conventional mechanism involving transition-metal cations in design of high-capacity battery cathode materials.

  19. Magnetic behavior of the oxide spinels:

    Indian Academy of Sciences (India)

    Magnetic behavior of the oxide spinels: Li0.5Fe2.5−2xAlxCrxO4. U N TRIVEDI, K B MODI and H H JOSHI. Department of Physics, Saurashtra University, Rajkot 360 005, India. Abstract. In order to study the effect of substitution of Fe3+ by Al3+ and Cr3+ in Li0.5Fe2.5O4 on its structural and magnetic properties, the spinel ...

  20. Ab-intitio studies of electronic properties of chalcogenide spinels.

    Science.gov (United States)

    Chshiev, Mairbek; Wang, Y.-H. A.; Gupta, Arunava; Bettinger, Joanna; Suzuki, Yuri; Butler, William H.

    2007-03-01

    CuCr2Se4 is a normal chalcogenide spinel which exhibits ferromagnetic properties including a relatively high Curie temperature of 450 K [1] which makes it a promising candidate for use in spintronics devices. Another chalcogenide spinel of enhanced interest for spintronics is CdCr2Se4 which seems to be a promising ferromagnetic semiconductor for electrical spin injection into III-V device heterostructures [2]. We report first principles calculations of the electronic structure of substoichiometric CuCr2Se4-x and CuxCd1-xCrSe4 spinels. The calculations were performed using the Vienna ab-initio simulation program (VASP) within the Generalized Gradient Approximation (GGA) of Density Functional Theory (DFT). Our calculations indicate that both Se deficient CuCr2Se4-x as well as CuxCd1-xCrSe4 show half-metallic behavior over a wide range of x with a gap around the Fermi level in the minority density of states. [1] F.K. Lotgering, Solid State Commun. 2 (1964) 55 [2] G. Kioseoglou et al., Nature Materials 3 (2004) 799

  1. A High-Voltage and High-Capacity Li1+x Ni0.5 Mn1.5 O4 Cathode Material: From Synthesis to Full Lithium-Ion Cells.

    Science.gov (United States)

    Mancini, Marilena; Axmann, Peter; Gabrielli, Giulio; Kinyanjui, Michael; Kaiser, Ute; Wohlfahrt-Mehrens, Margret

    2016-07-21

    We report Co-free, Li-rich Li1+x Ni0.5 Mn1.5 O4 (0high-voltage and high-capacity cathode materials for Li-ion cells. Their tailored morphology allows high density and facile processability for electrode development. In the potential range 2.4-4.9 V, the cathode material of composition Li1.5 Ni0.5 Mn1.5 O4 shows excellent performance in terms of capacity and cycling stability in half-cells. In addition, for the first time, we demonstrate the application of the high-voltage and high-capacity cathode in full Li-ion cells with graphite anodes with very high cycling stability. The electrochemical performance and low cost of the cathode material, together with the feasibility of a chemical method to obtain Li-rich Li1+x Ni0.5 Mn1.5 O4 (0high-energy density Li-ion batteries possible. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  2. Analysis of cathode materials of perovskite structure for solid oxide fuel cells, sofc s; Analisis de materiales catodicos de estructura perovskita para celdas de combustible de oxido solido, sofcs

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado F, J.; Espino V, J.; Avalos R, L. [Universidad Michoacana de San Nicolas de Hidalgo, Facultad de Ingenieria Quimica, Santiago Tapia 403, Morelia, Michoacan (Mexico)

    2015-07-01

    Fuel cells directly and efficiently convert the chemical energy of a fuel into electrical energy. Of the various types of fuel cells, the solid oxide (Sofc), combine the advantages in environmentally benign energy generation with fuel flexibility. However, the need for high operating temperatures (800 - 1000 grades C) has resulted in high costs and major challenges in relation to the compatibility the cathode materials. As a result, there have been significant efforts in the development of intermediate temperature Sofc (500 - 700 grades C). A key obstacle for operation in this temperature range is the limited activity of traditional cathode materials for electrochemical reduction oxygen. In this article, the progress of recent years is discussed in cathodes for Sofc perovskite structure (ABO{sub 3}), more efficient than the traditionally used La{sub 1-x}Sr{sub x}MnO{sub 3-δ} (LSM) or (La, Sr) CoO{sub 3}. Such is the case of mixed conductors (MIEC) double perovskite structure (A A B{sub 2}O{sub 5+δ}) using different doping elements as La, Sr, Fe, Ti, Cr, Sm, Co, Cu, Pr, Nd, Gd, dy, Mn, among others, which could improve the operational performance of existing cathode materials, promoting the development of optimized intermediate temperature Sofc designs. (Author)

  3. Thermal properties of spinel based solid solutions

    Science.gov (United States)

    O'Hara, Kelley Rae

    Solid solution formation in spinel based systems proved to be a viable approach to decreasing thermal conductivity. Samples with systematically varied additions of MgGa2O4 to MgAl2O 4 were prepared and thermal diffusivity was measured using the laser flash technique. Additionally, heat capacity was measured using differential scanning calorimetry and modeled for the MgAl2O4-MgGa 2O4 system. At 200°C thermal conductivity decreased 24% with a 5 mol% addition of MgGa2O4 to the system. The solid solution continued to decrease the thermal conductivity by 13% up to 1000°C with 5 mol% addition. The decrease in thermal conductivity ultimately resulted in a decrease in heat flux when applied to a theoretical furnace lining, which could lead to energy savings in industrial settings. The MgAl2O4-Al2O3 phase equilibria was investigated to fully understand the system and the thermal properties at elevated temperatures. The solvus line between MgAl2O4 and Al2O3 has been defined at 79.6 wt% Al 2O3 at 1500°C, 83.0 wt% Al2O4 at 1600°C, and 86.5 wt% Al2O3 at 1700°C. A metastable region has been identified at temperatures up to 1700°C which could have significant implications for material processing and properties. The spinel solid solution region has been extended to form an infinite solid solution with Al2O3 at elevated temperatures. A minimum in melting at 1975°C and a chemistry of 96 wt% Al2O3 rather than a eutectic is present. Thermal properties in the MgAl2O4-Al2O 3 system were investigated in both the single phase solid solution region and the two phase region. The thermal diffusivity decreased through the MgAl 2O4 solid solution region and was at a minimum through the entire metastable (nucleation and growth) region. As Al2O 3 became present as a second phase the thermal diffusivity increased with Al2O3 content. There was an 11.7% increase in thermal diffusivity with a change in overall chemistry of 85.20 wt% Al2O 3 to 87.71 wt% Al2O3, due to the drastic change in

  4. Solvothermal Synthesis of a Hollow Micro-Sphere LiFePO₄/C Composite with a Porous Interior Structure as a Cathode Material for Lithium Ion Batteries.

    Science.gov (United States)

    Liu, Yang; Zhang, Jieyu; Li, Ying; Hu, Yemin; Li, Wenxian; Zhu, Mingyuan; Hu, Pengfei; Chou, Shulei; Wang, Guoxiu

    2017-11-03

    To overcome the low lithium ion diffusion and slow electron transfer, a hollow micro sphere LiFePO₄/C cathode material with a porous interior structure was synthesized via a solvothermal method by using ethylene glycol (EG) as the solvent medium and cetyltrimethylammonium bromide (CTAB) as the surfactant. In this strategy, the EG solvent inhibits the growth of the crystals and the CTAB surfactant boots the self-assembly of the primary nanoparticles to form hollow spheres. The resultant carbon-coat LiFePO₄/C hollow micro-spheres have a ~300 nm thick shell/wall consisting of aggregated nanoparticles and a porous interior. When used as materials for lithium-ion batteries, the hollow micro spherical LiFePO₄/C composite exhibits superior discharge capacity (163 mAh g-1 at 0.1 C), good high-rate discharge capacity (118 mAh g-1 at 10 C), and fine cycling stability (99.2% after 200 cycles at 0.1 C). The good electrochemical performances are attributed to a high rate of ionic/electronic conduction and the high structural stability arising from the nanosized primary particles and the micro-sized hollow spherical structure.

  5. Freeze drying synthesis of Li{sub 3}MnO{sub 4} cathode material for Li-ion batteries: A physico-electrochemical study

    Energy Technology Data Exchange (ETDEWEB)

    Surace, Yuri; Simões, Mário; Karvonen, Lassi; Yoon, Songhak; Pokrant, Simone [Laboratory Materials for Energy Conversion, EMPA – Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf (Switzerland); Weidenkaff, Anke, E-mail: weidenkaff@imw.uni-stuttgart.de [Materials Chemistry, Institute for Materials Science, University of Stuttgart, Heisenbergstrasse 3, DE-70569 Stuttgart (Germany)

    2015-09-25

    Highlights: • Facilitated synthesis of Li{sub 3}MnO{sub 4} with a smaller thermal budget via freeze drying. • Electrochemical activity enhanced by micro- and nanostructure modifications. • Capacity increase of 30% at 1st discharge versus standard synthesis process. - Abstract: Li{sub 3}MnO{sub 4}, a lithium rich phase containing manganese (V), is a promising cathode material for Li-ion batteries due to its very high theoretical capacity (698 A h kg{sup −1}). Li{sub 3}MnO{sub 4} was synthesized from freeze dried precursors at 398 K. Combined structural, morphological and chemical characterization by XRD, TGA, SEM, TEM and XPS revealed improvements in the micro- and nanostructure in comparison to the material synthesized by a standard solid state chemistry route. The average particle size decreased from 10 μm to 3.5 μm and the average crystallite size from close to 100 nm to around 30 nm. These modifications enhanced the capacity (23% at 10 A kg{sup −1} and up to 31% at 50 A kg{sup −1} with a maximum discharge capacity of 290 A h kg{sup −1}) and the rate capability.

  6. Beneficial effect of boron in layered sodium-ion cathode materials - The example of Na2/3B0.11Mn0.89O2

    Science.gov (United States)

    Vaalma, Christoph; Buchholz, Daniel; Passerini, Stefano

    2017-10-01

    Sodium-ion batteries are regarded as a complementary drop-in technology to lithium-ion batteries because they promise lower cost and a higher degree of environmental friendliness. Among other reasons, these benefits come from the use of manganese-based materials, whose stabilization via cation substitution is intensively studied to improve the electrochemical performance. Although multiple elements have been considered as substituent, surprisingly, boron has not been reported for layered sodium-ion cathode materials up to date. Our investigation of layered Na2/3B0.11Mn0.89O2 reveals an unexpectedly good electrochemical performance, with charge and discharge capacities of more than 175 mAh g-1 at 10 mA g-1 and 135 mAh g-1 at 500 mA g-1. The measured capacities are among the highest ever reported for sodium-based layered oxides in the potential range of 4.0-2.0 V vs. Na/Na+.

  7. Effect of thermal treatment on the properties of electrospun LiFePO{sub 4}–carbon nanofiber composite cathode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Changhuan; Liang, Yinzheng; Yao, Lan; Qiu, Yiping, E-mail: ypqiu@dhu.edu.cn

    2015-04-05

    Graphical abstract: The composites prepared with the thermal treatment process of stabilization at 280 °C for 4 h with a heating rate of 2 °C min{sup −1} in air followed by carbonization at 800 °C for 14 h with a heating rate of 2 °C min{sup −1} in argon exhibit the optimal electrochemical properties. - Highlights: • Binder-free LiFePO{sub 4}–CNF composite cathode materials are prepared. • The conductive carbon and LiFePO{sub 4} formation take place simultaneously during thermal treatment. • The reaction behavior of the LiFePO{sub 4} precursors during thermal treatment are investigated. • Different thermal treatment processes would generate different electrochemical performance. • Cycling performance and rate capability are improved with a suitable thermal treatment condition. - Abstract: Binder-free LiFePO{sub 4}–carbon nanofiber (LiFePO{sub 4}–CNF) composites as lithium-ion battery cathode materials are fabricated by electrospinning and subsequent thermal treatments. The thermal decomposition behavior of the electrospun LiFePO{sub 4} precursor–polyacrylonitrile (LiFePO{sub 4} precursor–PAN) nanofiber composites and the reaction of the LiFePO{sub 4} precursors during thermal treatment are investigated. The effects of thermal treatment parameters such as heating rate, temperature, and duration for stabilization and carbonization on the microstructure, morphology, carbon content, crystal structure of the composites, and electrochemical performance of the resultant half-cell are also studied. When the electrospun LiFePO{sub 4} precursor–PAN nanofiber composites are first stabilized in air at 280 °C for 4 h with a heating rate of 2 °C min{sup −1} and then carbonized in argon at 800 °C for 14 h with a heating rate of 2 °C min{sup −1}, the obtained LiFePO{sub 4}–CNF composites exhibit optimal electrochemical properties in terms of a higher initial discharge capacity, more stable charge–discharge cycle behavior, and better rate

  8. The influence of cathode excavation of cathodic arc evaporator on thickness uniformity and erosion products angle distribution

    Directory of Open Access Journals (Sweden)

    D. V. Duhopel'nikov

    2014-01-01

    Full Text Available Cathodic arc evaporators are used for coating with functional films. Prolonged or buttend evaporators may be used for this purposes. In butt-end evaporator the cathode spots move continuously on the cathode work surface and evaporate cathode material. High depth excavation profile forms on the cathode work surface while the thick coating precipitation (tens or hundreds of microns. The cathode excavation profile is shaped like a “cup” with high walls for electrostatic discharge stabilization systems with axial magnetic fields. Cathode spots move on the bottom of the “cup”. It is very likely that high “cup” walls are formed as a result of lasting work time influence on the uniformity of precipitated films.In the present work the influence of excavation profile walls height on the uniformity of precipitated coating was carried out. The high profile walls are formed due to lasting work of DC vacuum arc evaporator. The cathode material used for tests was 3003 aluminum alloy. The extended substrate was placed parallel to the cathode work surface. Thickness distribution along the substrate length with the new cathode was obtained after 6 hours and after 12 hours of continuous operation.The thickness distribution of precipitated coating showed that the cathode excavation has an influence on the angular distribution of the matter escaping the cathode. It can be clearly seen from the normalized dependence coating thickness vs the distance from the substrate center. Also the angular distribution of the matter flow from the cathode depending on the cathode working time was obtained. It was shown that matter flow from the cathode differs from the LambertKnudsen law. The more the cathode excavation the more this difference.So, cathode excavation profile has an influence on the uniformity of precipitated coating and it is necessary to take in account the cathode excavation profile while coating the thick films.

  9. Particle size-controllable microwave-assisted solvothermal synthesis of the high-voltage cathode material LiCoPO4 using water/ethylene glycol solvent blends

    Science.gov (United States)

    Ludwig, Jennifer; Haering, Dominik; Doeff, Marca M.; Nilges, Tom

    2017-03-01

    Particle size-tuned platelets of the high-voltage cathode material LiCoPO4 for Li-ion batteries have been synthesized by a simple one-step microwave-assisted solvothermal process using an array of water/ethylene glycol (EG) solvent mixtures. Particle size control was achieved by altering the concentration of the EG co-solvent in the mixture between 0 and 100 vol%, with amounts of 0-80 vol% EG producing single phase, olivine-type LiCoPO4. The particle sizes of the olivine materials were significantly reduced from about 1.2 μm × 1.2 μm × 500 nm (0 vol% EG) to 200 nm × 100 nm × 50 nm (80 vol% EG) with increasing EG content, while specific surface areas increased from 2 to 13 m2 g-1. The particle size reduction could mainly be attributed to the modified viscosities of the solvent blends. Owing to the soft template effect of EG, the crystals exhibited the smallest dimensions along the [010] direction of the Li diffusion pathways in the olivine crystal structure, resulting in enhanced lithium diffusion properties. The relationship between the synthesis, crystal properties and electrochemical performance was further elucidated, indicating that the electrochemical performances of the as-prepared materials mainly depend on the solvent composition and the respective particle size range. LiCoPO4 products obtained from reaction media with low and high EG contents exhibited good electrochemical performances (initial discharge capacities of 87-124 mAh g-1 at 0.1 C), whereas materials made from medium EG concentrations (40-60 vol% EG) showed the highest capacities and gravimetric energy densities (up to 137 mAh g-1 and 658 Wh kg-1 at 0.1 C), excellent rate capabilities, and cycle life.

  10. Arc initiation in cathodic arc plasma sources

    Science.gov (United States)

    Anders, Andre

    2002-01-01

    A "triggerless" arc initiation method and apparatus is based on simply switching the arc supply voltage to the electrodes (anode and cathode). Neither a mechanical trigger electrode nor a high voltage flashover from a trigger electrode is required. A conducting path between the anode and cathode is provided, which allows a hot spot to form at a location where the path connects to the cathode. While the conductive path is eroded by the cathode spot action, plasma deposition ensures the ongoing repair of the conducting path. Arc initiation is achieved by simply applying the relatively low voltage of the arc power supply, e.g. 500 V-1 kV, with the insulator between the anode and cathode coated with a conducting layer and the current at the layer-cathode interface concentrated at one or a few contact points. The local power density at these contact points is sufficient for plasma production and thus arc initiation. A conductive surface layer, such as graphite or the material being deposited, is formed on the surface of the insulator which separates the cathode from the anode. The mechanism of plasma production (and arc initiation) is based on explosive destruction of the layer-cathode interface caused by joule heating. The current flow between the thin insulator coating and cathode occurs at only a few contact points so the current density is high.

  11. Highly efficient and robust cathode materials for low-temperature solid oxide fuel cells: PrBa0.5Sr0.5Co2−xFexO5+δ

    Science.gov (United States)

    Choi, Sihyuk; Yoo, Seonyoung; Kim, Jiyoun; Park, Seonhye; Jun, Areum; Sengodan, Sivaprakash; Kim, Junyoung; Shin, Jeeyoung; Jeong, Hu Young; Choi, YongMan; Kim, Guntae; Liu, Meilin

    2013-01-01

    Solid oxide fuel cells (SOFC) are the cleanest, most efficient, and cost-effective option for direct conversion to electricity of a wide variety of fuels. While significant progress has been made in anode materials with enhanced tolerance to coking and contaminant poisoning, cathodic polarization still contributes considerably to energy loss, more so at lower operating temperatures. Here we report a synergistic effect of co-doping in a cation-ordered double-perovskite material, PrBa0.5Sr0.5Co2−xFexO5+δ, which has created pore channels that dramatically enhance oxygen ion diffusion and surface oxygen exchange while maintaining excellent compatibility and stability under operating conditions. Test cells based on these cathode materials demonstrate peak power densities ~2.2 W cm−2 at 600°C, representing an important step toward commercially viable SOFC technologies. PMID:23945630

  12. In situ stress measurements during electrochemical cycling of lithium-rich cathodes

    Science.gov (United States)

    Nation, Leah; Li, Juchuan; James, Christine; Qi, Yue; Dudney, Nancy; Sheldon, Brian W.

    2017-10-01

    Layered lithium transition metal oxides (Li1+xM1-xO2, M = Ni, Mn, Co) are attractive cathode materials for lithium-ion batteries due to their high reversible capacity. However, they suffer from structural changes that lead to substantial voltage fade. In this study, we use stress as a novel way to track irreversible changes in Li1.2Mn0.55Ni0.125Co0.125O2 (LR-NMC) cathodes. A unique and unpredicted stress signature is observed during the first delithiation. Initially, a tensile stress is observed, consistent with volume contraction from lithium removal, however, the stress reverses and becomes compressive with continued charging beyond 4 V vs Li/Li+, indicating volume expansion; this phenomenon is present in the first cycle only. This irreversible stress during delithiation is likely to be at least partially due to oxygen loss and the resulting cation rearrangement. Raman spectroscopy provides evidence of the layered-to-spinel phase transition after cycling in the LR-NMC films, as well as recovery of the original spectra upon re-annealing in an oxygen environment.

  13. Synthesis and enhanced electrochemical performance of the honeycomb TiO2/LiMn2O4 cathode materials

    DEFF Research Database (Denmark)

    Zhang, J.Y.; Shen, J.X.; Wei, C.B.

    2016-01-01

    angle compare to LiMn2O4, implying that TiO2 doping induced a change of crystal structure. By performing electrochemical measurements, we observed an enhancement of specific capacity (127.28 mAhg−1) and an improvement of cycling stability in the TiO2/LiMn2O4 hybrid materials. After 100 cycles of charge...... characterized the morphology and structure of the synthesized materials by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The honeycomb morphology was identified using SEM. The XRD patterns show that the Bragg peak of the plane (111) for TiO2/LiMn2O4 appears at the lower diffraction...

  14. Detailed investigation of Na2.24FePO4CO3 as a cathode material for Na-ion batteries

    Science.gov (United States)

    Huang, Weifeng; Zhou, Jing; Li, Biao; Ma, Jin; Tao, Shi; Xia, Dingguo; Chu, Wangsheng; Wu, Ziyu

    2014-01-01

    Na-ion batteries are gaining an increased recognition as the next generation low cost energy storage devices. Here, we present a characterization of Na3FePO4CO3 nanoplates as a novel cathode material for sodium ion batteries. First-principles calculations reveal that there are two paths for Na ion migration along b and c axis. In-situ and ex-situ Fe K-edge X-ray absorption near edge structure (XANES) point out that in Na3FePO4CO3 both Fe2+/Fe3+ and Fe3+/Fe4+ redox couples are electrochemically active, suggesting also the existence of a two-electron intercalation reaction. Ex-situ X-ray powder diffraction data demonstrates that the crystalline structure of Na3FePO4CO3 remains stable during the charging/discharging process within the range 2.0–4.55 V. PMID:24595232

  15. Solvothermal synthesis of Mg-doped Li2FeSiO4/C nanocomposite cathode materials for lithium-ion batteries

    Science.gov (United States)

    Kumar, Ajay; Jayakumar, O. D.; Naik, V. M.; Nazri, G. A.; Naik, R.

    Lithium transition metal orthosilicates, such as Li2FeSiO4 and Li2MnSiO4, as cathode material have attracted much attention lately due to their high theoretical capacity ( 330 mAh/g), low cost, and environmental friendliness. However, they suffer from poor electronic conductivity and slow lithium ion diffusion in the solid phase. Several cation-doped orthosilicates have been studied to improve their electrochemical performance. We have synthesized partially Mg-substituted Li2Mgx Fe1-x SiO4-C, (x = 0.0, 0.01, 0.02, and 0.04) nano-composites by solvothermal method followed by annealing at 600oC in argon flow. The structure and morphology of the composites were characterized by XRD, SEM and TEM. The surface area and pore size distribution were measured by using N2 adsorption/desorption curves. The electrochemical performance of the Li2MgxFe1-x SiO4-C composites was evaluated by Galvanostatic cycling against metallic lithium anode, electrochemical impedance spectroscopy, and cyclic voltammetry. Li2Mg0.01Fe0.99SiO4-C sample shows a capacity of 278 mAh/g (at C/30 rate in the 1.5-4.6 V voltage window) with an excellent rate capability and stability, compared to the other samples. We attribute this observation to its higher surface area, enhanced electronic conductivity and higher lithium ion diffusion coefficient.

  16. Thermal expansion and specific heat of a superior IR-SOFC cathode material Sr1-xCexCoO3-δ

    Science.gov (United States)

    Srivastava, Archana; Thakur, Rasna; Gaur, N. K.

    2017-05-01

    We present the specific heat (Cv) and thermal expansion (α) of lightly doped Sr1-xCexCoO3-δ (x=0.0-0.15) using Modified Rigid Ion Model (MRIM) and a novel atomistic approach of Atom in Molecules(AIM) theory. We partial replaced the A-site Strontium cation by other element (Cerium) of different size, valence and mass. The effect of Cerium doping on lattice specific heat (Cv)lat, thermal expansion(α) of Sr1-xCexCoO3-δ (x = 0.0-0.15) as a function of temperature (20K≤T≤ 1000K) is reported probably for the first time. The results indicate better thermal compatibility of Sr0.95Ce0.05CoO3 with Samaria doped Ceria (SDC) electrolyte than other studied compounds. The Debye temperature of these perovskite material as cathode for Intermediate Range Solid Oxide Fuel Cell (IR-SOFC) is also predicted.

  17. Effect of the nanosized TiO2 particles in Pd/C catalysts as cathode materials in direct methanol fuel cells.

    Science.gov (United States)

    Choi, Mahnsoo; Han, Choonsoo; Kim, In-Tae; Lee, Ji-Jung; Lee, Hong-Ki; Shim, Joongpyo

    2011-07-01

    Pd-TiO2/C catalysts were prepared by impregnating titanium dioxide (TiO2) on carbon-supported Pd (Pd/C) for use as the catalyst for the oxygen reduction reaction (ORR) in direct methanol fuel cells (DMFCs). Transmission electron microscope (TEM), scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses were carried to confirm the distribution, morphology and structure of Pd and TiO2 on the carbon support. In fuel cell test, we confirmed that the addition of TiO2 nanoparticles make the improved catalytic activity of oxygen reduction. The electrochemical characterization of the Pd-TiO2/C catalyst for the ORR was carried out by cyclic voltammetry (CV) in the voltage window of 0.04 V to 1.2 V with scan rate of 25 mV/s. With the increase in the crystallite size of TiO2, the peak potential for OH(ads) desorption on the surface of Pd particle shifted to higher potential. This implies that TiO2 might affect the adsorption and desorption of oxygen molecules on Pd catalyst. The performance of Pd-TiO2/C as a cathode material was found to be similar to or better performance than that of Pt/C.

  18. High-Temperature Electrochemical Performance of FeF3/C Nanocomposite as a Cathode Material for Lithium-Ion Batteries

    Science.gov (United States)

    Tang, Mengyun; Zhang, Zhengfu; Wang, Zi; Liu, Jingfeng; Yan, Hongge; Peng, Jinhui

    2018-01-01

    Iron trifluoride has been studied as a cathode material due to its cost-effectiveness, low toxicity, and high theoretical capacities of 712 mA h g-1. However, FeF3 has serious shortcomings of poor electronic conductivity and a slow diffusion rate of lithium ions, leading to a lower reversible specific capacity. In this work, FeF3/C nanocomposite has been synthesized successfully via a high-energy ball-milling method, and acetylene black is used as the conductive agent to improve the conductivity of FeF3. The FeF3/C nanocomposite shows a high initial discharge capacity of 346.25 and 161.58 mA h g-1 after 40th cycle at 50 mA g-1. It exhibits good cycle performance and rate performance. The high-temperature discharge capacities decreased with increase in the temperature. The initial high-temperature discharge capacities are found to be 254.17, 300.01, 281.25 and 125.16, and 216.875, 156, 141.67, 150, and 64.98 mA h g-1 at 20th cycles at the 40, 50, 60, and 70 °C, respectively.

  19. (NH 4) 0.5V 2O 5 nanobelt with good cycling stability as cathode material for Li-ion battery

    Science.gov (United States)

    Wang, Haiyan; Huang, Kelong; Huang, Chenghuan; Liu, Suqin; Ren, Yu; Huang, Xiaobing

    (NH 4) 0.5V 2O 5 nanobelt is synthesized by sodium dodecyl benzene sulfonate (SDBS) assisted hydrothermal reaction as a cathode material for Li-ion battery. The as-prepared (NH 4) 0.5V 2O 5 nanobelts are 50-200 nm in diameter and several micrometers in length. The reversible lithium intercalation behavior of the nanobelts has been evaluated by cyclic voltammetry, galvanostatic discharge-charge cycling, and electrochemical impedance spectroscopy. The (NH 4) 0.5V 2O 5 delivers an initial specific discharge capacity of 225.2 mAh g -1 between 1.8 and 4.0 V at 15 mA g -1, and still maintains a high discharge capacity of 197.5 mAh g -1 after 11 cycles. It shows good rate capability with a discharge capacity of about 180 mAh g -1 remaining after 40 cycles at various rates and excellent cycling stability with the capacity retention of 81.9% after 100 cycles at 150 mA g -1. Interestingly, the excess 120 mAh g -1 capacity in the first charge process is observed, most of which could be attributed to the extraction of NH 4 + group, verified by Fourier transform Infrared (FT-IR) and X-ray diffraction (XRD) results.

  20. Ni-Co Binary Hydroxide Nanotubes with Three-Dimensionally Structured Nanoflakes: Synthesis and Application as Cathode Materials for Hybrid Supercapacitors.

    Science.gov (United States)

    Dai, Ziyang; Lin, Jianjian; Dong, Qiuchun; Yin, Zhihui; Zang, Xiaoxian; Shen, Lei; Kim, Jung Ho; Huang, Wei; Alshehri, Saad M; Young, Christine; Yamauchi, Yusuke; Dong, Xiaochen

    2017-07-26

    Nickel-cobalt binary hydroxide nanotubes were fabricated by a facile synthetic approach by using Cu2 O nanowires as sacrificial templates. The surface morphology of the binary hydroxide nanotubes can be easily controlled by adjusting the molar ratio of Ni to Co. With increasing Co content, the surfaces of the nanotubes tend to form hierarchical nanoflakes. The obtained nanotubes with high specific surface area exhibit typical battery-like electrochemical behavior. Among them, Ni-Co hydroxide nanotubes with Ni:Co=48:52 showed outstanding electrochemical characteristics, with a specific capacity of 209.9 mAh g(-1) at 1 Ag(-1) and remarkable cycling stability with 84.4 % capacity retention after 10 000 cycles at 20 A g(-1) . With the advantages of their unique nanostructure and the synergistic effect of the two elements, the Ni-Co binary hydroxide nanotubes are expected to be effective potential cathode materials for hybrid supercapacitors. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Acetonitrile mediated facile synthesis and self-assembly of silver vanadate nanowires into 3D spongy-like structure as a cathode material for lithium ion battery

    Science.gov (United States)

    Klockner, W.; Yadav, R. M.; Yao, J.; Lei, S.; Aliyan, A.; Wu, J.; Martí, A. A.; Vajtai, R.; Ajayan, P. M.; Denardin, J. C.; Serafini, D.; Melo, F.; Singh, D. P.

    2017-08-01

    We report the facile, one-step acetonitrile-mediated synthesis and self-assembly of β-AgVO3 nanowires into three-dimensional (3D) porous spongy-like hydrogel ( 4 cm diameter) as cathode material for lithium ion battery of high performance and long-term stability. 3D structures made with superlong, very thin, and monoclinic β-AgVO3 nanowires exhibit high specific discharge capacities of 165 mAh g-1 in the first cycle and 100 mAh g-1 at the 50th cycle, with a cyclic capacity retention of 53% at a current density of 50 mA g-1. 3D structures are synthesized by reaction between ammonium vanadate and silver nitrate solution containing 5 mL of acetonitrile followed by a hydrothermal treatment at 200 °C for 12 h. Acetonitrile (used here for the first time in the silver vanadate synthesis) plays an important role in the self-assembly of the silver vanadate nanowires. A tentative growth mechanism for the 3D structure and lithium ions intercalation into β-AgVO3 nanowires has been discussed and described.

  2. The Effect of Counterpart Material on the Sliding Wear of TiAlN Coatings Deposited by Reactive Cathodic Pulverization

    Directory of Open Access Journals (Sweden)

    Michell Felipe Cano Ordoñez

    2015-11-01

    Full Text Available This work aims to study the effect of the counterpart materials (100Cr6, Al2O3 and WC-Co on the tribological properties of TiAlN thin films deposited on AISI H13 steel substrate by reactive magnetron co-sputtering. The structural characterization of the TiAlN films, performed by X-ray diffraction, showed (220 textured fcc crystalline structure. The values of hardness and elastic modulus obtained by nanoindentation were 27 GPa and 420 GPa, respectively, which resulted in films with a relatively high resistance to plastic deformation. Ball-on-disk sliding tests were performed using normal loads of 1 N and 3 N, and 0.10 m/s of tangential velocity. The wear coefficient of the films was determined by measuring the worn area using profilometry every 1000 cycles. The mechanical properties and the chemical stability of the counterpart material, debris formation and the contact stress influences the friction and the wear behavior of the studied tribosystems. Increasing the hardness of the counterpart decreases the coefficient of friction (COF due to lower counterpart material transference and tribofilm formation, which is able to support the contact pressure. High shear stress concentration at the coating/substrate interface was reported for higher load promoting failure of the film-substrate system for all tribopairs

  3. In-situ time-of-flight neutron diffraction study of the structure evolution of electrode materials in a commercial battery with LiNi0.8Co0.15Al0.05O2 cathode

    Science.gov (United States)

    Bobrikov, I. A.; Samoylova, N. Yu.; Sumnikov, S. V.; Ivanshina, O. Yu.; Vasin, R. N.; Beskrovnyi, A. I.; Balagurov, A. M.

    2017-12-01

    A commercial lithium-ion battery with LiNi0.8Co0.15Al0.05O2 (NCA) cathode has been studied in situ using high-intensity and high-resolution neutron diffraction. Structure and phase composition of the battery electrodes have been probed during charge-discharge in different cycling modes. The dependence of the anode composition on the charge rate has been determined quantitatively. Different kinetics of Li (de)intercalation in the graphite anode during charge/discharge process have been observed. Phase separation of the cathode material has not been detected in whole voltage range. Non-linear dependencies of the unit cell parameters, atomic and layer spacing on the lithium content in the cathode have been observed. Measured dependencies of interatomic spacing and interlayer spacing, and unit cell parameters of the cathode structure on the lithium content could be qualitatively explained by several factors, such as variations of oxidation state of cation in oxygen octahedra, Coulomb repulsion of oxygen layers, changes of average effective charge of oxygen layers and van der Waals interactions between MeO2-layers at high level of the NCA delithiation.

  4. Effect of Glucose on Structure and Properties of LiFePO4 Cathode Material Prepared by Microwave Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    XIA Ao

    2016-10-01

    Full Text Available Orthorhombic LiFePO4/C composite material with olivine structure was prepared by microwave hydrothermal method using FeSO4·7H2O, LiOH·H2O and H3PO4 as raw materials, with glucose as carbon source and modifier. The influence of glucose on the composition, structure, morphology and electrochemical performance of LiFePO4 was investigated by means of XRD, SEM, EDS and constant current charge-discharge cycling. The results show that the as-obtained LiFePO4/C exhibits stronger bonding among Fe, P and O atoms, finer particle size and improved electrochemical properties than the pristine LiFePO4. From the SEM image, the LiFePO4 is coated by carbon in the LiFePO4/C composite. The LiFePO4/C shows the initial discharge capacity of 125.6mAh/g at 0.1C. Even at a rate of 1.0C, it still can deliver a discharge capacity of 106.2mAh/g, the capacity retention is 91.3% after 30 cycles.

  5. Effect of symbiotic compound Fe{sub 2}P{sub 2}O{sub 7} on electrochemical performance of LiFePO{sub 4}/C cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shuxin, E-mail: liushuxin88@126.com [School of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang, Sichuan 621000 (China); Gu, Chunlei [School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei 050018 (China); Wang, Haibin [School of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang, Sichuan 621000 (China); Liu, Ruijiang [School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Wang, Hong; He, Jichuan [School of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang, Sichuan 621000 (China)

    2015-10-15

    In order to study the effect of symbiotic compound Fe{sub 2}P{sub 2}O{sub 7} on electrochemical performance of LiFePO{sub 4}/C cathode materials, the LiFePO{sub 4}/Fe{sub 2}P{sub 2}O{sub 7}/C cathode materials were synthesized by in-situ synthesis method. The phase compositions and microstructures of the products were characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscope (FESEM). Results indicate that the existence of Fe{sub 2}P{sub 2}O{sub 7} does not alter LiFePO{sub 4} crystal structure and the existence of Fe{sub 2}P{sub 2}O{sub 7} decreases the particles size of LiFePO{sub 4}. The electrochemical behavior of cathode materials was analyzed using galvanostatic measurement and cyclic voltammetry (CV). The results show that the existence of Fe{sub 2}P{sub 2}O{sub 7} improves electrochemical performance of LiFePO{sub 4} cathode materials in specific capability and lithium ion diffusion rate. The charge–discharge specific capacity and apparent lithium ion diffusion coefficient increase with Fe{sub 2}P{sub 2}O{sub 7} content and maximizes around the Fe{sub 2}P{sub 2}O{sub 7} content is 5 wt%. It has been had further proved that the Fe{sub 2}P{sub 2}O{sub 7} adding enhances the lithium ion transport to improve the electrochemical performance of LiFePO{sub 4} cathode materials. However, excessive Fe{sub 2}P{sub 2}O{sub 7} will block the electron transfer pathway and affect the electrochemical performances of LiFePO{sub 4} directly. - Graphical abstract: The LiFePO{sub 4}/Fe{sub 2}P{sub 2}O{sub 7}/C cathode materials were synthesized by in-situ synthesis method. The existence of Fe{sub 2}P{sub 2}O{sub 7} does not alter LiFePO{sub 4} crystal structure and the existence of Fe{sub 2}P{sub 2}O{sub 7} decreases the particles size of LiFePO{sub 4}. The charge–discharge specific capacity and apparent lithium ion diffusion coefficient increase with Fe{sub 2}P{sub 2}O{sub 7} content. However, excessive Fe{sub 2}P{sub 2}O{sub 7} will

  6. P2 Orthorhombic Na0.7[Mn1-xLix]O2+y as Cathode Materials for Na-Ion Batteries.

    Science.gov (United States)

    Kwon, Mi-Sook; Lim, Shin Gwon; Park, Yuwon; Lee, Sang-Min; Chung, Kyung Yoon; Shin, Tae Joo; Lee, Kyu Tae

    2017-05-03

    P2-type manganese-based oxide materials have received attention as promising cathode materials for sodium ion batteries because of their low cost and high capacity, but their reaction and failure mechanisms are not yet fully understood. In this study, the reaction and failure mechanisms of β-Na0.7[Mn1-xLix]O2+y (x = 0.02, 0.04, 0.07, and 0.25), α-Na0.7MnO2+y, and β-Na0.7MnO2+z are compared to clarify the dominant factors influencing their electrochemical performances. Using a quenching process with various amounts of a Li dopant, the Mn oxidation state in β-Na0.7[Mn1-xLix]O2+y is carefully controlled without the inclusion of impurities. Through various in situ and ex situ analyses including X-ray diffraction, X-ray absorption near-edge structure spectroscopy, and inductively coupled plasma mass spectrometry, we clarify the dependence of (i) reaction mechanisms on disordered Li distribution in the Mn layer, (ii) reversible capacities on the initial Mn oxidation state, (iii) redox potentials on the Jahn-Teller distortion, (iv) capacity fading on phase transitions during charging and discharging, and (v) electrochemical performance on Li dopant vs Mn vacancy. Finally, we demonstrate that the optimized β-Na0.7[Mn1-xLix]O2+y (x = 0.07) exhibits excellent electrochemical performance including a high reversible capacity of ∼183 mA h g(-1) and stable cycle performance over 120 cycles.

  7. Lithium intercalation mechanism into FeF3·0.5H2O as a highly stable composite cathode material

    Science.gov (United States)

    Ali, Ghulam; Lee, Ji–Hoon; Chang, Wonyoung; Cho, Byung-Won; Jung, Hun-Gi; Nam, Kyung-Wan; Chung, Kyung Yoon

    2017-02-01

    The growing demand for lithium-ion batteries (LIBs) requires investigation of high-performance electrode materials with the advantages of being environmentally friendly and cost-effective. In this study, a nanocomposite of open-pyrochlore-structured FeF3·0.5H2O and reduced graphene oxide (RGO) is synthesized for use as a high-performance cathode in LIBs, where RGO provides high electrical conductivity to the composite material. The morphology of the composite shows that FeF3·0.5H2O spheres are embedded into RGO layers and high-resolution TEM image shows that those spheres are composed of primary nanoparticles with a size of ~5 nm. The cycling performance indicates that the composite electrode delivers an initial high discharge capacity of 223 mAh g-1 at 0.05 C, a rate capability up to a high C-rate of 10 C (47 mAh g-1) and stable cycle performance at 0.05 C (145 mAh g-1 after 100 cycles) and 0.2 C (93 mAh g-1 after 100 cycles) while maintaining high electrochemical reversibility. Furthermore, the responsible electrochemical reaction is investigated using in-situ XRD and synchrotron-based X-ray absorption spectroscopy (XAS), and the XRD results show that FeF3·0.5H2O transitions to an amorphous-like phase through a lithiation process. However, a reversible oxidation change of Fe3+ ↔ Fe2+ is identified by the XAS results.

  8. A closed-loop process for recycling LiNixCoyMn(1−x−yO2 from mixed cathode materials of lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Rujuan Zheng

    2017-01-01

    Full Text Available With the rapid development of consumer electronics and electric vehicles (EV, a large number of spent lithium-ion batteries (LIBs have been generated worldwide. Thus, effective recycling technologies to recapture a significant amount of valuable metals contained in spent LIBs are highly desirable to prevent the environmental pollution and resource depletion. In this work, a novel recycling technology to regenerate a LiNi1/3Co1/3Mn1/3O2 cathode material from spent LIBs with different cathode chemistries has been developed. By dismantling, crushing, leaching and impurity removing, the LiNi1/3Co1/3Mn1/3O2 (selected as an example of LiNixCoyMn(1−x−yO2 powder can be directly prepared from the purified leaching solution via co-precipitation followed by solid-state synthesis. For comparison purposes, a fresh-synthesized sample with the same composition has also been prepared using the commercial raw materials via the same method. X-ray diffraction (XRD, scanning electron microscopy (SEM and electrochemical measurements have been carried out to characterize these samples. The electrochemical test result suggests that the re-synthesized sample delivers cycle performance and low rate capability which are comparable to those of the fresh-synthesized sample. This novel recycling technique can be of great value to the regeneration of a pure and marketable LiNixCoyMn(1−x−yO2 cathode material with low secondary pollution. Keywords: Spent lithium-ion battery, Cathode material recycling, Acid leaching, Purification, Co-precipitation

  9. Recycling of LiCo0.59Mn0.26Ni0.15O2 cathodic material from spent Li-ion batteries by the method of the citrate gel combustion

    Directory of Open Access Journals (Sweden)

    Senćanski Jelena V.

    2017-01-01

    Full Text Available The Li-ion batteries are the main power source for the high technology devices, such as mobile phones and electric vehicles. Because of that, the number of spent Li-ion batteries significantly increases. Today, the number of active mobile phones crossed 7.19 billion. It is estimated that the mass of the spent lithium ion batteries in China will exceed 500,000 t by 2020. The trouble is in the ingredients of these batteries. They contain Li, Co, Mn, Ni, Cu, Al and toxic and flammable electrolytes which have a harmful affection to the environment. Because of that, the recycling procedure attracts raising attention of researches. Several commercial spent Li-ion batteries were recycled by the relatively fast, economic and simple procedure. The three ways of separating the cathode material from Al collector were examined after the manual dismantling of the components of batteries with the Li(Co–Mn–NiO2 as cathode material. These were: 1. dissolution of the Al collector in the alkali medium, 2. peeling off with N-methylpyrrolidone and 3. thermal decomposition of the adhesive at 700°C. The procedure with the highest yield was the one with the dissolution in alkali medium. The chemical analysis of the single batteries'' components (the crust, Al/Cu collector, cathode material were done by the atomic absorption spectrometry. The components, before the analysis, were dissolved. The re-synthesis of the cathode material by the method of the citrate gel combustion was done after the separating the cathode material and dissolving it in the nitric acid. The obtained product was, after annealing, characterized by the methods of X-ray diffraction and Raman spectroscopy. The recycled product was LiCo0.59Mn0.26Ni0.15O2 stoichiometry, with the hexagonal layered structure α-NaFeO2 type. The functionalization of the resynthesized material was examined in the 1 M solution LiClO4 in the propylene carbonate, by galvanostatic charging, with the current density of 0

  10. Facile synthesis of bimodal mesoporous spinel Co3O4 nanomaterials and their structural properties

    Science.gov (United States)

    Pudukudy, Manoj; Yaakob, Zahira; Narayanan, Binitha; Gopalakrishnan, Anila; Tasirin, Siti Masrinda

    2013-12-01

    Mesoporous spinel Co3O4 nanomaterials have been prepared effectively via simple solid state mixing of nitrate precursor with various modifiers, including citric acid, urea, glucose and sucrose, followed by thermal treatment. The as-synthesised spinel Co3O4 materials showed high porosity, and the particles were finely crystallised in the nanorange. The different organic modifiers used in the synthetic method played a major role in the development of various porous morphologies. Different analytical techniques were used to study the material’s structural and textural features. X-ray diffraction analysis revealed the cubic phase purity of the cobalt oxide nanomaterials. The monoclinic and face centred cubic phases of CoO were detected in the glucose- and sucrose-assisted samples. The scanning electron microscopic images confirmed the surface porosity of the spinels with various morphologies. Macro-porous morphology with large holes was noted in the citric acid-assisted sample. The transmission electron microscopy images indicated that the bimodal mesoporosity of the spinels started from the deep bulk to the surface. BET-BJH analysis indicated that the surface area and pore parameters of the spinels were related to the type of modifier. Moreover, a high surface area was noted for the citric acid-aided Co3O4 (29 m2/g). The bimodal pore-size distributions were clearly confirmed from the TEM and the BJH-porosity measurements.

  11. Local probing spinel and perovskite complex magnetic systems

    CERN Document Server

    De Pinho Oliveira, Goncalo; Lima Lopes, Armandina Maria

    Materials with multifunctional physical properties are crucial for the modern society, especially those which display a strong coupling between magnetic, lattice and polar degrees of freedom. This by far unexploited capability promises new paradigm-shift technologies for cooling technologies, magnetic data storage, high-frequency magnetic devices, spintronics, and micro-electromechanical systems. Alongside with the understanding of the properties of these materials, the need to improve them and to make them smaller and more efficient is a current goal. Device miniaturization towards very high-density data storage stands also as a trend in modern science and technology. Here, the integration of several functions into one material system has become highly desirable. Research in this area has already highlighted complex magnetic materials with po- tential for multifunctional applications based on spinel type structures like CdMn2O4 or multiferroic CdCr2S4 or even RCrO3 with orthorhombically distorted perovskite ...

  12. Combustion-synthesized LiNi{sub 0.6}Mn{sub 0.2}Co{sub 0.2}O{sub 2} as cathode material for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Wook [Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Lim, Sung Nam [Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Jung, Kyu-Nam; Yeon, Sun-Hwa [Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Kim, Kwang-Bum, E-mail: kbkim@yonsei.ac.kr [Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Song, Hoon Sub [Department of Chemical Engineering, University of Waterloo, 200 University Ave. W., Waterloo, ON N2L3G1 (Canada); Shin, Kyoung-Hee, E-mail: khshin@kier.re.kr [Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of)

    2014-10-01

    Highlights: • LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} is synthesized using low-temperature combustion method. • LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} sintered at 800 °C contains shows shorter diffusion path. • The prepared cathode material shows excellent electrochemical performance. - Abstract: A nitrate/urea mixture was used as fuel to simply combustion-synthesize LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} as a high-capacity cathode material for lithium ion batteries. The reaction formulas and physical properties of the resultant cathode materials sintered at various temperatures were examined using thermogravimetric analysis/simultaneous differential thermal analysis, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectrometry, and inductively coupled plasma/atomic emission spectrometry. The influence of sintering temperature on the electrochemical performance was evaluated by analyzing the charge/discharge profiles and cycling and rate-capability performances. The LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} cathode sintered at 800 °C exhibited a discharge capacity of 170 mA h g{sup −1} measured at a constant 20 mA g{sup −1}, 98.2% capacity retention after 30 cycles, and better rate capability than the cathodes sintered at 700, 900, and 1000 °C. The experimental results suggest that the enhanced electrochemical performance of the LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} cathode sintered at 800 °C is attributable to the pure, well-organized layered structure containing few mixed cations and to the shorter diffusion path resulting from the uniformly distributed nanoparticles.

  13. Inert Anode/Cathode Program: Fiscal Year 1986 annual report. [For Hall-Heroult cells

    Energy Technology Data Exchange (ETDEWEB)

    Brenden, B.B.; Davis, N.C.; Koski, O.H.; Marschman, S.C.; Pool, K.H.; Schilling, C.H.; Windisch, C.F.; Wrona, B.J.

    1987-06-01

    Purpose of the program is to develop long-lasting, energy-efficient anodes, cathodes, and ancillary equipment for Hall-Heroult cells used by the aluminum industry. The program is divided into four tasks: Inert Anode Development, Cathode Materials Evaluation, Cathode Bonding Development, and Sensor Development. To devise sensors to control the chemistry of Hall-Heroult cells using stable anodes and cathodes. This report highlights the major FY86 technical accomplishments, which are presented in the following sections: Management, Materials Development, Materials Evaluation, Thermodynamic Evaluation, Laboratory Cell Tests, Large-Scale Tests, Cathode Materials Evaluation, Cathode Bonding Development, and Sensor Development.

  14. Determination of ferrous and total iron in refractory spinels

    Energy Technology Data Exchange (ETDEWEB)

    Amonette, J.E. [Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Matyáš, J. [Material Science Department, Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2016-03-03

    Accurate and precise determination of the redox state of iron (Fe) in spinels presents a significant challenge due to their refractory nature. The resultant extreme conditions needed to obtain complete dissolution generally oxidize some of the Fe(II) initially present and thus prevent the use of colorimetric methods for Fe(II) measurements. To overcome this challenge we developed a hybrid oxidimetric/colorimetric approach, using Ag(I) as the oxidimetric reagent for determination of Fe(II) and 1,10-phenanthroline as the colorimetric reagent for determination of total Fe. This approach, which allows determination of Fe(II) and total Fe on the same sample, was tested on a series of four geochemical reference materials and then applied to the analysis of Fe(Ni) spinel crystals isolated from simulated high-level-waste (HLW) glass and of several reagent magnetites. Results for the reference materials were in excellent agreement with recommended values, with the exception of USGS BIR-1, for which higher Fe(II) values and lower total Fe values were obtained. The Fe(Ni) spinels showed Fe(II) values at the detection limit (ca. 0.03 wt% Fe) and total Fe values higher than obtained by ICP-AES analysis after decomposition by lithium metaborate/tetraborate fusion. For the magnetite samples, total Fe values were in agreement with reference results, but a wide range in Fe(II) values was obtained indicating various degrees of conversion to maghemite. Formal comparisons of accuracy and precision were made with 13 existing methods. Accuracy for Fe(II) and total Fe was at or near the top of the group. Precision varied with the parameter used to measure it but was generally in the middle to upper part of the group for Fe(II) while that for total Fe ranged from the bottom of the group to near the top. - Highlights: • Refractory samples, such as spinels, are the most difficult for Fe redox analysis. • Oxidimetric(Ag{sup +})/colorimetric (phen) method allows analysis of a single

  15. A novel family of Nb-doped Bi0.5Sr0.5FeO3-δ perovskite as cathode material for intermediate-temperature solid oxide fuel cells

    Science.gov (United States)

    Gao, Lei; Li, Qiang; Sun, Liping; Zhang, Xianfa; Huo, Lihua; Zhao, Hui; Grenier, Jean-Claude

    2017-12-01

    Cobalt-free provskite oxides Bi0.5Sr0.5Fe1-xNbxO3-δ (BSFNx, x = 0.05, 0.10 and 0.15) were prepared and evaluated as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). In particular, the effects of Nb substitution on phase evolution, thermal expansion behavior and electrochemical performance were systematically investigated. The average thermal expansion coefficient (TEC) of BSFNx decreases from 13.3 × 10-6 K-1 at x = 0.05 to 12.6 × 10-6 K-1 at x = 0.15 within a temperature range of 50-800 °C. Among the BSFNx materials, Bi0.5Sr0.5Fe0.9Nb0.1O3-δ (BSFN0.10) oxide shows the best electrochemical performance. The polarization resistances (Rp) of BSFN0.10 cathode on CGO electrolyte are 0.038, 0.075 and 0.156 Ω cm2 at 700, 650 and 600 °C, respectively. Meanwhile the maximum power densities of the anode-supported single cells are 1.28, 1.54 and 1.34 W cm-2 at 700 °C for BSFNx cathodes with x = 0.05, 0.10, and 0.15, respectively. Furthermore, the relationship study of oxygen partial pressure dependence on Rp indicates that the oxygen reduction reaction (ORR) rate-limiting step is the oxygen adsorption-dissociation on the electrode surface. The desirable electrochemical performance demonstrates that BSFNx oxides are potential cathode materials for IT-SOFCs.

  16. Transition metal alloy-modulated lithium manganese oxide nanosystem for energy storage in lithium-ion battery cathodes

    CSIR Research Space (South Africa)

    West, N

    2013-07-01

    Full Text Available This paper explores the synergistic and catalytic properties of a newly developed lithium ion battery (LIB) composite cathode of LiMn(sub2)O(Sub4) modified with bimetallic (Au–Fe) nanoparticle. Spinel phase LiMn(sub)2O(sub4) was doped...

  17. Layered P2-Na 2/3 Co 1/2 Ti 1/2 O 2 as a high-performance cathode material for sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Sabi, Noha; Doubaji, Siham; Hashimoto, Kazuki; Komaba, Shinichi; Amine, Khalil; Solhy, Abderrahim; Manoun, Bouchaib; Bilal, Essaid; Saadoune, Ismael

    2017-02-01

    Layered oxides are regarded as promising cathode materials for sodium-ion batteries. We present Na2/3Co1/2Ti1/2O2 as a potential new cathode material for sodium-ion batteries. The crystal features and morphology of the pristine powder were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The cathode material is evaluated in galvanostatic charge-discharge and galvanostatic intermittent titration tests, as well as ex-situ X-ray diffraction analysis. Synthesized by a high-temperature solid state reaction, Na2/3Co1/2Ti1/2O2 crystallizes in P2-type structure with P6(3)/mmc space group. The material presents reversible electrochemical behavior and delivers a specific discharge capacity of 100 mAh g(-1) when tested in Na half cells between 2.0 and 4.2 V (vs. Na+/Na), with capacity retention of 98% after 50 cycles. Furthermore, the electrochemical cycling of this titanium-containing material evidenced a reduction of the potential jumps recorded in the NaxCoO2 parent phase, revealing a positive impact of Ti substitution for Co. The ex-situ XRD measurements confirmed the reversibility and stability of the material. No structural changes were observed in the XRD patterns, and the P2-type structure was stable during the charge/discharge process between 2.0 and 4.2 V vs. Na+/Na. These outcomes will contribute to the progress of developing low cost electrode materials for sodium-ion batteries. (C) 2017 Elsevier B.V. All rights reserved.

  18. Growth mechanism and magnetic and electrochemical properties of Na{sub 0.44}MnO{sub 2} nanorods as cathode material for Na-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Demirel, S.; Oz, E. [Physic Department, Inonu University, Malatya 44120 (Turkey); Altin, E. [Scientific and Technological Research Center, Inonu University, 44120 (Turkey); Altin, S.; Bayri, A. [Physic Department, Inonu University, Malatya 44120 (Turkey); Kaya, P.; Turan, S. [Department of Materials Science and Engineering, Anadolu University, Eskisehir (Turkey); Avci, S., E-mail: sevdaavci@aku.edu.tr [Department of Materials Science and Engineering, Afyon Kocatepe University, Afyon 3200 (Turkey)

    2015-07-15

    Nanorods of Na{sub 0.44}MnO{sub 2} are a promising cathode material for Na-ion batteries due to their large surface area and single crystalline structure. We report the growth mechanism of Na{sub 0.44}MnO{sub 2} nanorods via solid state synthesis and their physical properties. The structure and the morphology of the Na{sub 0.44}MnO{sub 2} nanorods are investigated by X-ray diffraction (XRD), scanning and tunneling electron microscopy (SEM and TEM), and energy-dispersive X-ray (EDX) techniques. The growth mechanism of the rods is investigated and the effects of vapor pressure and partial melting of Na-rich regions are discussed. The magnetic measurements show an antiferromagnetic phase transition at 25 K and the μ{sub eff} is determined as 3.41 and 3.24 μ{sub B} from the χ–T curve and theoretical calculation, respectively. The electronic configuration and spin state of Mn{sup 3+} and Mn{sup 4+} are discussed in detail. The electrochemical properties of the cell fabricated using the nanorods are investigated and the peaks in the voltammogram are attributed to the diffusion of Na ions from different sites. Na intercalation process is explained by one and two Margules and van Laar models. - Highlights: • We synthesized Na{sub 0.44}MnO{sub 2} nanorods via a simple solid state reaction technique. • Our studies show that excess Na plays a crucial role in the nanorod formation. • Magnetization measurements show that Mn{sup 3+} ions are in LS and HS states. • The electrochemical properties of the cell fabricated using the nanorods are investigated. • Na intercalation process is explained by one and two Margules and van Laar models.

  19. Hierarchical core-shell structures of P-Ni(OH)2 rods@MnO2 nanosheets as high-performance cathode materials for asymmetric supercapacitors.

    Science.gov (United States)

    Li, Kunzhen; Li, Shikuo; Huang, Fangzhi; Yu, Xin-Yao; Lu, Yan; Wang, Lei; Chen, Hong; Zhang, Hui

    2018-01-18

    The hierarchical porous structure with phosphorus-doped Ni(OH)2 (P-Ni(OH)2) rods as the core and MnO2 nanosheets as the shell is fabricated directly by growth on a three-dimensional (3D) flexible Ni foam (NF) via a two-step hydrothermal process. As a binder-free electrode material, this unique hybrid structure exhibits excellent electrochemical properties, including an ultrahigh areal capacitance of 5.75 F cm-2 at a current density of 2 mA cm-2 and great cyclic stability without capacitance loss at a current density of 20 mA cm-2 after 10 000 cycles. Moreover, an all-solid-state asymmetric supercapacitor (AAS) based on a P-Ni(OH)2@MnO2 hybrid structure on Ni foam as the cathode and activated carbon (AC) as the anode is successfully assembled to enhance value the electrochemical properties. The AAS device also shows excellent electrochemical properties including a large potential window of 0∼1.6 V, an areal capacitance is 911.3 mF cm-2 at a current density of 1 mA cm-2 and long-term cycling performance. Meanwhile, the AAS device also delivers a high energy density of 0.324 mW h cm-2 at a power density of 0.8 mW cm-2; and can easily light colorful light-emitting diode (LED) lights, suggesting that 3D P-Ni(OH)2@MnO2 hybrid composite has promising potential for practical use in high-performance supercapacitors.

  20. Fabrication of Na0.7MnO2/C composite cathode material by simple heat treatment for high-power na-ion batteries

    Science.gov (United States)

    Sohn, DongRak; Lim, Sung-Jin; Nam, Do-Hwan; Hong, Kyung-Sik; Kim, Tae-Hee; Oh, SeKwon; Eom, Ji-Yong; Cho, EunAe; Kwon, HyukSang

    2018-01-01

    A Na0.7MnO2/C composite cathode material is synthesized by simple and costeffective two-step heat treatment for an improvement in the rate capability of Na0.7MnO2. The first heat treatment is to synthesize Na0.7MnO2, and the second one is a low temperature annealing at 350 °C for 1 h in air, which is necessary to suppress an interfacial reaction between the Na0.7MnO2 and C in the synthesis process of Na0.7MnO2/C composite. Structural analyses by XRD and XPS reveal that the Na0.7MnO2/C shows the same structural properties as that of the pristine Na0.7MnO2, and hence they exhibit the same initial discharge capacity of 175 mAh g-1 at 20 mA g-1. At a current density of 400 mA g-1, the discharge capacity of Na0.7MnO2 reduces to 50 mAh g-1 (28% of the initial discharge capacity), whereas that of Na0.7MnO2/C reduces to 108 mAh g-1 (61% of the initial discharge capacity). The enhanced rate capability of the Na0.7MnO2/C is attributed to the conductive carbon layer formed on the surface of Na0.7MnO2 particles, enabling the facile transport of electrons from the current collector to the surface of the Na0.7MnO2 particles. [Figure not available: see fulltext.

  1. Electrochemical evaluation of LiAl{sub 0.05}Ni{sub 0.05}Mn{sub 1.9}O{sub 4} cathode material synthesized via electrospinning method

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Xianan; Zhou, Hongwei [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); Department of Physical Chemistry, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); Liu, Guicheng [Beijing Institute of Nanoenergy and Nanosystem, Chinese Academy Sciences, 30 College Road, Beijing 100083 (China); Yin, Zhuang; Jiang, Ying; Wang, Xindong [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); Department of Physical Chemistry, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China)

    2015-05-25

    Highlights: • Dual-doped LiMn{sub 2}O{sub 4} nanofiber cathode is synthesized by electrospinning. • Nanofiber cathode forms porous “network-like” structures. • Al/Ni dual-dope markedly improved the cycle stability and rate performance. - Abstract: One-dimensional LiAl{sub 0.05}Ni{sub 0.05}Mn{sub 1.9}O{sub 4} nanofibers are prepared by an electrospinning method followed by calcination process to investigate the influences of Al/Ni dual-doping on the structural and electrochemical properties of as-prepared cathode materials for Li-ion batteries. X-ray diffraction (XRD) and scanning electron microscope (SEM) characterization results indicate that the as-prepared material have good crystallinity and uniform morphology. Galvanostatic charge–discharge tests demonstrate LiAl{sub 0.05}Ni{sub 0.05}Mn{sub 1.9}O{sub 4} has an improved cyclic performance at 25 °C and high temperature (55 °C), which originates from the enhanced stability by decreasing lattice constant and suppression of Jahn–Teller effect revealed by XPS analysis. Moreover, From the EIS analysis, it is revealed reduced charge transfer resistance of LiAl{sub 0.05}Ni{sub 0.05}Mn{sub 1.9}O{sub 4} compared with those of undoped LiMn{sub 2}O{sub 4}.

  2. Vacuum arc on the polycrystalline silica cathode

    Directory of Open Access Journals (Sweden)

    D. V. Duhopel'nikov

    2014-01-01

    Full Text Available Thin films of silica and its compounds are used in modern technology to produce Li-ion batteries, wear-resistant and protective coatings, thin-films insulators, etc. This coating is produced with CVD methods, with magnetron sputtering systems or with electron-beam evaporation. The vacuum arc evaporation method, presently, is not used.The paper demonstrates a possibility for a long-term operation of vacuum arc evaporator with polycrystalline silica-aluminum alloy (90% of silica cathode and with magnetic system to create a variable form of arch-like magnetic field on the cathode surface. It was shown that archlike configuration of magnetic field provides a stable discharge and uniform cathode spots moving with the velocities up to 5 m/s with magnetic fields induction about 10 mT. Thus, there is no local melting of the cathode, and this provides its long-term work without chips, cracks and destruction. Cathodes spots move over the cathode surface leaving t big craters with melted edges on its surface. The craters size was 150-450μm. The cathode spot movement character and the craters on the cathode surface were like the spots movement, when working on the copper or aluminum cathodes. With the magnetic field induction less than 1 mT, the cathode spots movement was the same as that of on the silica mono-crystal without magnetic field. Thus, the discharge volt-ampere characteristics for different values of magnetic fields were obtained. Voltampere characteristics were increasing and were shifted to the higher voltage with increasing magnetic field. The voltage was 18.7-26.5 V for the arc current 30-140 A.So, it was confirmed that vacuum arc evaporation method could be used for effective evaporation of silica and silica-based alloys and for thin films deposition of this materials.

  3. One-step hydrothermal synthesis and electrochemical performance of sodium-manganese-iron phosphate as cathode material for Li-ion batteries

    Science.gov (United States)

    Karegeya, Claude; Mahmoud, Abdelfattah; Vertruyen, Bénédicte; Hatert, Frédéric; Hermann, Raphaël P.; Cloots, Rudi; Boschini, Frédéric

    2017-09-01

    The sodium-manganese-iron phosphate Na2Mn1.5Fe1.5(PO4)3 (NMFP) with alluaudite structure was obtained by a one-step hydrothermal synthesis route. The physical properties and structure of this material were obtained through XRD and Mössbauer analyses. X-ray diffraction Rietveld refinements confirm a cationic distribution of Na+ and presence of vacancies in A(2)', Na+ and small amounts of Mn2+ in A(1), Mn2+ in M(1), 0.5 Mn2+ and Fe cations (Mn2+,Fe2+ and Fe3+) in M(2), leading to the structural formula Na2Mn(Mn0.5Fe1.5)(PO4)3. The particles morphology was investigated by SEM. Several reactions with different hydrothermal reaction times were attempted to design a suitable synthesis protocol of NMFP compound. The time of reaction was varied from 6 to 48 h at 220 °C. The pure phase of NMFP particles was firstly obtained when the hydrothermal reaction of NMFP precursors mixture was maintained at 220 °C for 6 h. When the reaction time was increased from 6 to 12, 24 and 48 h, the dandelion structure was destroyed in favor of NMFP micro-rods. The combination of NMFP (NMFP-6H, NMFP-12H, NMFP-24H and NMFP-48H) structure refinement and Mössbauer characterizations shows that the increase of the reaction time leads to the progressive increment of Fe(III) and the decrease of the crystal size. The electrochemical tests indicated that NMFP is a 3 V sodium intercalating cathode. The comparison of the discharge capacity evolution of studied NMFP electrode materials at C/5 current density shows different capacities of 48, 40, 34 and 34 mA h g-1 for NMFP-6H, NMFP-12H, NMFP-24H and NMFP-48H respectively. Interestingly, all samples show excellent capacity retention of about 99% during 50 cycles.

  4. Dielectric and impedance study of praseodymium substituted Mg-based spinel ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Farid, Hafiz Muhammad Tahir, E-mail: tahirfaridbzu@gmail.com [Department of Physics, Bahauddin Zakariya, University Multan, 60800 (Pakistan); Ahmad, Ishtiaq; Ali, Irshad [Department of Physics, Bahauddin Zakariya, University Multan, 60800 (Pakistan); Ramay, Shahid M. [College of Science, Physics and Astronomy Department, King Saud University, P.O. Box 2455, 11451 Riyadh (Saudi Arabia); Mahmood, Asif [Chemical Engineering Department, College of Engineering, King Saud University, Riyadh (Saudi Arabia); Murtaza, G. [Centre for Advanced Studies in Physics, GC University, Lahore 5400 (Pakistan)

    2017-07-15

    Highlights: • Magnesium based spinel ferrites were successfully synthesized by sol-gel method. • Dielectric constant shows the normal spinel ferrites behavior. • The dc conductivity are found to decrease with increasing temperature. • The samples with low conductivity have high values of activation energy. • The Impedance decreases with increasing frequency of applied field. - Abstract: Spinel ferrites with nominal composition MgPr{sub y}Fe{sub 2−y}O{sub 4} (y = 0.00, 0.025, 0.05, 0.075, 0.10) were prepared by sol-gel method. Temperature dependent DC electrical conductivity and drift mobility were found in good agreement with each other, reflecting semiconducting behavior. The dielectric properties of all the samples as a function of frequency (1 MHz–3 GHz) were measured at room temperature. The dielectric constant and complex dielectric constant of these samples decreased with the increase of praseodymium concentration. In the present spinel ferrite, Cole–Cole plots were used to separate the grain and grain boundary’s effects. The substitution of praseodymium ions in Mg-based spinel ferrites leads to a remarkable rise of grain boundary’s resistance as compared to the grain’s resistance. As both AC conductivity and Cole–Cole plots are the functions of concentration, they reveal the dominant contribution of grain boundaries in the conduction mechanism. AC activation energy was lower than dc activation energy. Temperature dependence normalized AC susceptibility of spinel ferrites reveals that MgFe{sub 2}O{sub 4} exhibits multi domain (MD) structure with high Curie temperature while on substitution of praseodymium, MD to SD transitions occurs. The low values of conductivity and low dielectric loss make these materials best candidate for high frequency application.

  5. Cathodic Protection Model Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Performs Navy design and engineering of ship and submarine impressed current cathodic protection (ICCP) systems for underwater hull corrosion control and...

  6. Cation disorder in high dose neutron irradiated spinel

    Energy Technology Data Exchange (ETDEWEB)

    Sickafus, K.E.; Larson, A.C.; Yu, N.; Nastasi, M. [Los Alamos National Lab., NM (United States); Hollenberg, G.W.; Garner, F.A. [Pacific Northwest Lab., Richland, WA (United States); Bradt, R.C. [Univ. of Nevada, Reno, NV (United States)

    1994-06-01

    The crystal structures of MgAl{sub 2}O{sub 4} spinel single crystals irradiated to high neutron fluences (>5{center_dot}10{sup 26} n/m{sup 2} (E{sub n}>0.1 MeV)), were examined by neutron diffraction. Crystal structure refinement of the highest dose sample indicated that the average scattering strength of the tetrahedral crystal sites decreased by {approximately}20% while increasing by {approximately}8% on octahedral sites. Since the neutron scattering length for Mg is considerably larger than for Al, this result is consistent with site exchange between Mg{sup 2+} ions on tetrahedral sites and Al{sup 3+} ions on octahedral sites. Least squares refinements also indicated that in all irradiated samples, at least 35% of Mg{sup 2+} and Al{sup 3+} ions in the crystal experienced disordering replacements. This retained dpa on the cation sublattices is the largest retained damage ever measured in an irradiated spinel material.

  7. Nanostructured Conductive Polymer Gels as a General Framework Material To Improve Electrochemical Performance of Cathode Materials in Li-Ion Batteries.

    Science.gov (United States)

    Shi, Ye; Zhou, Xingyi; Zhang, Jun; Bruck, Andrea M; Bond, Andrew C; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S; Yu, Guihua

    2017-03-08

    Controlling architecture of electrode composites is of particular importance to optimize both electronic and ionic conduction within the entire electrode and improve the dispersion of active particles, thus achieving the best energy delivery from a battery. Electrodes based on conventional binder systems that consist of carbon additives and nonconductive binder polymers suffer from aggregation of particles and poor physical connections, leading to decreased effective electronic and ionic conductivities. Here we developed a three-dimensional (3D) nanostructured hybrid inorganic-gel framework electrode by in situ polymerization of conductive polymer gel onto commercial lithium iron phosphate particles. This framework electrode exhibits greatly improved rate and cyclic performance because the highly conductive and hierarchically porous network of the hybrid gel framework promotes both electronic and ionic transport. In addition, both inorganic and organic components are uniformly distributed within the electrode because the polymer coating prevents active particles from aggregation, enabling full access to each particle. The robust framework further provides mechanical strength to support active electrode materials and improves the long-term electrochemical stability. The multifunctional conductive gel framework can be generalized for other high-capacity inorganic electrode materials to enable high-performance lithium ion batteries.

  8. Effect of MWCNT on prepared cathode material (Li{sub 2}Mn{sub (x)}Fe{sub (1-x)}SiO{sub 4}) for energy storage applications

    Energy Technology Data Exchange (ETDEWEB)

    Agnihotri, Shruti, E-mail: cecm.appsc.sa@gmail.com; Rattan, Sangeeta; Sharma, A. L., E-mail: alsharmaiitkgp@gmail.com [Centre for Physical Sciences, Central University of Punjab, Bathinda-151001 (India)

    2016-05-06

    The electrode material Li{sub 2}MnFeSiO{sub 4} was successfully synthesized by standard sol–gel method and further modified with multiwalled carbon nano tube (MWCNT) to achieve better electrochemical properties. Our strategy helps us to improve the performance and storage capacity as compared with the bared material. This novel composite structure constructs an efficient cation (Li{sup +}) and electron channel which significantly enhance the Li{sup +} ion diffusion coefficient and reduced charge transfer resistance. Hence leads to high conductivity and specific capacity. Characterization technique like Field emission scanning electron microscopy (FESEM) has been used to confirm its morphology, structure and particle size which comes out to be of the order of ∼20 to 30 nm. Lesser particle size reveals better electrochemical properties. Electrical conductivity (∼10{sup −5} Scm{sup −1}) of MWCNT doped oxide cathode materials was recorded using ac impedance spectroscopy technique which reflects tenfold increment when compared with pure oxide cathode materials. Cyclic voltametery analysis has been done to calculate specific capacity and potential window of materials with and without CNTs. The results obtained from different techniques are well correlated and suitable for energy storage applications.

  9. LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES

    Energy Technology Data Exchange (ETDEWEB)

    Harlan U. Anderson; Fatih Dogan; Vladimir Petrovsky

    2002-03-31

    This project has three main goals: Thin Films Studies, Preparation of Graded Porous Substrates and Basic Electrical Characterization and testing of Planar Single Cells. This period has continued to address the problem of making dense 1/2 to 5 {micro}m thick dense layers on porous substrates (the cathode LSM). Our current status is that we are making structures of 2-5 cm{sup 2} in area, which consist of either dense YSZ or CGO infiltrated into a 2-5 {micro}m thick 50% porous layer made of either nanoncrystalline CGO or YSZ powder. This composite structure coats a macroporous cathode or anode; which serves as the structural element of the bi-layer structure. These structures are being tested as SOFC elements. A number of structures have been evaluated both as symmetrical and as button cell configuration. Results of this testing indicates that the cathodes contribute the most to cell losses for temperatures below 750 C. In this investigation different cathode materials were studied using impedance spectroscopy of symmetric cells and IV characteristics of anode supported fuel cells. Cathode materials studied included La{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (LSCF), La{sub 0.7}Sr{sub 0.2}MnO{sub 3} (LSM), Pr{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}O{sub 3} (PSCF), Sm{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (SSCF), and Yb{sub .8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (SSCF). A new technique for filtering the Fourier transform of impedance data was used to increase the sensitivity of impedance analysis. By creating a filter specifically for impedance spectroscopy the resolution was increased. The filter was tailored to look for specific circuit elements like R//C, Warburg, or constant phase elements. As many as four peaks can be resolved using the filtering technique on symmetric cells. It may be possible to relate the different peaks to material parameters, like the oxygen exchange coefficient. The cathode grouped in order from lowest to highest ASR is

  10. A High Capacity Li-Ion Cathode: The Fe(III/VI Super-Iron Cathode

    Directory of Open Access Journals (Sweden)

    Stuart Licht

    2010-05-01

    Full Text Available A super-iron Li-ion cathode with a 3-fold higher reversible capacity (a storage capacity of 485 mAh/g is presented. One of the principle constraints to vehicle electrification is that the Li-ion cathode battery chemistry is massive, and expensive. Demonstrated is a 3 electron storage lithium cathodic chemistry, and a reversible Li super-iron battery, which has a significantly higher capacity than contemporary Li-ion batteries. The super-iron Li-ion cathode consists of the hexavalent iron (Fe(VI salt, Na2FeO4, and is formed from inexpensive and clean materials. The charge storage mechanism is fundamentally different from those of traditional lithium ion intercalation cathodes. Instead, charge storage is based on multi-electron faradaic reduction, which considerably enhances the intrinsic charge storage capacity.

  11. Single-layer graphene cathodes for organic photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Cox, Marshall P.; Gorodetsky, Alon A.; Kim, Bumjung; Kim, Keun Soo; Jia, Zhang; Kim, Philip; Nuckolls, Colin; Kymissis, Ioannis

    2011-01-01

    A laminated single-layer graphene is demonstrated as a cathode for organic photovoltaicdevices. The measured properties indicate that graphene offers two potential advantages over conventional photovoltaic electrode materials; work function matching via contact doping, and increased power conversion efficiency due to transparency. These findings indicate that flexible, light-weight all carbon solar cells can be constructed using graphene as the cathode material.

  12. Evaluation of the La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}} system as SOFC cathode material with 8YSZ and LSGM as electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Aguadero, A.; Escudero, M.J. [Centro de Investigaciones Energeticas Mediambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Alonso, J.A. [Instituto de Ciencia de Materiales de Madrid (CSIC),C/Sor Juana Ines de la Cruz 3, Campus Cantoblanco, 28049 Madrid (Spain); Daza, L. [Centro de Investigaciones Energeticas Mediambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica,(CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain)

    2008-05-31

    Materials formulated as La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}} (0 {<=} x {<=} 1) have been synthesised to be evaluated as possible cathode materials in SOFCs. Their crystal structures have been investigated by high-resolution neutron powder diffraction at RT so as to map out the phase diagram. The thermal expansion coefficients have been determined to be in the range of 10.8-13.0 x 10{sup -} {sup 6} K{sup -} {sup 1}. Total conductivity values are as good as 87 S cm{sup -} {sup 1} at 580 C for x = 0.4. In order to assess the performance of each oxide as cathode material, ac impedance measurements were carried out on La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}}/electrolyte/La{sub 2}Ni{sub 1} {sub -} {sub x}Cu{sub x}O{sub 4} {sub +} {sub {delta}} symmetrical cells with either LSGM or 8YSZ as electrolyte material. For all the electrode compositions studied, the best specific resistance (ASR) values were obtained with LSGM as electrolyte. The better performance of x = 0.4 and 0.6 (ASR {proportional_to} 1 and ohm; cm{sup 2} at 850 C) compositions has been associated with the magnitude of the total conductivity and the matching of the TEC values of the cathodes with those of the electrolytes. (author)

  13. Covalent hybrid of spinel manganese-cobalt oxide and graphene as advanced oxygen reduction electrocatalysts.

    Science.gov (United States)

    Liang, Yongye; Wang, Hailiang; Zhou, Jigang; Li, Yanguang; Wang, Jian; Regier, Tom; Dai, Hongjie

    2012-02-22

    Through direct nanoparticle nucleation and growth on nitrogen doped, reduced graphene oxide sheets and cation substitution of spinel Co(3)O(4) nanoparticles, a manganese-cobalt spinel MnCo(2)O(4)/graphene hybrid was developed as a highly efficient electrocatalyst for oxygen reduction reaction (ORR) in alkaline conditions. Electrochemical and X-ray near-edge structure (XANES) investigations revealed that the nucleation and growth method for forming inorganic-nanocarbon hybrids results in covalent coupling between spinel oxide nanoparticles and N-doped reduced graphene oxide (N-rmGO) sheets. Carbon K-edge and nitrogen K-edge XANES showed strongly perturbed C-O and C-N bonding in the N-rmGO sheet, suggesting the formation of C-O-metal and C-N-metal bonds between N-doped graphene oxide and spinel oxide nanoparticles. Co L-edge and Mn L-edge XANES suggested substitution of Co(3+) sites by Mn(3+), which increased the activity of the catalytic sites in the hybrid materials, further boosting the ORR activity compared with the pure cobalt oxide hybrid. The covalently bonded hybrid afforded much greater activity and durability than the physical mixture of nanoparticles and carbon materials including N-rmGO. At the same mass loading, the MnCo(2)O(4)/N-graphene hybrid can outperform Pt/C in ORR current density at medium overpotentials with stability superior to Pt/C in alkaline solutions.

  14. Preparation and Electrochemical Properties of Li3V2(PO4)3−xBrx/Carbon Composites as Cathode Materials for Lithium-Ion Batteries

    Science.gov (United States)

    Cao, Xiaoyu; Mo, Lulu; Zhu, Limin; Xie, Lingling

    2017-01-01

    Li3V2(PO4)3−xBrx/carbon (x = 0.08, 0.14, 0.20, and 0.26) composites as cathode materials for lithium-ion batteries were prepared through partially substituting PO43− with Br−, via a rheological phase reaction method. The crystal structure and morphology of the as-prepared composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and electrochemical properties were evaluated by charge/discharge cycling and electrochemical impedance spectroscopy (EIS). XRD results reveal that the Li3V2(PO4)3−xBrx/carbon composites with solid solution phase are well crystallized and have the same monoclinic structure as the pristine Li3V2(PO4)3/carbon composite. It is indicated by SEM images that the Li3V2(PO4)3−xBrx/carbon composites possess large and irregular particles, with an increasing Br− content. Among the Li3V2(PO4)3−xBrx/carbon composites, the Li3V2(PO4)2.86Br0.14/carbon composite shows the highest initial discharge capacity of 178.33 mAh·g−1 at the current rate of 30 mA·g−1 in the voltage range of 4.8–3.0 V, and the discharge capacity of 139.66 mAh·g−1 remains after 100 charge/discharge cycles. Even if operated at the current rate of 90 mA·g−1, Li3V2(PO4)2.86Br0.14/carbon composite still releases the initial discharge capacity of 156.57 mAh·g−1, and the discharge capacity of 123.3 mAh·g−1 can be maintained after the same number of cycles, which is beyond the discharge capacity and cycleability of the pristine Li3V2(PO4)3/carbon composite. EIS results imply that the Li3V2(PO4)2.86Br0.14/carbon composite demonstrates a decreased charge transfer resistance and preserves a good interfacial compatibility between solid electrode and electrolyte solution, compared with the pristine Li3V2(PO4)3/carbon composite upon cycling. PMID:28336886

  15. Manufacturing process scale-up of optical grade transparent spinel ceramic at ArmorLine Corporation

    Science.gov (United States)

    Spilman, Joseph; Voyles, John; Nick, Joseph; Shaffer, Lawrence

    2013-06-01

    While transparent Spinel ceramic's mechanical and optical characteristics are ideal for many Ultraviolet (UV), visible, Short-Wave Infrared (SWIR), Mid-Wave Infrared (MWIR), and multispectral sensor window applications, commercial adoption of the material has been hampered because the material has historically been available in relatively small sizes (one square foot per window or less), low volumes, unreliable supply, and with unreliable quality. Recent efforts, most notably by Technology Assessment and Transfer (TA and T), have scaled-up manufacturing processes and demonstrated the capability to produce larger windows on the order of two square feet, but with limited output not suitable for production type programs. ArmorLine Corporation licensed the hot-pressed Spinel manufacturing know-how of TA and T in 2009 with the goal of building the world's first dedicated full-scale Spinel production facility, enabling the supply of a reliable and sufficient volume of large Transparent Armor and Optical Grade Spinel plates. With over $20 million of private investment by J.F. Lehman and Company, ArmorLine has installed and commissioned the largest vacuum hot press in the world, the largest high-temperature/high-pressure hot isostatic press in the world, and supporting manufacturing processes within 75,000 square feet of manufacturing space. ArmorLine's equipment is capable of producing window blanks as large as 50" x 30" and the facility is capable of producing substantial volumes of material with its Lean configuration and 24/7 operation. Initial production capability was achieved in 2012. ArmorLine will discuss the challenges that were encountered during scale-up of the manufacturing processes, ArmorLine Optical Grade Spinel optical performance, and provide an overview of the facility and its capabilities.

  16. Chromium poisoning of LSM/YSZ and LSCF/CGO composite cathodes

    DEFF Research Database (Denmark)

    Bentzen, Janet Jonna; Høgh, Jens Valdemar Thorvald; Barfod, Rasmus

    2009-01-01

    An electrochemical study of SOFC cathode degradation, due to poisoning by chromium oxide vapours, was performed applying 3-electrode set-ups. The cathode materials comprised LSM/YSZ and LSCF/CGO composites, whereas the electrolyte material was 8YSZ. The degradation of the cathode performance...... from 300 to 2,970 h. Both LSM/YSZ and LSCF/CGO cathodes were sensitive to chromium poisoning; LSCF/CGO cathodes to a lesser extent than LSM/YSZ. Humid air aggravated the degradation of the cathode performance. Post-mortem electron microscopic investigations revealed several Cr-containing compounds...

  17. High Performance Pillared Vanadium Oxide Cathode for Lithium Ion Batteries

    Science.gov (United States)

    2015-04-24

    Performance Pillared Vanadium Oxide Cathode for Lithium Ion Batteries Siu on Tung, Krista L. Hawthorne, Yi Ding, James Mainero, and Levi T. Thompson...Automotive Research Development and Engineering Center, Warren, MI 48387, USA Keywords: nanostructured materials, lithium ion batteries , cathode...2014 to 00-00-2015 4. TITLE AND SUBTITLE High Performance Pillared Vanadium Oxide Cathode for Lithium Ion Batteries 5a. CONTRACT NUMBER 5b. GRANT

  18. High performance electrode material for supercapacitors based on α-Co(OH)2 nano-sheets prepared through pulse current cathodic electro-deposition (PC-CED)

    Science.gov (United States)

    Aghazadeh, Mustafa; Rashidi, Amir; Ganjali, Mohammad Reza

    2018-01-01

    In this paper, the well-defined nano-sheets of α-Co(OH)2 were prepared through the cathodic electrosynthesis from an additive-free aqueous cobalt nitrate bath. The pulse current cathodic electro-deposition (PC-CED) was used as the means for the controlling the OH- electrogeneration on the cathode surface. The characteristics and electrochemical behavior of the prepared cobalt hydroxide were also assessed through SEM, TEM, XRD, BET, and IR. The results proved the product to be composed of crystalline pure α phase of cobalt hydroxide with sheet-like morphology at nanoscale. Evaluations of the electrochemical behaviour of the α-Co(OH)2 nano-sheets revealed that they are capable to delivering the specific capacitance of 1122 F g-1 at a discharge load of 3 A g-1 and SC retention of 84% after 4000 continues discharging cycles, suggesting the nano-sheets as promising candidates for use in electrochemical supercapacitors. Further, the method used for the preparation of the compounds enjoys the capability of being scaled up. [Figure not available: see fulltext.

  19. Na-rich layered Na2Ti1-xCrxO3-x/2 (x = 0, 0.06): Na-ion battery cathode materials with high capacity and long cycle life.

    Science.gov (United States)

    Song, Shufeng; Kotobuki, Masashi; Chen, Yingqian; Manzhos, Sergei; Xu, Chaohe; Hu, Ning; Lu, Li

    2017-03-23

    Rechargeable lithium batteries have been well-known and indispensable for portable electronic devices, and have the potential to be used in electric vehicles and smart grids. However, the growing concerns about the availability of lithium resources for large-scale applications have revived interest in sodium ion batteries. Of many obstacles to commercialization of Na-ion batteries, achieving simultaneously a large reversible capacity and good cycling capability of electrode materials remains a major challenge. Here, we report a new cathode material, Na-rich layered oxide Na2Ti0.94Cr0.06O2.97, that delivers high reversible capacity of 336 mAh g(-1) at current density of 18.9 mA g(-1) along with promising cycling capability of 74% capacity retention over 1000 cycles at current of 378 mA g(-1). The high capacity is associated to the redox reaction of oxygen, which is confirmed here by a combined experimental and theoretical study. The present work therefore shows that materials beyond mainstream layered oxides and polyanion compounds should be considered as candidate high-performance cathodes for Na-ion batteries.

  20. Experimental Observations on Dynamic Response of Selected Transparent Armor Materials

    Science.gov (United States)

    2014-07-01

    10 describe the details of these tests. Results on Crystalline Ceramic Materials AlON EOI Tests AlON is isostructural with magnesium aluminate spinel... aluminate spinel, IJACT, Published on line, 22 October 2010 11. Krell A, Hutzler T, Klimke J (2009) Advanced spinel and Sub- micron Al2O3 for transparent...response on magnesium aluminate spinel. Mater Sci Eng A 528:5088–5095 13. Haney E, Subhash G (2011) Rate sensitive indentation of a coarse grained magnesium

  1. Microscopical characterization of carbon materials derived from coal and petroleum and their interaction phenomena in making steel electrodes, anodes and cathode blocks for the Microscopy of Carbon Materials Working Group of the ICCP

    Science.gov (United States)

    Predeanu, G.; Panaitescu, C.; Bălănescu, M.; Bieg, G.; Borrego, A.G.; Diez, M. A.; Hackley, Paul C.; Kwiecińska, B.; Marques, M.; Mastalerz, Maria; Misz-Kennan, M.; Pusz, S.; Suarez-Ruiz, I.; Rodrigues, S.; Singh, A. K.; Varma, A. K.; Zdravkov, A.; Zivotić, D.

    2015-01-01

    This paper describes the evaluation of petrographic textures representing the structural organization of the organic matter derived from coal and petroleum and their interaction phenomena in the making of steel electrodes, anodes and cathode blocks.This work represents the results of the Microscopy of Carbon Materials Working Group in Commission III of the International Committee for Coal and Organic Petrology between the years 2009 and 2013. The round robin exercises were run on photomicrograph samples. For textural characterization of carbon materials the existing ASTM classification system for metallurgical coke was applied.These round robin exercises involved 15 active participants from 12 laboratories who were asked to assess the coal and petroleum based carbons and to identify the morphological differences, as optical texture (isotropic/anisotropic), optical type (punctiform, mosaic, fibre, ribbon, domain), and size. Four sets of digital black and white microphotographs comprising 151 photos containing 372 fields of different types of organic matter were examined. Based on the unique ability of carbon to form a wide range of textures, the results showed an increased number of carbon occurrences which have crucial role in the chosen industrial applications.The statistical method used to evaluate the results was based on the “raw agreement indices”. It gave a new and original view on the analysts' opinion by not only counting the correct answers, but also all of the knowledge and experience of the participants. Comparative analyses of the average values of the level of overall agreement performed by each analyst in the exercises during 2009–2013 showed a great homogeneity in the results, the mean value being 90.36%, with a minimum value of 83% and a maximum value of 95%.

  2. Fundamental science of refractory: major components, their crystal structures and properties. Spinel (application). Taikabutsu no kisokagaku: kosei seibun no kessho kagaku to bussei. Spinel (oyo)

    Energy Technology Data Exchange (ETDEWEB)

    Kitai, T. (Harima Ceramics Co. Ltd., Hyogo (Japan))

    1994-07-10

    This review article describes the chromite and synthetic MgO[center dot]Al2O3 clinker. It also introduces the direct bond magnesite-chrome brick and Al2O3-MgO[center dot]Al2O3 type casting material. Chromite occurs naturally, and consists of solid solutions of various kind of spinel group minerals and a small amount of silicate. For the magnesite-chrome brick which is obtained through ultra-high temperature burning of the mixture of high purity magnesia and chromite with less impurities like SiO2, the secondary spinel is formed due to the diffusion of Cr2O3 and Al2O3 into MgO, to result in the direct bond. Consequently, the thermal shock resistance and hot strength are improved. On the other hand, MgO[center dot]Al2O3 is one of the spinel group minerals included in the chromite, and is used as the brick for cement rotary kiln and the castable casting material for casting runner. 29 refs., 5 figs., 6 tabs.

  3. An ionic-liquid-assisted approach to synthesize a reduced graphene oxide loading iron-based fluoride as a cathode material for sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Miaoling; Wang, Xianyou, E-mail: wxianyou@yahoo.com; Wei, Shuangying; Shen, Yongqiang; Hu, Hai

    2016-06-15

    A reduced graphene oxide loading iron-based fluoride (abbreviated as Fe{sub 2}F{sub 5}·H{sub 2}O/rGO) as a cathode material for sodium ion batteries (SIBs) has been successfully prepared by an ionic-liquid-assisted route. The morphology, structure, physicochemical properties and electrochemical performance are characterized by X-ray powder diffraction (XRD), Rietveld refinement of XRD pattern, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical tests. The XRD result shows that the crystal structure of the as-prepared sample can be indexed to the cubic Fd-3m space group and the lattice parameter is as follow: a = 1.04029 nm and V = 1.12581 nm{sup 3}. Moreover, the SEM and TEM images reveal that the as-prepared rGO has a rough wavy structure and flexural paper-like morphology, and numerous Fe{sub 2}F{sub 5}·H{sub 2}O particles are firmly adhered on the surface of the rGO to form an uniform Fe{sub 2}F{sub 5}·H{sub 2}O/rGO composite. Electrochemical tests show that the initial discharge capacity of Fe{sub 2}F{sub 5}·H{sub 2}O/rGO sample is 248.7 mAh g{sup −1} and the corresponding charging capacity up to 229.7 mAh g{sup −1} at a rate of 20 mA g{sup −1}. Especially, the Fe{sub 2}F{sub 5}·H{sub 2}O/rGO possesses good cycling stability, and it can deliver a discharge capacity of 164.2 mAh g{sup −1} at the 100th cycle. Besides, the rate capability tests show that a stable high capacity of 186.0 mAh g{sup −1} can be resumed when the current rate returns to 20 mA g{sup −1} after 20 cycles. - - Highlights: • The Fe{sub 2}F{sub 5}·H{sub 2}O/rGO has been successfully prepared by an ionic-liquid-assisted method. • The paper-like rGO could be obtained by a green hydrothermal method. • Numerous Fe{sub 2}F{sub 5}·H{sub 2}O particles are adhered firmly on the surface of the paper-like rGO. • The Fe{sub 2}F{sub 5}·H{sub 2}O/rGO shows excellent cycling stability and rate capability.

  4. Materials Challenges and Opportunities of Lithium-ion Batteries for Electrical Energy Storage

    Science.gov (United States)

    Manthiram, Arumugam

    2011-03-01

    Electrical energy storage has emerged as a topic of national and global importance with respect to establishing a cleaner environment and reducing the dependence on foreign oil. Batteries are the prime candidates for electrical energy storage. They are the most viable near-term option for vehicle applications and the efficient utilization of intermittent energy sources like solar and wind. Lithium-ion batteries are attractive for these applications as they offer much higher energy density than other rechargeable battery systems. However, the adoption of lithium-ion battery technology for vehicle and stationary storage applications is hampered by high cost, safety concerns, and limitations in energy, power, and cycle life, which are in turn linked to severe materials challenges. This presentation, after providing an overview of the current status, will focus on the physics and chemistry of new materials that can address these challenges. Specifically, it will focus on the design and development of (i) high-capacity, high-voltage layered oxide cathodes, (ii) high-voltage, high-power spinel oxide cathodes, (iii) high-capacity silicate cathodes, and (iv) nano-engineered, high-capacity alloy anodes. With high-voltage cathodes, a critical issue is the instability of the electrolyte in contact with the highly oxidized cathode surface and the formation of solid-electrolyte interfacial (SEI) layers that degrade the performance. Accordingly, surface modification of cathodes with nanostructured materials and self-surface segregation during the synthesis process to suppress SEI layer formation and enhance the energy, power, and cycle life will be emphasized. With the high-capacity alloy anodes, a critical issue is the huge volume change occurring during the charge-discharge process and the consequent poor cycle life. Dispersion of the active alloy nanoparticles in an inactive metal oxide-carbon matrix to mitigate this problem and realize long cycle life will be presented.

  5. Effect of cutting edge radius on surface roughness in diamond tool turning of transparent MgAl2O4 spinel ceramic

    Science.gov (United States)

    Yue, Xiaobin; Xu, Min; Du, Wenhao; Chu, Chong

    2017-09-01

    Transparent magnesium aluminate spinel (MgAl2O4) ceramic is one of an important optical materials. However, due to its pronounced hardness and brittleness, the optical machining of this material is very difficult. Diamond turning has advantages over the grinding process in flexibility and material removal rate. However, there is a lack of research that could support the use of diamond turning technology in the machining of MgAl2O4 spinel ceramic. Using brittle-ductile transition theory of brittle material machining, this work provides critical information that may help to realize ductile-regime turning of MgAl2O4 spinel ceramic. A characterization method of determination the cutting edge radius is introduced here. Suitable diamond tools were measured for sharpness and then chosen from a large number of candidate tools. The influence of rounded cutting edges on surface roughness of the MgAl2O4 spinel ceramic is also investigated. These results indicate that surface quality of MgAl2O4 spinel is relate to the radius of diamond tool's cutting edge, cutting speed, and feed rate. Sharp diamond tools (small radius of cutting edge) facilitated ductile-regime turning of MgAl2O4 spinel and shows great potential to reduce surface roughness and produce smoother final surface.

  6. Reducing DRIFT Backgrounds with a Submicron Aluminized-Mylar Cathode

    OpenAIRE

    Battat, J. S. R.; Daw, E.; Dorofeev, A.; Ezeribe, A. C.; Fox, J. R.; Gauvreau, J-L.; Gold, M; Harmon, L.; Harton, J.; Lafler, R.; Landers, J.; Lauer, R. J.; Lee, E.R.; Loomba, D.; Lumnah, A.

    2015-01-01

    Background events in the DRIFT-IId dark matter detector, mimicking potential WIMP signals, are predominantly caused by alpha decays on the central cathode in which the alpha particle is completely or partially absorbed by the cathode material. We installed a 0.9 micron thick aluminized-mylar cathode as a way to reduce the probability of producing these backgrounds. We study three generations of cathode (wire, thin-film, and radiologically clean thin-film) with a focus on the ratio of backgrou...

  7. NiCo2O4 surface coating Li[Ni0.03Mn1.97]O4 micro-/nano- spheres as cathode material for high-performance lithium ion battery

    Science.gov (United States)

    Ye, Pan; Dong, Hui; Xu, Yunlong; Zhao, Chongjun; Liu, Dong

    2018-01-01

    Here we report a novel transitional metal oxide (NiCo2O4) coated Li[Ni0.03Mn1.97]O4 micro-/nano- spheres as high-performance Li-ion battery cathode material. A thin layer of ∼10 nm NiCo2O4 was formed by simple wet-chemistry approach adjacent to the surface of Li[Ni0.03Mn1.97]O4 micro-/nano- spheres, leading to significantly enhanced battery electrochemical performance. The optimized sample(1 wt%) not only delivers excellent discharge capacity and cycling stability improvement at both room temperature and elevated temperatures, but also effectively prevents Mn dissolution while retaining its coating structure intact according to XRF and TEM results. The CV and EIS break-down analysis indicated a much faster electrochemical reaction kinetics, more reversible electrode process and greatly reduced charge transfer and Warburg resistance, clearly illustrating the dual role of NiCo2O4 coating to boost electron transport and Li+ diffusion, and alleviation of manganese dissolving. This approach may render as an efficient technique to realize high-performance lithium ion battery cathode material.

  8. Nanostructured sulfur cathodes

    KAUST Repository

    Yang, Yuan

    2013-01-01

    Rechargeable Li/S batteries have attracted significant attention lately due to their high specific energy and low cost. They are promising candidates for applications, including portable electronics, electric vehicles and grid-level energy storage. However, poor cycle life and low power capability are major technical obstacles. Various nanostructured sulfur cathodes have been developed to address these issues, as they provide greater resistance to pulverization, faster reaction kinetics and better trapping of soluble polysulfides. In this review, recent developments on nanostructured sulfur cathodes and mechanisms behind their operation are presented and discussed. Moreover, progress on novel characterization of sulfur cathodes is also summarized, as it has deepened the understanding of sulfur cathodes and will guide further rational design of sulfur electrodes. © 2013 The Royal Society of Chemistry.

  9. Nanostructured sulfur cathodes.

    Science.gov (United States)

    Yang, Yuan; Zheng, Guangyuan; Cui, Yi

    2013-04-07

    Rechargeable Li/S batteries have attracted significant attention lately due to their high specific energy and low cost. They are promising candidates for applications, including portable electronics, electric vehicles and grid-level energy storage. However, poor cycle life and low power capability are major technical obstacles. Various nanostructured sulfur cathodes have been developed to address these issues, as they provide greater resistance to pulverization, faster reaction kinetics and better trapping of soluble polysulfides. In this review, recent developments on nanostructured sulfur cathodes and mechanisms behind their operation are presented and discussed. Moreover, progress on novel characterization of sulfur cathodes is also summarized, as it has deepened the understanding of sulfur cathodes and will guide further rational design of sulfur electrodes.

  10. A general method of fabricating flexible spinel-type oxide/reduced graphene oxide nanocomposite aerogels as advanced anodes for lithium-ion batteries.

    OpenAIRE

    Zeng Guobo; Shi Nan; Hess Michael; Chen Xi; Cheng Wei; Fan Tongxiang; Niederberger Markus

    2015-01-01

    High capacity anode materials for lithium ion batteries (LIBs) such as spinel type metal oxides generally suffer from poor Li(+) and e( ) conductivities. Their drastic crystal structure and volume changes as a result of the conversion reaction mechanism with Li severely impede the high rate and cyclability performance toward their practical application. In this article we present a general and facile approach to fabricate flexible spinel type oxide/reduced graphene oxide (rGO) composite aerog...

  11. Chromian spinel-rich black sands from eastern shoreline of ...

    Indian Academy of Sciences (India)

    Black sands rich in chromian spinel commonly occur in pockets along the eastern shoreline of Andaman Island where various types of peridotites and volcanics belonging to the Andaman ophiolite suite are exposed in close vicinity. The chemistry of these detrital chromian spinels has been extensively used here in ...

  12. A cathode material based on the iron fluoride with an ultra-thin Li3FeF6 protective layer for high-capacity Li-ion batteries

    Science.gov (United States)

    Yang, Juan; Xu, Zhanglin; Zhou, Haochen; Tang, Jingjing; Sun, Hongxu; Ding, Jing; Zhou, Xiangyang

    2017-09-01

    Iron fluoride based on the multi-electron reaction is a typical representative among the new-style cathode materials for Lithium-ion batteries, which is attracting extensive attentions. To relieve the cathode dissolution and interfacial side reactions and improve the electrochemical performance of FeF3·0.33H2O, we design an ultra-thin Li3FeF6 protective layer, which is in-situ formed on the surface of FeF3·3H2O particles by a facile process. The prepared Li3FeF6/FeF3·0.33H2O (LF50) composite displays a superior rate performance (152 mAh g-1 at 1000 mA g-1), which is remarkable to many other carbon-free iron fluorides. And it is noticeable that a reversible capacity of 174 mAh g-1 can be retained after 100 cycles, indicating an outstanding cycling stability contrast to the bare FeF3·0.33H2O. The enhanced electrochemical performance is attributed to the protection of Li3FeF6 layer which reduces the cathode dissolution and interfacial side reactions. Moreover, the agglomeration of first particles in the calcination process is effectively suppressed resulting from the introduction of the Li3FeF6 protective layer, which promotes electrolyte penetration and charge transfer in the composites. It is expected that the strategy can provide a new approach for the modification of other metal fluoride.

  13. Interfacial characterisation in transparent spinel matrix reinforced by SiC fibre

    Czech Academy of Sciences Publication Activity Database

    Chlup, Zdeněk; Dlouhý, Ivo; Gürbüz, S.; Dericioglu, A. F.; Kozák, Vladislav

    2009-01-01

    Roč. 409, - (2009), s. 252-259 ISSN 1013-9826. [Fractography of Advanced Ceramics III. Stará Lesná, 07.09.20058-10.09.2008] R&D Projects: GA ČR(CZ) GA106/06/0724; GA AV ČR IAA200410502 Institutional research plan: CEZ:AV0Z20410507 Keywords : interface * composite * transparent spinel * SiC fibre * fracture characteristics Subject RIV: JI - Composite Materials

  14. Synthesis of high-surface-area spinel-type MgAl2O4 nanoparticles ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 40; Issue 1. Synthesis of high-surface-area spinel-type MgAl 2 O 4 nanoparticles by [Al(sal) 2 (H 2 O) 2 ] 2 [Mg(dipic) 2 ] and [Mg(H 2 O) 6 ][Al(ox) 2 (H 2 O) 2 ] 2 ·5H 2 O: influence of inorganic precursor type. Volume 40 Issue 1 February 2017 pp 45-53 ...

  15. Effects of strontium doping on the structure, oxygen nonstoichiometry and electrochemical performance of Pr2-xSrxNi0.6Cu0.4O4+δ (0.1 ≤ x ≤ 0.5) cathode materials

    Science.gov (United States)

    Li, Mingming; Cheng, Jigui; Gan, Yun; Li, Shisong; He, Beibei; Sun, Wenzhou

    2015-02-01

    Pr2-xSrxNi0.6Cu0.4O4+δ (PSNCO, x = 0.1, 0.3, 0.5) oxides with K2NiF4-type structure are synthesized by a glycine-nitrate process as potential cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). The influence of strontium substitution on the structure, oxygen nonstoichiometry, electrical property and electrochemical performance is investigated. Iodometric titration method is employed to study the oxygen nonstoichiometry and the formal valence of nickel. The maximum electrical conductivity reaches 109 S cm-1 at 450 °C in air for Pr1.7Sr0.3Ni0.6Cu0.4O4+δ material. Area specific resistance (ASR) values of all compositions are below 0.11 Ω cm2 at 800 °C, and the Pr1.7Sr0.3Ni0.6Cu0.4O4+δ composition has the lowest ASR value of 0.063 Ω cm2 at 800 °C. Open circuit voltage (OCV) and maximum power density of the single cell (NiO-SDC/SDC/PSNCO) are 0.767 V and 353 mW cm-2 at 800 °C, respectively. The preliminary results indicate that Pr2-xSrxNi0.6Cu0.4O4+δ materials could be good candidates for IT-SOFCs cathode materials.

  16. Compact Rare Earth Emitter Hollow Cathode

    Science.gov (United States)

    Watkins, Ronald; Goebel, Dan; Hofer, Richard

    2010-01-01

    A compact, high-current, hollow cathode utilizing a lanthanum hexaboride (LaB6) thermionic electron emitter has been developed for use with high-power Hall thrusters and ion thrusters. LaB6 cathodes are being investigated due to their long life, high current capabilities, and less stringent xenon purity and handling requirements compared to conventional barium oxide (BaO) dispenser cathodes. The new cathode features a much smaller diameter than previously developed versions that permit it to be mounted on axis of a Hall thruster ( internally mounted ), as opposed to the conventional side-mount position external to the outer magnetic circuit ("externally mounted"). The cathode has also been reconfigured to be capable of surviving vibrational loads during launch and is designed to solve the significant heater and materials compatibility problems associated with the use of this emitter material. This has been accomplished in a compact design with the capability of high-emission current (10 to 60 A). The compact, high-current design has a keeper diameter that allows the cathode to be mounted on the centerline of a 6- kW Hall thruster, inside the iron core of the inner electromagnetic coil. Although designed for electric propulsion thrusters in spacecraft station- keeping, orbit transfer, and interplanetary applications, the LaB6 cathodes are applicable to the plasma processing industry in applications such as optical coatings and semiconductor processing where reactive gases are used. Where current electrical propulsion thrusters with BaO emitters have limited life and need extremely clean propellant feed systems at a significant cost, these LaB6 cathodes can run on the crudest-grade xenon propellant available without impact. Moreover, in a laboratory environment, LaB6 cathodes reduce testing costs because they do not require extended conditioning periods under hard vacuum. Alternative rare earth emitters, such as cerium hexaboride (CeB6) can be used in this

  17. Li-storage and cycling properties of spinel, CdFe2 O4, as an anode ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 32; Issue 3. Li-storage and cycling properties of spinel, CdFe2O4, as an anode for lithium ion batteries. Yogesh Sharma N Sharma G V Subba Rao B V R Chowdari. Volume 32 Issue 3 June 2009 pp 295-304 ...

  18. Surface Modification of Li(Ni0.6Co0.2Mn0.2)O₂ Cathode Materials by Nano-Al₂O₃ to Improve Electrochemical Performance in Lithium-Ion Batteries.

    Science.gov (United States)

    Yoo, Kwang Soo; Kang, Yeon Hui; Im, Kyoung Ran; Kim, Chang-Sam

    2017-11-06

    Al₂O₃-coated Li(Ni0.6Co0.2Mn0.2)O₂ cathode materials were prepared by simple surface modification in water media through a sol-gel process with a dispersant. The crystallinity and surface morphology of the samples were characterized through X-ray diffraction analysis and scanning electron microscopy observation. The Li(Ni0.6Co0.2Mn0.2)O₂ cathode material was of a polycrystalline hexagonal structure and agglomerated with particles of approximately 0.3 to 0.8 μm in diameter. The nanosized Al₂O₃ particles of low concentration (0.06-0.12 wt %) were uniformly coated on the surface of Li(Ni0.6Co0.2Mn0.2)O₂. Measurement of electrochemical properties showed that Li(Ni0.6Co0.2Mn0.2)O₂ coated with Al₂O₃ of 0.08 wt % had a high initial discharge capacity of 206.9 mAh/g at a rate of 0.05 C over 3.0-4.5 V and high capacity retention of 94.5% at 0.5 C after 30 cycles (cf. uncoated sample: 206.1 mAh/g and 90.8%, respectively). The rate capability of this material was also improved, i.e., it showed a high discharge capacity of 166.3 mAh/g after 5 cycles at a rate of 2 C, whereas the uncoated sample showed 155.8 mAh/g under the same experimental conditions.

  19. Designed seamless outer surface: Application for high voltage LiNi0.5Mn1.5O4 cathode with excellent cycling stability

    Science.gov (United States)

    Zhang, Kan; Li, Ping; Ma, Ming; Park, Jong Hyeok

    2016-12-01

    Suppressing side reactions at the cathode-electrolyte interface (CEI) is critical for alleviating capacity fading of the high-voltage (>5 V) spinel cathode material LiNi0.5Mn1.5O4 (LNMO). The primary bottleneck in conventional nanoengineering of LNMO involves an antagonistic relationship between the positive effects of the nanometer particle size and negative effects stemming from the larger CEI area. Inspired by Buckminster Fuller's geodesic domes, we have designed a seamless LNMO hollow sphere (S-LNMO) that comprises average 120 nm-sized triangles and truncated triangle subunits by means of grain growth orientation. The "tensegrity" structure has efficiently hindered the interfacial side reaction, which occurs only within a depth of 5 nm from the surface, thereby improving its electrochemical stability. The embedded layered Li2TiO3 (LTO) in bulk S-LNMO (LTO:S-LNMO) region further improved the high-rate performance, demonstrating an ∼110 mAh/g capacity with 80.9% retention after 400 cycles at 5 C and remaining stable after 900 cycles at 5 C even after being stored at 50 °C for one week.

  20. Synthesis of magnesium aluminate spinel by periclase and alumina chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, Pablo, E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis Chacabuco y Pedernera, San Luis (Argentina); Barbosa, Lucía [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Instituto de Ciencias Básicas (ICB), Universidad Nacional de Cuyo Parque General San Martín, Mendoza (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis Chacabuco y Pedernera, San Luis (Argentina)

    2014-11-15

    Highlights: • Use of chlorination for the synthesis of magnesium aluminate spinel. • The reagents used were alumina, periclase and chlorine. • Isothermal and non-isothermal assays were performed in air and Cl{sub 2}–N{sub 2} flows. • The chlorination produced magnesium aluminate spinel at 700 °C. • Selectivity of the chlorination reaction to obtain spinel is very high. - Abstract: A pyrometallurgical route for the synthesis of magnesium aluminate spinel by thermal treatment of a mechanical mixture containing 29 wt% MgO (periclase) and 71 wt% Al{sub 2}O{sub 3} (alumina) in chlorine atmosphere was developed and the results were compared with those obtained by calcining the same mixture of oxides in air atmosphere. Isothermal and non-isothermal assays were performed in an experimental piece of equipment adapted to work in corrosive atmospheres. Both reagents and products were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD) and X-ray fluorescence (XRF). Thermal treatment in Cl{sub 2} atmosphere of the MgO–Al{sub 2}O{sub 3} mixture produces magnesium aluminate spinel at 700 °C, while in air, magnesium spinel is generated at 930 °C. The synthesis reaction of magnesium aluminate spinel was complete at 800 °C.

  1. Study of Mn dissolution from LiMn{sub 2}O{sub 4} spinel electrodes using rotating ring-disk collection experiments

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Li-Fang; Ou, Chin-Ching; Striebel, Kathryn A.; Chen, Jenn-Shing

    2003-07-01

    The goal of this research was to measure Mn dissolution from a thin porous spinel LiMn{sub 2}O{sub 4} electrode by rotating ring-disk collection experiments. The amount of Mn dissolution from the spinel LiMn{sub 2}O{sub 4} electrode under various conditions was detected by potential step chronoamperometry. The concentration of dissolved Mn was found to increase with increasing cycle numbers and elevated temperature. The dissolved Mn was not dependent on disk rotation speed, which indicated that the Mn dissolution from the disk was under reaction control. The in situ monitoring of Mn dissolution from the spinel was carried out under various conditions. The ring currents exhibited maxima corresponding to the end-of-charge (EOC) and end-of-discharge (EOD), with the largest peak at EOC. The results suggest that the dissolution of Mn from spinel LiMn{sub 2}O{sub 4} occurs during charge/discharge cycling, especially in a charged state (at >4.1 V) and in a discharged state (at <3.1 V). The largest peak at EOC demonstrated that Mn dissolution took place mainly at the top of charge. At elevated temperatures, the ring cathodic currents were larger due to the increase of Mn dissolution rate.

  2. Mesoporous delafossite CuCrO₂ and spinel CuCr₂O₄: synthesis and catalysis.

    Science.gov (United States)

    Zhang, Peng; Shi, Yifeng; Chi, Miaofang; Park, Jung-Nam; Stucky, Galen D; McFarland, Eric W; Gao, Lian

    2013-08-30

    Delafossite CuCrO2 and spinel CuCr2O4 with mesoporous structures have been successfully synthesized using nanocasting methods based on a KIT-6 template. The functional activity of the mesoporous materials was evaluated in applications as heterogeneous catalysts. The activity for photocatalytic hydrogen production of the delafossite structures with different morphologies was characterized and the oxidation state changes associated with photocorrosion of Cu(+) investigated using electron energy loss spectroscopy (EELS). Mg(2+) doping was found to facilitate the casting of ordered structures for CuCrO2 and improves the photocorrosion resistance of delafossite structures. The mesoporous spinel CuCr2O4 nanostructures were found to be active for low temperature CO oxidation.

  3. Contemporary artists' spinel pigments: Non-invasive characterization by means of electronic spectroscopy

    Science.gov (United States)

    Angelin, Eva Mariasole; Bacci, Mauro; Bartolozzi, Giovanni; Cantisani, Emma; Picollo, Marcello

    2017-02-01

    The identification of artistic materials represents a fundamental step in supporting the conservation of cultural heritage objects. The importance of their appropriate characterization is particularly relevant in modern-contemporary art, since they could be affected by the occurrence of rapid changes in chemical formulation over time. This paper focuses on an investigation of a series of contemporary blue-green commercial acrylic paints constituted of spinel pigments, using non-invasive spectroscopic techniques. The spectroscopic and color measurements obtained make it possible to characterize the acrylic paints under investigation and to compare the results obtained with those reported in the literature and in spectral databases. To be more precise, the proposed UV-vis-NIR reflectance spectroscopic technique was sensitive enough to characterize the acrylic paints according to their d-d ligand field and the charge transfer (CT) electronic transitions involved in the spinel structures. In addition, an overview of this class of inorganic pigments is also given.

  4. Effect of Bi oxide surface treatment on 5 V spinel LiNi{sub 0.5}Mn{sub 1.5-x}Ti{sub x}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Noguchi, Takehiro; Numata, Tatsuji; Shirakata, Masato [NEC Tokin Corporation, 1120, Shimokuzawa, Sagamihara, Kanagawa 229-1198 (Japan); Yamazaki, Ikiko [NEC Lamilion Energy, Ltd., 1120, Shimokuzawa, Sagamihara, Kanagawa 229-1198 (Japan)

    2007-12-06

    The effect of Bi surface treatment on LiNi{sub 0.5}Mn{sub 1.5-x}Ti{sub x}O{sub 4} was examined. As a result, Bi surface film around 20 nm thick was confirmed to be fabricated on the surface of 5 V spinel LiNi{sub 0.5}Mn{sub 1.5-x}Ti{sub x}O{sub 4} by transmission electron microscopy (TEM) and energy dispersion X-ray spectrometer (EDX) analysis. The Bi compound was confirmed to be Bi{sub 2}O{sub 3} by X-ray diffraction analysis. Cycle behavior was also found to be improved by Bi treatment. A retention capacity of up to around 85% was achieved after 500 cycles at 20 C, while a retention capacity as high as 70% was obtained after 500 cycles, even at 45 C. Storage performance was also improved with Bi treatment. Recovery capacity of more than 90% was obtained with Bi treatment after storage for 1 week at 60 C. The increased resistance in storage was also suppressed with Bi treatment, which would be due to the suppression of electrolyte decomposition by the Bi coating film. It was found that Bi treatment had the effect of decreasing the dissolution of Mn, Ni and Ti of the elements of the cathode active material, due to inductively coupled plasma (ICP) analysis. Based on these results, the Bi surface coating was found to have a remarkable effect on the improvement of the cells with 5 V spinel. (author)

  5. Time domain transients investigation on the lithium rich cathode material Li[Li{sub 0.2}Ni{sub 0.2}Mn{sub 0.6}]O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Lingxia; Zheng, Weidong; Xu, Xiaoping; Shui, Miao, E-mail: shuimiao@nbu.edu.cn; Cheng, Liangliang; Shu, Jie; Yang, Tianci; Feng, Lin; Ren, Yuanlong

    2013-12-15

    Time domain transients to current step of multiple current densities were calculated to evaluate the polarization and fractional contribution of lithium rich cathode material Li[Li{sub 0.2}Ni{sub 0.2}Mn{sub 0.6}]O{sub 2} based on the equivalent circuit determined from the electrochemical impedance spectrum. The calculated data matched the experimental profiles well. The contributions of the individual circuit elements, like charge transfer reaction, lithium transportation across the SEI film and solid-state lithium diffusion process, were successfully differentiated and the importance of each element was fully assessed. The results told us that they should be equally paid attention to and minimized by the optimized preparation method and cell design.

  6. Highly Efficient Micro Cathode Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek Company, Inc. proposes to develop a micro thermionic cathode that requires extremely low power and provides long lifetime. The basis for the cathode is a...

  7. Advanced Cathode Electrolyzer (ACE) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a static, cathode-fed, 2000 psi, balanced-pressure Advanced Cathode Electrolyzer (ACE) based on PEM electrolysis technology. It...

  8. Organic-Acid-Assisted Fabrication of Low-Cost Li-Rich Cathode Material (Li[Li1/6Fe1/6Ni1/6Mn1/2]O-2) for Lithium-Ion Battery

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Taolin; Chen, Shi; Li, Li; Zhang, Xiaoxiao; Wu, Huiming; Wu, Tianpin; Sun, Cheng-Jun; Chen, Renjie; Wu, Feng; Lu, Jun; Amine, Khalil

    2014-12-24

    A novel Li-rich cathode Li[Li1/6Fe1/6Ni1/6Mn1/2]O-2 (0.4Li(2)MnO(3-)0.6LiFe(1/3)Ni(1/3)Mn(1/3)O(2)) was synthesized by a solgel method, which uses citric acid (SC), tartaric acid (ST), or adipic acid (SA) as a chelating agent. The structural, morphological, and electrochemical properties of the prepared samples were characterized by various methods. X-ray diffraction showed that single-phase materials are formed mainly with typical alpha-NaFeO2 layered structure (R3 m), and the SC sample has the lowest Li/Ni cation disorder. The morphological study indicated homogeneous primary particles in good distribution size (100 nm) with small aggregates. The Fe, Ni, and Mn valences were determined by X-ray absorption near-edge structure analysis. In coin cell tests, the initial reversible discharge capacity of an SA electrode was 289.7 mAh g(-1) at the 0.1C rate in the 1.54.8 V voltage range, while an SC electrode showed a better cycling stability with relatively high capacity retention. At the 2C rate, the SC electrode can deliver a discharge capacity of 150 mAh g(-1) after 50 cycles. Differential capacity vs voltage curves were employed to further investigate the electrochemical reactions and the structural change process during cycling. This low-cost, Fe-based compound prepared by the solgel method has the potential to be used as the high capacity cathode material for Liion batteries.

  9. Orbital-Specific observation of O2p and Ni3d electrons in LiNi0.5Mn0.5O2, a cathode material for lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Yoshinori Satou

    2017-09-01

    Full Text Available Cathode materials for lithium-ion batteries containing Ni2+ have attracted much interest because of their high theoretical capacity. However, the precise electronic structures of these cathode materials have not yet been clearly observed, especially the energy positions of the O2p and Ni3d orbitals and the shape of the density of states. The aim of this study was to investigate the relative energy positions and shape of the density of states of O2p and Ni3d for LiNi0.5Mn0.5O2 experimentally. We cleaved a LiNi0.5Mn0.5O2 pellet in an Ar-filled glove box and performed synchrotron ultraviolet photoelectron spectroscopy for different photon energies, which enabled us to investigate the relative cross-section intensity of O2p and Ni3d. As a result, the valence-band structure was determined. We found that O2p electrons are itinerant and exist in the vicinity of the Fermi energy more than Ni3d electrons. Ni3d electrons are more localized and spread mainly from 1.2–1.5 eV below the Fermi energy. To validate the electronic structure, we measured the synchrotron O K-edge X-ray absorption fine structure of electrochemically lithium-extracted LiNi0.5Mn0.5O2. The electronic structure demonstrated that ligand holes in the oxygen atoms form below the Fermi level during the initial stage of Li extraction and that the formation rate of the holes decreases with Li extraction.

  10. Orbital-Specific observation of O2p and Ni3d electrons in LiNi0.5Mn0.5O2, a cathode material for lithium-ion batteries

    Science.gov (United States)

    Satou, Yoshinori; Komine, Shigeki; Shimizu, Sumera

    2017-09-01

    Cathode materials for lithium-ion batteries containing Ni2+ have attracted much interest because of their high theoretical capacity. However, the precise electronic structures of these cathode materials have not yet been clearly observed, especially the energy positions of the O2p and Ni3d orbitals and the shape of the density of states. The aim of this study was to investigate the relative energy positions and shape of the density of states of O2p and Ni3d for LiNi0.5Mn0.5O2 experimentally. We cleaved a LiNi0.5Mn0.5O2 pellet in an Ar-filled glove box and performed synchrotron ultraviolet photoelectron spectroscopy for different photon energies, which enabled us to investigate the relative cross-section intensity of O2p and Ni3d. As a result, the valence-band structure was determined. We found that O2p electrons are itinerant and exist in the vicinity of the Fermi energy more than Ni3d electrons. Ni3d electrons are more localized and spread mainly from 1.2-1.5 eV below the Fermi energy. To validate the electronic structure, we measured the synchrotron O K-edge X-ray absorption fine structure of electrochemically lithium-extracted LiNi0.5Mn0.5O2. The electronic structure demonstrated that ligand holes in the oxygen atoms form below the Fermi level during the initial stage of Li extraction and that the formation rate of the holes decreases with Li extraction.

  11. Deposition and characterization of thin films of materials with application in cathodes for lithium rechargeable micro batteries; Deposito y caracterizacion de peliculas delgadas de materiales con aplicacion en catodos para microbaterias recargables de litio

    Energy Technology Data Exchange (ETDEWEB)

    Lopez I, J. [UAEM, Facultad de Quimica, 50000 Toluca, Estado de Mexico (Mexico)

    2007-07-01

    In this thesis work is reported the deposition and characterization of thin films of materials of the type LiMO{sub 2}, with M=Co and Ni, which have application in cathodes for micro-batteries of lithium ions. In the last years some investigators have reported that the electrochemical operation of the lithium ions batteries it can improve recovering the cathode, in bundle form, with some metal oxides as the Al{sub 2}O{sub 3}; for that the study of the formation of thin films in bilayer form LiMO{sub 2}/AI{sub 2}O{sub 3} is of interest in the development of lithium ions micro batteries. The thin films were deposited using the laser ablation technique studying the effect of some deposit parameters in the properties of the one formed material, as: laser fluence, substrate temperature and working atmosphere, with the purpose of optimizing it. In the case of the LiCoO{sub 2} it was found that to use an inert atmosphere of argon allows to obtain the material with the correct composition. Additionally, with the use of a temperature in the substrate of 150 C is possible to obtain to the material with certain crystallinity grade that to the subjected being to a post-deposit thermal treatment at 300 C for three hours, it gives as result a totally crystalline material. In the case of the thin films of LiNiO{sub 2}, it was necessary to synthesize the oxide starting from a reaction of solid state among nickel oxide (NiO) and lithium oxide (Li{sub 2}O) obtaining stoichiometric LiNiO{sub 2}. For the formation of the thin films of LiNiO{sub 2} it was used an argon atmosphere and the laser fluence was varied, the deposits were carried out to two different substrates temperatures, atmosphere and 160 C. In both cases the material it was recovered with an alumina layer, found that this layer didn't modify the structural properties of the base oxide (LiCoO{sub 2} and LiNiO{sub 2}). (Author)

  12. Energy storage improvement through material science approaches

    Science.gov (United States)

    Kelly, Brandon Joseph

    A need for improved energy storage is apparent for the improvement of our society. Lithium ion batteries are one of the leading energy storage technologies being researched today. These batteries typically utilize coupled reduction/oxidation reactions with intercalation reactions in crystalline metal oxides with lithium ions as charge carriers to produce efficient and high power energy storage options. The cathode material (positive electrode) has been an emphasis in the recent research as it is currently the weakest link of the battery. Several systems of cathode materials have been studied with different structures and chemical makeup, all having advantages and disadvantages. One focus of the research presented below was creating a low cost and high performance cathode material by creating a composite of the low cost spinel structured LiMn2O4 and the higher capacity layered structure materials. Two compositional diagrams were used to map out the composition space between end members which include two dimensional layer structured LiCoO 2, LiNiO2, LiNi0.8Co0.2O2 and three dimensional spinel structured LiMn2O4. Several compositions in each composition map were electrochemically tested and structurally characterized in an attempt to discover a high performance cathode material with a lower cost precursor. The best performing composition in each system shows the desired mixed phase of the layered and spinel crystal structures, yielding improved performance versus the individual end member components. The surrounding compositions were then tested in order to find the optimum composition and performance. The best performing composition was 0.2LiCoO 2•0.7LiNi0.8Co0.2O2•0.1LiMn 2O4 and yielded a specific capacity of 182mAh/g. Another promising area of chemical energy storage is in the storage of hydrogen gas in chemical hydrides. Hydrogen gas can be used as a fuel in a variety of applications as a viable method for storing and transporting energy. Currently, the

  13. Power generation using an activated carbon and metal mesh cathode in a microbial fuel cell

    KAUST Repository

    Zhang, Fang

    2009-11-01

    An inexpensive activated carbon (AC) air cathode was developed as an alternative to a platinum-catalyzed electrode for oxygen reduction in a microbial fuel cell (MFC). AC was cold-pressed with a polytetrafluoroethylene (PTFE) binder to form the cathode around a Ni mesh current collector. This cathode construction avoided the need for carbon cloth or a metal catalyst, and produced a cathode with high activity for oxygen reduction at typical MFC current densities. Tests with the AC cathode produced a maximum power density of 1220 mW/m2 (normalized to cathode projected surface area; 36 W/m3 based on liquid volume) compared to 1060 mW/m2 obtained by Pt catalyzed carbon cloth cathode. The Coulombic efficiency ranged from 15% to 55%. These findings show that AC is a cost-effective material for achieving useful rates of oxygen reduction in air cathode MFCs. © 2009 Elsevier B.V. All rights reserved.

  14. Systematic Optimization of Battery Materials: Key Parameter Optimization for the Scalable Synthesis of Uniform, High-Energy, and High Stability LiNi0.6Mn0.2Co0.2O2 Cathode Material for Lithium-Ion Batteries.

    Science.gov (United States)

    Ren, Dong; Shen, Yun; Yang, Yao; Shen, Luxi; Levin, Barnaby D A; Yu, Yingchao; Muller, David A; Abruña, Héctor D

    2017-10-18

    Ni-rich LiNixMnyCo1-x-yO2 (x > 0.5) (NMC) materials have attracted a great deal of interest as promising cathode candidates for Li-ion batteries due to their low cost and high energy density. However, several issues, including sensitivity to moisture, difficulty in reproducibly preparing well-controlled morphology particles and, poor cyclability, have hindered their large scale deployment; especially for electric vehicle (EV) applications. In this work, we have developed a uniform, highly stable, high-energy density, Ni-rich LiNi0.6Mn0.2Co0.2O2 cathode material by systematically optimizing synthesis parameters, including pH, stirring rate, and calcination temperature. The particles exhibit a spherical morphology and uniform size distribution, with a well-defined structure and homogeneous transition-metal distribution, owing to the well-controlled synthesis parameters. The material exhibited superior electrochemical properties, when compared to a commercial sample, with an initial discharge capacity of 205 mAh/g at 0.1 C. It also exhibited a remarkable rate capability with discharge capacities of 157 mAh/g and 137 mAh/g at 10 and 20 C, respectively, as well as high tolerance to air and moisture. In order to demonstrate incorporation into a commercial scale EV, a large-scale 4.7 Ah LiNi0.6Mn0.2Co0.2O2 Al-full pouch cell with a high cathode loading of 21.6 mg/cm2, paired with a graphite anode, was fabricated. It exhibited exceptional cyclability with a capacity retention of 96% after 500 cycles at room temperature. This material, which was obtained by a fully optimized scalable synthesis, delivered combined performance metrics that are among the best for NMC materials reported to date.

  15. Single-layer graphene cathodes for organic photovoltaics

    Science.gov (United States)

    Cox, Marshall; Gorodetsky, Alon; Kim, Bumjung; Kim, Keun Soo; Jia, Zhang; Kim, Philip; Nuckolls, Colin; Kymissis, Ioannis

    2011-03-01

    A laminated single-layer graphene is demonstrated as a cathode for organic photovoltaic devices. The measured properties indicate that graphene offers two potential advantages over conventional photovoltaic electrode materials; work function matching via contact doping, and increased power conversion efficiency due to transparency. These findings indicate that flexible, light-weight all carbon solar cells can be constructed using graphene as the cathode material.

  16. Enhanced performance of sulfur-infiltrated bimodal mesoporous carbon foam by chemical solution deposition as cathode materials for lithium sulfur batteries

    Science.gov (United States)

    Jeong, Tae-Gyung; Chun, Jinyong; Cho, Byung-Won; Lee, Jinwoo; Kim, Yong-Tae

    2017-02-01

    The porous carbon matrix is widely recognized to be a promising sulfur reservoir to improve the cycle life by suppressing the polysulfide dissolution in lithium sulfur batteries (LSB). Herein, we synthesized mesocellular carbon foam (MSUF-C) with bimodal mesopore (4 and 30 nm) and large pore volume (1.72 cm2/g) using MSUF silica as a template and employed it as both the sulfur reservoir and the conductive agent in the sulfur cathode. Sulfur was uniformly infiltrated into MSUF-C pores by a chemical solution deposition method (MSUF-C/S CSD) and the amount of sulfur loading was achieved as high as 73% thanks to the large pore volume with the CSD approach. MSUF-C/S CSD showed a high capacity (889 mAh/g after 100 cycles at 0.2 C), an improved rate capability (879 mAh/g at 1C and 420 mAh/g at 2C), and a good capacity retention with a fade rate of 0.16% per cycle over 100 cycles.

  17. Cobalt terephthalate MOF-templated synthesis of porous nano-crystalline Co3O4 by the new indirect solid state thermolysis as cathode material of asymmetric supercapacitor

    Science.gov (United States)

    Bigdeli, Hadise; Moradi, Morteza; Hajati, Shaaker; Kiani, Mohammad Ali; Toth, Jozsef

    2017-10-01

    In this work, two different types of Co3O4 nano-crystals were synthesized by (i) conventional direct solid state thermolysis of cobalt terephthalate metal-organic framework (MOF-71) and (ii) new indirect solid state thermolysis of Co(OH)2 derived by alkaline aqueous treatment of MOF-71. The products were then characterized by X-ray diffraction technique (XRD), Fourier transforms infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Reflection electron energy loss spectroscopy (REELS), Brunauer, Emmett, and Teller (BET), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. By REELS analysis the energy band gap of MOF-71 was determined to be 3.7 eV. Further, electrochemical performance of each Co3O4 nanostructure was studied by the cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in a three-electrode system in KOH electrolyte. An asymmetric supercapacitor was fabricated using indirect Co3O4 nanoparticles as cathode and electrochemically reduced graphene oxide as anode, and the electrochemical properties were studied and showed a high energy density of 13.51 Wh kg-1 along with a power density of 9775 W kg-1 and good cycling stability with capacitance retention rate of 85% after 2000 cycles.

  18. Tailored Core Shell Cathode Powders for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Swartz, Scott [NexTech Materials, Ltd.,Lewis Center, OH (United States)

    2015-03-23

    In this Phase I SBIR project, a “core-shell” composite cathode approach was evaluated for improving SOFC performance and reducing degradation of lanthanum strontium cobalt ferrite (LSCF) cathode materials, following previous successful demonstrations of infiltration approaches for achieving the same goals. The intent was to establish core-shell cathode powders that enabled high performance to be obtained with “drop-in” process capability for SOFC manufacturing (i.e., rather than adding an infiltration step to the SOFC manufacturing process). Milling, precipitation and hetero-coagulation methods were evaluated for making core-shell composite cathode powders comprised of coarse LSCF “core” particles and nanoscale “shell” particles of lanthanum strontium manganite (LSM) or praseodymium strontium manganite (PSM). Precipitation and hetero-coagulation methods were successful for obtaining the targeted core-shell morphology, although perfect coverage of the LSCF core particles by the LSM and PSM particles was not obtained. Electrochemical characterization of core-shell cathode powders and conventional (baseline) cathode powders was performed via electrochemical impedance spectroscopy (EIS) half-cell measurements and single-cell SOFC testing. Reliable EIS testing methods were established, which enabled comparative area-specific resistance measurements to be obtained. A single-cell SOFC testing approach also was established that enabled cathode resistance to be separated from overall cell resistance, and for cathode degradation to be separated from overall cell degradation. The results of these EIS and SOFC tests conclusively determined that the core-shell cathode powders resulted in significant lowering of performance, compared to the baseline cathodes. Based on the results of this project, it was concluded that the core-shell cathode approach did not warrant further investigation.

  19. Microwave irradiation controls the manganese oxidation states of nanostructured (Li[Li0.2Mn0.52Ni0.13Co0.13Al0.02]O2) layered cathode materials for high-performance lithium ion batteries

    CSIR Research Space (South Africa)

    Jafta, CJ

    2015-02-01

    Full Text Available as LMNC-mic and LMNCA-mic). The nanoparticulate nature of these layered cathode materials were confirmed by SEM. The crystallinity and layeredness were determined from the XRD analysis. The XPS measurements proved a definite change in the oxidation states...

  20. Nanocrystalline spinel ferrites by solid state reaction route

    Indian Academy of Sciences (India)

    Wintec

    The powders are taken in a mold for cold compaction at a pressure of 5 bars and finally sintered in air for 2 h at 1100°C. X-ray diffraction patterns of the sintered samples show that all the expected lines of the MnFe2O4 spinel structure are present (Mishra et al 2006). Thus the present set of spinel ferrites are formed with Ti.

  1. Thermal expansion of spinel-type Si3N4

    DEFF Research Database (Denmark)

    Paszkowics, W.; Minkikayev, R.; Piszora, P.

    2004-01-01

    The lattice parameter and thermal expansion coefficient (TEC) for the spinel-type Si3N4 phase prepared under high-pressure and high-temperature conditions are determined for 14 K......The lattice parameter and thermal expansion coefficient (TEC) for the spinel-type Si3N4 phase prepared under high-pressure and high-temperature conditions are determined for 14 K...

  2. Improved Rare-Earth Emitter Hollow Cathode

    Science.gov (United States)

    Goebel, Dan M.

    2011-01-01

    An improvement has been made to the design of the hollow cathode geometry that was created for the rare-earth electron emitter described in Compact Rare Earth Emitter Hollow Cathode (NPO-44923), NASA Tech Briefs, Vol. 34, No. 3 (March 2010), p. 52. The original interior assembly was made entirely of graphite in order to be compatible with the LaB6 material, which cannot be touched by metals during operation due to boron diffusion causing embrittlement issues in high-temperature refractory materials. Also, the graphite tube was difficult to machine and was subject to vibration-induced fracturing. This innovation replaces the graphite tube with one made out of refractory metal that is relatively easy to manufacture. The cathode support tube is made of molybdenum or molybdenum-rhenium. This material is easily gun-bored to near the tolerances required, and finish machined with steps at each end that capture the orifice plate and the mounting flange. This provides the manufacturability and robustness needed for flight applications, and eliminates the need for expensive e-beam welding used in prior cathodes. The LaB6 insert is protected from direct contact with the refractory metal tube by thin, graphite sleeves in a cup-arrangement around the ends of the insert. The sleeves, insert, and orifice plate are held in place by a ceramic spacer and tungsten spring inserted inside the tube. To heat the cathode, an insulating tube is slipped around the refractory metal hollow tube, which can be made of high-temperature materials like boron nitride or aluminum nitride. A screw-shaped slot, or series of slots, is machined in the outside of the ceramic tube to constrain a refractory metal wire wound inside the slot that is used as the heater. The screw slot can hold a single heater wire that is then connected to the front of the cathode tube by tack-welding to complete the electrical circuit, or it can be a double slot that takes a bifilar wound heater with both leads coming out

  3. Synthesis of ultrasmall Li-Mn spinel oxides exhibiting unusual ion exchange, electrochemical, and catalytic properties.

    Science.gov (United States)

    Miyamoto, Yumi; Kuroda, Yoshiyuki; Uematsu, Tsubasa; Oshikawa, Hiroyuki; Shibata, Naoya; Ikuhara, Yuichi; Suzuki, Kosuke; Hibino, Mitsuhiro; Yamaguchi, Kazuya; Mizuno, Noritaka

    2015-10-12

    The efficient surface reaction and rapid ion diffusion of nanocrystalline metal oxides have prompted considerable research interest for the development of high functional materials. Herein, we present a novel low-temperature method to synthesize ultrasmall nanocrystalline spinel oxides by controlling the hydration of coexisting metal cations in an organic solvent. This method selectively led to Li-Mn spinel oxides by tuning the hydration of Li(+) ions under mild reaction conditions (i.e., low temperature and short reaction time). These particles exhibited an ultrasmall crystallite size of 2.3 nm and a large specific surface area of 371 ± 15 m(2) g(-1). They exhibited unique properties such as unusual topotactic Li(+)/H(+) ion exchange, high-rate discharge ability, and high catalytic performance for several aerobic oxidation reactions, by creating surface phenomena throughout the particles. These properties differed significantly from those of Li-Mn spinel oxides obtained by conventional solid-state methods.

  4. Novel Energy Sources -Material Architecture and Charge Transport in Solid State Ionic Materials for Rechargeable Li ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Katiyar, Ram S; Gómez, M; Majumder, S B; Morell, G; Tomar, M S; Smotkin, E; Bhattacharya, P; Ishikawa, Y

    2009-01-19

    Since its introduction in the consumer market at the beginning of 1990s by Sony Corporation ‘Li-ion rechargeable battery’ and ‘LiCoO2 cathode’ is an inseparable couple for highly reliable practical applications. However, a separation is inevitable as Li-ion rechargeable battery industry demand more and more from this well serving cathode. Spinel-type lithium manganate (e.g., LiMn2O4), lithium-based layered oxide materials (e.g., LiNiO2) and lithium-based olivine-type compounds (e.g., LiFePO4) are nowadays being extensively studied for application as alternate cathode materials in Li-ion rechargeable batteries. Primary goal of this project was the advancement of Li-ion rechargeable battery to meet the future demands of the energy sector. Major part of the research emphasized on the investigation of electrodes and solid electrolyte materials for improving the charge transport properties in Li-ion rechargeable batteries. Theoretical computational methods were used to select electrodes and electrolyte material with enhanced structural and physical properties. The effect of nano-particles on enhancing the battery performance was also examined. Satisfactory progress has been made in the bulk form and our efforts on realizing micro-battery based on thin films is close to give dividend and work is progressing well in this direction.

  5. Synchrotron Investigations of SOFC Cathode Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Idzerda, Yves

    2013-09-30

    The atomic variations occurring in cathode/electrolyte interface regions of La{sub 1-x}Sr{sub x}Co{sub y}Fe{sub 1-y}O{sub 3-δ} (LSCF) cathodes and other SOFC related materials have been investigated and characterized using soft X-ray Absorption Spectroscopy (XAS) and diffuse soft X-ray Resonant Scattering (XRS). X-ray Absorption Spectroscopy in the soft X-ray region (soft XAS) is shown to be a sensitive technique to quantify the disruption that occurs and can be used to suggest a concrete mechanism for the degradation. For LSC, LSF, and LSCF films, a significant degradation mechanism is shown to be Sr out-diffusion. By using the XAS spectra of hexavalent Cr in SrCrO4 and trivalent Cr in Cr2O3, the driving factor for Sr segregation was identified to be the oxygen vacancy concentration at the anode and cathode side of of symmetric LSCF/GDC/LSCF heterostructures. This is direct evidence of vacancy induced cation diffusion and is shown to be a significant indicator of cathode/electrolyte interfacial degradation. X-ray absorption spectroscopy is used to identify the occupation of the A-sites and B-sites for LSC, LSF, and LSCF cathodes doped with other transition metals, including doping induced migration of Sr to the anti-site for Sr, a significant cathode degradation indicator. By using spatially resolved valence mapping of Co, a complete picture of the surface electrochemistry can be determined. This is especially important in identifying degradation phenomena where the degradation is spatially localized to the extremities of the electrochemistry and not the average. For samples that have electrochemical parameters that are measured to be spatially uniform, the Co valence modifications were correlated to the effects of current density, overpotential, and humidity.

  6. Scalable and template-free synthesis of nanostructured Na{sub 1.08}V{sub 6}O{sub 15} as high-performance cathode material for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Shili, E-mail: slzheng@ipe.ac.cn [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing (China); Wang, Xinran; Yan, Hong [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing (China); University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing (China); Du, Hao; Zhang, Yi [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing (China)

    2016-09-15

    Highlights: • Nanostructured Na{sub 1.08}V{sub 6}O{sub 15} was synthesized through additive-free sol-gel process. • Prepared Na{sub 1.08}V{sub 6}O{sub 15} demonstrated high capacity and sufficient cycling stability. • The reaction temperature was optimized to allow scalable Na{sub 1.08}V{sub 6}O{sub 15} fabrication. - Abstract: Developing high-capacity cathode material with feasibility and scalability is still challenging for lithium-ion batteries (LIBs). In this study, a high-capacity ternary sodium vanadate compound, nanostructured NaV{sub 6}O{sub 15}, was template-free synthesized through sol-gel process with high producing efficiency. The as-prepared sample was systematically post-treated at different temperature and the post-annealing temperature was found to determine the cycling stability and capacity of NaV{sub 6}O{sub 15}. The well-crystallized one exhibited good electrochemical performance with a high specific capacity of 302 mAh g{sup −1} when cycled at current density of 0.03 mA g{sup −1}. Its relatively long-term cycling stability was characterized by the cell performance under the current density of 1 A g{sup −1}, delivering a reversible capacity of 118 mAh g{sup −1} after 300 cycles with 79% capacity retention and nearly 100% coulombic efficiency: all demonstrating its significant promise of proposed strategy for large-scale synthesis of NaV{sub 6}O{sub 15} as cathode with high-capacity and high energy density for LIBs.

  7. Morphology-controlled microwave-assisted solvothermal synthesis of high-performance LiCoPO4 as a high-voltage cathode material for Li-ion batteries

    Science.gov (United States)

    Ludwig, Jennifer; Marino, Cyril; Haering, Dominik; Stinner, Christoph; Gasteiger, Hubert A.; Nilges, Tom

    2017-02-01

    High-performance particles of the high-voltage cathode material LiCoPO4 for Li-ion batteries are synthesized by a simple and rapid one-step microwave-assisted solvothermal route at moderate temperatures (250 °C). Using a variety of water/alcohol 1:1 (v:v) solvent mixtures, including ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), tetraethylene glycol (TTEG), polyethylene glycol 400 (PEG), and benzyl alcohol (BA), the focus of the study is set on optimizing the electrochemical performance of the material by controlling the particle size and morphology. Scanning electron microscopy studies reveal a strong influence of the co-solvent on the particle size and morphology, resulting in the formation of variations between square, rhombic and hexagonal platelets. According to selected area electron diffraction experiments, the smallest crystal dimension is in the [010] direction for all materials, which is along the lithium diffusion pathways of the olivine crystal structure. The anisotropic crystal orientations with enhanced Li-ion diffusion properties result in high initial discharge capacities and gravimetric energy densities (up to 141 mAh g-1 at 0.1 C and 677 Wh kg-1 for LiCoPO4 obtained from TEG), excellent rate capabilities, and cycle life for 20 cycles.

  8. Unveiling the Role of Co in Improving the High-Rate Capability and Cycling Performance of Layered Na0.7Mn0.7Ni0.3-xCoxO2 Cathode Materials for Sodium-Ion Batteries.

    Science.gov (United States)

    Li, Zheng-Yao; Zhang, Jicheng; Gao, Rui; Zhang, Heng; Hu, Zhongbo; Liu, Xiangfeng

    2016-06-22

    Co substitution has been extensively used to improve the electrochemical performances of cathode materials for sodium-ion batteries (SIBs), but the role of Co has not been well understood. Herein, we have comprehensively investigated the effects of Co substitution for Ni on the structure and electrochemical performances of Na0.7Mn0.7Ni0.3-xCoxO2 (x = 0, 0.1, 0.3) as cathode materials for SIBs. In comparison with the Co-free sample, the high-rate capability and cycle performance have been greatly improved by the substitution of Co, and some new insights into the role of Co have been proposed for the first time. With the substitution of Co(3+) for Ni(2+) the lattice parameter a decreases; however, c increases, and the d-spacing of the sodium-ion diffusion layer has been enlarged, which enhances the diffusion coefficient of the sodium ion and the high-rate capability of cathode materials. In addition, Co substitution shortens the bond lengths of TM-O (TM = transition metal) and O-O due to the smaller size of Co(3+) than Ni(2+), which accounts for the decreased thickness and volume of the TMO6 octahedron. The contraction of TM-O and O-O bond lengths and the shrinkage of the TMO6 octahedron improve the structure stability and the cycle performance. Last but not least, the aliovalent substitution of Co(3+) for Ni(2+) can improve the electronic conductivity during the electrochemical reaction, which is also favorable to enhance the high-rate performance. This study not only unveils the role of Co in improving the high-rate capability and the cycle stability of layered Na0.7Mn0.7Ni0.3-xCoxO2 cathode materials but also offers some new insights into designing high performance cathode materials for SIBs.

  9. Synthesis and optical property of zinc aluminate spinel cryogels

    Directory of Open Access Journals (Sweden)

    Lifen Su

    2016-06-01

    Full Text Available Zinc aluminate spinel cryogels with various molar ratio of Al/Zn are synthesized by sol–gel technology followed by vacuum freeze drying. The structures and optical properties are both found to be affected by the molar ratios of Al/Zn and annealed temperatures. The peaks of zinc oxide (ZnO and zinc dialuminum oxide (ZnAl2O4 are both obtained for the samples with more Zn content annealed at 750 °C or upward. The composites have a large surface area (137 m2/g with mesoporous structure after annealing at 750 °C. The SEM images reveal that the ZnAl2O4 crystals formed a multilayer structure with redundant ZnO particles which deposited on it. Furthermore, the maximum infrared reflectance is about 80% with an improvement of 35% in the infrared region after annealing at 950 °C compared with that of 450 °C, which indicates that these porous cryogels have a potential application as thermal insulating materials at a high temperature.

  10. Incorporation of Technetium into Spinel Ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Lukens, Wayne W. [Chemical; Magnani, Nicola [Chemical; European; Tyliszczak, Tolek [Advanced; Pearce, Carolyn I. [Geosciences; Shuh, David K. [Chemical

    2016-11-21

    Technetium (99Tc) is a problematic fission product for the long-term disposal of nuclear waste due to its long half-life, high fission yield, and to the environmental mobility of pertechnetate, the stable species in aerobic environments. One approach to preventing 99Tc contamination is using sufficiently durable waste forms. We report the incorporation of technetium into a family of synthetic spinel ferrites that have environmentally durable natural analogs. A combination of X-ray diffraction, X-ray absorption fine structure spectroscopy, and chemical analysis reveals that Tc(IV) replaces Fe(III) in octahedral sites and illustrates how the resulting charge mismatch is balanced. When a large excess of divalent metal ions is present, the charge is predominantly balanced by substitution of Fe(III) by M(II). When a large excess of divalent metal ions is absent, the charge is largely balanced by creation of vacancies among the Fe(III) sites (maghemitization). In most samples, Tc is present in Tc-rich regions rather than being homogeneously distributed.

  11. Incorporation of Technetium into Spinel Ferrites.

    Science.gov (United States)

    Lukens, Wayne W; Magnani, Nicola; Tyliszczak, Tolek; Pearce, Carolyn I; Shuh, David K

    2016-12-06

    Technetium ((99)Tc) is a problematic fission product for the long-term disposal of nuclear waste due to its long half-life, high fission yield, and to the environmental mobility of pertechnetate, the stable species in aerobic environments. One approach to preventing (99)Tc contamination is using sufficiently durable waste forms. We report the incorporation of technetium into a family of synthetic spinel ferrites that have environmentally durable natural analogs. A combination of X-ray diffraction, X-ray absorption fine structure spectroscopy, and chemical analysis reveals that Tc(IV) replaces Fe(III) in octahedral sites and illustrates how the resulting charge mismatch is balanced. When a large excess of divalent metal ions is present, the charge is predominantly balanced by substitution of Fe(III) by M(II). When a large excess of divalent metal ions is absent, the charge is largely balanced by creation of vacancies among the Fe(III) sites (maghemitization). In most samples, Tc is present in Tc-rich regions rather than being homogeneously distributed.

  12. Characterization of Atomic and Electronic Structures of Electrochemically Active SOFC Cathode Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Blinn; Yongman Choi; Meilin Liu

    2009-08-11

    The objective of this project is to gain a fundamental understanding of the oxygen-reduction mechanism on mixed conducting cathode materials by means of quantum-chemical calculations coupled with direct experimental measurements, such as vibrational spectroscopy. We have made progress in the elucidation of the mechanisms of oxygen reduction of perovkite-type cathode materials for SOFCs using these quantum chemical calculations. We established computational framework for predicting properties such as oxygen diffusivity and reaction rate constants for adsorption, incorporation, and TPB reactions, and formulated predictions for LSM- and LSC-based cathode materials. We have also further developed Raman spectroscopy as well as SERS as a characterization tool for SOFC cathode materials. Raman spectroscopy was used to detect chemical changes in the cathode from operation conditions, and SERS was used to probe for pertinent adsorbed species in oxygen reduction. However, much work on the subject of unraveling oxygen reduction for SOFC cathodes remains to be done.

  13. Modification of Ni-Rich FCG NMC and NCA Cathodes by Atomic Layer Deposition: Preventing Surface Phase Transitions for High-Voltage Lithium-Ion Batteries

    Science.gov (United States)

    Mohanty, Debasish; Dahlberg, Kevin; King, David M.; David, Lamuel A.; Sefat, Athena S.; Wood, David L.; Daniel, Claus; Dhar, Subhash; Mahajan, Vishal; Lee, Myongjai; Albano, Fabio

    2016-05-01

    The energy density of current lithium-ion batteries (LIBs) based on layered LiMO2 cathodes (M = Ni, Mn, Co: NMC; M = Ni, Co, Al: NCA) needs to be improved significantly in order to compete with internal combustion engines and allow for widespread implementation of electric vehicles (EVs). In this report, we show that atomic layer deposition (ALD) of titania (TiO2) and alumina (Al2O3) on Ni-rich FCG NMC and NCA active material particles could substantially improve LIB performance and allow for increased upper cutoff voltage (UCV) during charging, which delivers significantly increased specific energy utilization. Our results show that Al2O3 coating improved the NMC cycling performance by 40% and the NCA cycling performance by 34% at 1 C/-1 C with respectively 4.35 V and 4.4 V UCV in 2 Ah pouch cells. High resolution TEM/SAED structural characterization revealed that Al2O3 coatings prevented surface-initiated layered-to-spinel phase transitions in coated materials which were prevalent in uncoated materials. EIS confirmed that Al2O3-coated materials had significantly lower increase in the charge transfer component of impedance during cycling. The ability to mitigate degradation mechanisms for Ni-rich NMC and NCA illustrated in this report provides insight into a method to enable the performance of high-voltage LIBs.

  14. Determination of lithium and transition metals in Li1 Ni1/3 Co1/3 Mn1/3 O2 (NCM) cathode material for lithium-ion batteries by capillary electrophoresis.

    Science.gov (United States)

    Vortmann-Westhoven, Britta; Lürenbaum, Constantin; Winter, Martin; Nowak, Sascha

    2017-02-01

    In this work, we present a novel electrophoretic method that was developed for the determination of lithium and transition metals in LiNi1/3 Co1/3 Mn1/3 O2 cathode material after microwave digestion. The cations in the digested LiNi1/3 Co1/3 Mn1/3 O2 material were separated by CE and the element content was determined by UV/Vis detection. To characterize the precision of the measurements, the RSDs and concentrations were calculated and compared to those obtained with ICP-optical emission spectrometry (ICP-OES). Furthermore, a certified reference material (BCR 176R-fly ash) was investigated for all techniques. For active material components, the LOD and LOQ were determined. The LODs and LOQs for the metals determined by CE were as follows: lithium (LOD/LOQ): 17.41/62.70 μg/L, cobalt (LOD/LOQ): 348.4/1283 μg/L, manganese (LOD/LOQ): 540.2/2095 μg/L, and nickel (LOD/LOQ): 838.0/2982 μg/L. Recovery rates for lithium were in the range of 95-103%. It could be proven that with the new technique, the results for the determination of the lithium content of active material were comparable with those obtained by ICP-OES and ion chromatography. Furthermore, the recovery rates of the transition metals were determined to be between 96 and 110% by CE and ICP-OES. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Empirical constraints on partitioning of platinum group elements between Cr-spinel and primitive terrestrial magmas

    Science.gov (United States)

    Park, Jung-Woo; Kamenetsky, Vadim; Campbell, Ian; Park, Gyuseung; Hanski, Eero; Pushkarev, Evgeny

    2017-11-01

    Recent experimental studies and in situ LA-ICP-MS analysis on natural Cr-spinel have shown that Rh and IPGEs (Ir-group platinum group elements: Ru, Ir, Os) are enriched in the lattice of Cr-spinel. However, the factors controlling the partitioning behaviour of these elements are not well constrained. In this study, we report the Rh, IPGE, and trace element contents in primitive Cr-spinel, measured by LA-ICP-MS, from nine volcanic suites covering various tectonic settings including island arc picrites, boninites, large igneous province picrites and mid-ocean ridge basalts. The aim is to understand the factors controlling the enrichment of Rh and IPGEs in Cr-spinels, to estimate empirical partition coefficients between Cr-spinel and silicate melts, and to investigate the role of Cr-spinel fractional crystallization on the PGE geochemistry of primitive magmas during the early stages of fractional crystallization. There are systematic differences in trace elements, Rh and IPGEs in Cr-spinels from arc-related magmas (Arc Group Cr-spinel), intraplate magmas (Intraplate Group Cr-spinel), and mid-ocean ridge magmas (MORB Group Cr-spinel). Arc Group Cr-spinels are systematically enriched in Sc, Co and Mn and depleted in Ni compared to the MORB Group Cr-spinels. Intraplate Group Cr-spinels are distinguished from the Arc Group Cr-spinels by their high Ni contents. Both the Arc and Intraplate Group Cr-spinels have total Rh and IPGE contents of 22-689 ppb whereas the MORB Group Cr-spinels are depleted in Rh and IPGE (total diagrams the Arc Group Cr-spinels are characterized by a fractionated pattern with high Rh and low Os. The Intraplate Group Cr-spinels show flat patterns with positive Ru anomalies. Our results, together with the experimental and empirical data from previous studies, show that PGE patterns of Cr-spinel largely mimic that of the rock in which they are found, and that Rh, Ir and Os contents increase with increasing Fe3+ contents (i.e. magnetite component) in Cr-spinel

  16. The effect of gradient boracic polyanion-doping on structure, morphology, and cycling performance of Ni-rich LiNi0.8Co0.15Al0.05O2 cathode material

    Science.gov (United States)

    Chen, Tao; Li, Xiang; Wang, Hao; Yan, Xinxiu; Wang, Lei; Deng, Bangwei; Ge, Wujie; Qu, Meizhen

    2018-01-01

    A gradient boracic polyanion-doping method is applied to Ni-rich LiNi0.8Co0.15Al0.05O2 (NCA) cathode material in this study to suppress the capacity/potential fade during charge-discharge cycling. Scanning electron microscope (SEM) results show that all samples present spherical morphology and the secondary particle size increases with increasing boron content. X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) results demonstrate that boracic polyanions are successfully introduced into the bulk material and more enriched in the outer layer. XPS analysis further reveals that the valence state of Ni3+ is partly reduced to Ni2+ at the surface due to the incorporation of boracic polyanions. From the electrochemical measurements, B0.015-NCA electrode exhibits excellent cycling performance, even at high potential and elevated temperature. Moreover, the SEM images illustrate the presence of cracks and a thick SEI layer on pristine particles after 100 cycles at high temperature, while the B0.015-NCA particles show an intact structure and thin SEI layer. Electrochemical impedance spectroscopy confirms that the boracic polyanion doping could hinder the impedance increase during cycling at elevated temperature. These results clearly indicate that the gradient boracic polyanion-doping contributes to the remarkable enhancement of structure stability and cycling performance of NCA.

  17. Comparison of nanorod-structured Li[Ni0.54 Co0.16 Mn0.30 ]O2 with conventional cathode materials for Li-ion batteries.

    Science.gov (United States)

    Noh, Hyung-Joo; Ju, Jin Wook; Sun, Yang-Kook

    2014-01-01

    We successfully synthesized a safe, high-capacity cathode material specifically engineered for EV applications with a full concentration gradient (FCG) of Ni and Co ions at a fixed Mn content throughout the particles. The electrochemical and thermal properties of the FCG Li[Ni(0.54)Co(0.16)Mn(0.30)]O2 were evaluated and compared to those of conventional Li[Ni(0.5) Co(0.2) Mn(0.3)]O2 and Li[Ni(1/3)Co(1/3)Mn(1/3)]O2 materials. It was found that the FCG Li[Ni(0.54)Co(0.16)Mn(0.30)]O2 demonstrated a higher discharge capacity and a superior lithium intercalation stability compared to Li[Ni(0.5) Co(0.2)Mn(0.3)]O2 and Li[Ni(1/3)Co(1/3)Mn(1/3)]O2 over all of the tested voltage ranges. The results of electrochemical impedance spectroscopy and transition-metal dissolution demonstrate that the microstructure of primary particle with rod-shaped morphology plays an important role in reducing metal dissolution, which thereby decreases the charge transfer resistance as a result of stabilization of the host structure. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Preparation of γ-LiV2O5 from polyoxovanadate cluster Li7[V15O36(CO3)] as a high-performance cathode material and its reaction mechanism revealed by operando XAFS

    Science.gov (United States)

    Wang, Heng; Isobe, Jin; Shimizu, Takeshi; Matsumura, Daiju; Ina, Toshiaki; Yoshikawa, Hirofumi

    2017-08-01

    γ-phase LiV2O5, which shows superior electrochemical performance as cathode material in Li-ion batteries, was prepared by annealing the polyoxovanadate cluster Li7 [V15O36(CO3)]. The reaction mechanism was studied using operando X-ray absorption fine structure (XAFS), powder X-ray diffraction (PXRD), and X-ray photoelectron spectroscopy (XPS) analyses. The X-ray absorption near edge structure (XANES) and XPS results reveal that γ-LiV2O5 undergoes two-electron redox reaction per V2O5 pyramid unit, resulting in a large reversible capacity of 260 Ah/kg. The extended X-ray absorption fine structure (EXAFS) and PXRD analyses also suggest that the V-V distance slightly increases, due to the reduction of V5+ to V4+ during Li ion intercalation as the material structure is maintained. As a result, γ-LixV2O5 shows highly reversible electrochemical reaction with x = 0.1-1.9.

  19. Insertion of Mono- vs. Bi- vs. Trivalent Atoms in Prospective Active Electrode Materials for Electrochemical Batteries: An ab Initio Perspective

    Directory of Open Access Journals (Sweden)

    Vadym V. Kulish

    2017-12-01

    Full Text Available Rational design of active electrode materials is important for the development of advanced lithium and post-lithium batteries. Ab initio modeling can provide mechanistic understanding of the performance of prospective materials and guide design. We review our recent comparative ab initio studies of lithium, sodium, potassium, magnesium, and aluminum interactions with different phases of several actively experimentally studied electrode materials, including monoelemental materials carbon, silicon, tin, and germanium, oxides TiO2 and VxOy as well as sulphur-based spinels MS2 (M = transition metal. These studies are unique in that they provided reliable comparisons, i.e., at the same level of theory and using the same computational parameters, among different materials and among Li, Na, K, Mg, and Al. Specifically, insertion energetics (related to the electrode voltage and diffusion barriers (related to rate capability, as well as phononic effects, are compared. These studies facilitate identification of phases most suitable as anode or cathode for different types of batteries. We highlight the possibility of increasing the voltage, or enabling electrochemical activity, by amorphization and p-doping, of rational choice of phases of oxides to maximize the insertion potential of Li, Na, K, Mg, Al, as well as of rational choice of the optimum sulfur-based spinel for Mg and Al insertion, based on ab initio calculations. Some methodological issues are also addressed, including construction of effective localized basis sets, applications of Hubbard correction, generation of amorphous structures, and the use of a posteriori dispersion corrections.

  20. Batteries: Overview of Battery Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Doeff, Marca M

    2010-07-12

    The very high theoretical capacity of lithium (3829 mAh/g) provided a compelling rationale from the 1970's onward for development of rechargeable batteries employing the elemental metal as an anode. The realization that some transition metal compounds undergo reductive lithium intercalation reactions reversibly allowed use of these materials as cathodes in these devices, most notably, TiS{sub 2}. Another intercalation compound, LiCoO{sub 2}, was described shortly thereafter but, because it was produced in the discharged state, was not considered to be of interest by battery companies at the time. Due to difficulties with the rechargeability of lithium and related safety concerns, however, alternative anodes were sought. The graphite intercalation compound (GIC) LiC{sub 6} was considered an attractive candidate but the high reactivity with commonly used electrolytic solutions containing organic solvents was recognized as a significant impediment to its use. The development of electrolytes that allowed the formation of a solid electrolyte interface (SEI) on surfaces of the carbon particles was a breakthrough that enabled commercialization of Li-ion batteries. In 1990, Sony announced the first commercial batteries based on a dual Li ion intercalation system. These devices are assembled in the discharged state, so that it is convenient to employ a prelithiated cathode such as LiCoO{sub 2} with the commonly used graphite anode. After charging, the batteries are ready to power devices. The practical realization of high energy density Li-ion batteries revolutionized the portable electronics industry, as evidenced by the widespread market penetration of mobile phones, laptop computers, digital music players, and other lightweight devices since the early 1990s. In 2009, worldwide sales of Li-ion batteries for these applications alone were US$ 7 billion. Furthermore, their performance characteristics (Figure 1) make them attractive for traction applications such as

  1. DARHT 2 kA Cathode Development

    Energy Technology Data Exchange (ETDEWEB)

    Henestroza, E.; Houck, T.; Kwan, J.W.; Leitner, M.; Miram, G.; Prichard, B.; Roy, P.K.; Waldron, W.; Westenskow, G.; Yu, S.; Bieniosek, F.M.

    2009-03-09

    value). We reexamined all the components in the cathode region and eliminated those parts that were suspected to be potential sources of contamination, e.g., feed-throughs with zinc coating. Finally, we considered a change in the cathode type, by using a different combination of impregnation and coating. Since the ETA-II accelerator at LLNL used a 12.5 cm diameter 311XW (barium oxide doped with scandium and coated with a osmium-tungsten thin film) cathode and emitted 2200A of beam current (i.e. 18 A/cm{sup 2}), it was reasonable to assume that DARHT can adopt this type of cathode to produce 2 kA (i.e., 10A/cm{sup 2}). However, it was later found that the 311XW has a higher radiation heat loss than the 612M and therefore resulted in a maximum operating temperature (as limited by filament damage) below that required to produce the high current. With the evidence provided by systematic emission tests using quarter-inch size cathodes, we confirmed that the 311XM (doped with scandium and has a osmium-ruthenium (M) coating) had the best combination of low work function and low radiation heat loss. Subsequently a 6.5-inch diameter 311XM cathode was installed in DARHT and 2 kA beam current was obtained on June 14, 2007. In testing the quarter-inch size cathode, we found that the beam current was sensitive to the partial pressure of various gases in the vacuum chamber. Furthermore, there was a hysteresis effect on the emission as a function of temperature. The phenomenon suggested that the work function of the cathode was dependent on the dynamic equilibrium between the diffusion of the impregnated material to the surface and the contamination rate from the surrounding gas. Water vapor was found to be the worst contaminant amongst the various gases that we have tested. Our data showed that the required vacuum for emitting at 10 A/cm{sup 2} is in the low 10{sup -8} Torr range.

  2. MOF-derived crumpled-sheet-assembled perforated carbon cuboids as highly effective cathode active materials for ultra-high energy density Li-ion hybrid electrochemical capacitors (Li-HECs)

    Science.gov (United States)

    Banerjee, Abhik; Upadhyay, Kush Kumar; Puthusseri, Dhanya; Aravindan, Vanchiappan; Madhavi, Srinivasan; Ogale, Satishchandra

    2014-03-01

    Lithium ion hybrid capacitors (Li-HECs) have attracted significant attention for use in next generation advanced energy storage technologies to satisfy the demand of both high power density as well as energy density. Herein we demonstrate the use of very high surface area 3D carbon cuboids synthesized from a metal-organic framework (MOF) as a cathode material with Li4Ti5O12 as the anode for high performance Li-HECs. The energy density of the cell is ~65 W h kg-1 which is significantly higher than that achievable with commercially available activated carbon (~36 W h kg-1) and a symmetric supercapacitor based on the same MOF-derived carbon (MOF-DC ~20 W h kg-1). The MOF-DC/Li4Ti5O12 Li-HEC assembly also shows good cyclic performance with ~82% of the initial value (~25 W h kg-1) retained after 10 000 galvanostatic cycles under high rate cyclic conditions. This result clearly indicates that MOF-DC is a very promising candidate for future P-HEVs in a Li-HEC configuration.Lithium ion hybrid capacitors (Li-HECs) have attracted significant attention for use in next generation advanced energy storage technologies to satisfy the demand of both high power density as well as energy density. Herein we demonstrate the use of very high surface area 3D carbon cuboids synthesized from a metal-organic framework (MOF) as a cathode material with Li4Ti5O12 as the anode for high performance Li-HECs. The energy density of the cell is ~65 W h kg-1 which is significantly higher than that achievable with commercially available activated carbon (~36 W h kg-1) and a symmetric supercapacitor based on the same MOF-derived carbon (MOF-DC ~20 W h kg-1). The MOF-DC/Li4Ti5O12 Li-HEC assembly also shows good cyclic performance with ~82% of the initial value (~25 W h kg-1) retained after 10 000 galvanostatic cycles under high rate cyclic conditions. This result clearly indicates that MOF-DC is a very promising candidate for future P-HEVs in a Li-HEC configuration. Electronic supplementary information

  3. Preparation of redox polymer cathodes for thin film rechargeable batteries

    Energy Technology Data Exchange (ETDEWEB)

    Skotheim, T.A.; Lee, H.S.; Okamoto, Yoshiyuki.

    1994-11-08

    The present invention relates to the manufacture of thin film solid state electrochemical devices using composite cathodes comprising a redox polymer capable of undergoing oxidation and reduction, a polymer solid electrolyte and conducting carbon. The polymeric cathode material is formed as a composite of radiation crosslinked polymer electrolytes and radiation crosslinked redox polymers based on polysiloxane backbones with attached organosulfur side groups capable of forming sulfur-sulfur bonds during electrochemical oxidation.

  4. Subzero-Temperature Cathode for a Sodium-Ion Battery.

    Science.gov (United States)

    You, Ya; Yao, Hu-Rong; Xin, Sen; Yin, Ya-Xia; Zuo, Tong-Tong; Yang, Chun-Peng; Guo, Yu-Guo; Cui, Yi; Wan, Li-Jun; Goodenough, John B

    2016-09-01

    A subzero-temperature cathode material is obtained by nucleating cubic prussian blue crystals at inhomogeneities in carbon nanotubes. Due to fast ionic/electronic transport kinetics even at -25 °C, the cathode shows an outstanding low-temperature performance in terms of specific energy, high-rate capability, and cycle life, providing a practical sodium-ion battery powering an electric vehicle in frigid regions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Microwave-hydrothermal synthesis and characterization of nanostructured copper substituted ZnM2O4 (M = Al, Ga) spinels as precursors for thermally stable Cu catalysts

    Science.gov (United States)

    Conrad, Franziska; Massue, Cyriac; Kühl, Stefanie; Kunkes, Edward; Girgsdies, Frank; Kasatkin, Igor; Zhang, Bingsen; Friedrich, Matthias; Luo, Yuan; Armbrüster, Marc; Patzke, Greta R.; Behrens, Malte

    2012-03-01

    Nanostructured CuxZn1-xAl2O4 with a Cu : Zn ratio of ¼ : ¾ has been prepared by a microwave-assisted hydrothermal synthesis at 150 °C and used as a precursor for Cu/ZnO/Al2O3-based catalysts. The spinel nanoparticles exhibit an average size of approximately 5 nm and a high specific surface area (above 250 m2 g-1). Cu nanoparticles of an average size of 3.3 nm can be formed by reduction of the spinel precursor in hydrogen and the accessible metallic Cu(0) surface area of the reduced catalyst was 8 m2 g-1. The catalytic performance of the material in CO2 hydrogenation and methanol steam reforming was compared with conventionally prepared Cu/ZnO/Al2O3 reference catalysts. The observed lower performance of the spinel-based samples is attributed to a lack of synergetic interaction of the Cu nanoparticles with ZnO due to the incorporation of Zn2+ in the stable spinel lattice. Despite its lower performance, however, the nanostructured nature of the spinel catalyst was stable after thermal treatment up to 500 °C in contrast to other Cu-based catalysts. Furthermore, a large fraction of the re-oxidized copper migrates back into the spinel upon calcination of the reduced catalyst, thereby enabling a regeneration of sintered catalysts after prolonged usage at high temperatures. Similarly prepared samples with Ga instead of Al exhibit a more crystalline catalyst with a spinel particle size around 20 nm. The slightly decreased Cu(0) surface area of 3.2 m2 g-1 due to less copper incorporation is not a significant drawback for the methanol steam reforming.Nanostructured CuxZn1-xAl2O4 with a Cu : Zn ratio of ¼ : ¾ has been prepared by a microwave-assisted hydrothermal synthesis at 150 °C and used as a precursor for Cu/ZnO/Al2O3-based catalysts. The spinel nanoparticles exhibit an average size of approximately 5 nm and a high specific surface area (above 250 m2 g-1). Cu nanoparticles of an average size of 3.3 nm can be formed by reduction of the spinel precursor in hydrogen

  6. Freestanding and flexible graphene papers as bioelectrochemical cathode for selective and efficient CO2 conversion

    DEFF Research Database (Denmark)

    Aryal, Nabin; Halder, Arnab; Zhang, Minwei

    2017-01-01

    During microbial electrosynthesis (MES) driven CO2 reduction, cathode plays a vital role by donating electrons to microbe. Here, we exploited the advantage of reduced graphene oxide (RGO) paper asnovel cathode material to enhance electron transfer between the cathode and microbe, which in turn fa...

  7. Observation of large low-field magnetoresistance in spinel cobaltite: A new half-metal

    KAUST Repository

    Li, Peng

    2015-12-10

    Low-field magnetoresistance is an effective and energy-saving way to use half-metallic materials in magnetic reading heads and magnetic random access memory. Common spin-polarized materials with low field magnetoresistance effect are perovskite-type manganese, cobalt, and molybdenum oxides. In this study, we report a new type of spinel cobaltite materials, self-assembled nanocrystalline NiCo2O4, which shows large low field magnetoresistance as large as –19.1% at 0.5 T and –50% at 9 T (2 K). The large low field magnetoresistance is attributed to the fast magnetization rotation of the core nanocrystals. The surface spin-glass is responsible for the observed weak saturation of magnetoresistance under high fields. Our calculation demonstrates that the half-metallicity of NiCo2O4 comes from the hopping eg electrons within the tetrahedral Co-atoms and the octahedral Ni-atoms. The discovery of large low-field magnetoresistance in simple spinel oxide NiCo2O4, a non-perovskite oxide, leads to an extended family of low-field magnetoresistance materials. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)

  8. Mixed polyanion glass cathodes: Iron phosphate vanadate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kercher, Andrew K [ORNL; Ramey, Joanne Oxendine [ORNL; Carroll, Kyler J [Massachusetts Institute of Technology (MIT); Kiggans Jr, James O [ORNL; Veith, Gabriel M [ORNL; Meisner, Roberta [Oak Ridge National Laboratory (ORNL); Boatner, Lynn A [ORNL; Dudney, Nancy J [ORNL

    2014-01-01

    Mixed polyanion (MP) glasses have been investigated for use as cathodes in lithium ion batteries. MP glass cathodes are similar in composition to theoretically promising crystalline polyanionic (CP) cathodes (e.g., lithium cobalt phosphate, lithium manganese silicate), but with proper polyanion substitution, they can be designed to overcome the key shortcomings of CP cathodes, such as poor electrical conductivity and irreversible phase changes. Iron phosphate/vanadate glasses were chosen as a first demonstration of the MP glass concept. Polyanion substitution with vanadate was shown to improve the intercalation capacity of an iron phosphate glass from almost zero to full theoretical capacity. In addition, the MP glass cathodes also exhibited an unexpected second high-capacity electrochemical reaction. X-ray absorption near-edge structure (XANES) and x-ray diffraction (XRD) of cathodes from cells having different states of charge suggested that this second electrochemical reaction is a glass-state conversion reaction. With a first demonstration established, MP glass materials utilizing an intercalation and/or glass-state conversion reaction are promising candidates for future high-energy cathode research.

  9. Smart polymeric cathode material with intrinsic overcharge protection based on a 2,5-di-tert-butyl- 1,4-dimethoxybenzene core structure

    Energy Technology Data Exchange (ETDEWEB)

    Weng, Wei; Zhang, Zhengcheng; Abouimrane, Ali; Redfern, Paul C.; Curtiss, Larry A.; Amine, Khalil [Chemical Sciences and Engineering, Division and Material Sciences Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, IL 60439 (United States)

    2012-11-07

    Polymer-based electroactive materials have been studied and applied in energy storage systems as a valid replacement for transition metal oxides. As early as 1999, Hass et al. proposed an interesting concept on the possible incorporation of both charge storage and overcharge protection functionality into a single material. However, there are virtually no examples of polymeric materials that can not only store the charge, but also consume the overcharge current. Herein, a new material based on a cross-linked polymer (I) with 2,5-di-tert-butyl-1,4-dimethoxybenzene as the core structure is reported. The cyclic voltammogram of the synthesized polymer shows a single oxidation/reduction peak at 3.9-4.0 V. At 1C rate (56 mA/g), polymer I shows stable cycling up to 200 cycles with <10% capacity loss. The redox shuttle mechanism remarkably can be activated when cell voltage is elevated to 4.3 V and the overcharge plateau at 4.2 V (2{sup nd} plateau) is persistent for more than 100 hours. The overcharge protection was due to the release of a chemical redox shuttle species in the electrolyte during the initial charging process. Both DFT calculations and NMR analysis of the aromatic signals in the {sup 1}H-NMR spectrum of electrolytes from ''overcharged'' cells provide evidence for this hypothesis. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Vanadium oxide based cpd. useful as a cathode active material - is used in lithium or alkali metal batteries to prolong life cycles

    DEFF Research Database (Denmark)

    1997-01-01

    A mixt. of metallic iron particles and vanadium pentoxide contg. V in its pentavalent state in a liq. is reacted to convert at least some of the pentavalent V to its tetravalent state and form a gel. The liq. phase is then sepd. from the oxide based gel to obtain a solid material(I) comprising Fe...

  11. Electroactive materials for rechargeable batteries

    Science.gov (United States)

    Wu, Huiming; Amine, Khalil; Abouimrane, Ali

    2015-04-21

    An as-prepared cathode for a secondary battery, the cathode including an alkaline source material including an alkali metal oxide, an alkali metal sulfide, an alkali metal salt, or a combination of any two or more thereof.

  12. Research and Development of a New Field Enhanced Low Temperature Thermionic Cathode that Enables Fluorescent Dimming and Loan Shedding without Auxiliary Cathode Heating

    Energy Technology Data Exchange (ETDEWEB)

    Feng Jin

    2009-01-07

    This is the final report for project entitled 'Research and development of a new field enhanced low temperature thermionic cathode that enables fluorescent dimming and load shedding without auxiliary cathode heating', under Agreement Number: DE-FC26-04NT-42329. Under this project, a highly efficient CNT based thermionic cathode was demonstrated. This cathode is capable of emitting electron at a current density two order of magnitude stronger then a typical fluorescent cathode at same temperatures, or capable of emitting at same current density but at temperature about 300 C lower than that of a fluorescent cathode. Detailed fabrication techniques were developed including CVD growth of CNTs and sputter deposition of oxide thin films on CNTs. These are mature technologies that have been widely used in industry for large scale materials processing and device fabrications, thus, with further development work, the techniques developed in this project can be scaled-up in manufacturing environment. The prototype cathodes developed in this project were tested in lighting plasma discharge environment. In many cases, they not only lit and sustain the plasma, but also out perform the fluorescent cathodes in key parameters such like cathode fall voltages. More work will be needed to further evaluate more detailed and longer term performance of the prototype cathode in lighting plasma.

  13. Spin Filtering in Epitaxial Spinel Films with Nanoscale Phase Separation

    KAUST Repository

    Li, Peng

    2017-05-08

    The coexistence of ferromagnetic metallic phase and antiferromagnetic insulating phase in nanoscaled inhomogeneous perovskite oxides accounts for the colossal magnetoresistance. Although the model of spin-polarized electron transport across antiphase boundaries has been commonly employed to account for large magnetoresistance (MR) in ferrites, the magnetic anomalies, the two magnetic phases and enhanced molecular moment, are still unresolved. We observed a sizable MR in epitaxial spinel films (NiCo2O4-δ) that is much larger than that commonly observed in spinel ferrites. Detailed analysis reveals that this MR can be attributed to phase separation, in which the perfect ferrimagnetic metallic phase and ferrimagnetic insulating phase coexist. The magnetic insulating phase plays an important role in spin filtering in these phase separated spinel oxides, leading to a sizable MR effect. A spin filtering model based on Zeeman effect and direct tunneling is developed to account for MR of the phase separated films.

  14. Impact of disorder on ionic charge in spinel compounds

    Science.gov (United States)

    Surblé, Suzy; Baldinozzi, Gianguido; Siméone, David; Gosset, Dominique; Thomé, Lionel

    2008-06-01

    In order to obtain a correlation between the ionic charge and the local environment, the evolution of valence charges of cations in different 2-3 spinel compounds was investigated as a function of the temperature. The evolution of the structural parameters in normal (MgAl2O4), mixed (MgGa2O4) and inverse (MgIn2O4) spinels as a function of the temperature was extracted from X-ray diffraction patterns collected during different thermal annealings. The evolution of these structural parameters as a function of the disorder is analyzed within the bond valence shell model: large variations of the cation valence are observed in these three spinel compounds. From this analysis, a strong correlation between the change of the cation valence and the local disorder is pointed out. Including this dependence in the microscopic models may provide a better agreement between experimental observations and simulations.

  15. Functionally Graded Cathodes for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    YongMan Choi; Meilin Liu

    2006-09-30

    This DOE SECA project focused on both experimental and theoretical understanding of oxygen reduction processes in a porous mixed-conducting cathode in a solid oxide fuel cell (SOFC). Elucidation of the detailed oxygen reduction mechanism, especially the rate-limiting step(s), is critical to the development of low-temperature SOFCs (400 C to 700 C) and to cost reduction since much less expensive materials may be used for cell components. However, cell performance at low temperatures is limited primarily by the interfacial polarization resistances, specifically by those associated with oxygen reduction at the cathode, including transport of oxygen gas through the porous cathode, the adsorption of oxygen onto the cathode surface, the reduction and dissociation of the oxygen molecule (O{sub 2}) into the oxygen ion (O{sup 2-}), and the incorporation of the oxygen ion into the electrolyte. In order to most effectively enhance the performance of the cathode at low temperatures, we must understand the mechanism and kinetics of the elementary processes at the interfaces. Under the support of this DOE SECA project, our accomplishments included: (1) Experimental determination of the rate-limiting step in the oxygen reduction mechanism at the cathode using in situ FTIR and Raman spectroscopy, including surface- and tip-enhanced Raman spectroscopy (SERS and TERS). (2) Fabrication and testing of micro-patterned cathodes to compare the relative activity of the TPB to the rest of the cathode surface. (3) Construction of a mathematical model to predict cathode performance based on different geometries and microstructures and analyze the kinetics of oxygen-reduction reactions occurring at charged mixed ionic-electronic conductors (MIECs) using two-dimensional finite volume models with ab initio calculations. (4) Fabrication of cathodes that are graded in composition and microstructure to generate large amounts of active surface area near the cathode/electrolyte interface using a

  16. Open-Structured V 2 O 5 · n H 2 O Nanoflakes as Highly Reversible Cathode Material for Monovalent and Multivalent Intercalation Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huali [Beijing Key Laboratory of Environmental Science and Engineering, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 China; Bi, Xuanxuan [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Lemont IL 60439 USA; Department of Chemistry and Biochemistry, Ohio State University, 100 West 18th Avenue Columbus OH 43210 USA; Bai, Ying [Beijing Key Laboratory of Environmental Science and Engineering, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 China; Wu, Chuan [Beijing Key Laboratory of Environmental Science and Engineering, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 China; Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing 100081 China; Gu, Sichen [Beijing Key Laboratory of Environmental Science and Engineering, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 China; Chen, Shi [Beijing Key Laboratory of Environmental Science and Engineering, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 China; Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing 100081 China; Wu, Feng [Beijing Key Laboratory of Environmental Science and Engineering, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 China; Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing 100081 China; Amine, Khalil [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Lemont IL 60439 USA; Lu, Jun [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue Lemont IL 60439 USA

    2017-04-21

    The high-capacity cathode material V2O5·nH2O has attracted considerable attention for metal ion batteries due to the multielectron redox reaction during electrochemical processes. It has an expanded layer structure, which can host large ions or multivalent ions. However, structural instability and poor electronic and ionic conductivities greatly handicap its application. Here, in cell tests, self-assembly V2O5·nH2O nanoflakes shows excellent electrochemical performance with either monovalent or multivalent cation intercalation. They are directly grown on a 3D conductive stainless steel mesh substrate via a simple and green hydrothermal method. Well-layered nanoflakes are obtained after heat treatment at 300 °C (V2O5·0.3H2O). Nanoflakes with ultrathin flower petals deliver a stable capacity of 250 mA h g-1 in a Li-ion cell, 110 mA h g-1 in a Na-ion cell, and 80 mA h g-1 in an Al-ion cell in their respective potential ranges (2.0–4.0 V for Li and Na-ion batteries and 0.1–2.5 V for Al-ion battery) after 100 cycles.

  17. Enthalpies of formation of layered LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} (0 ≤ x ≤ 0.5) compounds as lithium ion battery cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Masoumi, Maryam; Cupid, Damian M.; Reichmann, Thomas L.; Seifert, Hans J. [Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany). Inst. for Applied Materials - Applied Materials Physics; Chang, Keke; Music, Denis; Schneider, Jochen M. [RWTH Aachen Univ. (Germany). Materials Chemistry

    2017-11-15

    Layer-structured mixed transition metal oxides with the formula LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} (0 ≤ x ≤ 0.5) are considered as important cathode materials for lithium-ion batteries. In an effort to evaluate the relative thermodynamic stabilities of individual compositions in this series, the enthalpies of formation of selected stoichiometries are determined by high temperature oxide melt drop solution calorimetry and verified by ab-initio calculations. The measured and calculated data are in good agreement with each other, and the results show that LiCoO{sub 2}-LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} solid solution approaches ideal behavior. By increasing x, i.e. by equimolar substitution of Mn{sup 4+} and Ni{sup 2+} for Co{sup 3+}, the enthalpy of formation of LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} from the elements becomes more exothermic, implying increased energetic stability. This conclusion is in agreement with the literature results showing improved structural stability and cycling performance of Ni/Mn-rich LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} compounds cycled to higher cut-off voltages.

  18. Lifetime advantage and failure mechanism of a metal-ferroelectric cathode

    Science.gov (United States)

    Wu, Ping; Sun, Jun; Yang, Zhanfeng; Huo, Shaofei; Liu, Wenyuan

    2017-10-01

    The lifetime of explosive emission cathodes is important for high power microwave generators operating in the repetitive regime. For normal metallic cathodes, micropoints on the cathode surface with large field enhancement factors may be gradually consumed in explosive electron emission, which will lead to a limited lifetime. In this paper, a metal-ferroelectric cathode made of stainless steel and BaTiO3 is manufactured. Under voltage close to 1 MV and current near 10 kA, this cathode presents a much longer lifetime than the normal stainless steel cathode, demonstrating the lifetime advantage of the metal-ferroelectric cathode. Nevertheless, in the lifetime experiment of 1.28 × 105 pulses, this metal-ferroelectric cathode also presents obvious lifetime phenomena, one of which is the microwave duration generated by a relativistic backward wave oscillator decreasing from 27 ns to 19 ns. Observation of the cathode surface morphology shows that the emission property deterioration of the metal-ferroelectric cathode may originate from severe ablation of the ferroelectric ceramic layer, which leads to shortening of the ceramic layer relative to the metallic layer. Therefore, choosing the metallic material properly and decreasing the blade thickness of the metallic layer moderately may suppress the relative shortening of the ceramic layer and thus can further lengthen the lifetime of the metal-ferroelectric cathode.

  19. Neutral hydrophilic cathode catalyst binders for microbial fuel cells

    KAUST Repository

    Saito, Tomonori

    2011-01-01

    Improving oxygen reduction in microbial fuel cell (MFC) cathodes requires a better understanding of the effects of the catalyst binder chemistry and properties on performance. A series of polystyrene-b-poly(ethylene oxide) (PS-b-PEO) polymers with systematically varying hydrophilicity were designed to determine the effect of the hydrophilic character of the binder on cathode performance. Increasing the hydrophilicity of the PS-b-PEO binders enhanced the electrochemical response of the cathode and MFC power density by ∼15%, compared to the hydrophobic PS-OH binder. Increased cathode performance was likely a result of greater water uptake by the hydrophilic binder, which would increase the accessible surface area for oxygen reduction. Based on these results and due to the high cost of PS-b-PEO, the performance of an inexpensive hydrophilic neutral polymer, poly(bisphenol A-co-epichlorohydrin) (BAEH), was examined in MFCs and compared to a hydrophilic sulfonated binder (Nafion). MFCs with BAEH-based cathodes with two different Pt loadings initially (after 2 cycles) had lower MFC performance (1360 and 630 mW m-2 for 0.5 and 0.05 mg Pt cm-2) than Nafion cathodes (1980 and 1080 mW m -2 for 0.5 and 0.05 mg Pt cm-2). However, after long-term operation (22 cycles, 40 days), power production of each cell was similar (∼1200 and 700-800 mW m-2 for 0.5 and 0.05 mg Pt cm-2) likely due to cathode biofouling that could not be completely reversed through physical cleaning. While binder chemistry could improve initial electrochemical cathode performance, binder materials had less impact on overall long-term MFC performance. This observation suggests that long-term operation of MFCs will require better methods to avoid cathode biofouling. © 2011 The Royal Society of Chemistry.

  20. Importance of OH(-) transport from cathodes in microbial fuel cells.

    Science.gov (United States)

    Popat, Sudeep C; Ki, Dongwon; Rittmann, Bruce E; Torres, César I

    2012-06-01

    Cathodic limitation in microbial fuel cells (MFCs) is considered an important hurdle towards practical application as a bioenergy technology. The oxygen reduction reaction (ORR) needs to occur in MFCs under significantly different conditions compared to chemical fuel cells, including a neutral pH. The common reason cited for cathodic limitation is the difficulty in providing protons to the catalyst sites. Here, we show that it is not the availability of protons, but the transport of OH(-) from the catalyst layer to the bulk liquid that largely governs cathodic potential losses. OH(-) is a product of an ORR mechanism that has not been considered dominant before. The accumulation of OH(-) at the catalyst sites results in an increase in the local cathode pH, resulting in Nernstian concentration losses. For Pt-based gas-diffusion cathodes, using polarization curves developed in unbuffered and buffered solutions, we quantified this loss to be >0.3 V at a current density of 10 Am(-2) . We show that this loss can be partially overcome by replacing the Nafion binder used in the cathode catalyst layer with an anion-conducting binder and by providing additional buffer to the cathode catalyst directly in the form of CO(2) , which results in enhanced OH(-) transport. Our results provide a comprehensive analysis of cathodic limitations in MFCs and should allow researchers to develop and select materials for the construction of MFC cathodes and identify operational conditions that will help minimize Nernstian concentration losses due to pH gradients. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Structure and electrochemical properties of Zn and Co dual-doped (Li2Co1-xZnxMn3O8) as cathode material for rechargeable lithium-ion batteries

    Science.gov (United States)

    Qing Tan, Tze; Aina Maulat Osman, Rozana; Reddy, M. V.; Fhan Khor, Shing; Sobri Idris, Mohd

    2017-11-01

    Spinel Zn doped Li2CoMn3O8 (or also known as LiCo0.5Mn1.5O4) yielding formula Li2Co1-xZnxMn3O8 (0 ≤ x ≤ 1) were produced via conventional solid state method. XRD results and the variation of cell lattice and volume showed that the solid solution limit of these compositions was at x=0.6. Impurities were detected when the amount of Zn was beyond 60 %. The discharge capacities deteriorate as Zn content was increased. However, these Zn doped samples exhibited excellent cycle-ability (99.9% capacity retention) throughout 50 charging and discharging cycles which indicated that doping of Zn could possibly stabilised the spinel structure.

  2. Solid oxide materials research accelerated electrochemical testing

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, C.; Arey, B.

    1995-08-01

    The objectives of this work were to develop methods for accelerated testing of cathode materials for solid oxide fuel cells under selected operating conditions. The methods would be used to evaluate the performance of LSM cathode material.

  3. Solid oxide materials research accelerated electrochemical testing

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, T.R.; Windisch, C.; Arey, B.

    1995-12-31

    The objectives of this work were to develop methods for accelerated testing of cathode material for solid oxide fuel cells under selected operating conditions. The methods would be used to evaluate the performance of LSM cathode material.

  4. In-situ study of ferric iron distribution in synthetic spinels by electron microprobe analysis

    Science.gov (United States)

    Goncharov, Alexey; Olga, Sinelshikova; Rustam, Lukmanov

    2017-04-01

    The iron oxidation state in mantle minerals is a key value in oxygen fugacity calculation and the most widely used analytical approach for Fe3+/ΣFe determination is Mössbauer spectroscopy, which is a bulk method and there is a lack of information on Fe3+/ΣFe zonation in individual mineral grains and Fe3+/ΣFe in inclusions. Here we present application of the flank method using the electron microprobe by analysing the FeLα and FeLβ X-ray emission spectra to a suite of 20 synthetic MgAl2O2-Cr2O3-Fe2O3(FeO) spinels. Materials were done with 5 - 25 FeO wt.%, and 2-70 Cr2O3 wt.% and Fe3+/ΣFe = 0.10 to 0.80, where Fe3+/ΣFe was determined independently using Mössbauer spectroscopy on the same grains used for the flank method measurements. Synthesis of the samples produced using a pyrolysis method of organic salt compositions in MgAl2O2-Cr2O3-Fe2O3(FeO) system with following heating in corundum crucibles at 1300 ° C for 5 -10 hours under controlled oxygen fugacity. All synthetic materials were investigated by X-ray and Mössbauer spectroscopy to examine a phase and iron oxidation state features. In terms of chemical composition and Fe3+/ΣFe resulting synthetic material covers a whole range of spinels derived in mantle peridotites and pyroxenites. These synthetic products were used as a standard sample to investigate co-variations of ratios of intensities measured on the flanks of FeLα and Lβ peaks and Fe3+/ΣFe, FeO content and Cr#. The obtained correlations can be used to perform in-situ studies of ferric iron distribution in natural mantle spinels. The presented approach will allow investigating the difference in mantle spinel Fe3+/ΣFe at a microscale from core to rim in individual grain, inclusion, melting pocket and in intergrows with other mantle mineral assemblage. The reported study was funded by RFBR according to the research project № 16-35-60076 mol_a_dk.

  5. Wettable Ceramic-Based Drained Cathode Technology for Aluminum Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    J.N. Bruggeman; T.R. Alcorn; R. Jeltsch; T. Mroz

    2003-01-09

    The goal of the project was to develop the ceramic based materials, technology, and necessary engineering packages to retrofit existing aluminum reduction cells in order to reduce energy consumption required for making primary aluminum. The ceramic materials would be used in a drained cathode configuration which would provide a stable, molten aluminum wetted cathode surface, allowing the reduction of the anode-cathode distance, thereby reducing the energy consumption. This multi-tasked project was divided into three major tasks: (1) Manufacturing and laboratory scale testing/evaluation of the ceramic materials, (2) Pilot scale testing of qualified compositions from the first task, and (3) Designing, retrofitting, and testing the ceramic materials in industrial cells at Kaiser Mead plant in Spokane, Washington. Specific description of these major tasks can be found in Appendix A - Project Scope. Due to the power situation in the northwest, the Mead facility was closed, thus preventing the industrial cell testing.

  6. Elevated temperature cycling stability and electrochemical impedance of LiMn 2O 4 cathodes with nanoporous ZrO 2 and TiO 2 coatings

    Science.gov (United States)

    Walz, Kenneth A.; Johnson, Christopher S.; Genthe, Jamie; Stoiber, Lucas C.; Zeltner, Walter A.; Anderson, Marc A.; Thackeray, Michael M.

    In this study, nanoporous zirconia (ZrO 2) and titania (TiO 2) coatings are shown to stabilize the cycling performance of lithium-ion batteries with LiMn 2O 4 spinel cathodes. The effect of firing temperature on the coating pore size is discussed and the resulting performance of the coated cathodes is evaluated. Stabilization mechanisms, such as neutralization of acidic electrolytes by ZrO 2 and TiO 2 coatings, are examined. It is proposed that the establishment of a complex nanoporous network for lithium-ion transport results in a more uniform current distribution at the particle surface, thereby suppressing capacity fade that may be associated with surface instabilities of the spinel electrode.

  7. Behaviour of the spinel LiV/sub 2/O/sub 4/ as a positive electrode for secondary Li cells

    Energy Technology Data Exchange (ETDEWEB)

    Pistoia, G.; Pasquali, M.; De Picciotto, L.A.; Thackeray, M.M.

    1988-09-01

    The electrochemical behaviour of the spinel Li(V/sub 2/)O/sub 4/ has been examined in Li cells. At least one Li/sup +//mol can be inserted into the cubic structure without altering the basic (V/sub 2/)O/sub 4/ spinel framework. In the range 0.1< or approx.x< or approx.1, the OCV/x in Li/sub 1+x/(V/sub 2/)O/sub 4/ curve shows a two-phase region which consists of the Li(V/sub 2/)O/sub 4/ spinel phase and a cubic Li/sub 2/(V/sub 2/)O/sub 4/ rocksalt phase. In prolonged cyclic experiments with prototype Li cells, Li(V/sub 2/)O/sub 4/-based cathodes have provided satisfactory electrode capacities and cell energy densities. On account of the relatively high Li/sup +/ diffusion coefficient in the range 0

  8. Investigation of plasma flow in vacuum arc with hot cathode

    Science.gov (United States)

    Amirov, R.; Vorona, N.; Gavrikov, A.; Lizyakin, G.; Polistchook, V.; Samoylov, I.; Smirnov, V.; Usmanov, R.; Yartsev, I.

    2014-11-01

    One of the crucial problems which appear under development of plasma technology processing of spent nuclear fuel (SNF) is the design of plasma source. The plasma source must use solid SNF as a raw material. This article is devoted to experimental study of vacuum arc with hot cathode made of gadolinium that may consider as the simple model of SNF. This vacuum discharge was investigated in wide range of parameters. During the experiments arc current and voltage, cathode temperature, and heat flux to the cathode were measured. The data on plasma spectrum and electron temperature were obtained. It was shown that external heating of the cathode allows change significantly the main parameters of plasma. It was established by spectral and probe methods that plasma jet in studied discharge may completely consist of single charged ions.

  9. Lithium sulfur batteries and electrolytes and sulfur cathodes thereof

    Science.gov (United States)

    Visco, Steven J.; Goncharenko, Nikolay; Nimon, Vitaliy; Petrov, Alexei; Nimon, Yevgeniy S.; De Jonghe, Lutgard C.; Katz, Bruce D.; Loginova, Valentina

    2017-05-23

    Lithium sulfur battery cells that use water as an electrolyte solvent provide significant cost reductions. Electrolytes for the battery cells may include water solvent for maintaining electroactive sulfur species in solution during cell discharge and a sufficient amount of a cycle life-enhancing compound that facilitates charging at the cathode. The combination of these two components enhances one or more of the following cell attributes: energy density, power density and cycle life. For instance, in applications where cost per Watt-Hour (Wh) is paramount, such as grid storage and traction applications, the use of an aqueous electrolyte in combination with inexpensive sulfur as the cathode active material can be a key enabler for the utility and automotive industries, for example, providing a cost effective and compact solution for load leveling, electric vehicles and renewable energy storage. Sulfur cathodes, and methods of fabricating lithium sulfur cells, in particular for loading lithium sulfide into the cathode structures, provide further advantages.

  10. Nanostructured lanthanum manganate composite cathode

    DEFF Research Database (Denmark)

    Wang, Wei Guo; Liu, Yi-Lin; Barfod, Rasmus

    2005-01-01

    that the (La1-xSrx)(y)MnO3 +/-delta (LSM) composite cathodes consist of a network of homogenously distributed LSM, yttria-stabilized zirconia (YSZ), and pores. The individual grain size of LSM or YSZ is approximately 100 nm. The degree of contact between cathode and electrolyte is 39% on average. (c) 2005...

  11. Effect of MgCl2 addition on the sintering behavior of MgAl2O4 spinel and formation of nano-particles

    Directory of Open Access Journals (Sweden)

    Mohammadi F.

    2014-01-01

    Full Text Available In this paper, the effect of MgCl2 addition on the sintering behavior of MgAl2O4 spinel produced via oxide mixture method was investigated. For this reason, the stoichiometric mixture of magnesite and calcined alumina as raw materials was calcined at 1100°C. The calcined mixture was milled, pressed and then, fired at 1300 and 1500°C after addition of various amounts of MgCl2. Besides, the physical properties, phase composition and microstructure of fired samples were investigated. The results showed that MgCl2 addition has great effect on the densification and particle size of spinel. Besides, MgCl2 addition increases the amount of spinel phase at all firing temperatures. Due to the decomposition of MgCl2 and then formation of ultra-fine MgO particles, the nano-sized spinel is formed on the surface of the larger spinel particles.

  12. A general method of fabricating flexible spinel-type oxide/reduced graphene oxide nanocomposite aerogels as advanced anodes for lithium-ion batteries.

    Science.gov (United States)

    Zeng, Guobo; Shi, Nan; Hess, Michael; Chen, Xi; Cheng, Wei; Fan, Tongxiang; Niederberger, Markus

    2015-04-28

    High-capacity anode materials for lithium ion batteries (LIBs), such as spinel-type metal oxides, generally suffer from poor Li(+) and e(-) conductivities. Their drastic crystal structure and volume changes, as a result of the conversion reaction mechanism with Li, severely impede the high-rate and cyclability performance toward their practical application. In this article, we present a general and facile approach to fabricate flexible spinel-type oxide/reduced graphene oxide (rGO) composite aerogels as binder-free anodes where the spinel nanoparticles (NPs) are integrated in an interconnected rGO network. Benefiting from the hierarchical porosity, conductive network and mechanical stability constructed by interpenetrated rGO layers, and from the pillar effect of NPs in between rGO sheets, the hybrid system synergistically enhances the intrinsic properties of each component, yet is robust and flexible. Consequently, the spinel/rGO composite aerogels demonstrate greatly enhanced rate capability and long-term stability without obvious capacity fading for 1000 cycles at high rates of up to 4.5 A g(-1) in the case of CoFe2O4. This electrode design can successfully be applied to several other spinel ferrites such as MnFe2O4, Fe3O4, NiFe2O4 or Co3O4, all of which lead to excellent electrochemical performances.

  13. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. IBRAM GANESH. Articles written in Bulletin of Materials Science. Volume 34 Issue 2 April 2011 pp 327-335. Aqueous slip casting of MgAl2O4 spinel powder · Ibram Ganesh · More Details Abstract Fulltext PDF. A stoichiometric MgAl2O4 spinel (MAS) powder was synthesized ...

  14. Lithium extraction from orthorhombic lithium manganese oxide and the phase-transformation to spinel

    CSIR Research Space (South Africa)

    Gummow, RJ

    1993-12-01

    Full Text Available of a lithiated spinel phase showed greater electrochemical activity than pure LiMnO2. On delithiation, LiMnO2 transforms irreversibly to a spinel-type structure. A mechanism for the orthorhombic LixMnO2-spinel phase transformation is proposed....

  15. Study on the reversible capacity loss of layered oxide cathode during low-temperature operation

    Science.gov (United States)

    Li, Yiyang; Qian, Kun; He, Yan-Bing; Kaneti, Yusuf Valentino; Liu, Dongqing; Luo, Dan; Li, Hai; Li, Baohua; Kang, Feiyu

    2017-02-01

    In this study, commercial Li(Ni1/3Co1/3Mn1/3)O2/graphite (NCM/C) lithium-ion batteries were cycled at -10 °C under different current rates ranging from 0.2 C to 1C. Electrochemical measurements and post-mortem analysis were performed to identify the root causes of the degradation in the electrochemical performance of the cells. The results reveal that apart from the increase of lithium plating on the anode, there is a considerable and abnormal capacity loss on the NCM cathode with the increase in current rate. The different degradation mechanisms including the loss of lithium inventory (LLI) and the specific capacity loss of NCM material (LAM) during cycling at -10 °C were analyzed quantitatively. It is shown that the evolution trend of LLI with the increase in current rate (8.6%, 35.0%, 55.8% for 0.2 C, 0.5 C and 1 C respectively) corresponds closely to that of the capacity loss of the full-cells (8.6%, 45.5%, 63.6% for 0.2 C, 0.5 C and 1 C, respectively), which is different to the trend of LAM (7.2%, 8.8%, 22.3% for 0.2 C, 0.5 C and 1 C, respectively). Further analysis by XRD and HR-TEM clearly indicates that the crystallinity of the hexagonal layered structure of NCM was greatly impaired after low-temperature cycling at -10 °C, and spinel phase can be observed among the layered structure.

  16. Application of Co and Mn for a Co-Mn-Br or Co-Mn-C2H3O2 Petroleum Liquid Catalyst from the Cathode Material of Spent Lithium Ion Batteries by a Hydrometallurgical Route

    Directory of Open Access Journals (Sweden)

    Sung-Ho Joo

    2017-10-01

    Full Text Available We investigated the preparation of CMB (cobalt-manganese-bromide and CMA (cobalt-manganese-acetate liquid catalysts as petroleum liquid catalysts by simultaneously recovering Co and Mn from spent Li-ion battery cathode material. To prepare the liquid catalysts, the total preparation process for the liquid catalysts consisted of physical pre-treatments, such as grinding and sieving, and chemical processes, such as leaching, solvent extraction, and stripping. In the physical pre-treatment process, over 99% of Al was removed from material with a size of less than 0.42 mm. In the chemical process, the leaching solution as obtained under the following conditions: 2 mol/L sulfuric acid, 10 vol % H2O2, 0.1 of solid/liquid ratio, and 60 °C. In the solvent extraction process, the optimum concentration of bis (2,4,4-trimethylpentyl phosphinic acid (Cyanex 272, the equilibrium pH, the degree of saponification, the organic phase/aqueous phase ratio isotherm, and the stripping study for the extraction of Co and Mn were investigated. As a result, Co and Mn were recovered by 0.85 M Cyanex 272 with 50% saponification in counter current two extraction stages. Finally, a CMB and CMA liquid catalyst containing 33.1 g/L Co, 29.8 g/L Mn, and 168 g/L Br and 12.67 g/L Co, 12.0 g/L Mn, and 511 g/L C2H3O2, respectively, was produced by 2 M hydrogen bromide and 50 vol % acetic acid; it was also found that a shortage in the concentration can be compensated with cobalt and manganese salts.

  17. P2-type Na2/3Mn1-xAlxO2 cathode material for sodium-ion batteries: Al-doped enhanced electrochemical properties and studies on the electrode kinetics

    Science.gov (United States)

    Pang, Wei-Lin; Zhang, Xiao-Hua; Guo, Jin-Zhi; Li, Jin-Yue; Yan, Xin; Hou, Bao-Hua; Guan, Hong-Yu; Wu, Xing-Long

    2017-07-01

    Recently, sodium-ion batteries (SIBs) have been considered as the promising alternative for lithium-ion batteries. Although layered P2-type transition metal oxides are an important class of cathode materials for SIBs, there are still some hurdles for the practical applications, including low specific capacity as well as poor cycling and rate properties. In this study, the electrochemical properties of layered Mn-based oxides have been effectively improved via Al doping, which cannot only promote the formation of layered P2-type structure in the preparation processes but also stabilize the lattice during the successive Na-intercalation/deintercalation due to suppression of the Jahn-Teller distortion of Mn3+. Among the as-prepared series of Na2/3Mn1-xAlxO2 (x = 0, 1/18, 1/9, and 2/9), Na2/3Mn8/9Al1/9O2 with x = 1/9 exhibits the optimal doping effect with the best electrochemical properties, in terms of the highest specific capacity of 162.3 mA h g-1 at 0.1 C, the highest rate capability, and the best cycling stability in comparison to the undoped Na2/3MnO2 and the other two materials with different Al-doped contents. Both cyclic voltammetry at varied scan rates and galvanostatic intermittent titration technique disclose the optimal electrode kinetics (the highest Na-diffusion coefficient) of the best Na2/3Mn8/9Al1/9O2.

  18. Transmission Electron Microscopy study of Cu-containing spinel-type In2S3 nanocrystals prepared by rapid pyrolysis of a single molecular precursor

    OpenAIRE

    Quiroga-González, Enrique; Bensch, Wolfgang; Duppel, Viola; Kienle, Lorenz

    2010-01-01

    Abstract Cu-containing spinel-type In2S3 nanocrystals have been prepared by rapid pyrolysis (RP) from a single source inorganic-organic hybrid molecular precursor with an initial Cu:In:S ratio of 1:9:16.5. The precursor was synthesized in a one-step hydrothermal reaction with high yield. After a treatment of the precursor for 10 s at 1000 ?C a powdered material was obtained. The X-ray powder pattern exhibits broad reflections indicative for the spinel-type and crystallites in the n...

  19. Emission characteristics of laser ablation-hollow cathode glow discharge spectral source

    Directory of Open Access Journals (Sweden)

    Karatodorov Stefan

    2014-11-01

    Full Text Available The emission characteristics of a scheme combining laser ablation as sample introduction source and hollow cathode discharge as excitation source are presented. The spatial separation of the sample material introduction by laser ablation and hollow cathode excitation is achieved by optimizing the gas pressure and the sample-cathode gap length. At these conditions the discharge current is maximized to enhance the analytical lines intensity.

  20. Solid Oxide Fuel Cell Cathodes. Unraveling the Relationship Between Structure, Surface Chemistry and Oxygen Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Gopalan, Srikanth [Boston Univ., MA (United States)

    2013-03-31

    In this work we have considered oxygen reduction reaction on LSM and LSCF cathode materials. In particular we have used various spectroscopic techniques to explore the surface composition, transition metal oxidation state, and the bonding environment of oxygen to understand the changes that occur to the surface during the oxygen reduction process. In a parallel study we have employed patterned cathodes of both LSM and LSCF cathodes to extract transport and kinetic parameters associated with the oxygen reduction process.

  1. Chemical obtaining of LiMO2 and LiM2O4 (M=Co, Mn) oxides, for cathodic applications in Li-ion batteries

    Science.gov (United States)

    Y Neira-Guio, A.; Gómez Cuaspud, J. A.; López, E. Vera; Pineda Triana, Y.

    2017-12-01

    This paper describes the synthesis and characterization of two spinel and olivine-type multicomponent oxides based on LiMO2 and LiM2O4 systems (M=Co and Mn), which represent the current state of the art in the development of cathodes for Li-ion batteries. A simple combustion synthesis process was employed to obtain the nanometric oxides in powder form (crystal sizes around 5-8nm), with a number of improved surface characteristics. The characterization by X-Ray Diffraction (XRD), Scanning and Transmission Electron Microscopy (SEM, TEM) and X-Ray Fluorescence (XRF), allowed to evaluate the morphology and the stoichiometric compositions of solids, obtaining a concordant pure crystalline phase of LiCoO2 and LiMn2O4 oxides identified in a rhombohedral and cubic phase with punctual group R-3m (1 6 6) and Fm-3m (2 2 5) respectively. The electrical characterization of materials developed by impedance spectroscopy solid state, allowed to determine a p-type semiconducting behaviour with conductivity values of 6.2×10-3 and 2.7×10-7 S for LiCoO2 and LiMn2O4 systems, consistent with the state of the art for such materials.

  2. Development and characterization of nickel–zinc spinel ferrite for ...

    Indian Academy of Sciences (India)

    Wintec

    Department of Electronics and Computer Engineering, Indian Institute of Technology, Roorkee 247 667, India. MS received 5 January 2008; ... portable wireless devices operating in the ISM band because they are compact, light weight, less ... potential applications, a nickel–zinc spinel ferrite micro- wave absorber has been ...

  3. Petrology of spinel lherzolite xenoliths in alkali basalts from Liri ...

    African Journals Online (AJOL)

    91), clinopyroxene (5.0. % Al2O3), and Al-rich spinel occur in ..... crystallization. This is particularly obvious for the highest Ds/l values. On the other hand, under similar conditions, the Cs/Co ratio changes from 1 to 1.33 during partial melting.

  4. Chromian spinel-rich black sands from eastern shoreline of ...

    Indian Academy of Sciences (India)

    Chromian spinel-rich black sands from eastern shoreline of Andaman Island. 1389. Figure 1. (a) Regional tectonic framework of southeast Asia (redrawn after Mitchell 1985) and (b) the geological map of. Andaman Island (modified from Bandopadhyay 2005) showing the distribution of the Ophiolite Group along with other.

  5. Identification of Spinel Iron Oxide Nanoparticles by 57Fe NMR

    Directory of Open Access Journals (Sweden)

    SangGap Lee

    2011-12-01

    Full Text Available We have synthesized and studied monodisperse iron oxide nanoparticles of smaller than 10 nm to identify between the two spinel phases, magnetite and maghemite. It is shown that 57Fe NMR spectroscopy is a promising tool for distinguishing between the two phases.

  6. Development and characterization of nickel–zinc spinel ferrite for ...

    Indian Academy of Sciences (India)

    This paper deals with the development and characterization of nickel–zinc spinel ferrite (Ni(1–) ZnFe2O4) for microwave absorption at 2.4 GHz (ISM band). The ferrite powder was prepared by dry attrition and sintering process. Complex permittivity and permeability of the prepared sample have been determined by ...

  7. Life Cycle Assessment and Life Cycle Cost Analysis of Magnesia Spinel Brick Production

    Directory of Open Access Journals (Sweden)

    Aysun Özkan

    2016-07-01

    Full Text Available Sustainable use of natural resources in the production of construction materials has become a necessity both in Europe and Turkey. Construction products in Europe should have European Conformity (CE and Environmental Product Declaration (EPD, an independently verified and registered document in line with the European standard EN 15804. An EPD certificate can be created by performing a Life Cycle Assessment (LCA study. In this particular work, an LCA study was carried out for a refractory brick production for environmental assessment. In addition to the LCA, the Life Cycle Cost (LCC analysis was also applied for economic assessment. Firstly, a cradle-to-gate LCA was performed for one ton of magnesia spinel refractory brick. The CML IA method included in the licensed SimaPro 8.0.1 software was chosen to calculate impact categories (namely, abiotic depletion, global warming potential, acidification potential, eutrophication potential, human toxicity, ecotoxicity, ozone depletion potential, and photochemical oxidation potential. The LCC analysis was performed by developing a cost model for internal and external cost categories within the software. The results were supported by a sensitivity analysis. According to the results, the production of raw materials and the firing process in the magnesia spinel brick production were found to have several negative effects on the environment and were costly.

  8. How Rich is Rich? Placing Constraints on the Abundance of Spinel in the Pink Spinel Anorthosite Lithology on the Moon Through Space Weathering

    Science.gov (United States)

    Gross, J.; Gillis-Davis, J.; Isaacson, P. J.; Le, L.

    2015-01-01

    previously unknown lunar rock was recently recognized in the Moon Mineralogy Mapper (M(sup 3)) visible to near-infrared (VNIR) reflectance spectra. The rock type is rich in Mg-Al spinel (approximately 30%) and plagioclase and contains less than 5% mafic silicate minerals (olivine and pyroxene). The identification of this pink spinel anorthosite (PSA) at the Moscoviense basin has sparked new interest in lunar spinel. Pieters et al. suggested that these PSA deposits might be an important component of the lunar crust. However, Mg-Al spinel is rare in the Apollo and meteorite sample collections (only up to a few wt%), and occurs mostly in troctolites and troctolitic cataclastites. In this study, we are conducting a series of experiments (petrologic and space weathering) to investigate whether deposits of spinel identified by remote sensing are in high concentration (e.g. 30%) or whether the concentrations of spinel in these deposits are more like lunar samples, which contain only a few wt%. To examine the possibility of an impact-melt origin for PSA, conducted 1-bar crystallization experiments on rock compositions similar to pink spinel troctolite 65785. The VNIR spectral reflectance analyses of the low-temperature experiments yield absorption features similar to those of the PSA lithology detected at Moscoviense Basin. The experimental run products at these temperatures contain approximately 5 wt% spinel, which suggests that the spinel-rich deposits detected by M(sup 3) might not be as spinel-rich as previously thought. However, the effect of space weathering on spinel is unknown and could significantly alter its spectral properties including potential weakening of its diagnostic 2-micrometers absorption feature. Thus, weathered lunar rocks could contain more spinel than a comparison with the unweathered experimental charges would suggest. In this study, we have initiated space weathering experiments on 1) pure pink spinel, 2) spinel-anorthite mixtures, and 3) the low

  9. Mesoporous delafossite CuCrO2 and spinel CuCr2O4: synthesis and catalysis

    Science.gov (United States)

    Zhang, Peng; Shi, Yifeng; Chi, Miaofang; Park, Jung-Nam; Stucky, Galen D.; McFarland, Eric W.; Gao, Lian

    2013-08-01

    Delafossite CuCrO2 and spinel CuCr2O4 with mesoporous structures have been successfully synthesized using nanocasting methods based on a KIT-6 template. The functional activity of the mesoporous materials was evaluated in applications as heterogeneous catalysts. The activity for photocatalytic hydrogen production of the delafossite structures with different morphologies was characterized and the oxidation state changes associated with photocorrosion of Cu+ investigated using electron energy loss spectroscopy (EELS). Mg2+ doping was found to facilitate the casting of ordered structures for CuCrO2 and improves the photocorrosion resistance of delafossite structures. The mesoporous spinel CuCr2O4 nanostructures were found to be active for low temperature CO oxidation.

  10. Ion exchange membrane cathodes for scalable microbial fuel cells.

    Science.gov (United States)

    Zuo, Yi; Cheng, Shaoan; Logan, Bruce E

    2008-09-15

    One of the main challenges for using microbial fuel cells (MFCs) is developing materials and architectures that are economical and generate high power densities. The performance of two cathodes constructed from two low-cost anion (AEM) and cation (CEM) exchange membranes was compared to that achieved using an ultrafiltration (UF) cathode, when the membranes were made electrically conductive using graphite paint and a nonprecious metal catalyst (CoTMPP). The best performance in single-chamber MFCs using graphite fiber brush anodes was achieved using an AEM cathode with the conductive coating facing the solution, at a catalyst loading of 0.5 mg/cm2 CoTMPP. The maximum power densitywas 449 mW/ m2 (normalized to the projected cathode surface area) or 13.1 W/m3 (total reactor volume), with a Coulombic efficiency up to 70% in a 50 mM phosphate buffer solution (PBS) using acetate. Decreasing the CoTMPP loading by 40-80% reduced power by 28-56%, with only 16% of the power (72 mW/m2) generated using an AEM cathode lacking a catalyst. Using a current collector (a stainless steel mesh) pressed against the inside surface of the AEM cathode and 200 mM PBS, the maximum power produced was further increased to 728 mW/m2 (21.2 W/m3). The use of AEM cathodes and brush anodes provides comparable performance to similar systems that use materials costing nearly an order of magnitude more (carbon paper electrodes) and thus represent more useful materials for reducing the costs of MFCs for wastewater treatment applications.

  11. Influence of Spinel head window thickness on the performance characteristics of a submarine panoramic infrared imaging system

    Science.gov (United States)

    Nichols, Jonathan M.; Waterman, Jim R.; Bayya, Shyam; Sanghera, Jas S.; Aggarwal, Ish D.

    2011-06-01

    This work explores the influence of head window thickness on the performance of a mid-wave infrared, panoramic periscope imager. Our focus is on transparent spinel ceramic as the head window material. Spinel is an attractive material for IR applications due to its good strength and transmission properties (visible through mid-wave). However, there is some degradation in spinel transmission near the high end of the mid-wave band ( 5μm) as the head window thickness increases. In this work we predict the relationship between head window thickness and imager performance, as quantified by the Noise Equivalent Temperature Difference, and compare these predictions to values estimated from experimental data. We then discuss the implications for imager design and demonstrate a possible approach to correcting for the headwindow-induced losses. The imager used in this study is a compact, catadioptric, camera that provides a 360o horizontal azimuth by -10o to +30o elevation field of view and uses a 2048 x 2048, 15μm pitch InSb detector.

  12. Magnetron priming by multiple cathodes

    Science.gov (United States)

    Jones, M. C.; Neculaes, V. B.; Lau, Y. Y.; Gilgenbach, R. M.; White, W. M.; Hoff, B. W.; Jordan, N. M.

    2005-08-01

    A relativistic magnetron priming technique using multiple cathodes is simulated with a three-dimensional, fully electromagnetic, particle-in-cell code. This technique is based on electron emission from N /2 individual cathodes in an N-cavity magnetron to prime the π mode. In the case of the six-cavity relativistic magnetron, π-mode start-oscillation times are reduced up to a factor of 4, and mode competition is suppressed. Most significantly, the highest microwave field power is observed by utilizing three cathodes compared to other recently explored priming techniques.

  13. Cathodic protection for the bottoms of above ground storage tanks

    Energy Technology Data Exchange (ETDEWEB)

    Mohr, John P. [Tyco Adhesives, Norwood, MA (United States)

    2004-07-01

    Impressed Current Cathodic Protection has been used for many years to protect the external bottoms of above ground storage tanks. The use of a vertical deep ground bed often treated several bare steel tank bottoms by broadcasting current over a wide area. Environmental concerns and, in some countries, government regulations, have introduced the use of dielectric secondary containment liners. The dielectric liner does not allow the protective cathodic protection current to pass and causes corrosion to continue on the newly placed tank bottom. In existing tank bottoms where inadequate protection has been provided, leaks can develop. In one method of remediation, an old bottom is covered with sand and a double bottom is welded above the leaking bottom. The new bottom is welded very close to the old bottom, thus shielding the traditional cathodic protection from protecting the new bottom. These double bottoms often employ the use of dielectric liner as well. Both the liner and the double bottom often minimize the distance from the external tank bottom. The minimized space between the liner, or double bottom, and the bottom to be protected places a challenge in providing current distribution in cathodic protection systems. This study examines the practical concerns for application of impressed current cathodic protection and the types of anode materials used in these specific applications. One unique approach for an economical treatment using a conductive polymer cathodic protection method is presented. (author)

  14. The effect of A-site and B-site substitution on BaFeO3-δ: An investigation as a cathode material for intermediate-temperature solid oxide fuel cells

    Science.gov (United States)

    Wang, Jian; Saccoccio, Mattia; Chen, Dengjie; Gao, Yang; Chen, Chi; Ciucci, Francesco

    2015-11-01

    This work systematically investigates the effects of single A-site dopant (5 mol% La3+, Sm3+ and Gd3+) and single B-site dopant (5 mol% Zr4+ and Ce4+) on the structure and oxygen reduction reaction of BaFeO3-δ (BFO) used as a cathode for solid oxide fuel cells. The materials are prepared by solid-state method and their structural, electronic, electrocatalytic properties are characterized and compared. X-ray diffraction reveals 5 mol% A-site or B-site dopant is sufficient to stabilize the cubic phase of BFO, as predicted by the lattice calculation. X-ray photoelectron spectroscopy and iodometric titration demonstrates that neither of the two doping sites has obvious advantage over the other towards the formation of additional oxygen vacancies. B-site doped BFO shows a lower electrical conductivity than A-site doped ones, however, they have much quicker response to electrical conductivity relaxation, likely originating from the expanded lattice size. With the largest oxygen vacancy concentrations, Ba0.95La0.05FeO3-δ and BaFe0.95Zr0.05O3-δ stand out from the A-site and B-site doped BFO, respectively, and polarization resistances of 0.029 Ω cm2 and 0.020 Ω cm2 are achieved at 700 °C, PO2 = 0.2atm. With a similar amount of oxygen vacancies, B-site doping is more advantageous for enhancing oxygen bulk diffusion kinetics, and thus ORR activity.

  15. Zn-Doped LiNi1/3Co1/3Mn1/3O2 Composite as Cathode Material for Lithium Ion Battery: Preparation, Characterization, and Electrochemical Properties

    Directory of Open Access Journals (Sweden)

    Han Du

    2015-01-01

    Full Text Available Zn-doped LiNi1/3Co1/3Mn1/3O2 composite, Li(Ni1/3Co1/3Mn1/31–xZnxO2 (x = 0.02; 0.05; 0.08, is synthesized by the sol-gel method. The crystal structure, morphology, and electrochemical performance are investigated via X-ray diffraction (XRD, scanning electron microscope (SEM, cyclic voltammetry (CV, and constant current charge/discharge experiment. The result reveals that Zn-doping cathode material can reach the initial charge/discharge capacity of 188.8/162.9 mAh·g−1 for Li(Ni1/3Co1/3Mn1/30.98Zn0.02O2 and 179.0/154.1 mAh·g−1 for Li(Ni1/3Co1/3Mn1/30.95Zn0.05O2 with the high voltage of 4.4 V at 0.1 C. Furthermore, the capacity retention of Li(Ni1/3Co1/3Mn1/30.98Zn0.02O2 is 95.1% at 0.5 C after 50 cycles at room temperature. The improved electrochemical properties of Zn-doped LiNi1/3Co1/3Mn1/3O2 are attributed to reduced electrode polarization, enhanced capacity reversibility, and excellent cyclic performance.

  16. Electrochemical performances of co-substituted (La and Li) LiLa{sub x−y}Li{sub y}Ni{sub 1−x}O{sub 2} cathode materials for rechargeable lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, P.; Paruthimal Kalaignan, G., E-mail: pkalaignan@yahoo.com

    2013-09-01

    Graphical abstract: - Highlights: • LiLa{sub x−y}Li{sub x}Ni{sub 1−x}O{sub 2} powders were prepared by a sol–gel method at 600 °C for 10 h. • LiLa{sub x−y}Li{sub x}Ni{sub 1−x}O{sub 2} powder materials had well defined layer structure, and no impurities. • LiLa{sub 0.10}Li{sub 0.10}Ni{sub 0.80}O{sub 2} crystallite size was reduced compared with those of LiNiO{sub 2}. • Li/LiPF{sub 6}/LiLa{sub x−y}Li{sub x}Ni{sub 1−x}O{sub 2} cells were of high charge/discharge capacity, with columbic efficiency at 25 °C and 45 °C. • LiLa{sub 0.10}Li{sub 0.10}Ni{sub 0.80}O{sub 2} good cyclic stability, rate capability and better 45 °C. - Abstract: Co-substituted LiLa{sub x−y}Li{sub y}Ni{sub 1−x}O{sub 2} cathode materials were synthesized by sol–gel method using aqueous solutions of metal nitrates and tartaric acid as chelating agent at 600 °C for 10 h. The structure and electrochemical properties of the synthesized materials were characterized by using XRD, SEM, EDAX, TEM, cyclic voltammetry, charge/discharge and electrochemical impedance spectroscopy. XRD studies revealed a well defined layer structure and a linear variation of lattice parameters with the addition of lanthanum and lithium confirmed phase pure compounds in a rhombohedral structure. TEM and SEM analysis shows that LiLa{sub 0.10}Li{sub 0.10}Ni{sub 0.80}O{sub 2} has smaller particle size and regular morphological structure with narrow size distribution than those of LiNiO{sub 2}. Variations of dual mixing and hexagonal ordering with the substituted elements have enhanced the charge/discharge capacities at both room (25 °C) and elevated temperatures (45 °C), respectively. LiLa{sub 0.10}Li{sub 0.10}Ni{sub 0.80}O{sub 2} had high charge/discharge capacity, low irreversible capacity and better elevated temperature performance.

  17. Cobalt-free perovskite Pr{sub 0.5}Sr{sub 0.5}Fe{sub 1−x}Cu{sub x}O{sub 3−δ} (PSFC) as a cathode material for intermediate temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Caroline G., E-mail: caroline.materiais@gmail.com [Materials Science and Engineering Postgraduate Program, UFRN, 59078-970, Natal (Brazil); Grilo, João Paulo de F. [Materials Science and Engineering Postgraduate Program, UFRN, 59078-970, Natal (Brazil); Macedo, Daniel A., E-mail: damaced@gmail.com [Materials Science and Engineering Postgraduate Program, UFPB, 58051-900, João Pessoa (Brazil); Cesário, Moisés R.; Fagg, Duncan Paul [Department of Mec