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Sample records for li4sio4 ceramics prepared

  1. Fabrication and tritium release property of Li2TiO3-Li4SiO4 biphasic ceramics

    Science.gov (United States)

    Yang, Mao; Ran, Guangming; Wang, Hailiang; Dang, Chen; Huang, Zhangyi; Chen, Xiaojun; Lu, Tiecheng; Xiao, Chengjian

    2018-05-01

    Li2TiO3-Li4SiO4 biphasic ceramic pebbles have been developed as an advanced tritium breeder due to the potential to combine the advantages of both Li2TiO3 and Li4SiO4. Wet method was developed for the pebble fabrication and Li2TiO3-Li4SiO4 biphasic ceramic pebbles were successfully prepared by wet method using the powders synthesized by hydrothermal method. The tritium release properties of the Li2TiO3-Li4SiO4 biphasic ceramic pebbles were evaluated. The biphasic pebbles exhibited good tritium release property at low temperatures and the tritium release temperature was around 470 °C. Because of the isotope exchange reaction between H2 and tritium, the addition of 0.1%H2 to purge gas He could significantly enhance the tritium gas release and the fraction of molecular form of tritium increased from 28% to 55%. The results indicate that the Li2TiO3-Li4SiO4 biphasic ceramic pebbles fabricated by wet method exhibit good tritium release property and hold promising potential as advanced breeder pebbles.

  2. A promising tritium breeding material: Nanostructured 2Li2TiO3-Li4SiO4 biphasic ceramic pebbles

    Science.gov (United States)

    Dang, Chen; Yang, Mao; Gong, Yichao; Feng, Lan; Wang, Hailiang; Shi, Yanli; Shi, Qiwu; Qi, Jianqi; Lu, Tiecheng

    2018-03-01

    As an advanced tritium breeder material for the fusion reactor blanket of the International Thermonuclear Experimental Reactor (ITER), Li2TiO3-Li4SiO4 biphasic ceramic has attracted widely attention due to its merits. In this paper, the uniform precursor powders were prepared by hydrothermal method, and nanostructured 2Li2TiO3-Li4SiO4 biphasic ceramic pebbles were fabricated by an indirect wet method at the first time. In addition, the composition dependence (x/y) of their microstructure characteristics and mechanical properties were investigated. The results indicated that the crush load of biphasic ceramic pebbles was better than that of single phase ceramic pebbles under identical conditions. The 2Li2TiO3-Li4SiO4 ceramic pebbles have good morphology, small grain size (90 nm), satisfactory crush load (37.8 N) and relative density (81.8 %T.D.), which could be a promising breeding material in the future fusion reactor.

  3. Towards understanding the thermoanalysis of water sorption on lithium orthosilicate (Li4SiO4)

    International Nuclear Information System (INIS)

    Ortiz-Landeros, J.; Martinez-dlCruz, L.; Gomez-Yanez, C.; Pfeiffer, H.

    2011-01-01

    A systematic thermogravimetric study of hygroscopic and reactivity behaviors, at low temperatures of lithium orthosilicate (Li 4 SiO 4 ), are presented. Li 4 SiO 4 sample was prepared by solid-state reaction and then treated at different temperature-humidity conditions. Li 4 SiO 4 samples previously treated under different temperature-humidity conditions were characterized by Fourier transform infrared spectroscopy and thermogravimetric analyses. Different processes, adsorption and absorption, take place between the Li 4 SiO 4 and water vapor. Absorbed water produces superficial hydroxylated species such as Si-OH and Li-OH. In addition, a kinetic analysis was performed, and the different water absorption activation enthalpies were calculated. It was found that activation enthalpy (ΔH) values decrease when the relative humidity is incremented, from 5528.6 J/mol to 2074.2 J/mol at relative humidity levels of 60% and 75% respectively. These results show the impact of different humidity and temperature conditions on the stability and/or chemical reactivity of Li 4 SiO 4 , if this ceramic is used in different application fields, such as carbon dioxide captor or as a breeder ceramic into the fusion reactors.

  4. Li4SiO4-Based Artificial Passivation Thin Film for Improving Interfacial Stability of Li Metal Anodes.

    Science.gov (United States)

    Kim, Ji Young; Kim, A-Young; Liu, Guicheng; Woo, Jae-Young; Kim, Hansung; Lee, Joong Kee

    2018-03-14

    An amorphous SiO 2 (a-SiO 2 ) thin film was developed as an artificial passivation layer to stabilize Li metal anodes during electrochemical reactions. The thin film was prepared using an electron cyclotron resonance-chemical vapor deposition apparatus. The obtained passivation layer has a hierarchical structure, which is composed of lithium silicide, lithiated silicon oxide, and a-SiO 2 . The thickness of the a-SiO 2 passivation layer could be varied by changing the processing time, whereas that of the lithium silicide and lithiated silicon oxide layers was almost constant. During cycling, the surface of the a-SiO 2 passivation layer is converted into lithium silicate (Li 4 SiO 4 ), and the portion of Li 4 SiO 4 depends on the thickness of a-SiO 2 . A minimum overpotential of 21.7 mV was observed at the Li metal electrode at a current density of 3 mA cm -2 with flat voltage profiles, when an a-SiO 2 passivation layer of 92.5 nm was used. The Li metal with this optimized thin passivation layer also showed the lowest charge-transfer resistance (3.948 Ω cm) and the highest Li ion diffusivity (7.06 × 10 -14 cm 2 s -1 ) after cycling in a Li-S battery. The existence of the Li 4 SiO 4 artificial passivation layer prevents the corrosion of Li metal by suppressing Li dendritic growth and improving the ionic conductivity, which contribute to the low charge-transfer resistance and high Li ion diffusivity of the electrode.

  5. Photoluminescence analysis of Ce3+:Zn2SiO4 & Li++ Ce3+:Zn2SiO4: phosphors by a sol-gel method

    Science.gov (United States)

    Babu, B. Chandra; Vandana, C. Sai; Guravamma, J.; Rudramadevi, B. Hemalatha; Buddhudu, S.

    2015-06-01

    Here, we report on the development and photoluminescence analysis of Zn2SiO4, Ce3+:Zn2SiO4 & Li+ + Ce3+: Zn2SiO4 novel powder phosphors prepared by a sol-gel technique. The total amount of Ce3+ ions was kept constant in this experiment at 0.05 mol% total doping. The excitation and emission spectra of undoped (Zn2SiO4) and Ce3+ doped Zn2SiO4 and 0.05 mol% Li+ co-doped samples have been investigated. Cerium doped Zn2SiO4 powder phosphors had broad blue emission corresponding to the 2D3/2→2FJ transition at 443nm. Stable green-yellow-red emission has been observed from Zn2SiO4 host matrix and also we have been observed the enhanced luminescence of Li+ co-doped Zn2SiO4:Ce3+. Excitation and emission spectra of these blue luminescent phosphors have been analyzed in evaluating their potential as luminescent screen coating phosphors.

  6. Thermal cycling tests on Li4SiO4 and beryllium pebbles

    International Nuclear Information System (INIS)

    Dalle Donne, M.; Norajitra, P.; Weisenburger, A.

    1995-01-01

    The European B.O.T. Demo-relevant solid breeder blanket is based on the use of beds of beryllium and Li 4 SiO 4 pebbles. Particularly dangerous for the pebble integrity are the rapid temperature changes which could occur, for instance, by a sudden blanket power shut-down. A series of thermal cycle tests have been performed for various beds of beryllium and Li 4 SiO 4 pebbles. No breaking was observed in the beryllium pebbles, however the Li 4 SiO 4 pebbles broke by temperature rates of change of about -50 C/sec independently on pebbles size and lithium enrichment. This value is considerably higher than the peak temperature rates of change expected in the blanket. (orig.)

  7. Summary of mechanical properties data and correlations for Li2O, Li4SiO4, LiAlO2, and Be

    International Nuclear Information System (INIS)

    Billone, M.C.; Grayhack, W.T.

    1988-04-01

    The data base for thermal expansion, elastic constants, compressive and tensile failure strengths and secondary thermal creep of leading solid-breeder (Li 2 O, Li 4 SiO 4 , and LiAlO 2 ) and multiplier (Be) materials is reviewed, porosity, grain size, and stress (for thermal creep). Because the data base is rather sparse in some areas, general properties of ceramics and metals are used to help guide the formulation of the correlations. The primary purpose of the data base summary and correlation development is to pave the way for stress analysis sensitivity studies. These studies will help determine which properties are important enough to structural lifetime and deformation assessments to require more data. 18 refs., 5 figs., 20 tabs

  8. Effect of sweep gas chemistry on vaporization of Li4SiO4

    International Nuclear Information System (INIS)

    Yamawaki, M.; Yamaguchi, K.

    1995-01-01

    Gas/solid equilibria in the system Li 4 SiO 4 -D 2 -D 2 O were studied by means of Knudsen effusion mass spectrometry. A Knudsen effusion mass spectrometer was modified to enable studies of reactions of hydrogen and/or water vapor with ceramic breeder materials. A gas inlet system was constructed to allow the introduction of gases into a platinum Knudsen cell, from which the equilibrated gaseous reaction products effuse. From the experimental results, it has been deduced that the equilibrium constants of vaporization reactions differ correspondingly to the nonstoichiometry of lithium orthosilicate. ((orig.))

  9. Enhancement of reactivity in Li4SiO4-based sorbents from the nano-sized rice husk ash for high-temperature CO2 capture

    International Nuclear Information System (INIS)

    Wang, Ke; Zhao, Pengfei; Guo, Xin; Li, Yimin; Han, Dongtai; Chao, Yang

    2014-01-01

    Highlights: • The Li 4 SiO 4 sorbent from nano-sized rice husk ash was prepared and characterized. • The Aerosil and Quartz were comparably used for synthesized Li 4 SiO 4 . • The structure of sorbent was depended on the morphology of heated silicon materials. • The pretreatment sorbent showed increase in the CO 2 uptake and kinetic behavior. • This promising sorbent also maintained higher capacities during the multiple cycles. - Abstract: Using the cost-effective, renewable and nano-sized of citric acid pretreatment rice husk ash (CRHA) as silicon source, high efficient Li 4 SiO 4 (lithium orthosilicate)-based sorbents (CRHA-Li 4 SiO 4 ) for high-temperature CO 2 capture were prepared through the solid-state reaction at lower temperature (700 °C). Two typical raw materials (nano-structured Aerosil and crystalline Quartz powders) were used to synthesize Li 4 SiO 4 sorbents (Aerosil-Li 4 SiO 4 and Quartz-Li 4 SiO 4 ) for comparison purposes. The phase composition behavior, surface area, and morphology of the silicon sources, heat treated raw materials and as-received Li 4 SiO 4 sorbents were studied by analytical techniques. The CO 2 adsorption capacity and adsorption–desorption performance were tested by the thermo-gravimetric analyses (CO 2 atmosphere) and a fixed bed reactor, respectively. Compared with the case of its original samples, the morphology of heat treated raw materials had a greater effect on the phase composition, microstructure, special surface area and CO 2 adsorption properties of their resulting sorbents. Although the calcined Quartz sample maintained the structure of micron particles, its reactivity was not enough to react completely with Li 2 CO 3 . Due to the greater reactivity of nanoparticles, Aerosil-Li 4 SiO 4 presented pure of Li 4 SiO 4 whereas it obtained large particles with dense morphology, which was coming from the pronounced fusing of silica nanoparticles during the calcined process. Conversely, CRHA-Li 4 SiO 4

  10. Effect of surface water on tritium release behavior from Li4SiO4

    International Nuclear Information System (INIS)

    Hanada, T.; Fukada, S.; Nishikawa, M.; Suematsu, K.; Yamashita, N.; Kanazawa, T.

    2010-01-01

    The tritium release model to represent the release behavior of bred tritium from solid breeder materials has been developed by the blanket group of Kyushu University. It has been found that water is released to the purge gas from solid breeder materials and that this water affects the tritium release behavior. In this study, the amount of surface water released from Li 4 SiO 4 is quantified by the experiment. In addition, the tritium release behavior from Li 4 SiO 4 are estimated based on the tritium release model using parameters obtained in our studies under conditions of commercial reactor operation and ITER test blanket module operation. The effect of the surface water on tritium release behavior is discussed from the obtained results. Moreover, the tritium inventory of Li 4 SiO 4 is discussed based on calculation under the unsteady state condition. Further, the effects of grain size and temperature on distribution of tritium inventory under the steady state condition are evaluated, and the optimal grain size is discussed from the view point of tritium release from Li 4 SiO 4 .

  11. The far infrared radiation characteristics for Li2O.Al2O3.4SiO2(LAS) glass-ceramics and transition-metal oxide

    International Nuclear Information System (INIS)

    Huh, Nam Jung; Yang, Joong Sik

    1991-01-01

    The far infrared radiation characteristic for Li 2 O.Al 2 O 3 .4SiO 2 (LAS) glass, the LAS glass-ceramic and sintered transition metal oxides such as CuO, Fe 2 O 3 and Co 3 O 4 , were investigated. LAS glass and LAS glass-ceramic was higher than that of the LAS glass. Heat-treated CuO and Co 3 o 4 had radiation characteristic of high efficiency infrared radiant, and heat-treated Fe 2 O 3 had radiation characteristic that infrared emissivity decreased in higher was length above 15μm. (Author)

  12. Failure initiation and propagation of Li4SiO4 pebbles in fusion blankets

    International Nuclear Information System (INIS)

    Zhao Shuo; Gan Yixiang; Kamlah, Marc

    2013-01-01

    Lithium orthosilicate (Li 4 SiO 4 ) pebbles are considered to be a candidate as solid tritium breeder in the helium cooled pebble bed (HCPB) blanket. These ceramic pebbles might be crushed during thermomechanical loading in the blanket. In this work, the failure initiation and propagation of pebbles in pebble beds is investigated using the discrete element method (DEM). Pebbles are simplified as mono-sized elastic spheres. Every pebble has a contact strength in terms of critical strain energy, which is derived from a validated strength model and crush test data for pebbles from a specific batch of Li 4 SiO 4 pebbles. Pebble beds are compressed uniaxially and triaxially in DEM simulations. When the strain energy absorbed by a pebble exceeds its critical energy it fails. The failure initiation is defined as a given small fraction of pebbles crushed. It is found that the load level for failure initiation can be very low. For example, if failure initiation is defined as soon as 0.02% of the pebbles have been crushed, the pressure required for uniaxial loading is about 2.5 MPa. Therefore, it is essential to study the influence of failure propagation on the macroscopic response of pebble beds. Thus a reduction ratio defined as the size ratio of a pebble before and after its failure is introduced. The macroscopic stress–strain relation is investigated with different reduction ratios. A typical stress plateau is found for a small reduction ratio.

  13. Preparation and Characterization of SiO2/SiCN Core-shell Ceramic Microspheres

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    ZHANG Hai-yuan

    2017-05-01

    Full Text Available The SiO2/PSN core-shell microspheres were prepared via an emulsion reaction combined with the polymer-derived ceramics (PDCs method using polysilazane (PSN in situ polymerization on the surface of SiO2 modified by silane coupling agents MPS, followed by pyrolysis process to obtain SiO2/SiCN core-shell ceramic microspheres. The effects of raw mass ratio, curing time and pyrolysis temperature on the formation and the morphology of core-shell microspheres were studied. The morphology, chemical composition and phase transformation were characterized by SEM, EDS, TEM, FT-IR and XRD. The results show that after reaction for 4h at 200℃, SiO2 completely coated PSN forms a core-shell microsphere with rough surface when the mass ratio of SiO2 and PSN is 1:4; when pyrolysis temperature is at 800-1200℃, amorphous SiO2/SiCN core-shell ceramic microspheres are prepared; at 1400℃, the amorphous phase partially crystallizes to produce SiO2, SiC and Si3N4 phase.

  14. Synthesis of LiFePO4/Li2SiO3/reduced Graphene Oxide (rGO) Composite via Hydrothermal Method

    Science.gov (United States)

    Arifin, M.; Iskandar, F.; Aimon, A. H.; Munir, M. M.; Nuryadin, B. W.

    2016-08-01

    LiFePO4 is a type of cathode active material used for lithium ion batteries. It has a high electrochemical performance. However, it suffers from certain disadvantages such as a very low intrinsic electronic conductivity and low ionic diffusion. This study was conducted to increase the conductivity of LiFePO4. We have investigated the addition of Li2SiO3 and reduced graphene oxide (rGO) to LiFePO4. The objective of this research was to synthesize LiFePO4/Li2SiO3/rGO via hydrothermal method. Fourier transform infrared spectroscopy (FTIR) measurement showed that the peaks corresponded to the vibration of LiFePO4/Li2SiO3. Further, X-ray diffraction (XRD) measurement confirmed a single phase of LiFePO4. Finally, scanning electron microscopy (SEM) images showed that rGO was distributed on the LiFePO4/Li2SiO3 structure.

  15. Synthesis of LiFePO4/Li2SiO3/reduced Graphene Oxide (rGO) Composite via Hydrothermal Method

    International Nuclear Information System (INIS)

    Arifin, M; Iskandar, F; Aimon, A H; Munir, M M; Nuryadin, B W

    2016-01-01

    LiFePO 4 is a type of cathode active material used for lithium ion batteries. It has a high electrochemical performance. However, it suffers from certain disadvantages such as a very low intrinsic electronic conductivity and low ionic diffusion. This study was conducted to increase the conductivity of LiFePO4. We have investigated the addition of Li2SiO3 and reduced graphene oxide (rGO) to LiFePO4. The objective of this research was to synthesize LiFePO 4 /Li 2 SiO 3 /rGO via hydrothermal method. Fourier transform infrared spectroscopy (FTIR) measurement showed that the peaks corresponded to the vibration of LiFePO 4 /Li 2 SiO 3 . Further, X-ray diffraction (XRD) measurement confirmed a single phase of LiFePO4. Finally, scanning electron microscopy (SEM) images showed that rGO was distributed on the LiFePO 4 /Li 2 SiO 3 structure. (paper)

  16. Enhancement of photoluminescence properties and modification of crystal structures of Si3N4 doping Li2Sr0.995SiO4:0.005Eu2+ phosphors

    International Nuclear Information System (INIS)

    Song, Kaixin; Zhang, Fangfang; Chen, Daqin; Wu, Song; Zheng, Peng; Huang, Qingming; Jiang, Jun; Xu, Junming; Qin, Huibin

    2015-01-01

    Highlights: • Si 3 N 4 modified Li 2 Sr 0.995 SiO 4 :0.005Eu 2+ phosphors were prepared. • The luminescence intensity of Li 2 Sr 0.995 SiO 4 :Eu 2+ was enhanced by doping Si 3 N 4 . • The fluorescence decay times and thermal stability were enhanced by doping Si 3 N 4 . - Abstract: Si 3 N 4 modified Li 2 Sr 0.995 SiO 4 :0.005Eu 2+ (Li 2 Sr 0.995 SiO 4−3x/2 N x :0.005Eu 2+ ) phosphors were synthesized with the conventional solid-state reaction in the reduced atmosphere. The crystal structure and vibrational modes were analyzed by X-ray diffraction, Raman scattering spectroscopy and Rietveld crystal structure refinement. Photoluminescence (PL) and photoluminescence excitation (PLE) spectra showed that Li 2 Sr 0.995 SiO 4−3x/2 N x :0.005Eu 2+ powder exhibited a broad yellow emission band centered at 560 nm under the excitation of 460 nm visible light, due to the 4f 6 5d 1 → 4f 7 transition of Eu 2+ . The partial nitridation of Li 2 Sr 0.995 SiO 4−3x/2 N x :0.005Eu 2+ (x = 0.01) phosphors led to a large enhancement in the luminescence intensity, as much as 190%. At the same time, the fluorescence decay behavior curves further showed that the photoluminescence efficiencies of Li 2 Sr 0.995 SiO 4−3x/2 N x :0.005Eu 2+ phosphors were enhanced by addition of Si 3 N 4 . The temperature quenching characteristics confirmed that the oxynitride based Li 2 Sr 0.995 SiO 4−3x/2 N x :0.005Eu 2+ showed slightly higher stability. It is implied that Li 2 Sr 0.995 SiO 4−3x/2 N x :0.005Eu 2+ phosphors had a possible potential application on white LEDs to match blue light chips

  17. Composited reduced graphene oxide into LiFePO4/Li2SiO3 and its electrochemical impedance spectroscopy properties

    Science.gov (United States)

    Arifin, M.; Rus, Y. B.; Aimon, A. H.; Iskandar, F.; Winata, T.; Abdullah, M.; Khairurrijal, K.

    2017-03-01

    LiFePO4 is commonly used as cathode material for Li-ion batteries due to its stable operational voltage and high specific capacity. However, it suffers from certain disadvantages such as low intrinsic electronic conductivity and low ionic diffusion. This study was conducted to analyse the effect of reduced graphene oxide (rGO) on the electrochemical properties of LiFePO4/Li2SiO3 composite. This composite was synthesized by a hydrothermal method. Fourier transform infrared spectroscopy measurement identified the O-P-O, Fe-O, P-O, and O-Si-O- bands in the LiFePO4/Li2SiO3 composite. X-ray diffraction measurement confirmed the formation of LiFePO4. Meanwhile, Raman spectroscopy confirmed the number of rGO layers. Further, scanning electron microscopy images showed that rGO was distributed around the LiFePO4/Li2SiO3 particles. Finally, the electrochemical impedance spectroscopy results showed that the addition of 1 wt% of rGO to the LiFePO4/Li2SiO3 composite reduced charge transfer resistance. It may be concluded that the addition of 1 wt% rGO to LiFePO4/Li2SiO3 composite can enhance its electrochemical performance as a cathode material.

  18. Properties and Crystallization Phenomena in Li2Si2O5–Ca5(PO4)3F and Li2Si2O5–Sr5(PO4)3F Glass–Ceramics Via Twofold Internal Crystallization

    Science.gov (United States)

    Rampf, Markus; Dittmer, Marc; Ritzberger, Christian; Schweiger, Marcel; Höland, Wolfram

    2015-01-01

    The combination of specific mechanical, esthetic, and chemical properties is decisive for the application of materials in prosthodontics. Controlled twofold crystallization provides a powerful tool to produce special property combinations for glass–ceramic materials. The present study outlines the potential of precipitating Ca5(PO4)3F as well as Sr5(PO4)3F as minor crystal phases in Li2Si2O5 glass–ceramics. Base glasses with different contents of CaO/SrO, P2O5, and F− were prepared within the glasses of the SiO2–Li2O–K2O–CaO/SrO–Al2O3–P2O5–F system. Preliminary studies of nucleation by means of XRD and scanning electron microscopy (SEM) of the nucleated base glasses revealed X-ray amorphous phase separation phenomena. Qualitative and quantitative crystal phase analyses after crystallization were conducted using XRD in combination with Rietveld refinement. As a main result, a direct proportional relationship between the content of apatite-forming components in the base glasses and the content of apatite in the glass–ceramics was established. The microstructures of the glass–ceramics were investigated using SEM. Microstructural and mechanical properties were found to be dominated by Li2Si2O5 crystals and quite independent of the content of the apatite present in the glass–ceramics. Biaxial strengths of up to 540 MPa were detected. Ca5(PO4)3F and Sr5(PO4)3F influence the translucency of the glass–ceramics and, hence, help to precisely tailor the properties of Li2Si2O5 glass–ceramics. The authors conclude that the twofold crystallization of Li2Si2O5–Ca5(PO4)3F or Li2Si2O5–Sr5(PO4)3F glass–ceramics involves independent solid-state reactions, which can be controlled via the chemical composition of the base glasses. The influence of the minor apatite phase on the optical properties helps to achieve new combinations of features of the glass–ceramics and, hence, displays new potential for dental applications. PMID:26389112

  19. Comparison of the tritium residence times of various ceramic breeder materials irradiated in EXOTIC experiments 4 and 5

    International Nuclear Information System (INIS)

    Kwast, H.; Elen, J.D.; Conrad, R.; Casadio, S.; Werle, H.; Verstappen, G.

    1990-09-01

    Tritium residence times have been determined for various ceramic tritium breeding materials from in-situ release measurements. The irradiations, codenamed EXOTIC (EXtraction Of Tritium In Ceramics), were carried out in the High Flux Reactor (HFR) Petten. During the irradiation more than 450 transients were performed and the corresponding tritium release measured. Materials supplied by SCK/CEN (Li 2 ZrO 3 ), CEA (Li 2 ZrO 3 and LiAlO 2 ), ENEA (LiAlO 2 ), KfK (Li 4 SiO 4 ), NRL (Li 6 Zr 2 O 7 ) and ECN (Li 8 ZrO 6 ) were irradiated in EXOTIC-5 to compare the tritium residence times obtained under equal conditions. Apart from differences in density, grain size, pore size and OPV it appeared that the tritium residence times of the lithium zirconates (pellets) were shorter than those of the Li 4 SiO 4 pebbles. The tritium residence times of the Li 4 SiO 4 pebbles were shorter than those of the LiAlO 2 pellets. (author). 7 refs.; 5 figs.; 3 tabs

  20. Preliminary study in development of glass-ceramic based on SiO2-LiO2 system, starting of different SiO2 starting powders

    International Nuclear Information System (INIS)

    Daguano, J.K.M.F.; Santos, F.A.; Santos, C.; Marton, L.F.M.; Conte, R.A.; Rodrigues Junior, D.; Melo, F.C.L.

    2009-01-01

    In this work, lithium disilicate glass-ceramics were developed starting of the rice ash- SiO 2 and Li 2 CO 3 powders. The results were compared with glass ceramics based on the lithium disilicate obtained by commercial SiO 2 powders. Glass were melted at 1580 deg C, and annealed at 850 deg C. X-Ray diffraction and scanning electron microscopy were used for characterization of the materials, and hardness and fracture toughness were evaluated using Vickers indentation method. Glasses with amorphous structure were obtained in both materials. After annealing, 'rice-ash' samples presented Li 2 SiO 3 and residual SiO 2 as crystalline phases. On the other side, commercial SiO 2 - Samples presented only Li 2 Si 2 O 5 as crystalline phases and the better results of hardness and fracture toughness. (author)

  1. Exoelectron emission from surface layer of Li2B4O7 glass ceramics

    International Nuclear Information System (INIS)

    Kawamoto, Takamichi; Katsube, Shizuko; Yanagisawa, Hideo; Kikuchi, Riichi; Kawanishi, Masaharu.

    1984-01-01

    The thermally stimulated exoelectron emission (TESS) of Li 2 B 4 O 7 glass ceramics was investigated for its application to the dosimetric use. It has been found the TSEE glow patterns of Li 2 B 4 O 7 glass ceramics and of the thin layer of LiF evaporated on Li 2 B 4 O 7 glass ceramics depend on the kind of radiations irradiated. The TSEE glow pattern of the duplicated structure sample indicated a possibility of determining the dose of each kind of radiation separately in the mixed radiation field. (author)

  2. Tritium release in Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Linjie, E-mail: zhaolinjie1989@163.com; Long, Xinggui, E-mail: xingguil@caep.cn; Peng, Shuming, E-mail: pengshuming@caep.cn; Chen, Xiaojun; Xiao, Chengjian; Ran, Guangming; Li, Jiamao

    2016-12-15

    Li{sub 4+x}Si{sub 1−x}Al{sub x}O{sub 4} solid solution materials, which were designed as the advanced tritium breeders, were obtained by indirect solid state reactions. The behaviors of tritium release from Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} powders were investigated by temperature programmed desorption. The tritium release curves show different characteristics for the Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} ceramics. The main tritium release peak in the Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} powders is at approximately 600 °C after a high dose irradiation. Moreover, the temperature of the tritium release from Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} was lower than that of the release from Li{sub 4}SiO{sub 4}. This suggests a possible advantage to using the solid solutions as the advanced tritium breeding materials.

  3. A fast synthesis of Li 3V 2(PO 4) 3 crystals via glass-ceramic processing and their battery performance

    Science.gov (United States)

    Nagamine, Kenta; Honma, Tsuyoshi; Komatsu, Takayuki

    A synthesis of Li 3V 2(PO 4) 3 being a potential cathode material for lithium ion batteries was attempted via a glass-ceramic processing. A glass with the composition of 37.5Li 2O-25V 2O 5-37.5P 2O 5 (mol%) was prepared by a melt-quenching method and precursor glass powders were crystallized with/without 10 wt% glucose in N 2 or 7%H 2/Ar atmosphere. It was found that heat treatments with glucose at 700 °C in 7%H 2/Ar can produce well-crystallized Li 3V 2(PO 4) 3 in the short time of 30 min. The battery performance measurements revealed that the precursor glass shows the discharge capacity of 14 mAh g -1 at the rate of 1 μA cm -2 and the glass-ceramics with Li 3V 2(PO 4) 3 prepared with glucose at 700 °C in 7%H 2/Ar show the capacities of 117-126 mAh g -1 (∼96% of the theoretical capacity) which are independent of heat treatment time. The present study proposes that the glass-ceramic processing is a fast synthesizing route for Li 3V 2(PO 4) 3 crystals.

  4. Percolative ionic conduction in the LiAlSiO4 glass-ceramic system

    International Nuclear Information System (INIS)

    Biefeld, R.M.; Pike, G.E.; Johnson, R.T. Jr.

    1977-01-01

    The effect f crystallinity on the lithium ion conductivity in LiAlSiO 4 glass and glass-ceramic solid electrolytes has been determined. The ionic conductivity is thermally activated with an activation energy and pre-exponential factor that change in a marked and nonsimple manner as the volume fraction of crystallinity changes. These results are explained by using a continuum percolation model (effective-medium approximation) which assumes that ionic conduction in the glass-ceramic is almost entirely within the glass phase until the crystalline volume fraction rises above approx. 55%. The LiAlSiO 4 system would seem to be nearly ideal for application of percolation theory since the crystalline phase, β eucryptite, has nearly the same composition as the glass phase. Hence, as the crystallite volume fraction increases in the glass ceramic, the residual glass composition and conductivity remain the same. This is the first application of percolation theory to ionic transport in glass-ceramics and excellent agreement is obtained between theory and experiment for the LiAlSiO 4 system

  5. Synthesis of Li2SiO3 at low temperature

    International Nuclear Information System (INIS)

    Mondragon G, G.

    2007-01-01

    The main objective of this work is to develop a new synthesis method to obtain one of the more studied ceramics in this field Li 2 SiO 3 ) in a simple and economic way using different solutions (urea and ammonium hydroxide). The particular objectives are first to prepare the Li 2 SiO 3 ceramic, by means of the use of the reaction conventional technique in solid state at temperatures between 800 and 900 C to compare it with the one proposed in this work and this way to observe the advantages that it would gives us the new method. Later on, the same one was synthesized lithium ceramic (Li 2 SiO 3 ) by means of the new method at low temperature (between 80 and 90 C), using silicic acid and lithium hydroxide like precursory reagents and different solutions (urea and ammonium hydroxide) for the optimization in their synthesis. Finally, it was carried out the characterization of these materials by means of X-ray diffraction (XRD), electronic microscopes (SEM and TEM), nitrogen physisorption (method BET) and thermal gravimetric analysis (TGA) to observe the differences that exist among the conventional method and the proposed method and by this way to determine the advantages of the last method. (Author)

  6. Preparation and study of the critical-mass-free plutonium ceramics with neutron poisons Hf, Gd and Li

    International Nuclear Information System (INIS)

    Timoefeeva, L.F.; Orlov, V.K.; Malyukov, E.E.; Molomin, V.I.; Zhmak, V.A.; Semova, E.A.; Shishkov, N.V.; Nadykto, B.A.

    2002-01-01

    Powder sintering was used to produce homogeneous type oxide ceramics of Pu with Hf, Gd and Li 6 . In all the ceramics, there is the number of neutron poison (Hf, Gd and Li) atoms per plutonium atom needed, according to the physical calculation, for them to be free of critical mass. PuO 2 stabilizers high-temperature modifications of cubic HfO 2 or hexagonal Gd 2 O 3 , however, at the ratio given by the physical calculation, the plutonium is insufficient for their full stabilization. Addition of yttrium oxide as an additive stabilizing the fcc phase of HfO 2 resulted in cubic solid solution (Pu, Hf, Y)O 2-x . Pu/Li/Hf and Pu/Li/Si ceramics produced by sintering of PuO 2 and compound Li 2 HfO 3 or 6 Li 4 SiO 4 powders is characterized with presence of two phases. The method of differential thermal analysis demonstrated the phase stability of (Pu-Hf, Pu-Gd, Pu-Li-Hf) oxide ceramics in the 20-1500degC temperature range. Ceramic (Pu/Li/Si) has several endothermal effects. Tests in boiling water solutions of various composition suggest that the specimens of Pu, Hf oxides and ternary oxides (Pu, Hf, Y)O 2 are less stable in weakly acidic media than in weakly alkaline medium and distilled water. The obtained results were used as a basis to estimate the assumed solid solution region boundaries for binary Hf, Pu and ternary Hf, Pu, Y oxides on the side of HfO 2 . (author)

  7. A Li-Garnet composite ceramic electrolyte and its solid-state Li-S battery

    Science.gov (United States)

    Huang, Xiao; Liu, Cai; Lu, Yang; Xiu, Tongping; Jin, Jun; Badding, Michael E.; Wen, Zhaoyin

    2018-04-01

    A high strength Li-Garnet solid electrolyte composite ceramic is successfully prepared via conventional solid state method with Li6.4La3Zr1.4Ta0.6O12 and nano MgO powders. Well sintered ceramic pellets and bars are obtained with 0-9 wt.% MgO. Fracture strength is approximately 135 MPa for composite ceramics with 5-9 wt.% MgO, which is ∼50% higher than that of pure Li6.4La3Zr1.4Ta0.6O12 (90 MPa). Lithium-ion conductivity of the composite is above 5 × 10-4 S cm-1 at room temperature; comparable to the pure Li6.4La3Zr1.4Ta0.6O12 material. SEM cross-sections of the composite ceramic shows a much more uniform microstructure comparing with pure ones, owing to the grain growth inhibition effect of the MgO second phase. A battery cell consisting of Li/composite ceramics/Sulfur-Carbon at 25 °C exhibits a capacity of 685 mAh g-1 at 0.2 C at the 200th cycle, while maintaining a coulombic efficiency of 100%. These results indicate that the composite ceramic Li6.4La3Zr1.4Ta0.6O12-MgO is promising for the production of electrolyte membrane and fabrication of Li-Sulfur batteries.

  8. Sheet-like Li3V2(PO4)3 nanocomposite coated by SiO2 + C with better electrochemical properties for lithium-ion batteries

    International Nuclear Information System (INIS)

    Lai, Chunyan; Wu, Tingting; Wang, Zhen

    2016-01-01

    Sheet-like Li 3 V 2 (PO 4 ) 3 nanocomposite coated by SiO 2  + C layer was synthesized with one-step solid-state method. Dihydroxydiphenylsilane (DPSD) was used as the source of SiO 2 and C. The sheet-like Li 3 V 2 (PO 4 ) 3 nanocomposite has a thickness in the range of 20–30 nm. Because of the SiO 2  + C-coated layer and the sheet-like morphology, the Li 3 V 2 (PO 4 ) 3 /(SiO 2  + C) composites show better stability and higher capacity than pure Li 3 V 2 (PO 4 ) 3 material and granular Li 3 V 2 (PO 4 ) 3 /(SiO 2  + C) composites. The best sample, Li 3 V 2 (PO 4 ) 3 /(SiO 2  + C)(2:8), shows a discharge capacity of 193.7 mAh g −1 at 1C within the voltage range of 3.0–4.8 V and retains almost 90 % of the capacity after 50 cycles.

  9. The ceramic SiO2 and SiO2-TiO2 coatings on biomedical Ti6Al4VELI titanium alloy

    International Nuclear Information System (INIS)

    Surowska, B.; Walczak, M.; Bienias, J.

    2004-01-01

    The paper presents the study of intermediate SiO 2 and SiO 2 -TiO 2 sol-gel coatings and dental porcelain coatings on Ti6Al4VELI titanium alloy. Surface microstructures and wear behaviour by pin-on-disc method of the ceramic coatings were investigated. The analysis revealed: (1) a compact, homogeneous SiO 2 and SiO 2 -TiO 2 coating and (2) that intermediate coatings may provide a durable joint between metal and porcelain, and (3) that dental porcelain on SiO 2 and TiO 2 coatings shows high wear resistance. (author)

  10. Structure and Dielectric Properties of (Sr0.2Ca0.488Nd0.208) TiO3-Li3NbO4 Ceramic Composites

    Science.gov (United States)

    Xia, C. C.; Chen, G. H.

    2017-12-01

    The new ceramic composites of (1-x) Li3NbO4-x (Sr0.2Ca0.488Nd0.208)TiO3 were prepared by the conventional solid state reaction method. The sintering behavior, phase composition, microstructure and microwave dielectric properties of the ceramics were investigated specially. The SEM and XRD results show that (1-x) Li3NbO4-x (Sr0.2Ca0.488Nd0.208) TiO3 (0.35≤x≤0.5) composites were composed of two phase, i.e. perovskite and Li3NbO4. With the increase of x, the ɛr increases from 27.1 to 38.7, Q×f decreases from 55000 GHz to 16770 GHz, and the τ f increases from -49 ppm/°C to 226.7 ppm/°C. The optimized dielectric properties with ɛr∼31.4, Q×f~16770GHz and τf~-8.1ppm/°C could be obtained as x=0.4 sintered at 1100°C for 4h. The as-prepared ceramic is expected to be used in resonators, filters, and other microwave devices.

  11. Tritium behaviour in ceramic breeder blankets

    International Nuclear Information System (INIS)

    Miller, J.M.

    1989-01-01

    Tritium release from the candidate ceramic materials, Li 2 O, LiA10 2 , Li 2 SiO 3 , Li 4 SiO 4 and Li 2 ZrO 3 , is being investigated in many blanket programs. Factors that affect tritium release from the ceramic into the helium sweep gas stream include operating temperature, ceramic microstructure, tritium transport and solubility in the solid. A review is presented of the material properties studied and of the irradiation programs and the results are summarized. The ceramic breeder blanket concept is briefly reviewed

  12. Low-Temperature Sintering Li3Mg1.8Ca0.2NbO6 Microwave Dielectric Ceramics with LMZBS Glass

    Science.gov (United States)

    Wang, Gang; Zhang, Huaiwu; Liu, Cheng; Su, Hua; Jia, Lijun; Li, Jie; Huang, Xin; Gan, Gongwen

    2018-05-01

    Li3Mg1.8Ca0.2NbO6 ceramics doped with Li2O-MgO-ZnO-B2O3-SiO2 glass (LMZBS) were prepared via a solid-state route. The LMZBS glass effectively reduced the sintering temperature of Li3Mg1.8Ca0.2NbO6 ceramics to 950°C. The effects of the LMZBS glass on the sintering behavior, microstructures and microwave dielectric properties of Li3Mg1.8Ca0.2NbO6 ceramics are discussed in detail. Among all the LMZBS doped Li3Mg1.8Ca0.2NbO6 ceramics, the sample with 1 wt.% of LMZBS glass sintered at 950°C for 4 h exhibited good dielectric properties: ɛ r = 16.7, Q × f = 31,000 GHz (9.92 GHz), τ f = - 1.3 ppm/°C. The Li3Mg1.8Ca0.2NbO6 ceramics possessed excellent chemical compatibility with Ag electrodes, and could be applied in low temperature co-fired ceramics (LTCC) applications.

  13. New generation Li+ NASICON glass-ceramics for solid state Li+ ion battery applications

    Science.gov (United States)

    Sharma, Neelakshi; Dalvi, Anshuman

    2018-04-01

    Lithiumion conducting NASICON glass-ceramics have been prepared by a novel planetary ball milling assisted synthesis route. Structural, thermal and electrical investigations have been carried out on the novel composites composed of LiTi(PO4)3 (LTP) and 50[Li2SO4]-50[Li2O-P2O5] ionic glass reveal interesting results. Composites were prepared keeping the concentration of the ionic glass fixed at 20 wt%. X-ray diffraction and diffe rential thermal analysis confirm the glass-ceramic formation. Moreover, the structure of LTP remains intact during the glass -ceramic formation. Electrical conductivity of the glass-ceramic composite is found to be higher than that of the pristine glass (50LSLP) and LTP. The bulk and grain boundary conductivities of LTP exhibit improvement in composite. Owing to high ionic conductivity and thermal stability, novel glass -ceramic seems to be a promising candidate for all solid-state battery applications.

  14. Plasma diagnostic studies of the influence of process variables upon the atomic and molecular species ejected from (1-x)Li4SiO4:xLi3PO4 targets during rf-magnetron sputtering

    International Nuclear Information System (INIS)

    Wachs, A.L.; Bates, J.B.; Dudney, N.J.; Luck, C.F.

    1990-01-01

    The deposition of thin-film electrolytes is a critical step in the development of lithium microbatteries with the potential for circuit integration. We have performed a preliminary study of the rf-magnetron sputtering of (1-x)Li 4 SiO 4 :xLi 3 PO 4 targets used to deposit amorphous thin-film electrolytes formed of the three-component system Li 2 O--SiO 2 --P 2 O 5 . Mass and optical emission spectroscopies have been used to investigate the effects of target composition and the deposition conditions upon the atomic and molecular species ejected from the targets. The data provide important information for understanding the mechanism of film formation and for monitoring the Li atomic flux onto the substrates during film growth. 5 refs., 7 figs., 1 tab

  15. Site Occupancies, Luminescence, and Thermometric Properties of LiY9(SiO4)6O2:Ce3+ Phosphors.

    Science.gov (United States)

    Zhou, Weijie; Pan, Fengjuan; Zhou, Lei; Hou, Dejian; Huang, Yan; Tao, Ye; Liang, Hongbin

    2016-10-04

    In this work, we report the tunable emission properties of Ce 3+ in an apatite-type LiY 9 (SiO 4 ) 6 O 2 compound via adjusting the doping concentration or temperature. The occupancies of Ce 3+ ions at two different sites (Wyckoff 6h and 4f sites) in LiY 9 (SiO 4 ) 6 O 2 have been determined by Rietveld refinements. Two kinds of Ce 3+ f-d transitions have been studied in detail and then assigned to certain sites. The effects of temperature and doping concentration on Ce 3+ luminescence properties have been systematically investigated. It is found that the Ce 3+ ions prefer occupying Wyckoff 6h sites and the energy transfer between Ce 3+ at two sites becomes more efficient with an increase in doping concentration. In addition, the charge-transfer vibronic exciton (CTVE) induced by the existence of free oxygen ion plays an important role in the thermal quenching of Ce 3+ at 6h sites. Because of the tunable emissions from cyan to blue with increasing temperature, the phosphors LiY 9 (SiO 4 ) 6 O 2 :Ce 3+ are endowed with possible thermometric applications.

  16. Towards understanding the thermoanalysis of water sorption on lithium orthosilicate (Li{sub 4}SiO{sub 4})

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz-Landeros, J. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito exterior s/n, Ciudad Universitaria, CP 04510, Del. Coyoacan, Mexico DF (Mexico); Departamento de Ingenieria en Metalurgia y Materiales, ESIQIE, Instituto Politecnico Nacional, UPALM, Av. Instituto Politecnico Nacional s/n, CP 07738, Mexico DF (Mexico); Martinez-dlCruz, L. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito exterior s/n, Ciudad Universitaria, CP 04510, Del. Coyoacan, Mexico DF (Mexico); Gomez-Yanez, C. [Departamento de Ingenieria en Metalurgia y Materiales, ESIQIE, Instituto Politecnico Nacional, UPALM, Av. Instituto Politecnico Nacional s/n, CP 07738, Mexico DF (Mexico); Pfeiffer, H., E-mail: pfeiffer@iim.unam.mx [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito exterior s/n, Ciudad Universitaria, CP 04510, Del. Coyoacan, Mexico DF (Mexico)

    2011-03-10

    A systematic thermogravimetric study of hygroscopic and reactivity behaviors, at low temperatures of lithium orthosilicate (Li{sub 4}SiO{sub 4}), are presented. Li{sub 4}SiO{sub 4} sample was prepared by solid-state reaction and then treated at different temperature-humidity conditions. Li{sub 4}SiO{sub 4} samples previously treated under different temperature-humidity conditions were characterized by Fourier transform infrared spectroscopy and thermogravimetric analyses. Different processes, adsorption and absorption, take place between the Li{sub 4}SiO{sub 4} and water vapor. Absorbed water produces superficial hydroxylated species such as Si-OH and Li-OH. In addition, a kinetic analysis was performed, and the different water absorption activation enthalpies were calculated. It was found that activation enthalpy ({Delta}H) values decrease when the relative humidity is incremented, from 5528.6 J/mol to 2074.2 J/mol at relative humidity levels of 60% and 75% respectively. These results show the impact of different humidity and temperature conditions on the stability and/or chemical reactivity of Li{sub 4}SiO{sub 4}, if this ceramic is used in different application fields, such as carbon dioxide captor or as a breeder ceramic into the fusion reactors.

  17. Crystallization behavior of (1 - x)Li2O.xNa2O.Al2O3.4SiO2 glasses

    International Nuclear Information System (INIS)

    Wang, Moo-Chin; Cheng, Chih-Wei; Chang, Kuo-Ming; Hsi, Chi-Shiung

    2010-01-01

    The crystallization behavior of the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and energy dispersive spectroscopy (EDS). The crystalline phase was composed of β-spodumene. The isothermal crystallization kinetics of β-spodumene from the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses has also been studied by a quantitative X-ray diffraction method. The activation energy of β-spodumene formation decreases from 359.2 to 317.8 kJ/mol when the Na 2 O content increases from 0 to 0.4 mol and it increases from 317.8 to 376.9 kJ/mol when the Na 2 O content increases from 0.4 to 0.6 mol. The surface nucleation and plate-like growth were dominant in the crystallization of the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses.

  18. Preparation and Characterisation of LiFePO4/CNT Material for Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Rushanah Mohamed

    2011-01-01

    Full Text Available Li-ion battery cathode materials were synthesised via a mechanical activation and thermal treatment process and systematically studied. LiFePO4/CNT composite cathode materials were successfully prepared from LiFePO4 material. The synthesis technique involved growth of carbon nanotubes onto the LiFePO4 using a novel spray pyrolysis-modified CVD technique. The technique yielded LiFePO4/CNT composite cathode material displaying good electrochemical activity. The composite cathode exhibited excellent electrochemical performances with 163 mAh/g discharge capacity with 94% cycle efficiency at a 0.1 C discharge rate in the first cycle, with a capacity fade of approximately 10% after 30 cycles. The results indicate that carbon nanotube addition can enable LiFePO4 to display a higher discharge capacity at a fast rate with high efficiency. The research is of potential interest for the application of carbon nanotubes as a new conducting additive in cathode preparation and for the development of high-power Li-ion batteries for hybrid electric vehicles.

  19. CoFe2O4-SiO2 Composites: Preparation and Magnetodielectric Properties

    Directory of Open Access Journals (Sweden)

    T. Ramesh

    2016-01-01

    Full Text Available Cobalt ferrite (CoFe2O4 and silica (SiO2 nanopowders have been prepared by the microwave hydrothermal (M-H method using metal nitrates as precursors of CoFe2O4 and tetraethyl orthosilicate as a precursor of SiO2. The synthesized powders were characterized by XRD and FESEM. The (100-x (CoFe2O4 + xSiO2 (where x = 0%, 10%, 20%, and 30% composites with different weight percentages have been prepared using ball mill method. The composite samples were sintered at 800°C/60 min using the microwave sintering method and then their structural and morphological studies were investigated using X-ray diffraction (XRD, Fourier transformation infrared (FTIR spectra, and scanning electron microscopy (SEM, respectively. The effect of SiO2 content on the magnetic and electrical properties of CoFe2O4/SiO2 nanocomposites has been studied via the magnetic hysteresis loops, complex permeability, permittivity spectra, and DC resistivity measurements. The synthesized nanocomposites with adjustable grain sizes and controllable magnetic properties make the applicability of cobalt ferrite even more versatile.

  20. LOW-TEMPERATURE SINTERED (ZnMg2SiO4 MICROWAVE CERAMICS WITH TiO2 ADDITION AND CALCIUM BOROSILICATE GLASS

    Directory of Open Access Journals (Sweden)

    BO LI

    2011-03-01

    Full Text Available The low-temperature sintered (ZnMg2SiO–TiO2 microwave ceramic using CaO–B2O3–SiO2 (CBS as a sintering aid has been developed. Microwave properties of (Zn1-xMgx2SiO4 base materials via sol-gel method were highly dependent on the Mg-substituted content. Further, effects of CBS and TiO2 additives on the crystal phases, microstructures and microwave characteristics of (ZnMg2SiO4 (ZMS ceramics were investigated. The results indicated that CBS glass could lower the firing temperature of ZMS dielectrics effectively from 1170 to 950°C due to the liquid-phase effect, and significantly improve the sintering behavior and microwave properties of ZMS ceramics. Moreover, ZMS–TiO2 ceramics showed the biphasic structure and the abnormal grain growth was suppressed by the pinning effect of second phase TiO2. Proper amount of TiO2 could tune the large negative temperature coefficient of resonant frequency (tf of ZMS system to a near zero value. (Zn0.8Mg0.22SiO4 codoped with 10 wt.% TiO2 and 3 wt.% CBS sintered at 950°C exhibits the dense microstructure and excellent microwave properties: εr = 9.5, Q·f = 16 600 GHz and tf = −9.6 ppm/°C.

  1. Effects of the LiFePO4 content and the preparation method on the properties of (LiFePO4+AC/Li4Ti5O12 hybrid battery–capacitors

    Directory of Open Access Journals (Sweden)

    XUE BU HU

    2010-09-01

    Full Text Available Two composite cathode materials containing LiFePO4 and activated carbon (AC were synthesized by an in-situ method and a direct mixing technique, which are abbreviated as LAC and DMLAC, respectively. Hybrid battery–capacitors LAC/Li4Ti5O12 and DMLAC/Li4Ti5O12 were then assembled. The effects of the content of LiFePO4 and the preparation method on the cyclic voltammograms, the rate of charge–discharge and the cycle performance of the hybrid battery–capacitors were investigated. The results showed the overall electrochemical performance of the hybrid battery–capacitors was the best when the content of LiFePO4 in the composite cathode materials was in the range from 11.8 to 28.5 wt. %, while the preparation method had almost no impact on the electrochemical performance of the composite cathodes and hybrid battery–capacitors. Moreover, the hybrid battery–capacitor devices had a good cycle life performance at high rates. After 1000 cycles, the capacity loss of the DMLAC/Li4Ti5O12 hybrid battery–capacitor device at 4C was no more than 4.8 %. Moreover, the capacity loss would be no more than 9.6 % after 2000 cycles at 8C.

  2. Improved ferroelectric/piezoelectric properties and bright green/UC red emission in (Li,Ho)-doped CaBi4Ti4O15 multifunctional ceramics with excellent temperature stability and superior water-resistance performance.

    Science.gov (United States)

    Xiao, Ping; Guo, Yongquan; Tian, Mijie; Zheng, Qiaoji; Jiang, Na; Wu, Xiaochun; Xia, Zhiguo; Lin, Dunmin

    2015-10-21

    Multifunctional materials based on rare earth ion doped ferro/piezoelectrics have attracted considerable attention in recent years. In this work, new lead-free multifunctional ceramics of Ca1-x(LiHo)x/2Bi4Ti4O15 were prepared by a conventional solid-state reaction method. The great multi-improvement in ferroelectricity/piezoelectricity, down/up-conversion luminescence and temperature stability of the multifunctional properties is induced by the partial substitution of (Li0.5Ho0.5)(2+) for Ca(2+) ions in CaBi4Ti4O15. All the ceramics possess a bismuth-layer structure, and the crystal structure of the ceramics is changed from a four layered bismuth-layer structure to a three-layered structure with the level of (Li0.5Ho0.5)(2+) increasing. The ceramic with x = 0.1 exhibits simultaneously, high resistivity (R = 4.51 × 10(11)Ω cm), good piezoelectricity (d33 = 10.2 pC N(-1)), high Curie temperature (TC = 814 °C), strong ferroelectricity (Pr = 9.03 μC cm(-2)) and enhanced luminescence. These behaviours are greatly associated with the contribution of (Li0.5Ho0.5)(2+) in the ceramics. Under the excitation of 451 nm light, the ceramic with x = 0.1 exhibits a strong green emission peak centered at 545 nm, corresponding to the transition of the (5)S2→(5)I8 level in Ho(3+) ions, while a strong red up-conversion emission band located at 660 nm is observed under the near-infrared excitation of 980 nm at room temperature, arising from the transition of (5)F5→(5)I8 levels in Ho(3+) ions. Surprisingly, the excellent temperature stability of ferroelectricity/piezoelectricity/luminescence and superior water-resistance behaviors of piezoelectricity/luminescence are also obtained in the ceramic with x = 0.1. Our study suggests that the present ceramics may have potential applications in advanced multifunctional devices at high temperature.

  3. Tritium breeding optimization of Li4SiO4/Be/He/SS blankets for the NET

    International Nuclear Information System (INIS)

    Greenspan, E.; Karni, Y.

    1986-01-01

    In previous tritium breeding optimization studies, we considered idealized, machine-independent blankets. The purpose of the present work is to investigate possibilities for maximizing tritium production in more realistic blankets. The Li 4 /SiO 4 /Be/He/SS blanket recently designed for the Next European Torus (NET) is used as the reference. The one-dimensional tritium breeding ratio calculated for this blanket is 1.38, promising tritium self-sufficiency even when the NET blanket is expected to have a coverage efficiency of 80%. A specific goal of the present study is to determine whether a NET-like device could be designed to be tritium self-sufficient when tritium production is limited to the outer blanket. If realizable, it might be possible to simplify the reactor design, significantly, make it more compact, and lower the cost

  4. Solid state reaction in alumina nanoparticles/LZSA glass-ceramic composites

    International Nuclear Information System (INIS)

    Montedo, O.K.; Oliveira, A.N. de; Raupp-Pereira, F.

    2016-01-01

    Full text: The aim of this work is to present results related to solid state reactions on LZSA glass-ceramic composites containing alumina reinforcement nano-particles. A LZSA (Li2O-ZrO2-SiO2-Al2O3) glass-ceramic has been prepared by sintering of powders and characterized. Composites containing 0 to 77 vol.% of alumina nanoparticles (27-43 nm APS, 35 m2.g-1 SSA) and a 16.9Li2O•5.0ZrO2•65.1SiO2•8.6Al2O3 glass-ceramic matrix have been prepared. X-ray diffractometry studies have been performed in order of investigating the solid state reactions occurring in LZSA-based composites. Results of the XRD patterns have been related to the coefficient of thermal expansion (CTE), Young modulus, and dielectric constant, showing that, in comparison with the glass-ceramic composition, the composites showed a decrease of CTE with the alumina concentration increasing, due to the increasing of beta-spodumeness formation (solid solution of beta-spodumene, Li2O.Al2O3.4-10SiO2). The performance of the glass-ceramic was improved with the alumina nano-particles addition, showing potential of using in the preparation of Low Thermal Co-fired Ceramics (LTCC). (author)

  5. PHASE EVOLUTION AND MICROWAVE DIELECTRIC PROPERTIES OF (Li0.5Bi0.5)(W1-xMox)O4(0.0 ≤ x ≤ 1.0) CERAMICS WITH ULTRA-LOW SINTERING TEMPERATURES

    Science.gov (United States)

    Zhou, Di; Guo, Jing; Yao, Xi; Pang, Li-Xia; Qi, Ze-Ming; Shao, Tao

    2012-11-01

    The (Li0.5Bi0.5)(W1-xMox)O4(0.0 ≤ x ≤ 1.0) ceramics were prepared via the solid state reaction method. The sintering temperature decreased almost linearly from 755°C for (Li0.5Bi0.5)WO4 to 560°C for (Li0.5Bi0.5)MoO4. When the x≤0.3, a wolframite solid solution can be formed. For x = 0.4 and x = 0.6 compositions, both the wolframite and scheelite phases can be formed from the X-ray diffraction analysis, while two different kinds of grains can be revealed from the scanning electron microscopy and energy-dispersive X-ray spectrometer results. High performance of microwave dielectric properties were obtained in the (Li0.5Bi0.5)(W0.6Mo0.4)O4 ceramic sintered at 620°C with a relative permittivity of 31.5, a Qf value of 8500 GHz (at 8.2 GHz), and a temperature coefficient value of +20 ppm/°C. Complex dielectric spectra of pure (Li0.5Bi0.5)WO4 ceramic gained from the infrared spectra were extrapolated down to microwave range, and they were in good agreement with the measured values. The (Li0.5Bi0.5)(W1-xMox)O4(0.0 ≤ x ≤ 1.0) ceramics might be promising for low temperature co-fired ceramic technology.

  6. Preparation of. beta. -spodumene glass-ceramics from blast furnace slag. Koro slag wo genryo to shita. beta. -spodumene kei kesshoka glass no seizo

    Energy Technology Data Exchange (ETDEWEB)

    Wang, M. (National Kaoshing Institute Technology, Kaoshiung (Rep. of China)); Hon, M. (National Cheng Kung University, Tainan (Rep. of China))

    1990-07-01

    Li {sub 2} O-CaO-Al {sub 2} O {sub 3} -SiO {sub 2} (LCAS) glass-ceramics were prepared from blast furnace slag by quenching in water after heating at 1,450 {degree} C for 3 hours. Blast furnace slag (40.0wt%) containing CaO, MgO, Al {sub 2} O {sub 3} and SiO {sub 2} as major components was used as a raw material, and batch compositions were modified by mixing blast furnace slag with Al {sub 2} O {sub 3}, SiO {sub 2} and Li {sub 2} CO {sub 3}, and a nucleating agent TiO {sub 2}. The A specimen with TiO {sub 2} of 7.4wt% and B specimen with 4.6wt% were prepared, and the crystallization process of the glass was examined with X-ray diffraction, electron diffraction and so forth. As a result, a major crystalline phase was {beta} -spodumene (Li {sub 2} O-Al {sub 2} O {sub 3} -4SiO {sub 2}), and the average thermal expansion coefficients of A and B were 40.1 and 47.2 {times} 10 {sup {minus} 7} / {degree} C in the temperature range from 25 to 700 {degree} C, respectively. A small amount of titanite was also observed in A as a sub-phase. 14 refs., 5 figs., 3 tabs.

  7. Tritium release from Li{sub 4}SiO{sub 4} ceramic pebbles in high magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Ran, Guangming [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230027 (China); Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Xiao, Chengjian; Chen, Xiaojun; Gong, Yu; Zhao, Linjie [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Wang, Xiaolin [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230027 (China); China Academy of Engineering Physics, Mianyang 621900 (China)

    2015-12-15

    Highlights: • Behavior of tritium release from Li{sub 4}SiO{sub 4} pebbles in MF up to 7 T was investigated. • The MF effect on tritium release is not significant according to the TPD results. • Tritium release from the BIG sample is much easier than that from the SMALL sample. • The MF effect on tritium diffusion was probably weakened by surface desorption. - Abstract: The behavior of tritium release from Li{sub 4}SiO{sub 4} ceramic pebbles in high magnetic field (MF) was investigated by temperature programmed desorption (TPD). Two batches of Li{sub 4}SiO{sub 4} pebbles produced by wet method were used as the experimental samples, one batch with an average pebble diameter of 0.8 mm (the SMALL samples), and the other 1.2 mm (the BIG samples). A superconducting magnet was applied to generate MF up to 7 T in the sample area during annealing. For both batches of samples, the tritium release curves within and without MF showed very similar characteristics, indicating that the effect of high MF on tritium release behavior is not significant. The tritium release peaks for the BIG samples were observed at much lower temperatures than that for the SMALL samples, even though the grain sizes of the BIG samples are much bigger than that of the SMALL samples. It is considered that surface desorption process dominates the overall tritium release behavior in this work, which probably weakened the MF effect.

  8. [Effect of charge compensation on emission spectrum of Sr2SiO4 : Dy3+ phosphor].

    Science.gov (United States)

    Li, Pan-Lai; Wang, Zhi-Jun; Yang, Zhi-Ping; Guo, Qing-Lin

    2009-01-01

    The Sr2SiO4 : Dy3+ phosphor was synthesized by the high temperature solid-state reaction method in air. Dy2O3 (99.9%), SiO2 (99.9%), SrCO3 (99.9%), Li2CO3 (99.9%), Na2CO3 (99.9%) and K2CO3 (99.9%) were used as starting materials, and the Dy3+ doping concentration was 2 mol%. The emission spectrum was measured by a SPEX1404 spectrophotometer, and all the characterization of the phosphors was conducted at room temperature. The emission spectrum of Sr2 SiO4 : Dy3+ phosphor showed several bands centered at 486, 575 and 665 nm under the 365 nm excitation. The effect of Li+, Na+ and K+ on the emission spectra of Sr2SiO4 : Dy3+ phosphor was studied. The results show that the location of the emission spectrum of Sr2SiO4 : Dy3+ phosphor was not influenced by Li+, Na+ and K+. However, the emission spectrum intensity was greatly influenced by Li+, Na+ and K+, and the evolvement trend was monotone with different charge compensation, i. e. the emission spectrum intensity of Sr2SiO4 : Dy3+ phosphor firstly increased with increasing Li+ concentration, then decreased. However the charge compensation concentration corresponding to the maximum emission intensity was different with different charge compensation, and the concentration is 4, 3 and 3 mol% corresponding to Li+, Na+ and K+, respectively. And the theoretical reason for the above results was analyzed.

  9. Preparation, characteristics and electrochemical properties of surface-modified LiMn2O4 by doped LiNi0.05Mn1.95O4

    International Nuclear Information System (INIS)

    Yuan, Y.F.; Wu, H.M.; Guo, S.Y.; Wu, J.B.; Yang, J.L.; Wang, X.L.; Tu, J.P.

    2008-01-01

    The surface-modified spinel LiMn 2 O 4 by doped LiNi 0.05 Mn 1.95 O 4 was prepared by a tartaric acid gel method. Transmission electron microscope (TEM) images indicated that some small particles with 100-200 nm in diameter modified the surface of large particle LiMn 2 O 4 . Energy dispersive spectrometry (EDS) showed that the particles were LiNi 0.05 Mn 1.95 O 4 . Electrochemical properties of LiNi 0.05 Mn 1.95 O 4 -modified spinel LiMn 2 O 4 were intensively investigated by the galvanostatic charge-discharge tests, cyclic voltammetry (CV) and AC impedance measurements. The doped LiNi 0.05 Mn 1.95 O 4 -modified LiMn 2 O 4 cathode delivered the same initial discharge capacity as the unmodified LiMn 2 O 4 , but its cyclic stability was evidently improved, the capacity retention ratio reached 96% after 20 cycles, being higher than 89% of the unmodified LiMn 2 O 4 . Cyclic voltammograms of the LiNi 0.05 Mn 1.95 O 4 -modified LiMn 2 O 4 did not markedly change while the semicircle diameter of AC impedance spectra evidently decreased after 20 cycles, which showed that the surface modification with LiNi 0.05 Mn 1.95 O 4 improved the electrochemical activity and cycling stability of LiMn 2 O 4 .

  10. A facile synthesis of Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C composites as cathode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Yang, Rong; Wang, Liqing; Deng, Kunfa; Lv, Mengni; Xu, Yunhua

    2016-01-01

    The novel Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C has been successfully synthesized by a feasible solution process in ternary system. The spherical carbon-coated composites are obtained using a heat treatment in the presence of sucrose. X-ray diffraction (XRD) diffractogram displays that the Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C crystallized in an orthorhombic structure with a space group of Pmn21. The energy-dispersive X-ray spectroscopy mappings indicate that Fe, Mn and Ni elements are distributed homogenously in Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C nano-spherical particle with size less than 50 nm. The lithium storage capacity and cycling performance of the Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C presents good results when tested as cathode materials in lithium cells at room temperature. It delivers an initial discharge capacity of 181.4 mAh g"−"1 and a discharge capacity of 172.9 mAh g"−"1 after 20 cycles at 0.1C in the voltage range of 1.5–4.6V. Furthermore, it also exhibits an excellent rate capability with a capacity under different current densities of about 144.0 mAh g"−"1 (0.2 C), 117.9 mAh g"−"1 (0.5 C), 106.1 mAh g"−"1 (1 C), respectively and a good capacity cycling maintenance of 153.7 mAh g"−"1 after 60 cycles. Above results indicate that the spherical Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C becomes a very promising candidate for cathode material in lithium-ion batteries. - Highlights: • Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C was obtained by solution process in a ternary system. • The material was pure phase ternary solid solution with tetrahedral morphology. • The spherical particle size was less than 50 nm with graphitized carbon coating. • The nanocomposite revealed high discharge capacity and excellent rate capability.

  11. Optical properties of transparent Li2O-Ga2O3-SiO2 glass-ceramics embedding Ni-doped nanocrystals

    International Nuclear Information System (INIS)

    Suzuki, Takenobu; Murugan, Ganapathy Senthil; Ohishi, Yasutake

    2005-01-01

    Transparent Li 2 O-Ga 2 O 3 -SiO 2 (LGS) glass-ceramics embedding Ni:LiGa 5 O 8 nanocrystals were fabricated. An intense emission centered around 1300 nm with the width of more than 300 nm was observed by 976 nm photoexcitation of the glass-ceramics. The lifetime was more than 900 μs at 5 K and 500 μs at 300 K. The emission could be attributed to the 3 T 2g ( 3 F)→ 3 A 2g ( 3 F) transition of Ni 2+ in distorted octahedral sites in LiGa 5 O 8 . The product of stimulated emission cross section and lifetime for the emission was about 3.7x10 -24 cm 2 s and was a sufficiently practical value

  12. European DEMO BOT Solid Breeder Blanket: the concept based on the use of cooling plates and beds of beryllium and Li4SiO4 pebbles

    International Nuclear Information System (INIS)

    Dalle Donne, M.; Fischer, U.; Norajitra, P.; Reimann, G.; Reiser, H.

    1995-01-01

    The paper presents an important modification of the European DEMO BOT Solid Breeder Blanket. The new design uses cooling plates rather than tubes. This allows a considerable simplification of the blanket and the separation of the beryllium from the Li 4 SiO 4 pebbles. The neutronic, thermohydraulic and tritium performance of the new design is quite good and equivalent to that of the previous one. (orig.)

  13. Searching for “LiCrIIPO4

    International Nuclear Information System (INIS)

    Mosymow, E.; Glaum, R.; Kremer, R.K.

    2014-01-01

    The two new phosphates LiCr II 4 (PO 4 ) 3 and Li 5 Cr II 2 Cr III (PO 4 ) 4 are discovered as equilibrium phases (ϑ=800 °C) in the quarternary system Li/Cr/P/O. Their crystal structures have been determined from single-crystal X-ray diffraction data (LiCr II 4 (PO 4 ) 3 : violet-blue, Pnma (no. 62), Z=4, a=6.175(1) Å, b=14.316(3) Å, c=10.277(2) Å, 100 parameters, R 1 =0.028, wR 2 =0.08, 2060 unique reflections with F o >4σ(F o ); Li 5 Cr II 2 Cr III (PO 4 ) 4 : greyish-green, P1 ¯ (no. 2), Z=1, a=4.9379(7) Å, b=7.917(2) Å, c=8.426(2) Å, α=109.98(2)°, β=90.71(1)°, γ=104.91(1)°, 131 parameters, R 1 =0.022, wR 2 =0.067, 1594 unique reflections with F o >4σ(F o )). Li 5 Cr II 2 Cr III (PO 4 ) 4 adopts an hitherto unknown structure type. The crystal structure of LiCr II 4 (PO 4 ) 3 is isotypic to that of NaCd II 4 (PO 4 ) 3 and related to that of the mineral silicocarnotite Ca 5 (PO 4 ) 2 (SiO 4 ). Significant disorder between Li + and Cr 2+ is observed for both crystal structures. The oxidation states assigned to chromium in these two phosphates are in agreement with UV/vis/NIR absorption spectra and magnetic susceptibility data recorded for both compounds. Instead of “LiCr II PO 4 ” mixtures of LiCr II 4 (PO 4 ) 3 , Li 5 Cr II 2 Cr III (PO 4 ) 4 , Cr 2 O 3 , and CrP are observed at equilibrium. Instead of “Li 2 Cr II P 2 O 7 ” four-phase mixtures consisting of Li 9 Cr III 3 (P 2 O 7 ) 3 (PO 4 ) 2 , Li 3 Cr III 2 (PO 4 ) 3 , LiCrP 2 O 7 , and CrP were obtained. - Graphical abstract: Investigations on the equilibrium relations in the system Li/Cr/P/O revealed the two hitherto unknown phosphates Li 5 Cr II 2 Cr III (PO 4 ) 4 and LiCr II 4 (PO 4 ) 3 . They form instead of “LiCr II PO 4 ”. The crystal structures, magnetic behavior and optical spectra of these phosphates are reported. - Highlights: • The two new phosphates Li 5 Cr II 2 Cr III (PO 4 ) 4 and LiCr II 4 (PO 4 ) 3 have been characterized. • Optical spectra and paramagnetism of

  14. Enhanced electrochemical performance of LiMnPO4 by Li+-conductive Li3VO4 surface coatings

    International Nuclear Information System (INIS)

    Dong, Youzhong; Zhao, Yanming; Duan, He; Liang, Zhiyong

    2014-01-01

    By a simple wet ball-milling method, Li 3 VO 4 -coated LiMnPO 4 samples were prepared successfully for the first time. The thin Li 3 VO 4 coating layer with a three-dimensional Li + -ion transport path and high mobility of Li + -ion strongly adhered to the LiMnPO 4 material reduces Mn dissolution and increases the Li + flux through the surface of the LiMnPO 4 itself by preventing formation of phases on the surface that would normally block Li + as well as Li + -ion permeation into the surface of the LiMnPO 4 electrode and therefore improve the rate capability as well as the cycling stability of LiMnPO 4 materials. The electrochemical testing shows that the 5% Li 3 VO 4 -coated LiMnPO 4 sample shows a clear voltage plateau in the charge curves and a much higher reversible capacity at different discharge rates compared with the pristine LiMnPO 4 . EIS results also show that the surface charge transfer resistance and Warburg impedance of the Li 3 VO 4 -coated LiMnPO 4 samples significantly decreased. The surface charge transfer resistance and Warburg impedance for the pristine LiMnPO 4 are 955.1 Ω and 400.3 Ω, respectively. While, for the 5% Li 3 VO 4 -coated LiMnPO 4 , the value are only 400.2 Ω and 283.6 Ω, respectively. The surface charge transfer resistance decreases more than half. All of the improved performance will be favorable for application of the LiMnPO 4 in high-power lithium ion batteries

  15. 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.

  16. Characterisation and Properties of Lithium Disilicate Glass Ceramics in the SiO2-Li2O-K2O-Al2O3 System for Dental Applications

    Directory of Open Access Journals (Sweden)

    Naruporn Monmaturapoj

    2013-01-01

    Full Text Available This work proposes four different glass formulas derived from the SiO2-Li2O-K2O-Al2O3 system to investigate the effect of glass composition on their crystal formations and properties. Glass LD1 was SiO2-Li2O-K2O-Al2O3 system with the addition of P2O5 and CaF2 as nucleating agents. In Glass LD2, a slight amount of MgO was mixed in order to increase the viscosity of the melting glass. Finally, the important factor of Si : Li ratio was increased in Glasses LD3 and LD4 with compositions otherwise the same as LD1 and LD2. The results found that P2O5 and CaF2 served as a nucleating site for lithium phosphate and fluorapatite to encourage heterogenous nucleation and produce a fine-grained interlocking microstructure of lithium disilicate glass ceramics. MgO content in this system seemed to increase the viscosity of the melting glass and thermal expansion coefficient including the chemical solubility. Increasing the Si : Li ratio in glass compositions resulted in the change of the microstructure of Li2Si2O5 crystals.

  17. Li{sub 4}SiO{sub 4} based breeder ceramics with Li{sub 2}TiO{sub 3}, LiAlO{sub 2} and Li{sub X}La{sub Y}TiO{sub 3} additions, part I: Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Kolb, M.H.H., E-mail: Matthias.kolb@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021 Karlsruhe (Germany); Mukai, K.; Knitter, R. [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021 Karlsruhe (Germany); Hoshino, T. [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Fusion Energy Research and Development Directorate, National Institutes for Quantum and Radiological Science and Technology (QST) (Japan)

    2017-02-15

    Highlights: • This study shows that the emulsion method can easily be adapted to add different phases into Li4SiO4 breeder pebbles. • Slurries with various compositions to form LOS + LMT, LOS + LAO and LOS + LLTO were processed.The calculated activation behavior shows that samples with added LAO or LLTO qualify as low activation material. • Yet, the long-term activation of the LAO containing samples is problematic as hands-on level activity is not reached quickly. - Abstract: Wet-chemical fabrication processes are highly adaptable to a wide range of raw materials and are therefore well suited for evaluating new material compositions. Here the established emulsion method was modified to fabricate novel two-phase Li{sub 4}SiO{sub 4} pebbles of 1 mm diameter with additions of Li{sub 2}TiO{sub 3}, LiAlO{sub 2} or Li{sub x}La{sub y}TiO{sub 3}. As the lithium density of the latter two compounds is relatively low, only moderate contents were added. The Li{sub 2}TiO{sub 3} additions, however, cover the full compositional range. The fabrication process was characterized with regard to its constancy and aptness for the anticipated pebble compositions by optical pebble size measurements. Also the phase content and the elemental composition of the fabricated pebbles were analyzed by XRD and ICP-OES combined with XRF, respectively. This work shows that the emulsion method is an appropriate method to produce pebbles with the anticipated Li{sub 2}TiO{sub 3} and LiAlO{sub 2} concentrations in a Li{sub 4}SiO{sub 4} matrix. However, Li{sub 4}SiO{sub 4} and Li{sub x}La{sub y}TiO{sub 3} react with each other to a number of different phases. To evaluate the activation properties of the pebbles, FISPACT calculations with a DEMO relevant neutron source are applied as well. The addition of aluminum seems to be unfavorable for a fusion application, but moderate concentrations of lanthanum can be tolerated.

  18. Compatibility behavior of beryllium with LiAlO2 and Li2ZrO3 ceramics, with 316L and 1.4914 steels in Sibelius

    International Nuclear Information System (INIS)

    Flament, T.; Roux, N.; Abassin, J.J.; Briec, M.; Cruz, D.; Schuster, I.

    1991-01-01

    The compatibility under irradiation of beryllium with Li 2 O, LiAlO 2 , Li 4 SiO 4 and Li 2 ZrO 3 ceramics and with 316L and 1.4914 steels was investigated in SIBELIUS. The irradiation was performed in the SILOE reactor at 550 deg C for 1690 hours in He + 0.1%H 2 purge pas. Examinations of the LiAlO 2 /Be and Li 2 ZrO 3 /Be couples show a weak oxidation of beryllium and the presence of cavities near the interface with ceramics. Examinations of the 316L/Be and 1.4914/Be couples show the formation of an oxide layer on all beryllium and steel surfaces suggesting that corrosion arises from a species (most likely T 2 O and/or H 2 O) present in the environmental atmosphere. Post-irradiation annealing tests of beryllium indicate that the major part of helium is released during irradiation whereas the major part of tritium is released above 700 deg C

  19. Fabrication of Li{sub 4}SiO{sub 4} pebbles by gel-precipitation technology

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Z.; Wu, X.; Gu, Z. [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai (China)

    2007-07-01

    Full text of publication follows: Lithium orthosilicate (Li{sub 4}SiO{sub 4}) is considered as a promising candidate as breeder material for fusion reactors due to its high lithium content, high stability and favorable tritium release behavior. The shape the breeder materials adopted was determined by many factors, such as the tritium breeding ratio, the ease of diffusion of tritium, the release of thermal stress and irradiation cracking etc. At present pebble configuration has been recognized as the preferred option in most blanket designs for tritium breeders. In the fabrication of spheres of a ceramic material, there are several methods available: the agglomeration of powders, melt-spraying method, sol-gel process and gel-precipitation process. Li{sub 4}SiO{sub 4} pebbles with satisfying quality have been fabricated by melt-spraying method. But expensive experimental equipment and high temperature restrict the extensive application of the method. Gel-precipitation can be operated at room temperature and no special equipment is needed. The technique has been successfully used to produce lithium aluminate ceramic spheres. In this work, fabrication of Li{sub 4}SiO{sub 4} pebbles by gel-precipitation technology was first time investigated systematically. LiOH, citric acid and SiO{sub 2} (aerosil) were used as raw materials. SiO{sub 2} (aerosil) was dispersed in the gel formed by LiOH and citric acid, milky suspension was then obtained and Li{sub 4}SiO{sub 4} pebbles were produced from the milky suspension. The pebbles obtained displayed pure Li{sub 4}SiO{sub 4} phase, exhibited high sphericity, uniform distribution in size, small amount of pores and cracks. Phase transformation with the molar ratio of SiO{sub 2}/LiOH was investigated. The effect of sintering temperature on microstructure was discussed. The water-based gel-precipitation method for fabrication of Li{sub 4}SiO{sub 4} spheres was simple and convenient to realize mass production. (authors)

  20. Characterizations on the microstructures of LiMn2O4 prepared by a simple soft-chemical technique

    International Nuclear Information System (INIS)

    Wei Yingjin; Kim, Kwang Bum; Chen Gang; Park, Chul W.

    2008-01-01

    LiMn 2 O 4 powders were prepared by a simple soft-chemical technique at different temperatures. X-ray diffraction and thermogravimetric analysis suggested that the material prepared at 800 deg. C was stoichiometric LiMn 2 O 4 , whereas those prepared at 600 and 700 deg. C were Li[Mn 0.77 3+ Mn 1.23 4+ ]O 4.115 and Li[Mn 0.85 3+ Mn 1.15 4+ ]O 4.075 . Several typical XRD peaks of the compounds were investigated with an aim to elucidate (i) the Li immigration to the 16d octahedral sites, (ii) the partial tetragonal phase transition of the material and (iii) the mean coherent domain size and microstrain. SEM study showed that the particle size of the materials increased with heating temperature. The activation energy for the material particle growth was determined as 30.4 kJ mol -1

  1. Humidity Sensitivity of MgCr2O4-TiO2-LiO2 Ceramics Sensor Prepared by Sol-Gel Routes

    Directory of Open Access Journals (Sweden)

    H. Y. He

    2010-05-01

    Full Text Available 79.5MgCr2O4–19.5TiO2–Li2O porous ceramics were investigated as a humidity sensor. The sensors obtain by a cold isostatic pressing and sintering of the fine MgCr2O4 and TiO2 and LiCO3 powders. The MgCr2O4 and TiO2 powders were respectively synthesized by sol-gel methods. The effects of sintering temperature on the humidity sensitivity of sensors were studied by measuring electrical resistance in different conditions of relative humidity (R.H. at 27 °C. The results indicated that the calcining temperature obviously affected the resistance variation of the sensor in range of 11.3-84.7 % RH. The resistance variation was small at the calcining temperature of 600 oC for 2 h. With increasing calcining temperature, the resistance variation increased to 5.4×104% and 7.0×104 % at 800 oC and 1000 oC for 2 h, but decreased to 3.1×104 % at 1200 oC for 2 h respectively. The response times are 25 s and 35 s respectively for humidity adsorption and humidity desorption between 11.3 %RH and 84.7 %RH.

  2. Fabrication of Li{sub 4}SiO{sub 4} pebbles by a sol-gel technique

    Energy Technology Data Exchange (ETDEWEB)

    Wu Xiangwei [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Wen Zhaoyin [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)], E-mail: zywen@mail.sic.ac.cn; Xu Xiaogang; Liu Yu [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

    2010-04-15

    Li{sub 4}SiO{sub 4} pebbles are considered as candidate ceramic breeder materials in many blanket designs. In this work, Li{sub 4}SiO{sub 4} pebbles with adequate sphericity were fabricated by a water-based sol-gel process using LiOH and SiO{sub 2} (aerosil) as the raw materials, which has not been reported for fabrication of Li{sub 4}SiO{sub 4} pebbles previously. Thermal analysis, phase analysis and morphological observations were carried out systematically. The effects of LiOH/C{sub 6}H{sub 8}O{sub 7} molar ratios and sintering temperature on the microstructure and density of the pebbles were discussed. Experimental results showed that when the LiOH/C{sub 6}H{sub 8}O{sub 7} molar ratio was 3, the microstructure of the Li{sub 4}SiO{sub 4} pebbles was the most favorable. While sintered at 900 deg. C for 4 h, Li{sub 4}SiO{sub 4} pebbles with about 1.2 mm in diameter were obtained and the density of the pebbles achieved about 74%.

  3. Group 1B organometallic chemistry XXIX. Synthetic and structural aspects of polynuclear arylcopperlithium compounds Ar4Cu2Li2 ('arylcuprates') and interaggregate exchange phenomena in Ar4Cu4/Ar4Li4/Ar4Cu2Li2 systems

    NARCIS (Netherlands)

    Koten, G. van; Noltes, J.G.

    1979-01-01

    The thermally stable arylmetal-IB-lithium compounds (2-Me{2}NCHZC{6}H{4}){4}M{2}Li{2} (M = Cu, Ag or Au; Z = H or Me) and (2-Me{2}NC{6}H{4}){4}M{2}Li{2} have been prepared by a 21 molar reaction of the aryllithium compounds with the corresponding metal-IB halide (Cu or Ag) or metal-lB halide

  4. Low Temperature Synthesis of Li2SiO3: Effect on Its Morphological and Textural Properties

    Directory of Open Access Journals (Sweden)

    Georgina Mondragón-Gutiérrez

    2008-01-01

    Full Text Available Synthesis, at low temperature, of Li2SiO3 was investigated using different Li : Si molar ratios and urea, which was used as template. This new synthesis was performed in order to look for different textural and morphological properties than those obtained usually by conventional methods in this kind of ceramics. XRD and SEM analyses showed that Li2SiO3 was obtained pure and with ceramic particle morphology of hollow spheres of 2–6 μm. TEM analysis showed that those spheres were composed by needle-like particles crosslinked among them. This morphology provided a high surface area, probed by N2 adsorption. Therefore, this method of synthesis may be used to obtain other similar ceramics and test them in different applications.

  5. Synthesis and structure of Li{sub 4}GeS{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Y [National Inst. of Materials and Chemical Research, Tsukuba (Japan). High Pressure Lab.; Kanatzidis, M G [Michigan State Univ., East Lansing, MI (United States). Dept. of Chemistry

    1998-01-01

    The compound Li{sub 4}GeS{sub 4} has been prepared as transparent, light yellow moisture-sensitive crystals. Li{sub 4}GeS{sub 4} belongs to the space group Pnma with a = 14.107(6) A, b = 7.770(3) A and c = 6.162(2) A. The crystal structure was solved by direct-methods. The final R and R{sub w}-values are 1.85 and 1.65% for 866 observed reflections. The Li{sub 4}GeS{sub 4} structure has three crystallographically independent lithium sites and one germanium site. The lithium atoms adopt two different coordination types. The Li1 atom is coordinated to five sulfur atoms in a square pyramidal geometry, while the Li2 and Li3 atoms have distorted tetrahedral coordination. The Ge atom is tetrahedrally coordinated by four sulfur atoms and is found as [GeS{sub 4}]{sup 4-} units. The anisotropic three-dimensional crystal structure of Li{sub 4}GeS{sub 4} is described. (orig.) 57 refs.

  6. Synthesis and Luminescence Properties of Yellow-emitting SiO2/Zn2SiO4: Mn Nanocomposite

    Directory of Open Access Journals (Sweden)

    Karim OMRI

    2014-05-01

    Full Text Available Yellow light emitting Mn2+-doped b-Zn2SiO4 phosphor nanoparticles embedded in SiO2 host matrix, were prepared by a simple solid-phase reaction under natural atmosphere at 1500 °C for 2 hours after the incorporation of manganese doped zinc oxide nanoparticles in silica using sol-gel method. The SiO2/Zn2SiO4:Mn nanocomposite was characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM and photoluminescence (PL. The nanopowder was crystallized in triclinic b-Zn2SiO4 phase with a particles size varies between 70 nm and 84 nm. The SiO2/b-Zn2SiO4:Mn nanocomposite exhibited a broad yellow emission band at 575 nm under UV excitation light. The dependence of the intensity and energy position of the obtained PL band on measurement temperature and power excitation will be discussed.

  7. Role of PO4 tetrahedron in LiFePO4 and FePO4 system.

    Science.gov (United States)

    Zeng, Yuewu

    2015-06-01

    Using high resolution transmission electron microscopy with image simulation and Fourier analysis, the Li1- x FePO4 (x < 0.01), Li1- x FePO4 (x ∼ 0.5), and FePO4 particles, prepared by charging or discharging the 053048 electrochemical cells (thickness: 5 mm, width: 30 mm, height: 48 mm) and dismantled inside an Ar-filled dry box, were investigated. The high resolution images reveal: (1) the solid solution of Li1- x FePO4 (x < 0.01) contains some missing Li ions leading PO4 group distorted around M1 tunnel of the unit cell; (2) the texture of the particles of Li1- x FePO4 (x ∼0.5) has homogeneously distributed compositional domains of LiFePO4 and FePO4 resulting from spinodal decomposition which promote Li ion easily getting into the particle due to uphill diffusion, (3) the particles of FePO4 formed in charging have heavily distorted lattice and contain some isolated LiFePO4 , (4) interface between LiFePO4 and FePO4 and between amorphous and crystal region provides the lattice distortion of small polarons. © 2015 Wiley Periodicals, Inc.

  8. Elastic properties of various ceramic materials

    International Nuclear Information System (INIS)

    Zimmermann, H.

    1992-09-01

    The Young's modulus and the Poisson's ratio of various ceramics have been investigated at room temperature and compared with data from the literature. The ceramic materials investigated are Al 2 O 3 , Al 2 O 3 -ZrO 2 , MgAl 2 O 4 , LiAlO 2 , Li 2 SiO 3 , Li 4 SiO 4 , UO 2 , AlN, SiC, B 4 C, TiC, and TiB 2 . The dependence of the elastic moduli on porosity and temperature have been reviewed. Measurements were also performed on samples of Al 2 O 3 , AlN, and SiC, which had been irradiated to maximum neutron fluences of 1.6.10 26 n/m 2 (E>0.1 MeV) at different temperatures. The Young's modulus is nearly unaffected at fluences up to about 4.10 24 n/m 2 . However, it decreases with increasing neutron fluence and seems to reach a saturation value depending upon the irradiation temperature. The reduction of the Young's modulus is lowest in SiC. (orig.) [de

  9. Nanocrystalline LiMn2O4 thin film cathode material prepared by polymer spray pyrolysis method for Li-ion battery

    International Nuclear Information System (INIS)

    Karthick, S.N.; Richard Prabhu Gnanakan, S.; Subramania, A.; Kim, Hee-Je

    2010-01-01

    Nanocrystalline cubic spinel lithium manganese oxide thin film was prepared by a polymer spray pyrolysis method using lithium acetate and manganese acetate precursor solution and polyethylene glycol-4000 as a polymeric binder. The substrate temperature was selected from the thermogravimetric analysis by finding the complete crystallization temperature of LiMn 2 O 4 precursor sample. The deposited LiMn 2 O 4 thin films were annealed at 450, 500 and 600 o C for 30 min. The thin film annealed at 600 o C was found to be the sufficient temperature to form high phase pure nanocrystalline LiMn 2 O 4 thin film. The formation of cubic spinel thin film was confirmed by X-ray diffraction study. Scanning electron microscopy and atomic force microscopy analysis revealed that the thin film annealed at 600 o C was found to be nanocrystalline in nature and the surface of the films were uniform without any crack. The electrochemical charge/discharge studies of the prepared LiMn 2 O 4 film was found to be better compared to the conventional spray pyrolysed thin film material.

  10. Water vapor concentration dependence and temperature dependence of Li mass loss from Li{sub 2}TiO{sub 3} with excess Li and Li{sub 4}SiO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Shimozori, Motoki [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Katayama, Kazunari, E-mail: kadzu@nucl.kyushu-u.ac.jp [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Hoshino, Tsuyoshi [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Sector of Fusion Research and Development, Japan Atomic Energy Agency, 2-166 Obuch, Omotedate, Rokkasho-mura, Kamikita-gun, Aomori 039-3212 (Japan); Ushida, Hiroki; Yamamoto, Ryotaro; Fukada, Satoshi [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan)

    2015-10-15

    Highlights: • Li mass loss from Li{sub 2.11}TiO{sub 3} increased proportionally to water vapor pressure. • Li mass loss from Li{sub 2.11}TiO{sub 3} at 600 °C was significantly smaller than expected. • Differences of Li mass loss behavior from Li{sub 2.11}TiO{sub 3} and Li{sub 4}SiO{sub 4} were shown. - Abstract: In this study, weight reduction of Li{sub 2}TiO{sub 3} with excess Li and Li{sub 4}SiO{sub 4} at elevated temperatures under hydrogen atmosphere or water vapor atmosphere was investigated. The Li mass loss for the Li{sub 2}TiO{sub 3} at 900 °C was 0.4 wt% under 1000 Pa H{sub 2} atmosphere and 1.5 wt% under 50 Pa H{sub 2}O atmosphere. The Li mass loss for the Li{sub 2}TiO{sub 3} increased proportionally to the water vapor pressure in the range from 50 to 200 Pa at 900 °C and increased with increasing temperature from 700 to 900 °C although Li mass loss at 600 °C was significantly smaller than expected. It was found that water vapor concentration dependence and temperature dependence of Li mass loss for the Li{sub 2}TiO{sub 3} and the Li{sub 4}SiO{sub 4} used in this work were quite different. Water vapor is released from the ceramic breeder materials into the purge gas due to desorption of adsorbed water and water formation reaction. The released water vapor possibly promotes Li mass loss with the formation of LiOH on the surface.

  11. EPR experiments in LiTbF4, LiHoF4, and LiErF4 at submillimeter frequencies

    DEFF Research Database (Denmark)

    Magariño, J.; Tuchendler, J.; Beauvillain, P.

    1980-01-01

    Electron-paramagnetic-resonance experiments in LiTbF4, LiHoF4, and LiErF4 have been performed at frequencies between 70 and 600 GHz, in magnetic fields up to 60 kG and in the temperature range 1.4......Electron-paramagnetic-resonance experiments in LiTbF4, LiHoF4, and LiErF4 have been performed at frequencies between 70 and 600 GHz, in magnetic fields up to 60 kG and in the temperature range 1.4...

  12. Effects of TiO2 addition on microwave dielectric properties of Li2MgSiO4 ceramics

    Science.gov (United States)

    Rose, Aleena; Masin, B.; Sreemoolanadhan, H.; Ashok, K.; Vijayakumar, T.

    2018-03-01

    Silicates have been widely studied for substrate applications in microwave integrated circuits owing to their low dielectric constant and low tangent loss values. Li2MgSiO4 (LMS) ceramics are synthesized through solid-state reaction route using TiO2 as an additive to the pure ceramics. Variations in dielectric properties of LMS upon TiO2 addition in different weight percentages (0.5, 1.5, 2) are studied by keeping the sintering parameters constant. Crystalline structure, phase composition, and microstructure of LMS and LMS-TiO2 ceramics were studied using x-ray diffraction spectrometer and High Resolution Scanning electron microscope. Density was measured through Archimedes method and the microwave dielectric properties were examined by Cavity perturbation technique. LMS achieved relative permittivity (ε r) of 5.73 and dielectric loss (tan δ) of 5.897 × 10‑4 at 8 GHz. In LMS-TiO2 ceramics, 0.5 wt% TiO2 added LMS showed comparatively better dielectric properties than other weight percentages where ε r = 5.67, tan δ = 7.737 × 10‑4 at 8 GHz.

  13. Scratch resistance of SiO2 and SiO2 - ZrO2 sol-gel coatings on glass-ceramic obtained by sintering

    International Nuclear Information System (INIS)

    Soares, V. O.; Soares, P.; Peitl, O.; Zanotto, E. D.; Duran, A.; Castro, Y.

    2013-01-01

    The sol-gel process is widely used to obtain coatings on glass-ceramic substrates in order to improve the scratch and abrasion resistance, also providing a bright and homogeneous appearance of a glaze avoiding expensive final polishing treatments. This paper describes the preparation of silica and silica / zirconia coatings by sol-gel method on Li 2 O-Al 2 O3-SiO 2 (LAS) glassceramic substrates produced by sintering. The coatings were deposited by dip-coating on LAS substrates and characterized by optical microscopy and spectral ellipsometry. On the other hand, hardness and elastic modulus, coefficient of friction and abrasion and scratch resistance of the coatings were determined and compared with the substrate properties. Coatings deposited on LAS glass-ceramic confere the substrate a bright and homogeneous aspect, similar to a glaze, improving the appearance and avoiding the final polishing. However these coatings do not increase the scratch resistance of the substrate only equaling the properties of the glass-ceramic. (Author)

  14. Electronic Properties of LiFePO4 and Li doped LiFePO4

    International Nuclear Information System (INIS)

    Zhuang, G.V.; Allen, J.L.; Ross, P.N.; Guo, J.-H.; Jow, T.R.

    2005-01-01

    The potential use of different iron phosphates as cathode materials in lithium-ion batteries has recently been investigated.1 One of the promising candidates is LiFePO4. This compound has several advantages in comparison to the state-of-the-art cathode material in commercial rechargeable lithium batteries. Firstly, it has a high theoretical capacity (170 mAh/g). Secondly, it occurs as mineral triphylite in nature and is inexpensive, thermally stable, non-toxic and non-hygroscopic. However, its low electronic conductivity (∼10-9 S/cm) results in low power capability. There has been intense worldwide research activity to find methods to increase the electronic conductivity of LiFePO4, including supervalent ion doping,2 introducing non-carbonaceous network conduction3 and carbon coating, and the optimization of the carbon coating on LiFePO4 particle surfaces.4 Recently, the Li doped LiFePO4 (Li1+xFe1-xPO4) synthesized at ARL has yield electronic conductivity increase up to 106.5 We studied electronic structure of LiFePO4 and Li doped LiFePO4 by synchrotron based soft X-ray emission (XES) and X-ray absorption (XAS) spectroscopies. XAS probes the unoccupied partial density of states, while XES the occupied partial density of states. By combining XAS and XES measurements, we obtained information on band gap and orbital character of both LiFePO4 and Li doped LiFePO4. The occupied and unoccupied oxygen partial density of states (DOS) of LiFePO4 and 5 percent Li doped LiFePO4 are presented in Fig. 1. Our experimental results clearly indicate that LiFePO4 has wideband gap (∼ 4 eV). This value is much larger than what is predicted by DFT calculation. For 5 percent Li doped LiFePO4, a new doping state was created closer to the Fermi level, imparting p-type conductivity, consistent with thermopower measurement. Such observation substantiates the suggestion that high electronic conductivity in Li1.05Fe0.95 PO4 is due to available number of charge carriers in the material

  15. Thermal properties and crystallization of lithium–mica glass and glass-ceramics

    International Nuclear Information System (INIS)

    Nia, A. Faeghi

    2013-01-01

    Highlights: • Two groups of Li–mica glass-ceramics, have been compared. • By controlling the glass composition, crystalline lepidolite was obtained. • The T p of Li–mica was through the previous virgilite and eucryptite phase. - Abstract: The purpose of this study was the synthesis of two groups of Li–mica glass-ceramics denoted by lepidolite (Al 2.5 F 2 KLi 1.5 O 10 Si 3 ) and Li-phlogopite (LiMg 3 AlSi 3 O 10 F 2 ). The studied system was SiO 2 –Al 2 O 3 –MgO–K 2 O–Li 2 O. A total of 3 compositions were prepared. Bulk casted glasses and sintered glass-ceramics of Li-phlogopite and lepidolite systems, were prepared. Eucryptite and virgilite were two prior phases of lepidolite and Li-phlogopite crystallization. It was shown that the obtained glass-ceramics have lower TEC than corresponding glasses. Sinterability of lepidolite glass-ceramic was shown that improved by increasing the Al 2 O 3 content in glass composition. TEC and microhardness values were α = 6.08 × 10 −6 /°C, 755 ± 11.1, α = 7.86 × 10 −6 /°C, 739 ± 7.4 and α = 5.05 × 10 −6 /°C, 658 ± 6.2 HV for Li-lep, Klep1 and Klep2 glasses, respectively

  16. Lithium ceramics: sol-gel preparation and tritium release

    International Nuclear Information System (INIS)

    Renoult, O.

    1994-04-01

    Ceramics based on lithium aluminate (LiA1O 2 ), lithium zirconate (Li 2 ZrO 3 ) and lithium titanate (Li 2 TiO 3 ) are candidates as tritium breeder blanket materials for forthcoming nuclear fusion reactors. Lithium silico-aluminate Li 4+x A1 4-3x Si 2x O 8 (0 ≤ x ≤ 0,25) powders were synthetized from alkoxyde-hydroxyde sol-gel route. By direct sintering at 850-1100 deg C (without prior calcination), ceramics with controlled stoichiometry and homogenous microstructure were obtained. We have also prepared, using a comparable method, Li 2 Zr 1-x Ti x O 3 (x = 0, x = 0,1 et x = 1) materials. All these ceramics, with different microstructures and compositions, have been tested in out-of-reactor experiments. Concerning lithium aluminate microporous ceramics, the silicon substitution leads to a significant improvement of the tritrium release. Classical models taking into account independent surface mechanisms are not able to describe correctly the observed tritium release kinetics. We show, using a simple model, that the release kinetics is in fact limited by an intergranular diffusion followed by a desorption. The delay in tritium release, which occurs when the ceramic compacity increases, is explained in terms of an enhancement of the ionic T + diffusion path length. The energy required for desorption includes a leading term independent of hydrogen contained in the sweep gas. This term is attributed to the limiting recombination step of T + in molecular species HTO. For similar microstructures, the facility of tritium release for the different studied materials is explained by three properties: the crystal structure of the ceramic, the acidity of oxides and finally the presence of electronic non-stoichiometric defects. (author). 89 refs., 50 figs., 2 tabs., 1 annexe

  17. Crystallization and thermo-mechanical properties of Li2O-ZnO-CaOSiO2 glass-ceramics with In2O3 and Fe2O3 additives

    Directory of Open Access Journals (Sweden)

    Saad M. Salman

    2015-12-01

    Full Text Available Li2O-ZnO-CaO-SiO2 based glasses were prepared by the conventional melting technique and subsequently converted to glass-ceramics by controlled crystallization. The nucleation and crystallization temperatures were determined by differential thermal analysis (DTA. The effects of adding In2O3 and Fe2O3 addition on the crystallization behaviour and thermo-mechanical properties of the prepared glass-ceramics were investigated. A study on the microstructure, close to the internal phases of the resulting glass-ceramics, was followed by using scanning electron microscope (SEM. The dilatometric thermal expansion and Vickers’ microhardness of the crystalline products were also evaluated. The crystalline phases that can be found in the resulting glass-ceramics, identified by X-ray diffraction (XRD analysis, are α-quartz-[SiO2], lithium zinc silicate-[Li2ZnSiO4], lithium disilicate-[Li2Si2O5], wollastonite-[CaSiO3], wollastonite containing iron, ferrobustamite-[(Ca0.79Fe0.21SiO3], and lithium indium silicate of pyroxene type-[LiInSi2O6]. Average thermal expansion coefficient (in the temperature range 25–700 °C decreased from 191×10-7 1/°C to 115×10-7 1/°C and the Vickers’ microhardness increased from 3.56 to 5.44 GPa with the increase of In2O3 and Fe2O3 contents in the glass-ceramics. The changes in the obtained expansion coefficient and microhardness were due to the formation of different phases which in turn influenced the rigidity/bonding and microstructure in the resultant glass-ceramics.

  18. Bioactivity and mineralization of hydroxyapatite with bioglass as sintering aid and bioceramics with Na3Ca6(PO4)5 and Ca5(PO4)2SiO4 in a silicate matrix

    International Nuclear Information System (INIS)

    Demirkiran, Hande; Mohandas, Arunesh; Dohi, Motokazi; Fuentes, Alonso; Nguyen, Kytai; Aswath, Pranesh

    2010-01-01

    Hydroxyapatite and Bioglass-45S5 were sintered together creating new ceramic compositions that yielded increased apatite deposition and osteoblast differentiation and proliferation in vitro compared to hydroxyapatite. The sintered products characterized by X-ray diffraction, revealed hydroxyapatite as the main phase when small quantities (1, 2.5 and 5 wt.%) of bioglass was added. Bioglass behaved as a sintering aid with β-TCP (Ca 3 (PO 4 ) 2 ) being the minor phase. The amount of β-TCP increased with the amount of bioglass added. In compositions with larger additions of bioglass (10 and 25 wt.%), new phases with compositions of calcium phosphate silicate (Ca 5 (PO 4 ) 2 SiO 4 ) and sodium calcium phosphate (Na 3 Ca 6 (PO 4 ) 5 ) were formed respectively within amorphous silicate matrices. In vitro cell culture studies of the ceramic compositions were examined using bone marrow stromal cell (BMSC). Cell proliferation and differentiation of bone marrow stromal cells into osteoblasts were determined by Pico Green DNA assays and alkaline phosphatase (ALP) activity, respectively. All hydroxyapatite-bioglass co-sintered ceramics exhibited larger cell proliferation compared to pure hydroxyapatite samples. After 6 days in cell culture, the ceramic with Ca 5 (PO 4 ) 3 SiO 4 in a silicate matrix formed by reacting hydroxyapatite with 10 wt.% bioglass exhibited the maximum proliferation of the BMSC's. The ALP activity was found to be largest in the ceramic with Na 3 Ca 6 (PO 4 ) 5 embedded in a silicate matrix synthesized by reacting hydroxyapatite with 25 wt.% bioglass.

  19. Preparation of Ce- and La-Doped Li4Ti5O12 Nanosheets and Their Electrochemical Performance in Li Half Cell and Li4Ti5O12/LiFePO4 Full Cell Batteries

    Directory of Open Access Journals (Sweden)

    Meng Qin

    2017-06-01

    Full Text Available This work reports on the synthesis of rare earth-doped Li4Ti5O12 nanosheets with high electrochemical performance as anode material both in Li half and Li4Ti5O12/LiFePO4 full cell batteries. Through the combination of decreasing the particle size and doping by rare earth atoms (Ce and La, Ce and La doped Li4Ti5O12 nanosheets show the excellent electrochemical performance in terms of high specific capacity, good cycling stability and excellent rate performance in half cells. Notably, the Ce-doped Li4Ti5O12 shows good electrochemical performance as anode in a full cell which LiFePO4 was used as cathode. The superior electrochemical performance can be attributed to doping as well as the nanosized particle, which facilitates transportation of the lithium ion and electron transportation. This research shows that the rare earth doped Li4Ti5O12 nanosheets can be suitable as a high rate performance anode material in lithium-ion batteries.

  20. Preparation of Ce- and La-Doped Li4Ti5O12 Nanosheets and Their Electrochemical Performance in Li Half Cell and Li4Ti5O12/LiFePO4 Full Cell Batteries

    Science.gov (United States)

    Qin, Meng; Li, Yueming; Lv, Xiao-Jun

    2017-01-01

    This work reports on the synthesis of rare earth-doped Li4Ti5O12 nanosheets with high electrochemical performance as anode material both in Li half and Li4Ti5O12/LiFePO4 full cell batteries. Through the combination of decreasing the particle size and doping by rare earth atoms (Ce and La), Ce and La doped Li4Ti5O12 nanosheets show the excellent electrochemical performance in terms of high specific capacity, good cycling stability and excellent rate performance in half cells. Notably, the Ce-doped Li4Ti5O12 shows good electrochemical performance as anode in a full cell which LiFePO4 was used as cathode. The superior electrochemical performance can be attributed to doping as well as the nanosized particle, which facilitates transportation of the lithium ion and electron transportation. This research shows that the rare earth doped Li4Ti5O12 nanosheets can be suitable as a high rate performance anode material in lithium-ion batteries. PMID:28632167

  1. Preparation and characterization of Fe3O4/SiO2/Bi2MoO6 composite as magnetically separable photocatalyst

    International Nuclear Information System (INIS)

    Hou, Xuemei; Tian, Yanlong; Zhang, Xiang; Dou, Shuliang; Pan, Lei; Wang, Wenjia; Li, Yao; Zhao, Jiupeng

    2015-01-01

    Highlights: • Fe 3 O 4 /SiO 2 /Bi 2 MoO 6 composite was prepared by a hydrothermal method. • The composite has an enhanced visible absorption compared with pure Bi 2 MoO 6 . • The magnetic photocatalyst displayed excellent stability and reusability. • O 2 ·− and · OH play a major role during the photocatalytic process. - Abstract: In this paper, Fe 3 O 4 /SiO 2 /Bi 2 MoO 6 microspheres were prepared by a facile hydrothermal method. The scanning electron microscope (SEM) results revealed that flower-like three dimensional (3D) Bi 2 MoO 6 microspheres were decorated with Fe 3 O 4 /SiO 2 magnetic nanoparticles. The UV–vis diffuse reflection spectra showed extended absorption within the visible light range compared with pure Bi 2 MoO 6 . We evaluated the photocatalytic activities of Fe 3 O 4 /SiO 2 /Bi 2 MoO 6 microspheres on the degradation of Rhodamine B (RhB) under visible light irradiation and found that the obtained composite exhibited higher photocatalytic activity than pure Bi 2 MoO 6 and P25. Moreover, the Fe 3 O 4 /SiO 2 /Bi 2 MoO 6 composite also displayed excellent stability and their photocatalytic activity decreased slightly after reusing 5 cycles. Meanwhile, the composite could be easily separated by applying an external magnetic field. The trapping experiment results suggest that superoxide radical species O 2 ·− and hydroxyl radicals · OH play a major role in Fe 3 O 4 /SiO 2 /Bi 2 MoO 6 system under visible light irradiation. The combination of flower-like three dimensional (3D) Bi 2 MoO 6 microspheres and Fe 3 O 4 /SiO 2 magnetic nanospheres provides a useful strategy for designing multifunctional nanostructure materials with enhanced photocatalytic activities in the potential applications of water purification

  2. Preparation and encapsulation performance of Al_2O_3-SiO_2-B_2O_3 glass-ceramic for high temperature thermal storage

    International Nuclear Information System (INIS)

    Li, Ruguang; Zhu, Jiaoqun; Zhou, Weibing; Cheng, Xiaomin; Liu, Fengli

    2017-01-01

    Highlights: • Al_2O_3-B_2O_3-SiO_2 has good chemical durability, corrosion resistance and dense structure. • The material rarely used in high temperature thermal storage. • The material was prepared and characterized in the paper. - Abstract: In this paper, Al_2O_3-SiO_2-B_2O_3 glass-ceramic was prepared and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), further, the porosity was detected by Archimedes principle, thermo physical properties were investigated by differential scanning calorimeter (DSC), respectively. The phase composition was detected by XRD, and the morphology was observed by SEM. The results indicated that the thermal conductivities of the Al_2O_3-SiO_2-B_2O_3 glass-ceramic were between 1.3 and 1.5 W·(m·K)"−"1, and the material had good thermal stability in the range of 300–900 °C. The porosity and apparent density were increased with the temperature. The porosity of Al_2O_3-SiO_2-B_2O_3 glass-ceramic in ranging from 1.2 to 9.6%, the apparent density were between 2.12 and 2.67 g·cm"−"3, and heat capacities were between 0.64 and 0.79 kJ/(kg·K). All the results indicated that the Al_2O_3-SiO_2-B_2O_3 glass-ceramic can be applied as encapsulation material in high temperature latent thermal energy storage.

  3. Effect of Ti(+4) on in vitro bioactivity and antibacterial activity of silicate glass-ceramics.

    Science.gov (United States)

    Riaz, Madeeha; Zia, Rehana; Saleemi, Farhat; Hussain, Tousif; Bashir, Farooq; Ikhram, Hafeez

    2016-12-01

    A novel glass-ceramic series in (48-x) SiO2-36 CaO-4 P2O5-12 Na2O-xTiO2 (where x=0, 3.5, 7, 10.5 and 14mol %) system was synthesized by crystallization of glass powders, obtained by melt quenching technique. The differential scanning calorimetric analysis (DSC) was used to study the non-isothermal crystallization kinetics of the as prepared glasses. The crystallization behaviour of glasses was analyzed under non-isothermal conditions, and qualitative phase analysis of glass-ceramics was made by X-ray diffraction. The in vitro bioactivity of synthesized glass-ceramics was studied in stimulated body fluid at 37°C under static condition for 24days. The formation of hydroxyl-carbonated apatite layer; evident of bioactivity of the material, was elucidated by XRD, FTIR, AAS, SEM and EDX analysis. The result showed that partial substitution of TiO2 with SiO2 negatively influenced bioactivity; it decreased with increase in concentration of TiO2. As Ti(+4) having stronger field strength as compared to Si(+4) so its replacement became the cause for reduction in degradation that in turn improved the chemical stability. The compressive strength was also enhanced with progress addition of TiO2 in the system. The antibacterial properties were examined against Staphylococcus Epidermidis. Strong antibacterial efficacy was observed with the addition of TiO2 in the system. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Electrochemical performances of LiMnPO4 synthesized from non-stoichiometric Li/Mn ratio.

    Science.gov (United States)

    Xiao, Jie; Chernova, Natasha A; Upreti, Shailesh; Chen, Xilin; Li, Zheng; Deng, Zhiqun; Choi, Daiwon; Xu, Wu; Nie, Zimin; Graff, Gordon L; Liu, Jun; Whittingham, M Stanley; Zhang, Ji-Guang

    2011-10-28

    In this paper, the influences of the lithium content in the starting materials on the final performances of as-prepared Li(x)MnPO(4) (x hereafter represents the starting Li content in the synthesis step which does not necessarily mean that Li(x)MnPO(4) is a single phase solid solution in this work.) are systematically investigated. It has been revealed that Mn(2)P(2)O(7) is the main impurity when Li Li(3)PO(4) begins to form once x > 1.0. The interactions between Mn(2)P(2)O(7) or Li(3)PO(4) impurities and LiMnPO(4) are studied in terms of the structural, electrochemical, and magnetic properties. At a slow rate of C/50, the reversible capacity of both Li(0.5)MnPO(4) and Li(0.8)MnPO(4) increases with cycling. This indicates a gradual activation of more sites to accommodate a reversible diffusion of Li(+) ions that may be related to the interaction between Mn(2)P(2)O(7) and LiMnPO(4) nanoparticles. Among all of the different compositions, Li(1.1)MnPO(4) exhibits the most stable cycling ability probably because of the existence of a trace amount of Li(3)PO(4) impurity that functions as a solid-state electrolyte on the surface. The magnetic properties and X-ray absorption spectroscopy (XAS) of the MnPO(4)·H(2)O precursor, pure and carbon-coated Li(x)MnPO(4) are also investigated to identify the key steps involved in preparing a high-performance LiMnPO(4). This journal is © the Owner Societies 2011

  5. Organophosphonic acid as precursor to prepare LiFePO4/carbon nanocomposites for high-power lithium ion batteries

    International Nuclear Information System (INIS)

    Chen, Ming; Shao, Leng-Leng; Yang, Hua-Bin; Zhao, Qian-Yong; Yuan, Zhong-Yong

    2015-01-01

    Graphical abstract: LiFePO4/C nanocomposites were prepared by a quasi-sol–gel method with the use of organophosphonic acid, exhibiting improved electrochemical performance with excellent cycle stability. Display Omitted -- Highlights: •Amino tris(methylene phosphonic acid) is served as a novel precursor for LiFePO 4 /C. •Nano-sized and high-purity LiFePO 4 /C composites are obtained by a quasi-sol–gel route. •Core-shell structured LiFePO 4 /C nanocomposites are fabricated by further introducing sucrose. •Superior electrochemical performance is observed in the organophosphorus-synthesized LiFePO 4 /C. -- Abstract: Amino tris(methylene phosphonic acid) (ATMP) is selected as phosphorus and carbon co-source for the synthesis of uniformly nano-sized LiFePO 4 /C by a quasi-sol–gel method. This strategy using ATMP instead of conventional NH 4 H 2 PO 4 supplies two advantages: firstly, ATMP in situ chelates Li + onto its framework and subsequently binds with FeC 2 O 4 in aqueous solution, forming a molecule-scale homogeneous precursor which can obviously improve the purity of LiFePO 4 . Secondly, the organic carbon contained in ATMP can form uniformly distributed conductive carbon networks among LiFePO 4 particles after calcination, which improves the electrical conductivity. The resultant LiFePO 4 /C with 1.1 wt.% carbon achieves a higher discharge capacity than those of LiFePO 4 and LiFePO 4 /C prepared with inorganic NH 4 H 2 PO 4 . Moreover, core-shell structured LiFePO 4 /C nanocomposites are also fabricated by further introducing sucrose into the synthesis system. The high-quality carbon shell effectively hinders the LiFePO 4 particle growth and aggregation under high-temperature treatment, which further enhances the electrical conductivity and lithium-ion diffusion, resulting in the improved electrochemical performance with excellent cycle stability (the optimum discharge capacity of 158.6 mAh g −1 at 0.1 C and 138.4 mAh g −1 at 2 C). The high

  6. The preparation and electrochemical performances of LiFePO4-multiwalled nanotubes composite cathode materials for lithium ion batteries

    International Nuclear Information System (INIS)

    Feng Yan

    2010-01-01

    LiFePO 4 -MWCNTs (multi-walled carbon nanotubes) composite cathode materials were prepared by mixing LiFePO 4 and MWCNTs in ethanol followed by heat-treatment at 500 deg. C for 5 h. The structural, morphology and electrochemical performances of LiFePO 4 -MWCNTs composite materials were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic charge-discharge cycle tests, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results indicated that MWCNTs adding improved the electronic conductivity, the discharge capacity, cycle stability and lithium ion diffusion kinetics of LiFePO 4 , but MWCNTs adding did not charge the orthorhombic olivine-type structure of LiFePO 4 . In all these prepared LiFePO 4 with x wt.% MWCNTs (x = 4, 7, 10) composites, 7 wt.% MWCNTs adding composite cathode shows the best electrochemical performance, which gets an initial discharge capacity of 152.7 mAh g -1 at 0.18 C discharge rates with capacity retention ratio of 97.77% after 100 cycles.

  7. Preparation of LiMn2O4 Graphene Hybrid Nanostructure by Combustion Synthesis and Their Electrochemical Properties

    Directory of Open Access Journals (Sweden)

    Dinesh Rangappa

    2014-10-01

    Full Text Available The LiMn2O4 graphene hybrid cathode material has been synthesized by spray drying combustion process. The spinel structure cubic phase LiMn2O4 graphene hybrid material was prepared by spray drying process at 120 ℃ and subsequent heat treatment at 700 ℃ for 1 hour. The result indicates that the spinel shaped LiMn2O4 particles wrapped with graphene sheets were formed with particle size in the range of 60-70 nm. The charge-discharge measurement indicates that the LiMn2O4 graphene hybrid material shows an improved discharge capacity of 139 mAh/g at 0.1C rate. The pristine LiMn2O4 nano crystals present only about 132 mAh/g discharge capacity. The LiMn2O4 graphene hybrid samples show good cyclic performance with only 13% of capacity fading in 30 cycles when compared to the pristine LiMn2O4 that shows 22% of capacity fading in 30 cycles. The capacity retention of the LiMn2O4 graphene hybrid samples is about 10% higher than the pristine cycle after 30 cycles.

  8. Luminescence characteristics of Mg2SiO4:Nd

    International Nuclear Information System (INIS)

    Indira, P.; Subrahmanyam, R.V.; Murthy, K.V.R.

    2011-01-01

    Thermoluminescence (TL) properties of Magnesium Ortho silicate (2:1) Mg 2 SiO 4 doped with various concentrations of rare earth (Nd) have been studied. The phosphor material were prepared using standard solid state reaction technique and heated specimens at 1100 ± 20 deg C for two hours. 4% Ammonium chloride was used as flux. The received material was grinded in an agate mortar and pestle. The TL exhibited by the Mg 2 SiO 4 with varying concentration of Nd is interesting in nature. It is interesting to note but as the concentration of Nd increases the peak around 125 deg C TL peak intensity increases. But the hump around 200 deg C resolved as TL peak at 253 deg C with high intensity. (author)

  9. The phase transformation and crystallization kinetics of (1 - x)Li2O-xNa2O-Al2O3-4SiO2 glasses

    International Nuclear Information System (INIS)

    Wang, Moo-Chin; Li, Wang-Long; Cheng, Chih-Wei; Chang, Kuo-Ming; Chen, Yong-Feng; Hsi, Chi-Shiung

    2010-01-01

    The phase transformation and crystallization kinetics of (1 - x)Li 2 O-xNa 2 O-Al 2 O 3 -4SiO 2 glasses have been studied by using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) analysis. The crystallization temperature at the exothermic peak increases from 1171 to 1212 K when the Na 2 O content increases from 0 to 0.6 mol. The crystalline phase is composed of spodumene crystallization when the Na 2 O content increases from 0 to 0.6 mol. The activation energy of spodumene crystallization decreases from 444.0 ± 22.2 to 284.0 ± 10.8 kJ mol -1 when the Na 2 O content increases from 0 to 0.4 mol. Moreover, the activation energy increases from 284.0 ± 10.8 to 446.0 ± 23.2 kJ mol -1 when the Na 2 O content increases from 0.4 to 0.6 mol. The crystallization parameters m and n approach 2, indicating that the surface nucleation and two-dimensional growth are dominant in (1 - x)Li 2 O-xNa 2 O-Al 2 O 3 -4SiO 2 glasses.

  10. Synthesis and electrochemical properties of olivine LiFePO{sub 4} prepared by a carbothermal reduction method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hui-ping; Wang, Zhi-xing; Li, Xin-hai; Guo, Hua-jun; Peng, Wen-jie; Zhang, Yun-he; Hu, Qi-yang [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China)

    2008-10-01

    LiFePO{sub 4}/C composite cathode material was prepared by carbothermal reduction method, which uses NH{sub 4}H{sub 2}PO{sub 4}, Li{sub 2}CO{sub 3} and cheap Fe{sub 2}O{sub 3} as starting materials, acetylene black and glucose as carbon sources. The precursor of LiFePO{sub 4}/C was characterized by differential thermal analysis and thermogravimetry. X-ray diffraction (XRD), scanning electron microscopy (SEM) micrographs showed that the LiFePO{sub 4}/C is olivine-type phase, and the addition of the carbon reduced the LiFePO{sub 4} grain size. The carbon is dispersed between the grains, ensuring a good electronic contact. The products sintered at 700 C for 8 h with glucose as carbon source possessed excellent electrochemical performance. The synthesized LiFePO{sub 4} composites showed a high electrochemical capacity of 159.3 mAh g{sup -1} at 0.1C rate, and the capacity fading is only 2.2% after 30 cycles. (author)

  11. Cd2SiO4/Graphene nanocomposite: Ultrasonic assisted synthesis, characterization and electrochemical hydrogen storage application.

    Science.gov (United States)

    Masjedi-Arani, Maryam; Salavati-Niasari, Masoud

    2018-05-01

    For the first time, a simple and rapid sonochemical technique for preparing of pure Cd 2 SiO 4 nanostructures has been developed in presence of various surfactants of SDS, CTAB and PVP. Uniform and fine Cd 2 SiO 4 nanoparticle was synthesized using of polymeric PVP surfactant and ultrasonic irradiation. The optimized cadmium silicate nanostructures added to graphene sheets and Cd 2 SiO 4 /Graphene nanocomposite synthesized through pre-graphenization. Hydrogen storage capacity performances of Cd 2 SiO 4 nanoparticle and Cd 2 SiO 4 /Graphene nanocomposite were compared. Obtained results represent that Cd 2 SiO 4 /Graphene nanocomposites have higher hydrogen storage capacity than Cd 2 SiO 4 nanoparticles. Cd 2 SiO 4 /Graphene nanocomposites and Cd 2 SiO 4 nanoparticles show hydrogen storage capacity of 3300 and 1300 mAh/g, respectively. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Preparation and catalytic effect of porous Co3O4 on the hydrogen storage properties of a Li-B-N-H system

    Directory of Open Access Journals (Sweden)

    You Li

    2017-02-01

    Full Text Available A porous Co3O4 with a particle size of 1–3 µm was successfully prepared by heating Co-based metal organic frameworks MOF-74(Co up to 500 °C in air atmospheric conditions. The as-prepared porous Co3O4 significantly reduced the dehydrogenation temperatures of the LiBH4-2LiNH2 system and improved the purity of the released hydrogen. The LiBH4-2LiNH2-0.05/3Co3O4 sample started to release hydrogen at 140 °C and released hydrogen levels of approximately 9.7 wt% at 225 °C. The end temperature for hydrogen release was lowered by 125 °C relative to that of the pristine sample. Structural analyses revealed that the as-prepared porous Co3O4 is in-situ reduced to metallic Co, which functions as an active catalyst, reducing the kinetic barriers and lowering the dehydrogenation temperatures of the LiBH4-2LiNH2 system. More importantly, the porous Co3O4-containing sample exhibited partially improved reversibility for hydrogen storage in the LiBH4-2LiNH2 system.

  13. Multilayered ion-imprinted membranes with high selectivity towards Li+ based on the synergistic effect of 12-crown-4 and polyether sulfone

    Science.gov (United States)

    Lu, Jian; Qin, Yingying; Zhang, Qi; Wu, Yilin; Cui, Jiuyun; Li, Chunxiang; Wang, Liang; Yan, Yongsheng

    2018-01-01

    High-selective multilayered Li+-imprinted membranes (Li-IIMs) with enhanced hydrophilicity and stability were developed based on polyether sulfone substrate membranes. The multilayered structure was prepared with polydopamine (pDA) as the interfacial adhesion layer, SiO2 nanoparticles as the hydrophilic layer and Li+-imprinted polymers as the imprinted layer. The selective ;Li+-recognition sites; were formed using 12-crown-4 (12C4) as the adsorbing units. The optimal relative selectivity coefficients (α) of Li+/Na+ and Li+/K+ reached up to 1.85 and 2.07 with the imprinting factor (β) of 2.51, and the high permselectivity factors (γ) of Na+/Li+ (7.39) and K+/Li+ (9.86) were achieved on Li-IIMs. The Langmuir isotherm model and the pseudo-second-order kinetics model best fitted the rebinding data of Li-IIMs, as well as the rebinding capacities reached up to 90.3% of initial binding after 5 cycles of adsorption/desorption and just declined to 88.1% after another 5 cycles a month later. Therefore, the as-prepared Li-IIMs would have potential applications for the separation of lithium ions from salt lake brines.

  14. Structural and impedance characterization of ceramics prepared from NPK fertilizer

    Directory of Open Access Journals (Sweden)

    Diouma Kobor

    2015-06-01

    Full Text Available One of the main objectives of this work was to study the possibilities of valorising the phosphates through the development of a conductive ceramics using NPK fertilizer as a precursor. Phosphorus based powders were synthesized using solid state technique from NPK fertilizer, lithium chloride and iron chloride at different temperatures up to 900 °C and ceramic samples were prepared by the powder pressing and sintering at 1100 °C. XRD spectra of the calcined powders show various sharp peaks indicating a relatively high degree of crystallinity and presence of different crystalline phases, such as: phosphorus based crystalline compounds (AlPO4 and LiFePO4, ferrite (Fe3O4 and DyFeO3, CaSO4 and K3DyCl6. The prepared phosphorus based ceramics showed very interesting electrical and dielectric properties. Thus, in the future the obtained ceramics could find application in electronic or energy storage devices. However, further investigations are necessary to understand the exact chemical composition and structural characteristics of this material, to better understand the origin of the obtained electrical and dielectric behaviour.

  15. Phase relations in the M2MoO4 - Ag2MoO4 - Hf(MoO4)2 (M=Li, Na) systems

    International Nuclear Information System (INIS)

    Bazarova, Zh.G.; Bazarov, B.G.; Balsanova, L.V.

    2002-01-01

    The M 2 MoO 4 - Ag 2 MoO 4 - Hf(MoO 4 ) 2 (M=Li, Na) systems were studied by X-ray diffraction and differential thermal analyses in the subsolidus area (450 - 500 Deg C) for the first time. The formation of the binary compound with the variable composition Li 4-x Hf 1+0.2x (MoO 4 ) 4 (0 ≤ x ≤ 0.6) in the Li 2 MoO 4 - Hf(MoO 4 ) 2 system and the ternary molybdates Li 4 Ag 2 Hf(MoO 4 ) 5 (S 1 ) and Na 2 Ag 2 Hf(MoO 4 ) 4 (S 2 ) was established and the thermal characteristics of the prepared compounds were examined. The new binary molybdate Ag 2 Hf(MoO 4 ) 3 was prepared by the reaction between Ag 2 MoO 4 and Hf(MoO 4 ) 2 [ru

  16. Proceedings of the eleventh international workshop on ceramic breeder blanket interactions

    International Nuclear Information System (INIS)

    Enoeda, Mikio

    2004-07-01

    This report is the Proceedings of 'the Eleventh International Workshop on Ceramic Breeder Blanket Interactions' which was held as a workshop on ceramic breeders Under the IEA Implementing Agreement on the Nuclear Technology of Fusion Reactors, and the Japan-US Fusion Collaboration Framework. This workshop was held in Tokyo, Japan on December 15-17, 2003. About thirty experts from China, EU, Japan, Korea, Latvia, Russia and USA attended the workshop. The scope of the workshop included 1) evolutions in ceramic breeder blanket design, 2) progress in ceramic breeder material development, 3) irradiation testing, 4) breeder material properties, 5) out-of-pile pebble bed experiment, 6) modeling of the thermal, mechanical and tritium transfer behavior of pebble beds and 7) interfacing issues of solid breeder blanket. In the workshop, information exchange was performed for designs of solid breeder blankets and test blankets in EU, Russia and Japan, recent results of irradiation tests, HICU, EXOTIC-8 and the irradiation tests by IVV-2M, modeling study on tritium release behavior of Li 2 TiO 3 and so on, fabrication technology developments and characterization of the Li 2 TiO 3 and Li 4 SiO 4 pebbles, research on measurements and modeling of thermo-mechanical behaviors of Li 2 TiO 3 and Li 4 SiO 4 pebbles, and interfacing issues, such as, fabrication technology for blanket box structure, neutronics experiments of blanket mockups by fusion neutron source and tritium recovery system. The 26 of the presented papers are indexed individually. (J.P.N.)

  17. Synthesis of some (eta-arene)dihydridorhenium cations and their reactions with LiAlH4 and LiAlD4

    International Nuclear Information System (INIS)

    Baudrey, D.; Boydell, P.; Ephritikhine, M.

    1986-01-01

    A series of cations [Re(eta-arene)H 2 (PPh 3 ) 2 ] + (arene benzene, toluene, p-xylene, or mesitylene) was prepared from the corresponding neutral dihydridocyclohexadienyl complexes by treatment with CPh 3 BF 4 . These cations reacted with LiAlH 4 and LiAlD 4 to form dihydridocyclohexadienyl complexes. The unusual selectivity of the hydride attack is explained by steric interactions between the ring methyl groups and the bulky phosphine ligands. The initial product of the reaction of the eta-mesitylene cation with LiAlD 4 allows the isomerisation mechanism for the cyclohexadienyl complexes to be clarified. (author)

  18. Nano-Ticl 4 .SiO 2 : a Versatile and Efficient Catalyst for Synthesis of ...

    African Journals Online (AJOL)

    Nano-TiCl4.SiO2 has been found to be an extremely efficient catalyst for the preparation of 3,4-dihydropyrimidinones/thiones via three-component reactions of an aldehyde, β-ketoester or β-diketone and urea or thiourea under mild conditions. Nano-TiCl4.SiO2 as a solid Lewis acid has been synthesized by reaction of ...

  19. [Influence of La2O3 and Li2O on glass powder for infiltrating ZTA all-ceramic dental material formed by gel-casting].

    Science.gov (United States)

    Jin, Qiong; Wang, Xiao-fei; Yang, Zheng-yu; Tong, Yi-ping; Zhu, Li; Ma, Jian-feng

    2012-10-01

    The influence of La2O3 and Li2O on glass powder was studied in this paper, which is to infiltrate ZTA all-ceramic dental material formed by gel-casting. The performance of different component was analyzed to optimize glass formula. Six groups of glass powder were designed and prepared by conventional melt-quenching method. ZTA ceramic blocks were covered with glass paste, which were formed by gel-casting and sintered in 1200 degrees centigrade, then infiltrated in 1150 degrees centigrade for twice to make glass/ZTA ceramic composites. By detecting differential thermal analysis and melting range of infiltration glass power, as well as flexural strength, linear shrinkage, SEM and EDS of glass/ZTA ceramic composites, the optimized glass group was determined out. Statistical analysis was performed using SPSS 13.0 software package by means of paired t test or one way ANOVA. The bending strength of group Li1 was (291.2±27.9) MPa, significantly higher than group Li2 and group La2(Pglass of group Li1 can lubricate ZTA ceramics well, their structure was compact and had a few small pores. Intergranular fracture existed on cross surface as well as transgranular fracture. The results showed that Li1(30%La2O3-15%Al2O3-15%SiO2-15%B2O3-5%Li2O) glass infiltrated ZTA ceramic composite had the best capability. Glass/ZTA composite material can be prepared by gel-casting and infiltrating way, and this process is simple and economically suitable for general dental laboratory.

  20. Superior electrode performance of LiFePO4/C composite prepared by an in situ polymerization restriction method

    International Nuclear Information System (INIS)

    Chen, Jian; Zou, Yong-Cun; Zhang, Feng; Zhang, Yuan-Chun; Guo, Fei-Fan; Li, Guo-Dong

    2013-01-01

    Highlights: ► LiFePO 4 /C composite was prepared by an in situ polymerization restriction method. ► The size of LiFePO 4 in the composite is effectively restricted. ► The high-rate capability and cycling performance of LiFePO 4 are enhanced greatly. -- Abstract: The LiFePO 4 /C composite is prepared by heating the mixture of resorcinol–formaldehyde gel and FePO 4 , synthesized by an in situ polymerization restriction method, and lithium acetate dihydrate in the atmosphere of nitrogen. The physical and electrochemical properties of the LiFePO 4 /C composite are investigated by X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy and electrochemical measurements. The discharge capacity of LiFePO 4 is as high as 155.6 mA h g −1 in the first cycle at 0.5C, and it could remain 144.0 mA h g −1 after 50 cycles. Even at the high rates of 10C, 20C and 50C, the initial discharge capacities of the electrodes exhibit 115.6 mA h g −1 , 84.5 mA h g −1 and 67.8 mA h g −1 , and the electrodes deliver capacity retention of 89.5%, 90.9% and 85.7% after 1000 cycles, respectively. The outstanding electrochemical performance could be attributed to the small particle size and good electronic conductivity of the composite

  1. Preparation of submicrocrystal LiMn2O4 used Mn3O4 as precursor and its electrochemical performance for lithium ion battery

    International Nuclear Information System (INIS)

    Liu, Bao-Sheng; Wang, Zhen-Bo; Zhang, Yin; Yu, Fu-Da; Xue, Yuan; Ke, Ke; Li, Fang-Fei

    2015-01-01

    Graphical abstract: Spinal LiMn 2 O 4 particles synthesized at 800 °C for 12 h has the best crystallinity with a submicron size and smallest cation disorder, resulting in a superior capacity retention ratio of 90.4% after 200 cycles at 1 °C at room temperature, which possesses an initial capacity of 106.8 mA h/g. - Highlights: • High purity spinel LiMn 2 O 4 was synthesized from industrial grade raw materials. • LiMn 2 O 4 prepared by optimal conditions has the smallest cation mixing. • Optimized LiMn 2 O 4 has the highest initial capacity with 112.9 mA h/g. • Capacity retention of optimized LiMn 2 O 4 is 90.4% after 200 cycles at 1 °C. - Abstract: Spinel LiMn 2 O 4 has been synthesized by solid state reaction with industrial grade Mn 3 O 4 and Li 2 CO 3 as precursors without purification, and its electrochemical performance for lithium ion battery has been investigated by CR2025 coin cell. The results of X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) images show that the size of LiMn 2 O 4 particles grow up with increasing temperature of calcination, and the sample synthesized at 800 °C for 12 h has the best crystallinity with a submicron size. It can deliver initial capacity of 112.9 mA h/g with capacity retention ratio of 89.1% after 200 cycles at charge/discharge rate of 1 C. The results of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) also show that it has the highest electrochemical activity and lowest charge transfer impedance

  2. A novel material Li{sub 2}NiFe{sub 2}O{sub 4}: Preparation and performance as anode of lithium ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Keqiang, E-mail: dkeqiang@263.net [College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang, Hebei, 050024 (China); Zhao, Jing [College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang, Hebei, 050024 (China); Zhou, Jinming, E-mail: zhoujm@iccas.ac.cn [College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang, Hebei, 050024 (China); Zhao, Yongbo; Chen, Yuying; Liu, Likun [College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang, Hebei, 050024 (China); Wang, Li [Institute of Nuclear & New Energy Technology, Beijing Key Lab of Fine Ceramics, Tsinghua University, Beijing, 100084 (China); He, Xiangming, E-mail: hexm@tsinghua.edu.cn [Institute of Nuclear & New Energy Technology, Beijing Key Lab of Fine Ceramics, Tsinghua University, Beijing, 100084 (China); Guo, Zhanhu, E-mail: zguo10@utk.edu [Integrated Composites Laboratory (ICL), Chemical and Biomolecular Engineering Department, University of Tennessee Knoxville, Knoxville, NT, 37996 (United States)

    2016-07-01

    For the first time, the preparation and characterization of a novel anode material Li{sub 2}NiFe{sub 2}O{sub 4} are reported in this work. The preparation of Li{sub 2}NiFe{sub 2}O{sub 4} is conducted under the air conditions by using a subsection calcination method. The influence of annealing periods on the properties of the resultant materials is thoroughly explored. The characteristics of the materials are mainly examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), galvanostatic charge-discharge tests and electrochemical impedance spectroscopy (EIS). The results of the XRD patterns effectively demonstrate the formation of crystalline Li{sub 2}NiFe{sub 2}O{sub 4}, and the SEM images indicate that particles with octahedron crystal morphology are prepared and the 9 h-annealed sample has the smallest particle size among all the prepared samples. The results of electrochemical measurements reveal that 9 h-calcined sample delivers a high specific capacity of 203 mAh g{sup −1} after 20 cycles at a current density of 100 mA g{sup −1}. The successful preparation of Li{sub 2}NiFe{sub 2}O{sub 4} is believed to be able to trigger the research work concerning the novel group of Li{sub 2}MFe{sub 2}O{sub 4} materials. - Highlights: • A novel anode material Li{sub 2}NiFe{sub 2}O{sub 4} was prepared under the air conditions. • Li{sub 2}NiFe{sub 2}O{sub 4} showed well-defined octahedron crystal morphology. • 9 h-annealed Li{sub 2}NiFe{sub 2}O{sub 4} delivered a capacity of 203 mAh g{sup −1}.

  3. Calcium cation enhanced cathode/electrolyte interface property of Li2FeSiO4/C cathode for lithium-ion batteries with long-cycling life

    Science.gov (United States)

    Qu, Long; Li, Mingtao; Tian, Xiaolu; Liu, Pei; Yi, Yikun; Yang, Bolun

    2018-03-01

    Currently, the cycle performance at low rate is one of the most critical factor for realizing practical applications of Li2FeSiO4/C as a cathode of the lithium-ion batteries. To meet this challenge, calcium (Ca)-doped Li2FeSiO4/C is prepared by using the sol-gel method with soluble Li, Fe, Si and Ca sources. X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy measurements are carried out to determine the crystal structures, morphologies, particle sizes and chemical valence states of the resulting products. Rietveld refinement confirms that Ca-doped Li2FeSiO4 has a monoclinic P21/n structure and that a Ca cation occupies the Fe site in the Li2FeSiO4 lattice. The grain size of Ca-doped Li2FeSiO4 is approximately 20 nm and the nanoparticles are interconnected tightly with amorphous carbon layer. As a cathode material for the lithium-ion batteries, Li2Fe0.97Ca0.03SiO4/C delivers a high discharge capacity of 186 mAh g-1 at a 0.5 C rate. Its capacity retention after the 100th cycle reaches 87%, which increases by 25 percentage points compared with Li2FeSiO4/C. The Li2Fe0.97Ca0.03SiO4/C cathode exhibits good rate performance, with corresponding discharge capacities of 170, 157, 144 and 117 mAh g-1 at 1 C, 2 C, 5 C and 10 C rates, respectively. In summary, the improvement of the electrochemical performance can be attributed to a coefficient of the strengthened crystal structure stability during Li+ deintercalation-intercalation and restrained side reactions between electrode and electrolyte.

  4. Thermal properties of lithium ceramics for fusion applications

    International Nuclear Information System (INIS)

    Hollenberg, G.W.; Baker, D.E.

    1982-03-01

    Specific heat, thermal diffusivity and thermal conductivity were measured on Li 2 O, Li 4 SiO 4 , Li 2 ZrO 3 and LiAlO 2 . Data on these properties were needed for design of an irradiation experiment to be performed on these materials. In general, the specific heat of a ceramic is primarily enrichment-dependent, but the thermal diffusivity and thermal expansion coefficient may be influenced by microstructure. Hence, it will be necessary to duplicate these measurements on the engineering materials finally selected for a particular design

  5. Study on ceramic breeder and related materials by means of work function measurement under irradiation

    International Nuclear Information System (INIS)

    Luo, G.N.; Terai, T.; Yamawaki, M.; Yamaguchi, K.

    2002-01-01

    Ceramic breeder materials, Li 2 O, LiAlO 2 and Li 4 SiO 4 , under irradiation have been studied using a Kelvin probe that measures work function changes of materials. Surface charging was observed to influence greatly the probe output, which can be explained qualitatively employing a model concerning induction electric field due to external field and free charges on ceramic surface. It is found that the insulating ceramics could not be studied properly with the Kelvin probe. A probable solution is to heat the ceramics, so as to raise their electric conductivities high enough to root out the surface charging. Also briefly discussed is the application of the probe to metals under ion irradiation. (orig.)

  6. Espumas vítreas do sistema Li2O-ZrO2-SiO2-Al2O 3 produzidas pelo processo gelcasting Li2O-ZrO2-SiO2 -Al2O3 glass-ceramic foams produced by the gelcasting process

    Directory of Open Access Journals (Sweden)

    E. de Sousa

    2009-06-01

    Full Text Available Espumas vítreas do sistema Li2O-ZrO2-SiO2-Al2O 3 (LZSA foram produzidas pelo processo gelcasting, associado à aeração de suspensões cerâmicas, sem controle atmosférico. Por meio da adição de diferentes concentrações de agente espumante (Fongraminox foi possível obter espumas vítreas com densidade relativa variando entre uma estreita faixa (0,10-0,15. As espumas vítreas apresentaram resistência à compressão de 2,5-3,7 MPa, que correspondem a porosidade entre 85 e 89% e macroestrutra com poros aproximadamente esféricos e interconectados. Tais características tornam esses materiais atraentes para as seguintes aplicações tecnológicas: filtros para metais fundidos e gases quentes e, suportes catalíticos.Vitreous foams in the Li2O-ZrO2-SiO2-Al2O 3 (LZSA system were produced by the gelcasting process with aeration of ceramic suspensions and without atmospheric control. By the addition of different concentrations of foaming agent (Fongraminox it was possible to attain glass-ceramic foams in a narrow range of relative density (0.10-0.15. The glass-ceramic foams showed compressive strength of 2.5-3.7 MPa, which corresponds to porosity between 85-89%, and macrostructure with pores nearly spherical and interconnected, these characteristics make these materials attractive for the following applications technology: filters of molten metals and hot gas, and catalytic support.

  7. Spectroscopic analysis of LiHoF4 and LiErF4

    DEFF Research Database (Denmark)

    Christensen, H.P.

    1979-01-01

    The polarized absorption spectra for Ho3+ and Er3+ in LiHoF4 and LiErF4, respectively, have been recorded in the spectral interval 4000-26 000 cm-1 at 2 K. Parts of the spectra were examined at higher temperatures. The experimental levels for Ho3+ and Er3+ in LiRF4 were close to those found in Li...

  8. Synthesis of spherical LiMnPO4/C composite microparticles

    International Nuclear Information System (INIS)

    Bakenov, Zhumabay; Taniguchi, Izumi

    2011-01-01

    Highlights: → We could prepare LiMnPO 4 /C composites by a novel preparation method. → The LiMnPO 4 /C composites were spherical particles with a mean diameter of 3.65 μm. → The LiMnPO 4 /C composite cathode exhibited 112 mAh g -1 at 0.05 C. → It also showed a good rate capability up to 5 C at room temperature and 55 o C. -- Abstract: Spherical LiMnPO 4 /C composite microparticles were prepared by a combination of spray pyrolysis and spray drying followed by heat treatment and examined as a cathode material for lithium batteries. The structure, morphology and electrochemical performance of the resulting spherical LiMnPO 4 /C microparticles were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electronic microscopy and standard electrochemical techniques. The final sample was identified as a single phase orthorhombic structure of LiMnPO 4 and spherical powders with a geometric mean diameter of 3.65 μm and a geometric standard deviation of 1.34. The electrochemical cells contained the spherical LiMnPO 4 /C microparticles exhibited first discharge capacities of 112 and 130 mAh g -1 at 0.05 C at room temperature and 55 o C, respectively. These also showed a good rate capability up to 5 C at room temperature and 55 o C.

  9. Glass-ceramic enamels derived from the Li2O-Na2O-Al2O3-TiO2-SiO2 system

    Directory of Open Access Journals (Sweden)

    SNEZANA R. GRUJIC

    2002-02-01

    Full Text Available The results of research on the conditions for obtaining model glass-ceramic enamels, derived from the basic Li2O-Na2O-Al2O3-TiO2-SiO2 system, by varying the initial composition and thermal treatment conditions, are presented in this paper. Segregation of the crystal phases in the glassy-matrix was carried out during subsequent thermal treatment. The formation of different crystal phases was evidenced through the results of differential-thermal analysis and X-ray powder diffraction analysis.

  10. Enhanced electrochemical performance of different morphological C/LiMnPO4 nanoparticles from hollow-sphere Li3PO4 precursor via a delicate polyol-assisted hydrothermal method

    Science.gov (United States)

    Cui, Yu-Ting; Xu, Ning; Kou, Li-Qin; Wu, Meng-Tao; Chen, Li

    2014-03-01

    With the hollow-sphere Li3PO4 as precursor, a delicate polyol-assisted hydrothermal method is devised to synthesize high-performance LiMnPO4. Orthorhombic shaped, irregular flaky shaped and sphere-like LiMnPO4 are sequentially prepared by decreasing the water-diethylene glycol (DEG) ratio. The capacity, cycling stability and rate performance of all samples prepared by the new synthesis method are improved significantly. And the C/LiMnPO4 with irregular flaky shape exhibits a capacity of 154.1 mA h g-1 at C/20, 147.4 mA h g-1 at C/10 and 102.5 mA h g-1 at 2 C, which is the best performance ever reported for LiMnPO4 active material with similar carbon additives.

  11. Effects of recording time and residue on dose-response by LiMgPO4: Tb, B ceramic disc synthesized via improved sintering process

    Science.gov (United States)

    Kong, Xirui; Fu, Zhilong; Que, Huiying; Fan, Yanwei; Chen, Zhaoyang; He, Chengfa

    2018-05-01

    The LiMgPO4: Tb, B ceramic disc is successfully synthesized via improved sintering method which enables the disc sample to have two flat and smooth surfaces. It is worth mentioning that the OSL signal intensity of LiMgPO4: Tb, B disc attenuates much faster than that of commercial Al2O3: C. It costs only 1 s to reduce the intensity to 10%, but the Al2O3:C needs more than 40 s to finish it. Some essential OSL properties related to the dose detection method of this sample also have been systematically investigated. Although the dose-response cure would have better linearity with longer recording time, extended recording time (≥6 s) will not make any contribution to the linearity of the curve. If the bleaching time is more than 35 s, the residue created by previous detection (high dose of 10 Gy) would do almost no influence (with a positive deviation lower than 5.59%) on next lower-dose detection (0.1 Gy). The material would reach its service life when the total-ionizing dose runs up to 30 k Gy. Therefore, the LiMgPO4: Tb, B ceramic material is a potential candidate for real-time dose monitoring with optical fiber telemetering technology.

  12. Single-crystalline LiFePO4 nanosheets for high-rate Li-ion batteries.

    Science.gov (United States)

    Zhao, Yu; Peng, Lele; Liu, Borui; Yu, Guihua

    2014-05-14

    The lithiation/delithiation in LiFePO4 is highly anisotropic with lithium-ion diffusion being mainly confined to channels along the b-axis. Controlling the orientation of LiFePO4 crystals therefore plays an important role for efficient mass transport within this material. We report here the preparation of single crystalline LiFePO4 nanosheets with a large percentage of highly oriented {010} facets, which provide the highest pore density for lithium-ion insertion/extraction. The LiFePO4 nanosheets show a high specific capacity at low charge/discharge rates and retain significant capacities at high C-rates, which may benefit the development of lithium batteries with both favorable energy and power density.

  13. Revising the Subsystem Nurse’s A-Phase-Silicocarnotite within the System Ca3(PO42–Ca2SiO4

    Directory of Open Access Journals (Sweden)

    Patricia Ros-Tárraga

    2016-04-01

    Full Text Available The subsystem Nurse’s A-phase-silicocarnotite within the system Ca3(PO42–Ca2SiO4 was conducted as a preliminary step toward obtaining new biomaterials with controlled microstructures. Phase composition of the resulting ceramics was studied by X-ray diffraction, differential thermal analysis, and scanning electron microscopy with attached wavelength dispersive spectroscopy. The results showed that the sub-system presents an invariant eutectoid point at 1366 ± 4 °C with a composition of 59.5 wt % Ca3(PO42 and 40.5 wt % Ca2SiO4, and typical eutectoid microstructure of lamellae morphology. These results are in disagreement with the previous reported data, which locate the invariant eutectoid point at 1250 ± 20 °C with a composition of 55 wt % Ca3(PO42 and 45 wt % Ca2SiO4. In addition, cell attachment testing showed that the new eutectoid material supported the mesenchymal stem cell adhesion and spreading, and the cells established close contact with the ceramic after 28 days of culture. These findings indicate that the new ceramic material with eutectoid microstructure of lamellae morphology possesses good bioactivity and biocompatibility and might be a promising bone implant material.

  14. Local structure of vanadium in doped LiFePO4

    International Nuclear Information System (INIS)

    Zhao, Ting; Xu, Wei; Ye, Qing; Cheng, Jie; Zhao, Haifeng; Chu, Wangsheng; Wu, Ziyu; Univ. of Science and Technology of China, Hefei; Xia, Dingguo

    2010-01-01

    LiFePO 4 composites with 5 at.% vanadium doping are prepared by solid state reactions. X-ray absorption fine-structure spectroscopy is used as a novel technique to identify vanadium sites. Both experimental analyses and theoretical simulations show that vanadium does not enter into the LiFePO 4 crystal lattice. When the vanadium concentration is lower then 1 at.%, the dopant remains insoluble. Thus, a single-phase vanadium-doped LiFePO4 cannot be formed and the improved electrochemical properties of vanadium doped LiFePO 4 previously reported cannot be associated with crystal structure changes of the LiFePO 4 via vanadium doping. (orig.)

  15. The PrPS4 type structure and a filled variant: the compounds TbPS4 and LiEuPS4

    International Nuclear Information System (INIS)

    Joergens, S.; Alili, L.; Mewis, A.

    2005-01-01

    Colourless single crystals of TbPS 4 (a = 10.696(2), c = 19.053(4) Aa) were obtained by reaction of the elements (750 C; 30 h). The compound crystallizes with the PrPS 4 type structure (I4 1 /acd; Z = 16). The structure consists of isolated PS 4 tetrahedra each surrounded by four Tb 3+ cations. Both crystallographically different Tb 3+ cations are coordinated by eight sulfur atoms which are part of four PS 4 tetrahedra. Orange single crystals of LiEuPS 4 (a = 11.498(2), c = 19.882(4) Aa) were prepared by reaction of Eu and P with Li 2 S 4 (700 C; 20 h). The crystal structure corresponds to the PrPS 4 type, in which tubes running along [001] are occupied by Li atoms, which are surrounded by four S atoms in strongly distorted tetrahedra. LiS 4 and PS 4 tetrahedra are connected via common edges into alternating chains. (orig.)

  16. Sol–gel synthesis and electrochemical properties of 9LiFePO4·Li3V2(PO4)3/C composite cathode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Zhong Shengkui; Wu Ling; Liu Jiequn

    2012-01-01

    Highlights: ► Nano-sized 9LiFePO 4 ·Li 3 V 2 (PO 4 ) 3 /C powders are prepared by a sol–gel method. ► Mutual doping in 9LiFePO 4 ·Li 3 V 2 (PO 4 ) 3 /C can improve its electronic conductivity. ► The addition of Li 3 V 2 (PO 4 ) 3 can improve the ionic diffusivity of LiFePO 4 . ► LiFePO 4 , Li 3 V 2 (PO 4 ) 3 and LiFePO 4Li 3 V 2 (PO 4 ) 3 unit cells coexist in the composite. - Abstract: 9LiFePO 4 ·Li 3 V 2 (PO 4 ) 3 /C composite cathode material is prepared by a sol–gel method, using ferric citrate, V 2 O 5 , Li 2 CO 3 , NH 4 H 2 PO 4 and citric acid as raw materials. The composite material is composed of the olivine LiFePO 4 and monoclinic Li 3 V 2 (PO 4 ) 3 phases. XRD results indicate that most of the iron and vanadium in the raw materials tend to form the LiFePO 4 and Li 3 V 2 (PO 4 ) 3 phases, and only small amounts of Fe and V as the dopants enter into the lattice of Li 3 V 2 (PO 4 ) 3 and LiFePO 4 , respectively. The electronic conductivity and Li + diffusion coefficient of 9LiFePO 4 ·Li 3 V 2 (PO 4 ) 3 /C are 6.615 × 10 −3 S cm −1 and ∼10 −10 cm 2 s −1 , which are three orders of magnitude and one order of magnitude larger than those of the LiFePO 4 /C, respectively. The composite material shows a first discharge specific capacity of 131.3 mAh g −1 and capacity retention of 95.1% after 200 cycles at 10 C rate. Compared with the LiFePO 4 /C, its rate capability and cycle performance are both remarkably improved.

  17. PENGUJIAN AKTIVITAS KOMPOSIT Fe2O3-SiO2 SEBAGAI FOTOKATALIS PADA FOTODEGRADASI 4-KLOROFENOL (The Activity Test of Fe2O3-SiO2 Composite As Photocatalyst on 4-Chlorophenol Photodegradation

    Directory of Open Access Journals (Sweden)

    Eko Sri Kunarti

    2009-03-01

    Full Text Available ABSTRAK  Pada penelitian ini telah dilakukan pengujian aktivitas komposit Fe2O3-SiO2 sebagai fotokatalis pada fotodegradasi 4-klorofenol. Penelitian diawali dengan preparasi dan karakterisasi fotokatalis Fe2O3-SiO2. Preparasi dilakukan dengan metode sol-gel pada temperatur kamar menggunakan tetraetil ortosilikat (TEOS dan besi (III nitrat sebagai prekursor diikuti dengan perlakuan termal pada temperature 500 oC. Karakterisasi dilakukan dengan metode spektrometri inframerah, difraksi sinar-X dan spektrometri fluoresensi sinar-X. Uji aktivitas komposit untuk fotodegradasi 4-klorofenol dilakukan dalam reaktor tertutup yang dilengkapi dengan lampu UV. Pada uji ini telah dipelajari pengaruh waktu penyinaran dan pH larutan terhadap efektivitas fotodegradasi 4-klorofenol. Hasil penelitian menunjukkan bahwa komposit Fe2O3-SiO2 dapat dipreparasi dengan metode sol-gel pada temperatur kamar diikuti perlakuan termal. Komposit Fe2O3-SiO2 dapat meningkatkan efektivitas fotodegradasi 4-klorofenol dari 11,86 % menjadi 55,38 %. Efektivitas fotodegradasi 4- klorofenol dipengaruhi waktu penyinaran dan pH larutan yang semakin lama waktu penyinaran efektifitas fotodegradasi semakin tinggi, namun waktu penyinaran yang lebih lama dari 4 jam dapat menurunkan efektivitasnya. pH larutan memberikan pengaruh yang berbeda-beda pada efektivitas fotodegradasi 4-klorofenol.   ABSTRACT The activity test of Fe2O3-SiO2 composite as photocatalyst on 4-chlorophenol photodegradation has been studied. The research was initiated by preparation of Fe2O3-SiO2 photocatalyst and followed by characterization. The preparation was conducted by sol-gel method at room temperature using tetraethylorthosilicate (TEOS and iron (III nitrate as precursors followed by thermal treatment at a temperature of 500oC. The characterizations were performed by X-ray Diffraction (XRD, Infrared and X-ray Fluorescence Spectrophotometry. The photocatalytic activity test of composites for 4 chlorophenol

  18. Prospects of ceramic tritium breeder materials

    International Nuclear Information System (INIS)

    Roth, E.; Roux, N.; Conservatoire National des Arts et Metiers; CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette

    1989-01-01

    In this paper the authors examine the prospects of the main ceramics proposed as breeder materials for fusion reactors, i.e. Li-2O, Li-2ZrO-3, LiAlO-2, Li-4SiO-4. To do so they review terms of reference of contemplated blankets for NET, ITER and DEMO, and the proposed blanket concepts and materials. Issues respective to the use of each breeder material are examined, and from this review it is concluded that ceramics are the most favorable breeder materials whose use can be contemplated as well for a driver blanket for NET or ITER and for a DEMO blanket. Ceramics are then compared between themselves and it is seen that, subject to the confirmation of recent experimental results, lithium zirconate could be used with advantage in any of the present blanket concepts, except in those employing lithium at its natural isotopic abundance, in which case only Li-2O can be used. However in specific cases, or in parts of a blanket, other ceramics may be profitably employed. As a general conclusion suggestions are made to further improve ceramic breeder performances, and it is recommended to intensify also work on problems that have to be solved in order to operate ceramic breeder blankets e.g. tritium extraction and recovery systems and conditions of beryllium use. (author). 37 refs.; 12 tabs

  19. Nano-sized Li4Ti5O12 anode material with excellent performance prepared by solid state reaction: The effect of precursor size and morphology

    International Nuclear Information System (INIS)

    Li, Xiangru; Hu, Hao; Huang, Sheng; Yu, Gaige; Gao, Lin; Liu, Haowen; Yu, Ying

    2013-01-01

    Graphical abstract: - Highlights: • Nano-sized Li 4 Ti 5 O 12 has been prepared through solid state reaction by using axiolitic TiO 2 as precursor. • The prepared nano-sized Li 4 Ti 5 O 12 anode material shows excellent electrochemical performance. • The utilization of precursor with special morphology and size is one of the useful ways to prepare more active electrode materials. - Abstract: Spinel nano-sized Li 4 Ti 5 O 12 anode material of secondary lithium-ion battery has been successfully prepared by solid state reaction using axiolitic TiO 2 assembled by 10–20 nm nanoparticles and Li 2 CO 3 as precursors. The synthesis condition, grain size effect and corresponding electrochemical performance of the special Li 4 Ti 5 O 12 have been studied in comparison with those of the normal Li 4 Ti 5 O 12 originated from commercial TiO 2 . We also propose the mechanism that using the nano-scaled TiO 2 with special structure and unexcess Li 2 CO 3 as precursors can synthesize pure phase nano-sized Li 4 Ti 5 O 12 at 800 °C through solid state reaction. The prepared nano-sized Li 4 Ti 5 O 12 anode material for Li-ion batteries shows excellent capacity performance with rate capacity of 174.2, 164.0, 157.4, 146.4 and 129.6 mA h g −1 at 0.5, 1, 2, 5 and 10 C, respectively, and capacity retention of 95.1% after 100 cycles at 1 C. In addition, the specific capacity fade for the cell with the different Li 4 Ti 5 O 12 active materials resulted from the increase of internal resistance after 100 cycles is compared

  20. 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.

  1. Sintering behavior of LZSA glass-ceramics

    Directory of Open Access Journals (Sweden)

    Oscar Rubem Klegues Montedo

    2009-06-01

    Full Text Available The LZSA glass-ceramic system (Li2O-ZrO2-SiO2-Al2O 3 shows interesting properties, such as good chemical resistance, low thermal expansion, high abrasion resistance, and a low dielectric constant. However, in order to obtain a high performance material for specific applications, the sintering behavior must be better understood so that the porosity may be reduced and other properties improved. In this context, a sintering investigation for a specific LZSA glass-ceramic system composition was carried out. A 18.8Li2O-8.3ZrO2-64.2SiO2-8.7Al 2O3 glass was prepared by melting the solids, quenching the melt in water, and grinding the resulting solid in order to obtain a powder (3.68 μm average particle diameter. Subsequently, the glass powder was characterized (chemical analysis and determination of thermal properties and the sintering behavior was investigated using optical non-contact dilatometry measurements. The results showed that the crystallization process strongly reduced the sintering in the temperature interval from 785 to 940 °C, and a maximum thermal shrinkage of 15.4% was obtained with operating conditions of 1020 °C and 180 minutes.

  2. CoO-doped MgO-Al2O3-SiO2-colored transparent glass-ceramics with high crystallinity

    Science.gov (United States)

    Tang, Wufu; Zhang, Qian; Luo, Zhiwei; Yu, Jingbo; Gao, Xianglong; Li, Yunxing; Lu, Anxian

    2018-02-01

    To obtain CoO-doped MgO-Al2O3-SiO2 (MAS)-colored transparent glass-ceramics with high crystallinity, the glass with the composition 21MgO-21Al2O3-54SiO2-4B2O3-0.2CoO (in mol %) was prepared by conventional melt quenching technique and subsequently thermal treated at several temperatures. The crystallization behavior of the glass, the precipitated crystalline phases and crystallinity were analyzed by X-ray diffraction (XRD). The microstructure of the glass-ceramics was characterized by field emission scanning electron microscopy (FSEM). The transmittance of glass-ceramic was measured by UV spectrophotometer. The results show that a large amount of α-cordierite (indianite) with nano-size was precipitated from the glass matrix after treatment at 1020 °C for 3 h. The crystallinity of the transparent glass-ceramic reached up to 97%. Meanwhile, the transmittance of the glass-ceramic was 74% at 400 nm with a complex absorption band from 450 nm to 700 nm. In addition, this colored transparent glass-ceramic possessed lower density (2.469 g/cm3), lower thermal expansion coefficient (1.822 × 10-6 /℃), higher Vickers hardness (9.1 GPa) and higher bending strength (198 MPa) than parent glass.

  3. Synthesis of some (eta-arene)dihydridorhenium cations and their reactions with LiAlH/sub 4/ and LiAlD/sub 4/

    Energy Technology Data Exchange (ETDEWEB)

    Baudrey, D.; Boydell, P.; Ephritikhine, M.

    1986-03-01

    A series of cations (Re(eta-arene)H/sub 2/(PPh/sub 3/)/sub 2/)/sup +/ (arene benzene, toluene, p-xylene, or mesitylene) was prepared from the corresponding neutral dihydridocyclohexadienyl complexes by treatment with CPh/sub 3/BF/sub 4/. These cations reacted with LiAlH/sub 4/ and LiAlD/sub 4/ to form dihydridocyclohexadienyl complexes. The unusual selectivity of the hydride attack is explained by steric interactions between the ring methyl groups and the bulky phosphine ligands. The initial product of the reaction of the eta-mesitylene cation with LiAlD/sub 4/ allows the isomerisation mechanism for the cyclohexadienyl complexes to be clarified.

  4. Synthesis of lithium silicates generators of tritium by a modified method of combustion

    International Nuclear Information System (INIS)

    Cruz G, D.

    2003-01-01

    The ceramics of lithium have been proposed as generating materials of tritium through the following reaction: 6 Li + 1 n → 4 He + 3 H . In previous works carried out by Pfeiffer and collaborators, the lithium silicates generators of tritium were prepared using the following methods: reactions of solid state, precipitation and sol-gel synthesis. Although those methods have advantages, it is required of heating at high temperatures (900 C during four hours) to be able to obtain the crystalline compounds. Those products found in these works were diverse crystallization forms of the lithium silicates and of SiO 2 , such as, Li 2 SiO 3 , Li 2 Si 2 0 5 , Li 4 SiO 4 , and quartz (SiO 2 ). The combustion method uses exothermic reactions to take place ceramic compounds. The precursor solutions are mixtures of the nitrate of metal oxidizer and the fuels (urea, glycine, carbohydrazide). However the reported method in the literature, it is not useful to prepare lithium silicates, for what was modified using non oxidizers compounds. The lithium hydroxide (LiOH) and the silicic acid (H 2 SiO 3 ) they were the compounds non oxidizers used, and the urea (CH 4 N 2 O) it was the one fuel. They were carried out two series of experiments; inside the series 1 of experiments are varied the molar ratio of lithium hydroxide and urea (LiOH : H 2 SiO 3 = 1, 2 and 3, LiOH : CH 4 N 2 O = 1, 2, 3, 4 and 5) and the prepared mixtures were taken to one muffle previously preheated to a temperature of 450 C during 5 minutes. In the series 2 of experiments was studied the effect of the temperature and of the washed with distilled water in the prepared samples with the following molar ratios: LiOH : H 2 SiO 3 : CH 4 N 2 O = 1:1:3, 2:1:3, 3:1:3 and 3:1:6, those which were heated to temperatures from 450 C up to 750 C and were washed. The obtained samples were characterized by X-ray diffraction (XRD), Infrared spectroscopy (I S), semiquantitative elemental analysis (EDS) and Thermal gravimetric

  5. Composition and crystallization kinetics of R2O-Al2O3-SiO2 glass-ceramics

    International Nuclear Information System (INIS)

    Xiong, Dehua; Cheng, Jinshu; Li, Hong

    2010-01-01

    The crystallization behavior and microstructure of R 2 O-Al 2 O 3 -SiO 2 (R means K, Na and Li) glass were investigated by means of differential scanning calorimeter (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystallization kinetic parameters including the crystallization apparent activation energy (E a ), the Avrami parameter (n), glass transition temperature (T g ) and the activity energy of glass transition (E t ) were also measured with different methods. The results have shown that: the DSC traces of composition A parent glass have two different precipitation crystallization peaks corresponding to E a1 (A) = 151.4 kJ/mol (Li 2 SiO 3 ) and E a2 (A) = 623.1 kJ/mol (Li 2 Si 2 O 5 ), the average value of n = 1.70 (Li 2 Si 2 O 5 ) for the surface crystallization and E t (A) = 202.8 kJ/mol. And E a (B) = 50.7 kJ/mol (Li 2 SiO 3 ), the average value of n = 3.89 (Li 2 SiO 3 ) for the bulk crystallization and E t (B) = 220.4 kJ/mol for the composition B parent glass. Because of the content of R 2 O is bigger than composition A, composition B parent glass has a lower E a , T g and a larger n, E t .

  6. Non-isothermal crystallization kinetics and phase transformation of Bi2O3-SiO2 glass-ceramics

    Directory of Open Access Journals (Sweden)

    Guo H.W.

    2011-01-01

    Full Text Available The Bi2O3-SiO2 (BS glass-ceramics were prepared by melt-quench technique, and the crystallization kinetics and phase transformation behavior were investigated in accordance with Kissinger and Johson-Mehl-Avrami equation, DSC, XRD and SEM. The results show that in the heat treatment process (or termed as re-crystallizing process Bi2SiO5 and Bi4Si3O12 crystals were found consequently. Respectively, the crystallization activation energies of the two crystals are Ep1=14.8kJ/mol and Ep2=34.1kJ/mol. And the average crystallization index of n1=1.73 and n2=1.38 suggested volume nucleation, one-dimensional growth and surface nucleation, one-dimensional growth from surface to the inside respectively. The meta-stable needle-like Bi2SiO5 crystals are easily to be transformed into stable prismatic Bi4Si3O12 crystals. By quenching the melt and hold in 850°C for 1h, the homogenous single Bi4Si3O12 crystals were found in the polycrystalline phase of the BS glassceramics system.

  7. Fabrication of graphene oxide decorated with Fe3O4@SiO2 for immobilization of cellulase

    Science.gov (United States)

    Li, Yue; Wang, Xiang-Yu; Jiang, Xiao-Ping; Ye, Jing-Jing; Zhang, Ye-Wang; Zhang, Xiao-Yun

    2015-01-01

    Fe3O4@SiO2-graphene oxide (GO) composites were successfully fabricated by chemical binding of functional Fe3O4@SiO2 and GO and applied to immobilization of cellulase via covalent attachment. The prepared composites were further characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. Fe3O4 nanoparticles (NPs) were monodisperse spheres with a mean diameter of 17 ± 0.2 nm. The thickness of SiO2 layer was calculated as being 6.5 ± 0.2 nm. The size of Fe3O4@SiO2 NPs was 24 ± 0.3 nm, similar to that of Fe3O4@SiO2-NH2. Fe3O4@SiO2-GO composites were synthesized by linking of Fe3O4@SiO2-NH2 NPs to GO with the catalysis of EDC and NHS. The prepared composites were used for immobilization of cellulase. A high immobilization yield and efficiency of above 90 % were obtained after the optimization. The half-life of immobilized cellulase (722 min) was 3.34-fold higher than that of free enzyme (216 min) at 50 °C. Compared with the free cellulase, the optimal temperature of the immobilized enzyme was not changed; but the optimal pH was shifted from 5.0 to 4.0, and the thermal stability was enhanced. The immobilized cellulase could be easily separated and reused under magnetic field. These results strongly indicate that the cellulase immobilized onto the Fe3O4@SiO2-GO composite has potential applications in the production of bioethanol.

  8. Morphology and conductivity study of solid electrolyte Li{sub 3}PO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Prayogi, Lugas Dwi, E-mail: ldprayodi@gmail.com; Faisal, Muhamad [Engineering Physics, Sepuluh Nopember Institute of Technology ITS Campus, Sukolilo, Surabaya 6011 (Indonesia); Kartini, Evvy, E-mail: kartini@batan.go.id; Honggowiranto, Wagiyo; Supardi [Center for Science and Technology of Advanced Materials, National Nuclear Energy Agency Kawasan Puspiptek Serpong, Tangerang Selatan15314, Banten (Indonesia)

    2016-02-08

    The comparison between two different methods of synthesize of solid electrolyte Li{sub 3}PO{sub 4} as precursor material for developing lithium ion battery, has been performed. The first method is to synthesize Li{sub 3}PO{sub 4} prepared by wet chemical reaction from LiOH and H{sub 3}PO{sub 4} which provide facile, abundant available resource, low cost, and low toxicity. The second method is solid state reaction prepared by Li{sub 2}CO{sub 3} and NH{sub 4}H{sub 2}PO{sub 4.} In addition, the possible morphology identification of comparison between two different methods will also be discussed. The composition, morphology, and additional identification phase and another compound of Li{sub 3}PO{sub 4} powder products from two different reaction are characterized by SEM, EDS, and EIS. The Li{sub 3}PO{sub 4} powder produced from wet reaction and solid state reaction have an average diameter of 0.834 – 7.81 µm and 2.15 – 17.3 µm, respectively. The density of Li{sub 3}PO{sub 4} prepared by wet chemical reaction is 2.238 gr/cm{sup 3}, little bit lower than the sample prepared by solid state reaction which density is 2.3560 gr/cm{sup 3}. The EIS measurement result shows that the conductivity of Li{sub 3}PO{sub 4} is 1.7 x 10{sup −9} S.cm{sup −1} for wet chemical reaction and 1.8 x 10{sup −10} S.cm{sup −1} for solid state reaction. The conductivity of Li{sub 3}PO{sub 4} is not quite different between those two samples even though they were prepared by different method of synthesize.

  9. Effects of cobalt doping on structural, morphological, and optical properties of Zn2SiO4 nanophosphors prepared by sol-gel method

    Directory of Open Access Journals (Sweden)

    Norhafizah Mohd Rasdi

    Full Text Available In this paper, undoped and cobalt (II (3, and 5 mol % doped zinc silicate nanophosphors prepared by a sol-gel method which were heated at 1000 °C were studied in detail. From the XRD result, undoped and Co2+ doped zinc silicate sample yields α- and β-Zn2SiO4. This also shows that α-Zn2SiO4 acts as the primary phase in the crystal structure of the sample. For FESEM, the grain size decreases as the dopant increases where undoped sample indicates average grain size of 181 nm while 3 and 5 mol % exhibits containing ones 136.89 nm and 176.22 nm respectively. With FTIR transmission a major peak at range of 1100 cm−1, 880, 550, and 350 assigning as Si-O-Si asymmetric stretching, SiO4 asymmetric stretching, ZnO4 symmetric stretching, and Si-O asymmetric deformation vibration were observed respectively. The absorption band of doped Zn2SiO4 exhibited a higher absorbance intensity in the UV region compared to undoped Zn2SiO4. Besides, all the samples depict that the sample was having a red shift in which the band shifted to the longer wavelength. The energy band gap value of undoped sample shows 3.07 eV and when Co2+ dopant (3 and 5 mol % was introduced, the energy band gap started to decrease (2.46 and 2.42 eV respectively. PL emission presents two peaks at blue emissions (420 and 480 nm and a green emission (525 nm. The result present that Co2+:Zn2SiO4 is potentially good to use as blue and green phosphors for luminescent optical material. Keywords: Cobalt (II doped zinc silicate, Transition metal, Sol-gel method, Nanophosphors, Photoluminescence

  10. Nanoconfined LiBH4 as a Fast Lithium Ion Conductor

    DEFF Research Database (Denmark)

    Blanchard, Didier; Nale, Angeloclaudio; Sveinbjörnsson, Dadi Þorsteinn

    2015-01-01

    is associated with a fraction of the confined borohydride that shows no phase transition, and most likely located close to the interface with the SiO2 pore walls. These results point to a new strategy to design low-temperature ion conducting solids for application in all solid-state lithium ion batteries, which......Designing new functional materials is crucial for the development of efficient energy storage and conversion devices such as all solid-state batteries. LiBH 4 is a promising solid electrolyte for Li-ion batteries. It displays high lithium mobility, although only above 110 °C at which a transition...

  11. Proceedings of the sixth international workshop on ceramic breeder blanket interactions

    International Nuclear Information System (INIS)

    Noda, Kenji

    1998-03-01

    This report is the Proceedings of ''the Sixth International Workshop on Ceramic Breeder Blanket Interactions'' which was held as a workshop on ceramic breeders under Annex II of IEA Implementing Agreement on a Programme of Research and Development on Fusion Materials, and Japan-US Workshop 97FT4-01. This workshop was held in Mito city, Japan on October 22-24, 1997. About forty experts from EU, Japan, USA, and Chile attended the workshop. The scope of the workshop included the following: 1) fabrication and characterization of ceramic breeders, 2) properties data for ceramic breeders, 3) tritium release characteristics, 4) modeling of tritium behavior, 5) irradiation effects on performance behavior, 6) blanket design and R and D requirements, 7) hydrogen behavior in materials, and 8) blanket system technology and structural materials. In the workshop, information exchange was performed for fabrication technology of ceramic breeder pebbles in EU and Japan, data of various properties of Li 2 TiO 3 , tritium release behavior of Li 2 TiO 3 and Li 2 ZrO 3 including tritium diffusion, modeling of tritium release from Li 2 ZrO 3 in ITER condition, helium release behavior from Li 2 O, results of tritium release irradiation tests of Li 4 SiO 4 pebbles in EXOTIC-7, R and D issues for ceramic breeders for ITER and DEMO blankets, etc. The 23 of the papers are indexed individually. (J.P.N.)

  12. Co-hydrothermal synthesis of LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C nano-hybrid cathode material with enhanced electrochemical performance for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhang, Jun; Luo, Shaohua; Chang, Longjiao; Hao, Aimin; Wang, Zhiyuan; Liu, Yanguo; Xu, Qian; Wang, Qing; Zhang, Yahui

    2017-01-01

    Highlights: • A co-hydrothermal approach to synthesize LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C composite material in water/PEG system is present. • The Mn_1_-_xMg_xPO_4 precursor is prepared by precipitation reaction. • Co-modified with Mg"2"+ doping and LiAlO_2 compositing strategies play an important role in improving the electronic conductivity and facilitating the diffusion of lithium ion. • LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C composite material exhibits a high specific discharge capacity of 151.8 mAh/g at 0.05C. - Abstract: LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C is synthesized by a co-hydrothermal method in water/PEG system using Li_2CO_3, AAO and Mn_1_-_xMg_xPO_4 as raw material. The electronic structure and micromorphology of multi-component compound LiMn_1_-_xMg_xPO_4/C (x = 0, 1/24, 1/12, 1/6) and nano-hybrid LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C cathode materials are studied by first-principles calculation and experimental research including XRD, SEM, TEM. The calculated band gap of LiMn_2_3_/_2_4Mg_1_/_2_4PO_4/C is 2.296 eV, which is lower than other percentages Mg"2"+ doping samples. Electrochemical tests exhibit LiMn_2_3_/_2_4Mg_1_/_2_4PO_4/C has better cycling performance and rate capability than other contents Mg"2"+ doping samples with the discharge capacity of 143.5 mAh/g, 141.5 mAh/g, 139.2 mAh/g and 136.3 mAh/g at 0.05C, 0.1C, 0.5C and 1C in order. After compositing and preparation of LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C composite material by co-hydrothermal route, the initial discharge capacity reaches up to 151.8 mAh/g, which suggests that co-modified with Mg"2"+ doping and LiAlO_2 compositing material can improve the electronic conductivity of LiMnPO_4/C by facilitating the lithium ion diffusion rate in the interior of the materials.

  13. In-situ ionic conductivity measurement of lithium ceramics under high energy heavy ion irradiation

    International Nuclear Information System (INIS)

    Nakazawa, Tetsuya; Noda, Kenji; Ishii, Yoshinobu; Ohno, Hideo; Watanabe, Hitoshi; Matsui, Hisayuki.

    1992-01-01

    To obtain fundamental information regarding the radiation damage in some lithium ceramics, e.g. Li 2 O, Li 4 SiO 4 etc., candidate of breeder materials exposed to severe irradiation environment, an in-situ experiment technique for the ionic conductivity measurement, which allows the specimen temperature control and the beam current monitoring, have been developed. This paper describes the features of an apparatus to measure in situ the ionic conductivity under the irradiation environment and presents some results of ionic conductivity measured for typical ceramic breeders using this apparatus. (J.P.N.)

  14. Density functional theory study of the structural, electronic, lattice dynamical, and thermodynamic properties of Li4SiO4 and its capability for CO2 capture

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yuhua; Parlinski, K.

    2011-01-01

    The structural, electronic, lattice dynamical, optical, thermodynamic, and CO{sub 2} capture properties of monoclinic and triclinic phases of Li{sub 4}SiO{sub 4} are investigated by combining density functional theory with phonon lattice dynamics calculations. We found that these two phases have some similarities in their bulk and thermodynamic properties. The calculated bulk modulus and the cohesive energies of these two phases are close to each other. Although both of them are insulators, the monoclinic phase of Li{sub 4}SiO{sub 4} has a direct band gap of 5.24 eV while the triclinic Li{sub 4}SiO{sub 4} phase has an indirect band gap of 4.98 eV. In both phases of Li{sub 4}SiO{sub 4}, the s orbital of O mainly contributes to the lower-energy second valence band (VB{sub 2}) and the p orbitals contribute to the fist valence band (VB{sub 1}) and the conduction bands (CBs). The s orbital of Si mainly contributes to the lower portions of the VB1 and VB{sub 2}, and Si p orbitals mainly contribute to the higher portions of the VB{sub 1} and VB{sub 2}. The s and p orbitals of Li contribute to both VBs and to CBs, and Li p orbitals have a higher contribution than the Li s orbital. There is possibly a phonon soft mode existing in triclinic {gamma}-Li{sub 4}SiO{sub 4}; in the monoclinic Li{sub 4}SiO{sub 4}, there are three phonon soft modes, which correspond to the one type of Li disordered over a few sites. Their LO-TO splitting indicates that both phases of Li{sub 4}SiO{sub 4} are polar anisotropic materials. The calculated infrared absorption spectra for LO and TO modes are different for these two phases of Li{sub 4}SiO{sub 4}. The calculated relationships of the chemical potential versus temperature and CO{sub 2} pressure for reaction of Li{sub 4}SiO{sub 4} with CO{sub 2} shows that Li{sub 4}SiO{sub 4} could be a good candidate for a high-temperature CO{sub 2} sorbent while used for postcombustion capture technology.

  15. Vancomycin-modified Fe3O4@SiO2@Ag microflowers as effective antimicrobial agents

    Directory of Open Access Journals (Sweden)

    Wang C

    2017-04-01

    Full Text Available Chongwen Wang,1,2,* Kehan Zhang,2,* Zhe Zhou,2,* Qingjun Li,2 Liting Shao,2 Rong Zhang Hao,3 Rui Xiao,2 Shengqi Wang1,2 1College of Life Sciences & Bio-Engineering, Beijing University of Technology, 2Beijing Key Laboratory of New Molecular Diagnosis Technologies for Infectious Diseases, Beijing Institute of Radiation Medicine, Beijing, 3Institute for Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, People’s Republic of China *These authors contributed equally to this work Abstract: Nanomaterials combined with antibiotics exhibit synergistic effects and have gained increasing interest as promising antimicrobial agents. In this study, vancomycin-modified magnetic-based silver microflowers (Van/Fe3O4@SiO2@Ag microflowers were rationally designed and prepared to achieve strong bactericidal ability, a wide antimicrobial spectrum, and good recyclability. High-performance Fe3O4@SiO2@Ag microflowers served as a multifunction-supporting matrix and exhibited sufficient magnetic response property due to their 200 nm Fe3O4 core. The microflowers also possessed a highly branched flower-like Ag shell that provided a large surface area for effective Ag ion release and bacterial contact. The modified-vancomycin layer was effectively bound to the cell wall of bacteria to increase the permeability of the cell membrane and facilitate the entry of the Ag ions into the bacterium, resulting in cell death. As such, the fabricated Van/Fe3O4@SiO2@Ag microflowers were predicted to be an effective and environment-friendly antibacterial agent. This hypothesis was verified through sterilization of Gram-negative Escherichia coli and Gram-positive methicillin-resistant Staphylococcus aureus, with minimum inhibitory concentrations of 10 and 20 µg mL-1, respectively. The microflowers also showed enhanced effect compared with bare Fe3O4@SiO2@Ag microflowers and free-form vancomycin, confirming the synergistic effects of the combination of the

  16. La{sub 2-x}Sr{sub x}NiO{sub 4+{delta}} ceramic powders prepared by combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Colomer, M.T.; Chinarro, E.; Jurado, J.R. [Consejo Nacional de Investigaciones Cientificas, Madrid (Spain). Ist. de Ceramica y Vidrio

    2002-07-01

    Combustion synthesis provides an attractive method of producing ceramic powders because of its low cost, process simplicity and fastness. Materials based on La{sub 2}NiO{sub 4+{delta}} can be successfully prepared by combustion synthesis. La{sub 2-x}Sr{sub x}NiO{sub 4+{delta}} (x = 0, 0.1) accommodates oxygen excess by oxygen interstitials rather than by the more usual cation vacancies. A high concentration of oxygen interstitials offers the possibility of rapid oxygen transport through the ceramic material and thus provide a new type of mixed ionic-electronic conductor. The fast oxide ion diffusion combined with its thermal stability indicate that these materials would be good candidates for use in ceramic oxygen generators (COGs) and intermediate temperature solid oxide fuel cells (IT-SOFCs). The present work discusses a combustion synthesis technique to prepare La{sub 2-x}Sr{sub x}NiO{sub 4+{delta}} (x = 0, 0.1) powders using the corresponding metal nitrates-urea mixtures, at low temperature and short reaction times. The as-prepared combustion powders were characterized by XRD, DTA-TG, SEM/TEM-EDX and BET. La{sub 2-x}Sr{sub x}NiO{sub 4} (x = 0, 0.1) powders with a good compositional control and homogeneity are attained. The as-prepared powders obtained at 300 C (ignition temperature) showed much higher specific surface area than powders obtained via alternative routes and contained La{sub 2-x}Sr{sub x}NiO{sub 4+{delta}}, as the major phase present, together with La{sub 2}O{sub 3} and a small amount of NiO. La{sub 2-x}Sr{sub x}NiO{sub 4+{delta}} single phase is achieved, respectively at 950 C for x =0.1 and at 975 C for x = 0. (orig.)

  17. On the observation of a huge lattice contraction and crystal habit modifications in LiMn2O4 prepared by a fuel assisted solution combustion

    International Nuclear Information System (INIS)

    Ragavendran, K.; Sherwood, D.; Vasudevan, D.; Emmanuel, Bosco

    2009-01-01

    Two batches of poly-crystalline lithium manganate were prepared by a fuel assisted solution combustion method. LiMn 2 O 4 (S) was prepared using starch as the fuel and LiMn 2 O 4 (P) was prepared using poly vinyl alcohol (PVA) as the fuel. XRD studies indicated a significant and consistent shift in the 2θ values of all the hkl peaks to higher values in LiMn 2 O 4 (P) compared to LiMn 2 O 4 (S) indicating a lattice contraction in the former. TG/DTA studies indicated a higher formation temperature (∼25 deg. C higher) for LiMn 2 O 4 (P). The higher formation temperature most likely promotes the oxidation of some Mn 3+ to Mn 4+ with a lower ionic radius causing a lattice contraction. This hypothesis is confirmed through XPS studies which indicated the presence of a higher fraction of Mn 4+ in LiMn 2 O 4 (P) than that present in LiMn 2 O 4 (S). A crystal shape algorithm was used to generate the crystal habits of lithium manganate from their XRD data leading to an understanding on the exposed hkl planes in these materials. From the atomic arrangement on the exposed hkl planes it is predicted that LiMn 2 O 4 (P) would be less prone to manganese dissolution and hence would possess a higher cycle life when compared to LiMn 2 O 4 (S).

  18. On the observation of a huge lattice contraction and crystal habit modifications in LiMn 2O 4 prepared by a fuel assisted solution combustion

    Science.gov (United States)

    Ragavendran, K.; Sherwood, D.; Vasudevan, D.; Emmanuel, Bosco

    2009-08-01

    Two batches of poly-crystalline lithium manganate were prepared by a fuel assisted solution combustion method. LiMn 2O 4(S) was prepared using starch as the fuel and LiMn 2O 4(P) was prepared using poly vinyl alcohol (PVA) as the fuel. XRD studies indicated a significant and consistent shift in the 2 θ values of all the hkl peaks to higher values in LiMn 2O 4(P) compared to LiMn 2O 4(S) indicating a lattice contraction in the former. TG/DTA studies indicated a higher formation temperature (∼25 °C higher) for LiMn 2O 4(P). The higher formation temperature most likely promotes the oxidation of some Mn 3+ to Mn 4+ with a lower ionic radius causing a lattice contraction. This hypothesis is confirmed through XPS studies which indicated the presence of a higher fraction of Mn 4+ in LiMn 2O 4(P) than that present in LiMn 2O 4(S). A crystal shape algorithm was used to generate the crystal habits of lithium manganate from their XRD data leading to an understanding on the exposed hkl planes in these materials. From the atomic arrangement on the exposed hkl planes it is predicted that LiMn 2O 4(P) would be less prone to manganese dissolution and hence would possess a higher cycle life when compared to LiMn 2O 4(S).

  19. Solid state opto-impedance of LiNiVO4 and LiMn2O4

    International Nuclear Information System (INIS)

    Kalyani, P; Sivasubramanian, S; Prabhu, S Naveen; Ragavendran, K; Kalaiselvi, N; Ranganathan, N G; Madhu, S; SundaraRaj, A; Manoharan, S P; Jagannathan, R

    2005-01-01

    Spinel type LiMn 2 O 4 and inverse spinel LiNiVO 4 systems serve as standard cathode materials or potential cathode systems for application in high energy density lithium-ion batteries. Upon photo-excitation using UV radiation of energy ∼5 eV, the LiNiVO 4 system shows significant modification in the solid state impedance pattern while the LiMn 2 O 4 system does not. This study has revealed a significant difference in the opto-impedance pattern for LiNiVO 4 with respect to LiMn 2 O 4 , which may be due to the different electronic processes involved. An attempt has been made to study this behaviour from the solid-state viewpoint

  20. Fabrication of graphene oxide decorated with Fe3O4@SiO2 for immobilization of cellulase

    International Nuclear Information System (INIS)

    Li, Yue; Wang, Xiang-Yu; Jiang, Xiao-Ping; Ye, Jing-Jing; Zhang, Ye-Wang; Zhang, Xiao-Yun

    2015-01-01

    Fe 3 O 4 @SiO 2 –graphene oxide (GO) composites were successfully fabricated by chemical binding of functional Fe 3 O 4 @SiO 2 and GO and applied to immobilization of cellulase via covalent attachment. The prepared composites were further characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. Fe 3 O 4 nanoparticles (NPs) were monodisperse spheres with a mean diameter of 17 ± 0.2 nm. The thickness of SiO 2 layer was calculated as being 6.5 ± 0.2 nm. The size of Fe 3 O 4 @SiO 2 NPs was 24 ± 0.3 nm, similar to that of Fe 3 O 4 @SiO 2 –NH 2 . Fe 3 O 4 @SiO 2 –GO composites were synthesized by linking of Fe 3 O 4 @SiO 2 –NH 2 NPs to GO with the catalysis of EDC and NHS. The prepared composites were used for immobilization of cellulase. A high immobilization yield and efficiency of above 90 % were obtained after the optimization. The half-life of immobilized cellulase (722 min) was 3.34-fold higher than that of free enzyme (216 min) at 50 °C. Compared with the free cellulase, the optimal temperature of the immobilized enzyme was not changed; but the optimal pH was shifted from 5.0 to 4.0, and the thermal stability was enhanced. The immobilized cellulase could be easily separated and reused under magnetic field. These results strongly indicate that the cellulase immobilized onto the Fe 3 O 4 @SiO 2 –GO composite has potential applications in the production of bioethanol

  1. Solution based synthesis of mixed-phase materials in the Li{sub 2}TiO{sub 3}–Li{sub 4}SiO{sub 4} system

    Energy Technology Data Exchange (ETDEWEB)

    Hanaor, Dorian A.H., E-mail: dorian.hanaor@sydney.edu.au [School of Civil Engineering, University of Sydney, NSW 2006 (Australia); Kolb, Matthias H.H. [Institute for Applied Materials, Karlsruhe Institute of Technology, 76021 (Germany); Gan, Yixiang [School of Civil Engineering, University of Sydney, NSW 2006 (Australia); Kamlah, Marc; Knitter, Regina [Institute for Applied Materials, Karlsruhe Institute of Technology, 76021 (Germany)

    2015-01-15

    Highlights: • Investigation of phase stability in the quasi-binary Li{sub 2}TiO{sub 3}–Li{sub 4}SiO{sub 4} system. • Sol-based syntheses of mixed phase materials from organometallic precursors. • LiCl based synthesis results in greater lithium deficiency than LiOH synthesis. • The Li{sub 2}TiO{sub 3}–Li{sub 4}SiO{sub 4} quasi binary system appears to exhibit monotectic behaviour. • Mixed phase materials show liquid formation from melting of silicate material at 1100 °C. - Abstract: As candidate tritium breeder materials for use in the ITER helium cooled pebble bed, ceramic multiphasic compounds lying in the region of the quasi-binary lithium metatitanate–lithium orthosilicate system may exhibit mechanical and physical advantages relative to single phase materials. Here we present an organometallic solution-based synthesis procedure for the low-temperature fabrication of compounds in the Li{sub 2}TiO{sub 3}–Li{sub 4}SiO{sub 4} region and investigate phase stability and transformations through temperature varied X-ray diffraction and scanning calorimetry. Results demonstrate that the metatitanate and metasilicate phases Li{sub 2}TiO{sub 3} and Li{sub 2}SiO{sub 3} readily crystallise in nanocrystalline form at temperatures below 180 °C. Lithium deficiency in the region of 5% results from Li sublimation from Li{sub 4}SiO{sub 4} and/or from excess Li incorporation in the metatitanate phase and brings about a stoichiometry shift, with product compounds exhibiting mixed lithium orthosilicate/metasilicate content towards the Si rich region and predominantly Li{sub 2}TiO{sub 3} content towards the Ti rich region. Above 1150 °C the transformation of monoclinic to cubic γ-Li{sub 2}TiO{sub 3} disordered solid-solution occurs while the melting of silicate phases indicates a likely monotectic type system with a solidus line in the region 1050–1100 °C. Synthesis procedures involving a lithium chloride precursor are not likely to be a viable option for

  2. Preparation of lithium indium oxide via a rheological phase route and its electrochemical characteristics in LiOH and Li{sub 2}SO{sub 4} solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guo-Qing [Department of Chemistry and Environment Science of Yangtze Normal University, 408100 Chongqing (China); College of Chemistry and Chemical Engineering of Chongqing University, Chongqing 400030 (China); Zhang, Sheng-Tao [College of Chemistry and Chemical Engineering of Chongqing University, Chongqing 400030 (China); Wu, Xing-Fa [Department of Chemistry and Environment Science of Yangtze Normal University, 408100 Chongqing (China)

    2010-01-15

    Submicrometer-sized lithium indium oxide (LiInO{sub 2}) powder via a rheological phase method using trilithium citrate tetra hydrate (C{sub 6}H{sub 5}Li{sub 3}O{sub 7} . 4H{sub 2}O) and indium oxide (In{sub 2}O{sub 3}) has been prepared in this work for the first time. The optimal pyrolyzing temperature range to prepare crystalline LiInO{sub 2} is between 650 and 900 C, which was confirmed by thermal gravimetric and differential thermogravimetric analysis of the precursor and X-ray diffraction analysis. The pure phase LiInO{sub 2} sample obtained has a uniform particle morphology and submicrosize, which was observed by scanning electron microscopy. The electrochemical studies show that a new pair of cathodic and anodic peaks at 0.23 and 0.38 V (vs. saturated calomel electrode) was obviously observed from the cyclic voltammetry curve of LiInO{sub 2} in 1 M LiOH solution, indicating a battery characteristic of the material in this electrolyte. While in 1 M Li{sub 2}SO{sub 4} solution, the sample presents a supercapacitive characteristic within the same potential range. The reasons for different electrochemical behaviors in these two electrolytes can be attributed to the fact that the reaction of lithium ion insertion/extraction into/out of a LiInO{sub 2} electrode takes place in the bulk material in LiOH electrolyte solution, whereas it takes place on the electrode/electrolyte interface for Li{sub 2}SO{sub 4} electrolyte case. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  3. On the preparation of electron sensor using LiRbSO4 samples

    Science.gov (United States)

    El-Muraikhi, M.; Kassem, M. E.; Gaafar, M.; Abdel Gawad, M. M. H.; Ragab, I. M.

    2005-01-01

    The dielectric spectroscopy of metal-metal sulfate LiRbSO4 samples are described with particular emphasis on sensor performance to be used in the field of radiation. The obtained results as the effect of different electron energy beams at fixed dose, 0.5 Gy, showed abrupt change of the electrical properties (electrical conductivity, capacitance, and loss tangent). The results can be explained on the basis of radiation-induced defects followed by radiation quenching. The prepared samples can be used in the field of radiation dosimeter.

  4. Controllable synthesis of porous LiFePO4 for tunable electrochemical Li-insertion performance

    International Nuclear Information System (INIS)

    Tian, Xiaohui; Zhou, Yingke; Wu, Guan; Wang, Pengcheng; Chen, Jian

    2017-01-01

    Highlights: • A templated freeze-drying method is developed to prepare the porous LiFePO 4 . • The pore size and porosity can be controlled by adjusting the conditions. • The effects of the porous properties on the Li-insertion performances are studied. • The optimized composite presents excellent specific capacity and rate capability. - Abstract: A templated freeze-drying method is developed to prepare the porous LiFePO 4 materials with the controlled pore size and porosity, by conveniently adjusting the size and content of the template in the precursor solution. The morphology and structure of the porous LiFePO 4 materials are characterized and the relavant electrochemical lithium-insertion performances are systematically studied. It’s found that the porous characteristics play a critical role in the lithium-ion intercalation processes and significantly affect the power capability of LiFePO 4 . The optimized porous LiFePO 4 material presents remarkable specific capacity (167 mAh g −1 at 0.1 C), rate capability (151 mAh g −1 at 1 C and 110 mAh g −1 at 10 C) and cycling stability (99.3% retention after 300 cycles at 1 C). These findings demonstrate that the electrochemical performance of the electrode material can be purposely tuned and remarkably improved by the rational design and introduction of the suitable pores, which open up new strategies for the synthesis of advanced porous materials for the lithium-ion power battery applications.

  5. Microwave dielectric properties of low-fired Li_2TiO_3–MgO ceramics for LTCC applications

    International Nuclear Information System (INIS)

    Ma, Jian-Li; Fu, Zhi-Fen; Liu, Peng; Wang, Bing; Li, Yang

    2016-01-01

    Graphical abstract: This figure gives the Q × f and τ_f of Li_2TiO_3–MgO ceramics sintered at various temperatures with different LiF contents. Addition of LiF enhanced the sinterability and optimized the microwave dielectric properties of Li_2TiO_3–MgO ceramics. The excellent microwave dielectric properties (ε_r = 15.8, Q × f = 64,500 GHz, and τ_f = −0.2 ppm/°C) of Li_2TiO_3–MgO ceramics sintered at 850 °C illustrated that LiF is a simple effective sintering aids for Li_2TiO_3–MgO ceramics. Such sample was compatible with Ag electrodes, suitable for the low-temperature co-fired ceramics (LTCC) applications. - Highlights: • Temperature stability of Li_2TiO_3 ceramics were improved by doping MgO. • The low-fired Li_2TiO_3–MgO ceramics are fabricated. • LiF liquid phase reduced sintering temperature of Li_2TiO_3–MgO ceramics to 850 °C. • The low-fired Li_2TiO_3–MgO ceramics possess well microwave dielectric properties. • The sample was compatible with Ag electrodes and suitable for LTCC applications. - Abstract: We fabricated the low-fired Li_2TiO_3–MgO ceramics doped with LiF by a conventional solid-state route, and investigated systematically their sintering characteristics, microstructures and microwave dielectric properties. The results showed that temperature stability of Li_2TiO_3 ceramics were improved by doping MgO. Well microwave dielectric properties for Li_2TiO_3–13 wt%MgO (LTM) ceramics with ε_r = 16.4, Q × f = 87,500 GHz, and τ_f = −1.2 ppm/°C were obtained at 1325 °C. Furthermore, addition of LiF enhanced the sinterability and optimized the microwave dielectric properties of LTM ceramics. A typically sample of LTM-4 wt%LiF ceramics with optimum dielectric properties (ε_r = 15.8, Q × f = 64,500 GHz, and τ_f = −0.2 ppm/°C) were achieved at 850 °C for 4 h. Such sample was compatible with Ag electrodes, suitable for the low-temperature co-fired ceramics (LTCC) applications.

  6. Nanoporous LiMn2O4 spinel prepared at low temperature as cathode material for aqueous supercapacitors

    Science.gov (United States)

    Wang, F. X.; Xiao, S. Y.; Gao, X. W.; Zhu, Y. S.; Zhang, H. P.; Wu, Y. P.; Holze, R.

    2013-11-01

    LiMn2O4 spinel was prepared by a hydrothermal method using α-MnO2 nanotubes as precursor at 180 °C, a temperature much lower than that in previously reported methods. It is nanoporous with a pore size of about 40-50 nm and a BET surface area of 9.76 m2 g-1. It exhibits a high specific capacitance of 189 F g-1 at 0.3 A g-1 as a cathode for an aqueous supercapacitor. Even at 12 A g-1, it still has a capacitance of 166 F g-1. After 1500 cycles, there is no evident capacity fading. The LiMn2O4 cathode can deliver an energy density of 31.9 Wh kg-1 at 3480 W kg-1 and even maintain 19.4 Wh kg-1 at about 5100 W kg-1 based on the mass of LiMn2O4.

  7. Synthesis of flower-like LiMnPO4/C with precipitated NH4MnPO4·H2O as precursor

    International Nuclear Information System (INIS)

    Liu Jiali; Hu Dongge; Huang Tao; Yu Aishui

    2012-01-01

    Highlights: ► Flower-like NH 4 MnPO 4 ·H 2 O is obtained by novel precipitating method. ► It is used as the precursor to synthesize LiMnPO 4 /C. ► Subsequent heat treatment would not destroy the precursor morphology. ► As-prepared LiMnPO 4 /C showed discharge capacity of 85 mAh/g at 0.05 C. - Abstract: Ammonium magnesium phosphate monohydrate (NH 4 MnPO 4 ·H 2 O) precursor was prepared by a novel precipitating process with manganese citrate complexes as intermediate. The morphology of the precursor observed by Scanning Electron Microscope (SEM) was flower-like which was self-assembled by plate-like particles. Further analysis by X-ray diffraction (XRD) revealed that the lattice of the plate crystal was orientated along (0 1 0) plane. By solid-state reaction of the precursor, with lithium acetate and glucose as carbon source, pure olivine structured LiMnPO 4 /C composite was obtained and meanwhile, the original flower-like morphology could be retained.

  8. Magnetic SiO2/Fe3O4 colloidal crystals

    International Nuclear Information System (INIS)

    Huang, C-K; Hou, C-H; Chen, C-C; Tsai, Y-L; Chang, L-M; Wei, H-S; Hsieh, K-H; Chan, C-H

    2008-01-01

    We proposed a novel technique to fabricate colloidal crystals by using monodisperse SiO 2 coated magnetic Fe 3 O 4 (SiO 2 /Fe 3 O 4 ) microspheres. The magnetic SiO 2 /Fe 3 O 4 microspheres with a diameter of 700 nm were synthesized in the basic condition with ferric sulfate, ferrous sulfate, tartaric acid and tetraethyl orthosilicate (TEOS) in the reaction system. Monodisperse SiO 2 /Fe 3 O 4 superparamagnetic microspheres have been successfully used to fabricate colloidal crystals under the existing magnetic field

  9. Electrochemical activity of Li{sub 2}FeTiO{sub 4} and Li{sub 2}MnTiO{sub 4} as potential active materials for Li ion batteries: A comparison with Li{sub 2}NiTiO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Kuezma, Mirjana; Dominko, Robert; Bele, Marjan; Jamnik, Janko [National Institute of Chemistry, Ljubljana (Slovenia); Meden, Anton [Faculty of Chemistry and Chemical Technology, University of Ljubljana (Slovenia); Makovec, Darko [Jozef Stefan Institute, Ljubljana (Slovenia); Gaberscek, Miran [National Institute of Chemistry, Ljubljana (Slovenia); Faculty of Chemistry and Chemical Technology, University of Ljubljana (Slovenia)

    2009-04-01

    We demonstrate, for the first time, a considerable electrochemical activity of two members of lithium transition element titanates: Li{sub 2}FeTiO{sub 4} and Li{sub 2}MnTiO{sub 4}. Both materials consist of 10-20 nm particles embedded in a conductive carbon coating. We show that not the coating but the small particle size is decisive for materials' activity. Li{sub 2}FeTiO{sub 4} shows a stable reversible capacity of up to 123 mA hg{sup -1} at C/20 and 60 C which is 83% of the theoretical value for exchange of 1 electron (148 mA hg{sup -1}). Li{sub 2}MnTiO{sub 4} could only be prepared in a nanosized form that contained about 30% of impurities. The capacity of the whole material (including impurities) is comparable to that of Li{sub 2}FeTiO{sub 4} but the cycling stability is much poorer. In contrast to the Fe and Mn analogues, the third member of the titanate family, Li{sub 2}NiTiO{sub 4}, shows a good electrochemistry even when the particle size is much larger (about 100 nm). During initial cycles at C/10 and 60 C, exchange of more than 1 electron per compound formula has been observed. The cycling stability at high temperatures, however, is poor. (author)

  10. FE3O4@SIO2-OSO3H NANOCOMPOSITE AS AN EFFICIENT CATALYST FOR THE PREPARATION OF TRICARBOXAMIDES

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Ghasemzadeh

    Full Text Available In this research a highly efficient one-pot preparation of tricarboxamide derivatives via five-component reactions of isocyanides, aldehydes Meldrum's acid and 2equiv. of amines have been developed in the presence of Fe3O4@SiO2-OSO3H nanocomposite. Nano-Fe3O4 encapsulated-silica particles bearing sulfonic acid was readily recovered using an external magnet and could be reused several times without significant loss of reactivity. The catalyst was fully characterized by VSM, FT-IR, SEM, XRD, EDX and TEM analysis.

  11. Characterization of plasticized PMMA–LiBF4 based solid polymer ...

    Indian Academy of Sciences (India)

    Unknown

    Polymer electrolyte films prepared from poly(methyl methacrylate) and LiBF4 with different con- centrations of ... 1. Introduction. Many types of ionically conducting polymers, generally ... 2. Experimental. Thin films of PMMA–LiBF4–DBP in different mole ratios ... remains very close to that of a liquid electrolyte. It is con-.

  12. Nanoconfined NaAlH4 Conversion Electrodes for Li Batteries

    DEFF Research Database (Denmark)

    Huen, Priscilla; Peru, Filippo; Charalambopoulou, Georgia

    2017-01-01

    -Type anode in Li-ion batteries. Here, NaAlH4 nanoconfined in carbon scaffolds as an anode material for Li-ion batteries is reported for the first time. Nanoconfined NaAlH4 was prepared by melt infiltration into mesoporous carbon scaffolds. In the first cycle, the electrochemical reversibility of nanoconfined...

  13. Mg doped Li2FeSiO4/C nanocomposites synthesized by the solvothermal method for lithium ion batteries.

    Science.gov (United States)

    Kumar, Ajay; Jayakumar, O D; Jagannath; Bashiri, Parisa; Nazri, G A; Naik, Vaman M; Naik, Ratna

    2017-10-14

    A series of porous Li 2 Fe 1-x Mg x SiO 4 /C (x = 0, 0.01, 0.02, 0.04) nanocomposites (LFS/C, 1Mg-LFS/C, 2Mg-LFS and 4Mg-LFS/C) have been synthesized via a solvo-thermal method using the Pluronic P123 polymer as an in situ carbon source. Rietveld refinement of the X-ray diffraction data of Li 2 Fe 1-x Mg x SiO 4 /C composites confirms the formation of the monoclinic P2 1 structure of Li 2 FeSiO 4 . The addition of Mg facilitates the growth of impurity-free Li 2 FeSiO 4 with increased crystallinity and particle size. Despite having the same percentage of carbon content (∼15 wt%) in all the samples, the 1Mg-LFS/C nanocomposite delivered the highest initial discharge capacity of 278 mA h g -1 (∼84% of the theoretical capacity) at the C/30 rate and also exhibited the best rate capability and cycle stability (94% retention after 100 charge-discharge cycles at 1C). This is attributed to its large surface area with a narrow pore size distribution and a lower charge transfer resistance with enhanced Li-ion diffusion coefficient compared to other nanocomposites.

  14. Synthesis and Electrochemical Properties of LiFePO4/C for Lithium Ion Batteries.

    Science.gov (United States)

    Gao, Hong; Wang, Jiazhao; Yin, Shengyu; Zheng, Hao; Wang, Shengfu; Feng, Chuanqi; Wang, Shiquan

    2015-03-01

    LiFePO4/C was prepared through a facile rheological phase reaction method by using Fe3(PO4)2, Li3PO4 · 8H2O, and glucose as reactants. The LiFePO4/C samples were characterized by X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The electrochemical properties of the samples were investigated. The results show that the LiFePO4/C samples have single-phase olivine-type structure, and their particles feature a spherical shape. The carbon coating on the particles of LiFePO4 is about 1.8% of the LiFePO4/C by weight. The particle size was distributed from 0.2 to 1 µm. The initial discharge capacity of LiFePO4/C reached 154 mA h/g at 0.1 C. The retained discharge capacity of LiFePO4/C was 152.9 mA h g(-1) after 50 cycles. The LiFePO4/C also showed better cycling performance than that of the bare LiPeO4 at a higher charge/discharge rate (1 C). The LIFePO4/C prepared in this way could be a promising cathode material for lithium ion battery application.

  15. Preparation and characterization of conducting polyaniline-coated LiVPO4F nanocrystals with core-shell structure and its application in lithium-ion batteries

    International Nuclear Information System (INIS)

    Yan, Haiyan; Wu, Xinming; Li, Yongfei

    2015-01-01

    Highlights: • Conducting PANI-coated LiVPO 4 F has been firstly prepared and investigated. • The unique core-shell structure is helpful for the performance of LiVPO 4 F/PANI. • PANI can enhance the electronic conductivity and increase the lithium diffusion coefficient. • LiVPO 4 F/PANI nanocomposite exhibits superior capacity and cycle stability. - Abstract: In this paper, the electrochemical performance of the pure LiVPO 4 F electrode is significantly improved by coating it with the conducting polyaniline via sol-gel method followed by a self-assembly process. X-ray diffraction (XRD) results indicate that the as-prepared sample crystallized in a triclinic LiVPO 4 F phase. Scanning and transmission electron microscopy images show that the particle size of the composite is about hundreds of nanometer and the conducting layer of polyaniline is uniformly coated on the surface of LiVPO 4 F particles. Electrochemical tests reveal that the polyaniline-coated LiVPO 4 F composite exhibits superior capacity and cycle stability, delivering an initial discharge capacity of 149.3 mAh g −1 at 0.1 C in the voltage range of 3.0–4.5 V. Even at high current rates, it can still present discharge capacities of 146.7, 140.1, 131.9 and 121.5 mAh g −1 at 0.2, 1, 2 and 5 C, respectively. The superior electrochemical performance of the electrode could be attributed to the uniform conducting polymer layer, which improves the electronic conductivity and Li-ions diffusion of LiVPO 4 F. Therefore, it can be drawn a conclusion that the remarkable electrochemical performance of the polyaniline-coated LiVPO 4 F makes this 4 V-class electrode a promising alternative for next-generation lithium-ion batteries.

  16. Microstructural changes in NiFe_2O_4 ceramics prepared with powders derived from different fuels in sol-gel auto-combustion technique

    International Nuclear Information System (INIS)

    Chauhan, Lalita; Sreenivas, K.; Bokolia, Renuka

    2016-01-01

    Structural properties of Nickel ferrite (NiFe_2O_4) ceramics prepared from powders derived from sol gel auto-combustion method using different fuels (citric acid, glycine and Dl-alanine) are compared. Changes in the structural properties at different sintering temperatures are investigated. X-ray diffraction (XRD) confirms the formation of single phase material with cubic structure. Ceramics prepared using the different powders obtained from different fuels show that that there are no significant changes in lattice parameters. However increasing sintering temperatures show significant improvement in density and grain size. The DL-alanine fuel is found to be the most effective fuel for producing NIFe_2O_4 powders by the sol-gel auto combustion method and yields highly crystalline powders in the as-burnt stage itself at a low temperature (80 °C). Subsequent use of the powders in ceramic manufacturing produces dense NiFe_2O_4 ceramics with a uniform microstructure and a large grain size.

  17. Microstructural changes in NiFe2O4 ceramics prepared with powders derived from different fuels in sol-gel auto-combustion technique

    Science.gov (United States)

    Chauhan, Lalita; Bokolia, Renuka; Sreenivas, K.

    2016-05-01

    Structural properties of Nickel ferrite (NiFe2O4) ceramics prepared from powders derived from sol gel auto-combustion method using different fuels (citric acid, glycine and Dl-alanine) are compared. Changes in the structural properties at different sintering temperatures are investigated. X-ray diffraction (XRD) confirms the formation of single phase material with cubic structure. Ceramics prepared using the different powders obtained from different fuels show that that there are no significant changes in lattice parameters. However increasing sintering temperatures show significant improvement in density and grain size. The DL-alanine fuel is found to be the most effective fuel for producing NIFe2O4 powders by the sol-gel auto combustion method and yields highly crystalline powders in the as-burnt stage itself at a low temperature (80 °C). Subsequent use of the powders in ceramic manufacturing produces dense NiFe2O4 ceramics with a uniform microstructure and a large grain size.

  18. Rigid'' skeleton dynamics of Li sub 3 In sub 2 (PO sub 4 ) sub 3 superionic conductor

    Energy Technology Data Exchange (ETDEWEB)

    Naganovsky, Y K; Sigaryov, S E [Inst. of Crystallography, Academy of Sciences, Moscow (USSR)

    1992-01-01

    The effect studied is made by the thermal prehistory of the Li{sub 3}In{sub 2}(PO{sub 4}){sub 3} ceramics on their structural and electrophysical characteristics. Annealing at T>1290 K is shown to result in a monoclinic (HT) and at T<1230 K, rhombohedral (LT) modifications of the crystal structure of Li{sub 3}In{sub 2}(PO{sub 4}){sub 3}. At the same temperature the ionic conductivity ({sigma}) of the HT-modification is found to be higher than that of LT-modification. Annealing of LT-ceramics at {proportional to}985 K leads to a decrease of {sigma} by as much as two order of magnitude seems due to Li{sup +}-ions redistribution in the (In{sub 2}P{sub 3}O{sub 12}){sub 3{infinity}}{sup 3-} skeleton cavities. In the 290-650 K temperature range phase transitions both in LT- and HT-Li{sub 3}In{sub 2}(PO{sub 4}){sub 3} are observed. (orig.).

  19. Composition Screening in Blue-Emitting Li4Sr1+xCa0.97-x(SiO4)2:Ce3+ Phosphors for High Quantum Efficiency and Thermally Stable Photoluminescence.

    Science.gov (United States)

    Zhang, Jingchen; Zhang, Jilin; Zhou, Wenli; Ji, Xiaoyu; Ma, Wentao; Qiu, Zhongxian; Yu, Liping; Li, Chengzhi; Xia, Zhiguo; Wang, Zhengliang; Lian, Shixun

    2017-09-13

    Photoluminescence quantum efficiency (QE) and thermal stability are important for phosphors used in phosphor-converted light-emitting diodes (pc-LEDs). Li 4 Sr 1+x Ca 0.97-x (SiO 4 ) 2 :0.03Ce 3+ (-0.7 ≤ x ≤ 1.0) phosphors were designed from the initial model of Li 4 SrCa(SiO 4 ) 2 :Ce 3+ , and their single-phased crystal structures were found to be located in the composition range of -0.4 ≤ x ≤ 0.7. Depending on the substitution of Sr 2+ for Ca 2+ ions, the absolute QE value of blue-emitting composition-optimized Li 4 Sr 1.4 Ca 0.57 (SiO 4 ) 2 :0.03Ce 3+ reaches ∼94%, and the emission intensity at 200 °C remains 95% of that at room temperature. Rietveld refinements and Raman spectral analyses suggest the increase of crystal rigidity, increase of force constant in CeO 6 , and decrease of vibrational frequency by increasing Sr 2+ content, which are responsible for the enhanced quantum efficiency and thermal stability. The present study points to a new strategy for future development of the pc-LEDs phosphors based on local structures correlation via composition screening.

  20. Preparation of Li4Ti5O12 by solution ion-exchange of sodium titanate nanotube and evaluation of electrochemical performance

    International Nuclear Information System (INIS)

    Zhang, Jingwei; Zhang, Fenli; Li, Jiuhe; Cai, Wei; Zhang, Jiwei; Yu, Laigui; Jin, Zhensheng; Zhang, Zhijun

    2013-01-01

    Nano-sized spinel lithium titanate (Li 4 Ti 5 O 12 ) was synthesized using sodium titanate nanotube as precursor via a facile solution ion-exchange method in association with subsequent calcination treatment at relatively low temperature. The influences of precursors, ion-exchange condition, and calcination temperature on the microstructure and electrochemical performance of the products were studied. Results indicate that pure-phase Li 4 Ti 5 O 12 can be harvested from sodium titanate nanotube precursor through an ion-exchanging at room temperature and calcination at 500 °C. The products exhibit a better performance as Li-ion battery anode material than the counterparts prepared from protonic titanate nanotube (H-titanate) precursor. The reason may lie in that sodium titanate nanotube is easier than protonic titanate nanotube to synthesize lithium titanate without TiO 2 impurity, resulting in reduced electron transfer ability and Li-ion transport ability. The capacity of Li 4 Ti 5 O 12 prepared from sodium titanate nanotube is 146 mAh/g at 10 C, and it has only 0.7 % decay after 200 charge/discharge cycles

  1. Light up conversion effects in Erbium doped CaBi4Ti4O15 ceramics

    International Nuclear Information System (INIS)

    Bokolia, Renuka; Sreenivas, K.

    2013-01-01

    In recent years the rare earth doped bismuth layered structured ferroelectric (BLSF) compositions such as CaBi 4 Ti 4 O 15 , SrBi 4 Ti 4 O 15 and BaBi 4 Ti 4 O 15 ceramics have shown interesting light up-conversion emission effects. The observation of such novel effects has generated a lot of scientific interest, and there is a need to further improve their dielectric, piezoelectric and light up-conversion properties. In the present study, Erbium doped CaBi 4 Ti 4 O 15 (CBT), and SrBi 4 Ti 4 O 15 (SBT) ferroelectric ceramic have been prepared by the conventional solid state reaction method. Formation of single phase material is confirmed by X-Ray Diffraction (XRD), and changes occurring in the lattice parameters with Erbium dopant are analysed. Room temperature dielectric studies and ferroelectric studies will be discussed. (author)

  2. K2SO4 and LiKSO4 crystals luminescence

    International Nuclear Information System (INIS)

    Charapiev, B.; Nurakhmetov, T.N.

    2002-01-01

    In the paper a nature of X-ray and tunnel luminescence in LiKSO 4 and Li 2 SO 4 ·H 2 O crystals are discussed. It is shown, that X-ray luminescence and Li 2 SO 4 ·H 2 O and LiKSO 4 appeals in the result of electrons recombination with auto-localized holes (SO 4 - ), and tunnel luminescence appeals at electrons transfer from ground state of electron center into hole center capture ground state. Under heating of irradiated crystal de-localized holes at recombination moment with electron capture centers are forming auto-localized excitons, which are disintegrating with photon emitting, and so X-ray luminescence spectrum and thermally induces luminescence peaks are coinciding. Nature of radiation appealing in LiKSO 4 at ultraviolet excitation is discussing

  3. Outstanding Li-storage performance of LiFePO4@MWCNTs cathode material with 3D network structure for lithium-ion batteries

    Science.gov (United States)

    Sun, Xiaodong; Zhang, Le

    2018-05-01

    In this work, the MWCNTs-decorated LiFePO4 microspheres (LiFePO4@MWCNTs) with a 3D network structure have been synthesized by a facile and efficient spray-drying approach followed by solid-state reaction in a reduction atmosphere. In the as-prepared composite, the MWCNTs around LiFePO4 nanoparticles can provide 3D conductive networks which greatly facilitate the transport of Li+-ion and electron during the electrochemical reaction. Compared to the pure LiFePO4 material, the LiFePO4@MWCNTs composite as cathode for lithium-ion batteries exhibits significantly improved Li-storage performance in terms of rate capability and cyclic stability. Therefore, we can speculate that the spray-drying approach is a promising route to prepare the high-performance electrode materials with 3D network structure for electrochemical energy storage.

  4. High-performance Li3V2(PO4)3/C cathode materials prepared via a sol–gel route with double carbon sources

    International Nuclear Information System (INIS)

    Zhang Lulu; Li Ying; Peng Gang; Wang Zhaohui; Ma Jun; Zhang Wuxing; Hu Xianluo; Huang Yunhui

    2012-01-01

    Graphical abstract: Double carbon sources were employed to prepare core–shell Li 3 V 2 (PO 4 ) 3 /C composites, giving rise to uniform carbon coating and high conducting network. The as-obtained composites showed remarkably enhanced capacity and rate capability. Highlights: ► Double carbon sources were used to prepare core–shell Li 3 V 2 (PO 4 ) 3 /C composites. ► An improved oxalic acid-based sol–gel method was developed. ► Uniform carbon coating and high conducting network were attained for Li 3 V 2 (PO 4 ) 3 . ► Remarkably enhanced capacity and rate capability were obtained. - Abstract: Li 3 V 2 (PO 4 ) 3 /C (LVP/C) composites have been successfully synthesized via an oxalic acid-based sol–gel process assisted by glucose, in which oxalic acid and glucose serve as double carbon sources. X-ray diffraction patterns show that all samples are well crystallized. Transmission electron microscopy images reveal that the LVP/C sample prepared with 15 wt% glucose is uniformly coated by carbon layer with an appropriate thickness of 8–10 nm, resulting in a high electrical conductivity and a fast kinetics. The Li + -ion diffusion coefficient in the LVP/C sample prepared with glucose is ∼10 −10 cm 2 s −1 , which is larger than that of the LVP/C sample prepared without glucose. The LVP/C sample prepared with 15 wt% glucose exhibits the best electrochemical performance with discharge capacity as high as 171 mAh g −1 at 0.1 C and 119 mAh g −1 at 10 C. The present work provides a valuable route for preparing lithium metal phosphates with double carbon sources to improve the conductivity and hence the electrochemical performance.

  5. Preparation of Li4Ti5O12 electrode thin films by a mist CVD process with aqueous precursor solution

    Directory of Open Access Journals (Sweden)

    Kiyoharu Tadanaga

    2015-03-01

    Full Text Available Spinel Li4Ti5O12 thin films were prepared by a mist CVD process, using an aqueous solution of lithium nitrate and a water-soluble titanium lactate complex as the source of Li and Ti, respectively. In this process, mist particles ultrasonically atomized from a source aqueous solution were transferred by nitrogen gas to a heating substrate to prepare thin films. Scanning electron microscopy observation showed that thin films obtained by this process were dense and smooth, and thin films with a thickness of about 500 nm were obtained. In the X-ray diffraction analysis, formation of Li4Ti5O12 spinel phase was confirmed in the obtained thin film sintered at 700 °C for 4 h. The cell with the thin films as an electrode exhibited a capacity of about 110 mAh g−1, and the cell showed good cycling performance during 10 cycles.

  6. Study of the structure, dielectric and ferroelectric behavior of BaBi4+δTi4O15 ceramics

    Science.gov (United States)

    Khokhar, Anita; Goyal, Parveen K.; Thakur, O. P.; Sreenivas, K.

    2016-05-01

    The structure and ferroelectric properties of excess bismuth doped barium bismuth titanate BaBi4+δTi4O15 (δ = 2 - 10 wt.%)) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material with a change in the orthorhombic distortion with varying excess of bismuth content. There is no change in the phase transition temperature (Tm) while the relaxor behaviour has been modified significantly with excess of bismuth doping. Saturated hysteresis loops with high remnant polarization (Pr ~ 12.5 µC/cm2), low coercive fields (Ec ~ 26 kV/cm) are measured and a high piezoelectric coefficient (d33 ~ 29 pC/N) is achieved in poled BaBi4Ti4O15 ceramics prepared with up to 8 wt.% of excess bismuth oxide. The improvement in the ferroelectric properties with increase in the excess bismuth content in BaBi4Ti4O15 ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of excess bismuth.

  7. Li{sub 4}SiO{sub 4} based breeder ceramics with Li{sub 2}TiO{sub 3}, LiAlO{sub 2} and Li{sub X}La{sub Y}TiO{sub 3} additions, part II: Pebble properties

    Energy Technology Data Exchange (ETDEWEB)

    Kolb, M.H.H., E-mail: Matthias.kolb@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021, Karlsruhe (Germany); Knitter, R. [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021, Karlsruhe (Germany); Hoshino, T. [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Fusion Energy Research and Development Directorate, National Institutes for Quantum and Radiological Science and Technology (QST) (Japan)

    2017-02-15

    Highlights: • The mechanical strength of Li{sub 4}SiO{sub 4}-based breeder pebbles can be improved by adding either LMT, LAO or LLTO as second phase. • The increase in strength is closely linked to a reduction of the open porosity of the pebbles. • All fabricated pebbles show a highly homogenous microstructure with mostly low closed porosity. • Adding LLTO, although it decomposes during sintering, greatly improves the strength of the pebbles. - Abstract: The pebble properties of novel two-phase Li{sub 4}SiO{sub 4} pebbles of 1 mm diameter with additions of Li{sub 2}TiO{sub 3}, LiAlO{sub 2} or Li{sub x}La{sub y}TiO{sub 3} are evaluated in this work as a function of the second phase concentration and the microstructure of the pebbles. The characterization focused on the mechanical strength, microstructure and open as well as closed porosity. Therefore crush load tests, SEM analyses as well as helium pycnometry and optical image analysis were performed, respectively. This work shows that generally additions of a second phase to Li{sub 4}SiO{sub 4} considerably improve the mechanical strength. It also shows that the fabrication processes have to be well-controlled to achieve high mechanical strengths. When Li{sub 2}TiO{sub 3} is added in different concentrations, the determinant for the crush load seems to be the open porosity of the pebbles. The strengthening effect of LiAlO{sub 2} compared to Li{sub 2}TiO{sub 3} is similar, while additions of Li{sub x}La{sub y}TiO{sub 3} increase the mechanical strength much more. Yet, Li{sub 4}SiO{sub 4} and Li{sub x}La{sub y}TiO{sub 3} react with each other to a number of different phases upon sintering. In general the pebble properties of all samples are favorable for use within a fusion breeder blanket.

  8. High Q ceramics in the ACe2(MoO4)4 (A = Ba, Sr and Ca) system for LTCC applications

    International Nuclear Information System (INIS)

    Surjith, A.; Ratheesh, R.

    2013-01-01

    Highlights: ► Solid state synthesis of phase pure ACe 2 (MoO 4 ) 4 (A = Ba, Sr and Ca) ceramics. ► Structural and microstructural evaluation of the synthesized ceramic materials. ► Microwave dielectric property studies of ACe 2 (MoO 4 ) 4 (A = Ba, Sr and Ca) ceramics. ► Structure-property correlation through Laser Raman studies. - Abstract: Novel low temperature sinterable high Q ceramic systems ACe 2 (MoO 4 ) 4 (A = Ba, Sr and Ca) have been prepared through solid state ceramic method. The effect of ionic radii of alkaline earth cations on the structure, microstructure and microwave dielectric properties of these ceramics were studied using powder X-ray diffraction, Laser Raman spectroscopy, scanning electron microscopy and Vector Network Analyzer. A structural change from monoclinic to tetragonal structure was observed while substituting Sr 2+ and Ca 2+ cations in place of Ba 2+ . The Sr and Ca analogues possess better microwave dielectric properties compared to BaCe 2 (MoO 4 ) 4 . All the ceramics were well sintered below 840 °C with dielectric constant in the range 10.2–12.3 together with good quality factor. The SrCe 2 (MoO 4 ) 4 ceramic exhibits an unloaded quality factor of 6762 at 8.080662 GHz with a temperature coefficient of resonant frequency of −46 ppm/°C while the CaCe 2 (MoO 4 ) 4 ceramic shows an unloaded quality factor of 7549 at 6.928868 GHz and a temperature coefficient of resonant frequency of −44 ppm/°C.

  9. Tritium release kinetics in lithium orthosilicate ceramic pebbles irradiated with low thermal-neutron fluence

    International Nuclear Information System (INIS)

    Xiao, Chengjian; Gao, Xiaoling; Kobayashi, Makoto; Kawasaki, Kiyotaka; Uchimura, Hiromichi; Toda, Kensuke; Kang, Chunmei; Chen, Xiaojun; Wang, Heyi; Peng, Shuming; Wang, Xiaolin; Oya, Yasuhisa; Okuno, Kenji

    2013-01-01

    Tritium release kinetics in lithium orthosilicate (Li 4 SiO 4 ) ceramic pebbles irradiated with low thermal-neutron fluence was studied by out-of-pile annealing experiments. It was found that the tritium produced in Li 4 SiO 4 pebbles was mainly released as tritiated water vapor (HTO). The apparent desorption activation energy of tritium on the pebble surface was consistent with the diffusion activation energy of tritium in the crystal grains, indicating that tritium release was mainly controlled by diffusion process. The diffusion coefficients of tritium in the crystal grains at temperatures ranging from 450 K to 600 K were obtained by isothermal annealing tests, and the Arrhenius relation was determined to be D = 1 × 10 −7.0 exp (−40.3 × 10 3 /RT) cm 2 s −1

  10. Preparation of Biomorphic SiC/C Ceramics from Pine Wood via Supercritical Ethanol Infiltration

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Biomorphic (wood derived) carbide ceramics with an overall composition in the SiC/C was produced by supercritical ethanol infiltration of low viscosity tetraethylorthosilicate/supercritical ethanol into biologically derived carbon templates (CB-templates) and in situ hydrolysis into Si(OH)4-gel, the Si(OH)4-gel was calcined at 1400℃ to promote the polycondensation of Si(OH)4-gel into SiO2-phase and then carbonthermal reduction of the SiO2 with the biocarbon template into highly porous, biomorphic SiC/C ceramics. The phases and morphology conversion mechanism of resulting porous SiC/C ceramics have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). Experimental results showed that the biomorphic cellular morphology of pinewood charcoal was remained in the porous SiC/C ceramic with high precision that consisted of β-SiC with minority of α-SiC and the remain free carbon existed in amorphous phase.

  11. Topotactic insertion of lithium in the layered structure Li4VO(PO4)2: The tunnel structure Li5VO(PO4)2

    International Nuclear Information System (INIS)

    Satya Kishore, M.; Pralong, V.; Caignaert, V.; Malo, S.; Hebert, S.; Varadaraju, U.V.; Raveau, B.

    2008-01-01

    A new V(III) lithium phosphate Li 5 VO(PO 4 ) 2 has been synthesized by electrochemical insertion of lithium into Li 4 VO(PO 4 ) 2 . This phase, which crystallizes in the space group I4/mcm, exhibits a tunnel structure closely related to the layered structure of Li 4 VO(PO 4 ) 2 and to the tunnel structure of VO(H 2 PO 4 ) 2 . The topotactic reactions that take place during lithium exchange and intercalation, starting from VO(H 2 PO 4 ) 2 and going to the final phase Li 5 VO(PO 4 ) 2 are explained on the basis of the flexible coordinations of V 4+ and V 3+ species. The electrochemical and magnetic properties of this new phase are also presented and explained on the basis of the structure dimensionality. - Graphical abstract: Electrochemical synthesis of a new 3D V(III) lithium phosphate, Li 5 VO(PO 4 ) 2 . Starting from the 2D Li 4 VO(PO 4 ) 2 , the topotactic reaction that take place during lithium intercalation is explained on the basis of the flexible coordinations of V 4+ and V 3+ species

  12. EXOTIC: Development of ceramic tritium breeding materials

    International Nuclear Information System (INIS)

    Flipot, A.J.; Kennedy, P.; Conrad, R.

    1989-03-01

    As part of the joint European Programme on fusion blanket technology three laboratories, Northern Research Laboratories (NRL), Springfields in the UK, SCK/CEN-Mol in Belgium and ECN-Petten in conjunction with JRC-Petten in the Netherlands have worked closely together since 1983 on the development of ceramic breeder materials, the programme being codenamed EXOTIC. Lithium oxides, aluminates, silicates and zirconates have been produced, characterised and irradiated in the HFR-Petten in experiments EXOTIC-1, -2 and -3. EXOTIC-4 is in preparation. In this fourth annual progress report the work achieved in 1987 is reported. For EXOTIC-1 to -3 mainly post irradiation examinations have been carried out like: visual inspection, puncturing of closed capsules, tritium retention measurements and material characterisation. Moreover, tritium release experiments on small specimens have started. SCK/CEN performed a general study on lithium silicates, in particular on the thermal stability. Finally, the fabrication and the characterisation of the materials to be irradiated in experiment EXOTIC-4 are presented. The eight capsules of EXOTIC-4 will be loaed with samples of Li 2 SiO 3 , Li 2 O, Li 2 ZrO 3 , Li 6 Zr 2 O 7 and Li 8 ZrO 6 . The irradiation will last 4 reactor cycles or about 100, Full Power Day, FPD. The main objective is to determine the tritium residence time of the various lithium zirconates. 18 figs., 8 refs., 15 tabs

  13. Electrochemical characterization of LiFePO{sub 4}/poly (sodium 4-styrenesulfonate)-multi walled carbon nanotube composite cathode material for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Van Hiep; Wang, Wan Lin; Jin, En Mei; Gu, Hal-Bon, E-mail: hbgu@chonnam.ac.kr

    2013-08-25

    Highlights: •LiFePO{sub 4}/PSS–MWCNT successfully prepared by a hydrothermal method. •LiFePO{sub 4}/PSS(2.5%)–MWCNT(2.5%) shows the best electrochemical performances. •PSS stacks and forms a layer about 3–6 nm around the surface of LiFePO{sub 4} particles. •The electronic conductivity of LiFePO{sub 4}/PSS(2.5%)–MWCNT(2.5%) is 6.3 × 10{sup −3} S cm{sup −1}. -- Abstract: LiFePO{sub 4} is a promising cathode material for lithium ion batteries and is prepared by a hydrothermal method. However, its practical application is limited due to its poor conductivity. In order to improve the electronic conductivity, we added poly (sodium 4-styrenesulfonate) (PSS) and multi walled carbon nanotube (MWCNT) in LiFePO{sub 4}. In the results, PSS stacks and forms a layer about 3–6 nm around the surface of LiFePO{sub 4} particles. MWCNT provides pathways for electron transport. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic discharge testing results indicate that LiFePO{sub 4}/PSS–MWCNT composite exhibits higher discharge capacity than pure LiFePO{sub 4}. LiFePO{sub 4}/PSS(2.5%)–MWCNT(2.5%) shows the best discharge capacity of 144 mAh g{sup −1} at 2nd cycle, and high electronic conductivity of 6.3 × 10{sup −3} S cm{sup −1}.

  14. Study of the structure, dielectric and ferroelectric behavior of BaBi_4_+_δTi_4O_1_5 ceramics

    International Nuclear Information System (INIS)

    Khokhar, Anita; Goyal, Parveen K.; Sreenivas, K.; Thakur, O. P.

    2016-01-01

    The structure and ferroelectric properties of excess bismuth doped barium bismuth titanate BaBi_4_+_δTi_4O_1_5 (δ = 2 - 10 wt.%)) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material with a change in the orthorhombic distortion with varying excess of bismuth content. There is no change in the phase transition temperature (T_m) while the relaxor behaviour has been modified significantly with excess of bismuth doping. Saturated hysteresis loops with high remnant polarization (P_r ~ 12.5  µC/cm"2), low coercive fields (E_c ~ 26 kV/cm) are measured and a high piezoelectric coefficient (d_3_3 ~ 29 pC/N) is achieved in poled BaBi_4Ti_4O_1_5 ceramics prepared with up to 8 wt.% of excess bismuth oxide. The improvement in the ferroelectric properties with increase in the excess bismuth content in BaBi_4Ti_4O_1_5 ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of excess bismuth.

  15. Improving thermal insulation of TC4 using YSZ-based coating and SiO2 aerogel

    OpenAIRE

    Jin, Lei; Li, Peizhong; Zhou, Haibin; Zhang, Wei; Zhou, Guodong; Wang, Chun

    2015-01-01

    In this paper, air plasmas spray (APS) was used to prepare YSZ and Sc2O3–YSZ (ScYSZ) coating in order to improve the thermal insulation ability of TC4 alloy. SiO2 aerogel was also synthesized and affixed on TC4 titanium alloy to inhabit thermal flow. The microstructures, phase compositions and thermal insulation performance of three coatings were analyzed in detail. The results of thermal diffusivity test by a laser flash method showed that the thermal diffusivities of YSZ, Sc2O3–YSZ and SiO2...

  16. Oxalate molecule as the trap for gamma-irradiation energy in the amorphous aluminosilicate Al2(OH)6H4SiO4

    International Nuclear Information System (INIS)

    Nothig-Laslo, V.; Horvath, L.; Bilinski, H.

    1990-01-01

    Paramagnetic species which were the products of gamma irradiation at 77 K and at room temperature were studied by ESR spectroscopy in the amorphous aluminosilicate, Al2(OH)6H4SiO4, prepared in the presence and in the absence of oxalate ion. The aluminosilicate precipitated from the solution containing the oxalate ion in 10(-4) mol dm-3 concentration contained the oxalate only in trace amounts. When gamma-irradiated at 77 K and at room temperature, this compound gave the stable paramagnetic species represented by the single ESR line centered at g = 2.000. We ascribe this spectrum to the CO2- radical formed from the oxalate ion. The same aluminosilicate prepared in the absence of the oxalate either produced no stable paramagnetic product after gamma irradiation at room temperature or resulted in composite ESR spectra, indicating the presence of several paramagnetic species if irradiated at 77 K. Complex ESR spectra were transformed by heating to the stable paramagnetic centers which differed from the one obtained from oxalate ion. We conclude that in Al2(OH)6H4SiO4 oxalate acts as a trap for the gamma-radiation energy

  17. Phase formation in the Li2MoO4-Rb2MoO4-Ln2(MoO4)3 systems and the properties of LiRbLn2(MoO4)4

    International Nuclear Information System (INIS)

    Basovich, O.M.; Khajkina, E.G.; Vasil'ev, E.V.; Frolov, A.M.

    1995-01-01

    Phase equilibria within subsolidus range of ternary salt systems Li 2 MoO 4 -Rb 2 MoO 4 -Ln 2 (MoO 4 ) 4 (Ln - Nd, Er) are analyzed. Formation of ternary molybdate LiRbNd 2 (MoO 4 ) 4 is proved along LiNd(MoO 4 ) 2 -RbNd(MoO 4 )-2 cross-section. Phase diagram of this cross-section is plotted. Similar compounds are synthesized for Ln = La-Eu. The parameters of their monoclinic elementary cells are determined. Luminescent properties of LiRbLa 2 (MoO 4 ) 4 -Nd 3+ are studied. 17 refs., 4 figs., 2 tabs

  18. Microstructural changes in NiFe{sub 2}O{sub 4} ceramics prepared with powders derived from different fuels in sol-gel auto-combustion technique

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Lalita, E-mail: chauhan.lalita5@gmail.com; Sreenivas, K. [Department of Physics & Astrophysics, University of Delhi, Delhi-110007 (India); Bokolia, Renuka

    2016-05-23

    Structural properties of Nickel ferrite (NiFe{sub 2}O{sub 4}) ceramics prepared from powders derived from sol gel auto-combustion method using different fuels (citric acid, glycine and Dl-alanine) are compared. Changes in the structural properties at different sintering temperatures are investigated. X-ray diffraction (XRD) confirms the formation of single phase material with cubic structure. Ceramics prepared using the different powders obtained from different fuels show that that there are no significant changes in lattice parameters. However increasing sintering temperatures show significant improvement in density and grain size. The DL-alanine fuel is found to be the most effective fuel for producing NIFe{sub 2}O{sub 4} powders by the sol-gel auto combustion method and yields highly crystalline powders in the as-burnt stage itself at a low temperature (80 °C). Subsequent use of the powders in ceramic manufacturing produces dense NiFe{sub 2}O{sub 4} ceramics with a uniform microstructure and a large grain size.

  19. Synthesis and electrochemical properties of LiNi0.4Mn1.5Cr0.1O4 and Li4Ti5O12

    CSIR Research Space (South Africa)

    Liu, GQ

    2011-08-01

    Full Text Available Spinel compound LiNi0.4Mn1.5Cr0.1O4 (LNMCO) and Li4Ti5O12 (LTO) were synthesized by the sol-gel method and the solid-state method, respectively. The particle sizes of the products LiNi0.4Mn1.5Cr0.1O4 and Li4Ti5O12 were 0.5 to 2 um and 0.5 to 0.8 um...

  20. Quaternary system LiF-LiCl-LiVO3-Li2MoO4

    International Nuclear Information System (INIS)

    Anipchenko, B.V.; Garkushin, I.K.

    2000-01-01

    Interactions in the LiF-LiCl-LiVO 3 -Li 2 MoO 4 system are studied by differential thermal analysis. Rate of heating/cooling of the samples comprised 15 Grad/min, mass of sample composed 0.2 g. The system was investigated in the 300-650 Deg C range. X-ray diffraction method was used for determination of purity of the reagents. Composition and temperature of quaternary component eutectics are determined: 16.5 mol. % of LiF, 47.0 mol. % of LiCl, 28.8 mol. % of LiVO 3 , 7.6 mol. % of Li 2 MoO 4 ; 387 Deg C. Mean value of melting enthalpy of quaternary eutectics mixture in the LiF-LiCl-LiVO 3 -Li 2 MoO 4 system on the results of the tests was in the range of 222 kJ/kg [ru

  1. Deposition of Li{sub 4}Ti{sub 5}O{sub 12} and LiMn{sub 2}O{sub 4} films on the lithium-ion conductor of Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} sintered pellet

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xian Ming, E-mail: xianmingwu@163.com [College of Chemistry and Chemical Engineering, Jishou University, Jishou Hunan 416000 (China); Xiangxi Minerals and New Materials Research and Service Center, Jishou Hunan 416000 (China); Chen, Shang [College of Chemistry and Chemical Engineering, Jishou University, Jishou Hunan 416000 (China); Xiangxi Minerals and New Materials Research and Service Center, Jishou Hunan 416000 (China); He, Ze Qiang; Chen, Shou Bin; Li, Run Xiu [College of Chemistry and Chemical Engineering, Jishou University, Jishou Hunan 416000 (China)

    2015-08-31

    LiMn{sub 2}O{sub 4} and Li{sub 4}Ti{sub 5}O{sub 12} films were deposited on the lithium-ion conductor of Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} sintered pellet by spray technique. The effect of annealing temperature, annealing time, Li:Ti and Li:Mn molar ratio on the phase and crystallization of the films were investigated with X-ray diffraction. The LiMn{sub 2}O{sub 4}/Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3}/Li{sub 4}Ti{sub 5}O{sub 12} thin-film lithium-ion battery using Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} sintered pellet as both electrolyte and substrate was also studied. The results show that the effect of annealing temperature, annealing time, Li:Ti and Li:Mn molar ratio has great effect on the phase and crystallization of Li{sub 4}Ti{sub 5}O{sub 12} and LiMn{sub 2}O{sub 4} films deposited on the Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} sintered pellet. The optimal Li:Ti and Li:Mn molar ratio for the deposition of Li{sub 4}Ti{sub 5}O{sub 12} and LiMn{sub 2}O{sub 4} films on Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} sintered pellet are 7.2:5 and 1.05:2, respectively. The optimal annealing temperature and time for the deposition of LiMn{sub 2}O{sub 4} film on Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} sintered pellet are 650 °C and 10 min. While those for Li{sub 4}Ti{sub 5}O{sub 12} film are 700 °C and 10 min. The LiMn{sub 2}O{sub 4}/Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3}/Li{sub 4}Ti{sub 5}O{sub 12} thin-film battery offers a working voltage about 2.25 V and can be easily cycled. - Highlights: • LiMn{sub 2}O{sub 4} and Li{sub 4}Ti{sub 5}O{sub 12} films spray deposited on Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} sintered pellet • Film crystal phase depends on the spray solution composition and annealing conditions. • Prepared thin-film lithium-ion battery employs sintered pellet as electrolyte and substrate. • LiMn{sub 2}O{sub 4}/Li{sub 1.3}Al{sub 0.3}Ti{sub 1

  2. Estudio del Sistema Li2SO4 – Na2SO4. Diagrama de fases y caracterización del LiNaSO4

    Directory of Open Access Journals (Sweden)

    Font-Bardia, M.

    2004-08-01

    Full Text Available An exhaustive study of the phase diagram of binary system Li2SO4-Na2SO4 is presented. Phase diagram was determined using thermo-X-ray diffraction in powder samples and calorimetry ATD. A new phase with formula Li2-xNaxSO4 has been obtained, with 1 ≤ x ≤ 1.22. The crystal structure of β-LiNaSO4 was determined from single-crystal X-ray diffraction. This study shows that the crystals usually become twinned when the growth is by solution; which explains the poor spontaneous polarization. The Raman dispersion of Li2SO4, Na2SO4 and LiNaSO4 compounds is explained from the structural data. The measurements have been made at different heating and cooling rate.Se presenta un estudio exhaustivo del diagrama de fase del sistema binario Li2SO4-Na2SO4. El diagrama de fases se determinó mediante termo-difractometría de rayos-X en muestras de polvo y calorimetría ATD. Se obtiene una nueva fase de fórmula Li2-xNaxSO4, con 1 ≤ x ≤ 1.22. La estructura cristalina de β-LiNaSO4 se determinó por difracción de rayos-X sobre un monocristal. Este estudio muestra que los cristales usualmente se maclan cuando el crecimiento es por solución, lo cual explica la baja polarización espontánea. Se explica la dispersión Raman de los compuestos Li2SO4, Na2SO4 y LiNaSO4, a partir de los datos estructurales. Las medidas experimentales se han efectuado a diferentes velocidades de calentamiento y enfriamiento.

  3. Solid state opto-impedance of LiNiVO{sub 4} and LiMn{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Kalyani, P; Sivasubramanian, S; Prabhu, S Naveen; Ragavendran, K; Kalaiselvi, N; Ranganathan, N G; Madhu, S; SundaraRaj, A; Manoharan, S P; Jagannathan, R [Central Electrochemical Research Institute, Karaikudi-630006, Tamil Nadu (India)

    2005-04-07

    Spinel type LiMn{sub 2}O{sub 4} and inverse spinel LiNiVO{sub 4} systems serve as standard cathode materials or potential cathode systems for application in high energy density lithium-ion batteries. Upon photo-excitation using UV radiation of energy {approx}5 eV, the LiNiVO{sub 4} system shows significant modification in the solid state impedance pattern while the LiMn{sub 2}O{sub 4} system does not. This study has revealed a significant difference in the opto-impedance pattern for LiNiVO{sub 4} with respect to LiMn{sub 2}O{sub 4}, which may be due to the different electronic processes involved. An attempt has been made to study this behaviour from the solid-state viewpoint.

  4. Targeted partial surface modification with nano-SiO2@Li2CoPO4F as high-voltage cathode material for LIBs

    Science.gov (United States)

    Chang, Caiyun; Huang, Zhipeng; Tian, Runsai; Jiang, Xinyu; Li, Chunsheng; Feng, Jijun

    2017-10-01

    Tuning whole/partial surface modification on cathode material with oxide material is a sought-after method to enhance the electrochemical performance in power storage field. Herein, nano-SiO2 targeted partial surface modified high voltage cathode material Li2CoPO4F has been successfully fabricated via a facile self-assembly process in silica dispersion at ambient temperature. With the aid of polar -OH groups attracted on the surface of SiO2 micelles, the nano-SiO2 preferentially nestle up along the borders and boundaries of Li2CoPO4F particles, where protection should be deployed with emphasis against the undesirable interactions between materials and electrolytes. Compared with pristine Li2CoPO4F, the SiO2 selectively modified Li2CoPO4F cathode materials, especially LCPF-3S, exhibit desirable electrochemical performances with higher discharge capacity, more outstanding cycle stability and favorable rate capability without any additional carbon involved. The greatly enhanced electrochemical properties can be attributed to the improved lithium-ion diffusion kinetics and structure tolerance during repeated lithiation/delithiation process. Such findings reveal a great potential of nano-SiO2 modified Li2CoPO4F as high energy cathode material for lithium ion batteries.

  5. Preparation of LiMn2O4 cathode thin films for thin film lithium secondary batteries by a mist CVD process

    International Nuclear Information System (INIS)

    Tadanaga, Kiyoharu; Yamaguchi, Akihiro; Sakuda, Atsushi; Hayashi, Akitoshi; Tatsumisago, Masahiro; Duran, Alicia; Aparacio, Mario

    2014-01-01

    Highlights: • LiMn 2 O 4 thin films were prepared by using the mist CVD process. • An aqueous solution of lithium and manganese acetates is used for the precursor solution. • The cell with the LiMn 2 O 4 thin films exhibited a capacity of about 80 mAh/g. • The cell showed good cycling performance during 10 cycles. - Abstract: LiMn 2 O 4 cathode thin films for thin film lithium secondary batteries were prepared by using so-called the “mist CVD process”, employing an aqueous solution of lithium acetate and manganese acetate, as the source of Li and Mn, respectively. The aqueous solution of starting materials was ultrasonically atomized to form mist particles, and mists were transferred by nitrogen gas to silica glass substrate to form thin films. FE-SEM observation revealed that thin films obtained by this process were dense and smooth, and thin films with a thickness of about 750 nm were obtained. The electrochemical cell with the thin films obtained by sintering at 700 °C exhibited a capacity of about 80 mAh/g, and the cell showed good cycling performance during 10 cycles

  6. High Tap Density Li4Ti5O12 Microspheres: Synthetic Conditions and Advanced Electrochemical Performance

    KAUST Repository

    Ming, Jun; Zheng, Junwei; Zhou, Qun; Ren, Jianxin; Ming, Hai; Jia, Zhenyong; Zhang, Yanqing

    2017-01-01

    Preparation of uniform spherical Li4Ti5O12 with high tap density is significant to achieve a high volumetric energy density in lithium-ion batteries. Herein, Li4Ti5O12 micro-spheres with variable tap-density and tunable size distribution were synthesized by a newly designed industrial spray drying approach. The slurry concentration, sintering time and sintering conditions after spray, the effect of Li/Ti molar ratio on the lithium ion (Li+) storage capability were investigated. A narrow particle size distribution around 10 μm and high tap-density close to 1.4 g cm-3 of the Li4Ti5O12 spheres can be obtained under the optimized conditions. The Li4Ti5O12 spheres can deliver much higher capacity of 168 mAh g-1 at 1 C-rate and show high capacity retention of 97.7% over 400 cycles. The synthetic conditions are confirmed to be critical for improving the electron conductivity and Li+ diffusivity by adjusting the crystal and spatial structures. As-prepared high performance Li4Ti5O12 is an ideal electrode for Li-ion batteries or capacitors; meanwhile the presented approach is also applicable for preparing other kind of spherical materials.

  7. High Tap Density Li4Ti5O12 Microspheres: Synthetic Conditions and Advanced Electrochemical Performance

    KAUST Repository

    Ming, Jun

    2017-03-17

    Preparation of uniform spherical Li4Ti5O12 with high tap density is significant to achieve a high volumetric energy density in lithium-ion batteries. Herein, Li4Ti5O12 micro-spheres with variable tap-density and tunable size distribution were synthesized by a newly designed industrial spray drying approach. The slurry concentration, sintering time and sintering conditions after spray, the effect of Li/Ti molar ratio on the lithium ion (Li+) storage capability were investigated. A narrow particle size distribution around 10 μm and high tap-density close to 1.4 g cm-3 of the Li4Ti5O12 spheres can be obtained under the optimized conditions. The Li4Ti5O12 spheres can deliver much higher capacity of 168 mAh g-1 at 1 C-rate and show high capacity retention of 97.7% over 400 cycles. The synthetic conditions are confirmed to be critical for improving the electron conductivity and Li+ diffusivity by adjusting the crystal and spatial structures. As-prepared high performance Li4Ti5O12 is an ideal electrode for Li-ion batteries or capacitors; meanwhile the presented approach is also applicable for preparing other kind of spherical materials.

  8. Dosimetric properties of Li2 B4 O7: Tm pellets

    International Nuclear Information System (INIS)

    Rzyski, B.M.; Morato, S.P.

    1987-10-01

    Pellets produced out of thulium doped lithium tetraborate, (Li 2 B 4 O 7 :Tm), for thermoluminescent, (TL), dosimetry present low sensibility to environment conditions. Humidity, ambiet temperature, fading and handling during TL reading have almost no influence on the TL properties of the pellets prepared according the receipt given in this paper. The structure of the TL glow curve for the irradiated Li 2 B 4 O 7 : Tm pellet is rather simple and the TL response is linear in the range of 3x10 -4 to 7x10 2 Gy. The dosimetric properties of Li 2 B 4 O 7 : Tm in pellet form makes it a competitor with other TL phosphors. (author) [pt

  9. The thermochemistry of lithium silicates in view of their use as breeder materials

    International Nuclear Information System (INIS)

    Ihle, H.R.; Penzhorn, R.D.; Schuster, P.

    1989-01-01

    Employing Knudsen effusion mass spectrometry the partial pressures of Li, O 2 , Li 2 O, LiO and Li 3 O over solid and/or liquid Li 4 SiO 4 were measured as a function of temperature. From the data it is deduced that the main vaporization process for solid and liquid Li 4 SiO 4 can be described by the equations: Li 4 SiO 4 (cr)=2 Li(g)+0.5 O 2 (g)+Li 2 SiO 3 (cr) (1), ΔH 0 298 =(960.70±2.38) kJ/mol and Li 4 SiO 4 (I)=2 Li(g)+0.5 O 2 (g)+Li 2 SiO 3 (l) (2), ΔH 0 298 =(946.34±0.73) kJ/mol. The enthalpy changes for the reactions Li 4 SiO 4 (cr)=Li 2 O(g)+Li 2 SiO 3 (cr) (3) and Li 2 O(g)=2 Li(g)+0.5 O 2 (g) (5) were als determined and found to be thermodynamically consistent with that of reaction (1). The same is observed for the corresponding equilibria over the liquid. Assuming thermodynamic equilibrium and excluding effects from structural materials and/or reducing gas streams which lower the oxygen activity, tritium will be released from lithium orthosilicate predominantly as T 2 O in the temperature range of operation of a reactor blanket. An examination of the ceramic compounds of the systems, Li 2 O/Al 2 O 3 , Li 2 O/ZrO 2 and Li 2 O/SiO 2 reveals that among the ceramics of each particular system the reaction enthalpy, ΔH 0 298,r , of formation from the constituent oxides per mol Li 2 O varies in the reversed order of the lithium density, which is related to the tritium breeding capability. Of the three systems discussed, the lithium silicates show the highest thermal stability among the ceramics of comparable lithium density. (orig.)

  10. 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%.

  11. Rate-dependent, Li-ion insertion/deinsertion behavior of LiFePO4 cathodes in commercial 18650 LiFePO4 cells.

    Science.gov (United States)

    Liu, Qi; He, Hao; Li, Zhe-Fei; Liu, Yadong; Ren, Yang; Lu, Wenquan; Lu, Jun; Stach, Eric A; Xie, Jian

    2014-03-12

    We have performed operando synchrotron high-energy X-ray diffraction (XRD) to obtain nonintrusive, real-time monitoring of the dynamic chemical and structural changes in commercial 18650 LiFePO4/C cells under realistic cycling conditions. The results indicate a nonequilibrium lithium insertion and extraction in the LiFePO4 cathode, with neither the LiFePO4 phase nor the FePO4 phase maintaining a static composition during lithium insertion/extraction. On the basis of our observations, we propose that the LiFePO4 cathode simultaneously experiences both a two-phase reaction mechanism and a dual-phase solid-solution reaction mechanism over the entire range of the flat voltage plateau, with this dual-phase solid-solution behavior being strongly dependent on charge/discharge rates. The proposed dual-phase solid-solution mechanism may explain the remarkable rate capability of LiFePO4 in commercial cells.

  12. Lithium ceramics: sol-gel preparation and tritium release; Ceramiques lithiees: elaboration sol-gel et relachement du tritium

    Energy Technology Data Exchange (ETDEWEB)

    Renoult, O

    1994-04-01

    Ceramics based on lithium aluminate (LiA1O{sub 2}), lithium zirconate (Li{sub 2}ZrO{sub 3}) and lithium titanate (Li{sub 2}TiO{sub 3}) are candidates as tritium breeder blanket materials for forthcoming nuclear fusion reactors. Lithium silico-aluminate Li{sub 4+x}A1{sub 4-3x}Si{sub 2x}O{sub 8} (0 {<=} x {<=} 0,25) powders were synthetized from alkoxyde-hydroxyde sol-gel route. By direct sintering at 850-1100 deg C (without prior calcination), ceramics with controlled stoichiometry and homogenous microstructure were obtained. We have also prepared, using a comparable method, Li{sub 2}Zr{sub 1-x}Ti{sub x}O{sub 3} (x = 0, x = 0,1 et x = 1) materials. All these ceramics, with different microstructures and compositions, have been tested in out-of-reactor experiments. Concerning lithium aluminate microporous ceramics, the silicon substitution leads to a significant improvement of the tritrium release. Classical models taking into account independent surface mechanisms are not able to describe correctly the observed tritium release kinetics. We show, using a simple model, that the release kinetics is in fact limited by an intergranular diffusion followed by a desorption. The delay in tritium release, which occurs when the ceramic compacity increases, is explained in terms of an enhancement of the ionic T{sup +} diffusion path length. The energy required for desorption includes a leading term independent of hydrogen contained in the sweep gas. This term is attributed to the limiting recombination step of T{sup +} in molecular species HTO. For similar microstructures, the facility of tritium release for the different studied materials is explained by three properties: the crystal structure of the ceramic, the acidity of oxides and finally the presence of electronic non-stoichiometric defects. (author). 89 refs., 50 figs., 2 tabs., 1 annexe.

  13. Fabrication and characterization of lithium orthosilicate pebbles using LiOH as a new raw material

    International Nuclear Information System (INIS)

    Knitter, R.; Reimann, J.; Risthaus, P.; Boccaccini, L.V.; Piazza, G.

    2004-01-01

    For the European Helium Cooled Pebble Bed (HCPB) blanket slightly overstoichiometric lithium orthosilicate pebbles (Li 4 SiO 4 +SiO 2 ) have been chosen as one optional breeder material. This material is developed in collaboration between Research Centre Karlsruhe (FZK) and the Schott Glas, Mainz. The lithium orthosilicate (OSi) pebbles are fabricated by the melting and spraying method in a semi-industrial scale facility. In the past, the not enriched pebbles were produced from a mixture of Li 4 SiO 4 and SiO 2 powders, but due to the fact that enriched Li 4 SiO 4 is not available on the market, highly enriched carbonate powder was used that finally resulted in nonsatisfying pebble characteristics. Enriched LiOH powder is commercially available, therefore, a new production route was pursued based on the following, simplified reaction: 4 LiOH + SiO 2 → Li 4 SiO 4 + 2 H 2 O. The melting process of LiOH and SiO 2 is less difficult to control than the melting of Li 2 CO 3 in spite of the decomposition of water. The pebbles produced from LiOH and SiO 2 are similar to those produced from Li 4 SiO 4 and SiO 2 . They exhibit a distinctly dendritic structure and show only a small amount of pores and cracks. In addition to the main constituent Li 4 SiO 4 , the high temperature phase Li 6 Si 2 O 7 was detected due to the quenching process and the excess of SiO 2 . This minor constituent, however, decomposes to Li 4 SiO 4 and Li 2 SiO 3 during annealing. In compressive crush load tests of single pebbles a crush load of about 9.5 N was measured for pebbles after drying at 300degC. The chemical analysis revealed a further advantage of the use of LiOH in the melting process. As LiOH is available in high-purity quality, the pebbles contain impurities to a lower degree than pebbles produced from Li 4 SiO 4 or Li 2 CO 3 . In order to obtain characteristic pebble bed data, first Uniaxial Compression Tests (UCTs) were performed at temperatures between ambient and at 850deg

  14. Microwave-assisted reactive sintering and lithium ion conductivity of Li1.3Al0.3Ti1.7(PO4)3 solid electrolyte

    Science.gov (United States)

    Hallopeau, Leopold; Bregiroux, Damien; Rousse, Gwenaëlle; Portehault, David; Stevens, Philippe; Toussaint, Gwenaëlle; Laberty-Robert, Christel

    2018-02-01

    Li1.3Al0.3Ti1.7(PO4)3 (LATP) materials are made of a three-dimensional framework of TiO6 octahedra and PO4 tetrahedra, which provides several positions for Li+ ions. The resulting high ionic conductivity is promising to yield electrolytes for all-solid-state Li-ion batteries. In order to elaborate dense ceramics, conventional sintering methods often use high temperature (≥1000 °C) with long dwelling times (several hours) to achieve high relative density (∼90%). In this work, an innovative synthesis and processing approach is proposed. A fast and easy processing technique called microwave-assisted reactive sintering is used to both synthesize and sinter LATP ceramics with suitable properties in one single step. Pure and crystalline LATP ceramics can be achieved in only 10 min at 890 °C starting from amorphous, compacted LATP's precursors powders. Despite a relative density of 88%, the ionic conductivity measured at ambient temperature (3.15 × 10-4 S cm-1) is among the best reported so far. The study of the activation energy for Li+ conduction confirms the high quality of the ceramic (purity and crystallinity) achieved by using this new approach, thus emphasizing its interest for making ion-conducting ceramics in a simple and fast way.

  15. Fe3O4@HKUST-1 and Pd/Fe3O4@ HKUST-1 as magnetically recyclable catalysts prepared via conversion from a Cu-based ceramic

    OpenAIRE

    Toyao, Takashi; Styles, Mark J.; Yago, Tokuichiro; Sadiq, Muhammad M.; Ricco, Raffaele; Suzuki, Kiyonori; Horiuchi, Yu; Takahashi, Masahide; Matsuoka, Masaya; Falcaro, Paolo

    2017-01-01

    Nanocomposites obtained by integrating iron oxide magnetic nanoparticles (Fe3O4) into a metal-organic framework (HKUST-1 or Cu-3(BTC)(2), BTC = 1,3,5-benzenetricarboxylate) are synthesized through conversion from a composite of a Cu-based ceramic material and Fe3O4. In situ small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) measurements reveal that the presence of Fe3O4 leads to the fast conversion and synthesis of HKUST-1 with small particle sizes. The prepared MOF co...

  16. Density functional theory study of lithium diffusion at the interface between olivine-type LiFePO4 and LiMnPO4

    Science.gov (United States)

    Shi, Jianjian; Wang, Zhiguo; Qing Fu, Yong

    2016-12-01

    Coating LiMnPO4 with a thin layer of LiFePO4 shows a better electrochemical performance than the pure LiFePO4 and LiMnPO4, thus it is critical to understand Li diffusion at their interfaces to improve the performance of electrode materials. Li diffusion at the (1 0 0)\\text{LiFeP{{\\text{O}}4}} //(1 0 0)\\text{LiMnP{{\\text{O}}4}} , (0 1 0)\\text{LiFeP{{\\text{O}}4}} //(0 1 0)\\text{LiMnP{{\\text{O}}4}} , and (0 0 1)\\text{LiFeP{{\\text{O}}4}} //(0 0 1)\\text{LiMnP{{\\text{O}}4}} interfaces between LiFePO4 and LiMnPO4 was investigated using density functional theory. The calculated diffusion energy barriers are 0.55 eV for Li to diffuse along the (0 0 1) interface, 0.44 and 0.49 eV for the Li diffusion inside the LiMnPO4 and along the (1 0 0) interface, respectively. When Li diffuses from the LiFePO4 to LiMnPO4 by passing through the (0 1 0) interfaces, the diffusion barriers are 0.45 and 0.60 eV for the Li diffusions in both sides. The diffusion barriers for Li to diffuse in LiMnPO4 near the interfaces decrease compared with those in the pure LiMnPO4. The calculated diffusion coefficient of Li along the (1 0 0) interface is in the range of 3.65  ×  10-11-5.28  ×  10-12 cm2 s-1, which is larger than that in the pure LiMnPO4 with a value of 7.5  ×  10-14 cm2 s-1. Therefore, the charging/discharging rate performance of the LiMnPO4 can be improved by surface coating with the LiFePO4.

  17. In-situ preparation of poly(ethylene oxide)/Li3PS4 hybrid polymer electrolyte with good nanofiller distribution for rechargeable solid-state lithium batteries

    Science.gov (United States)

    Chen, Shaojie; Wang, Junye; Zhang, Zhihua; Wu, Linbin; Yao, Lili; Wei, Zhenyao; Deng, Yonghong; Xie, Dongjiu; Yao, Xiayin; Xu, Xiaoxiong

    2018-05-01

    Nano-sized fillers in a polymer matrix with good distribution can play a positive role in improving polymer electrolytes in the aspects of ionic conductivity, mechanical property and electrochemical performance of Li-ion cells. Herein, polyethylene oxide (PEO)/Li3PS4 hybrid polymer electrolyte is prepared via a new in-situ approach. The ionic conductivities of the novel hybrid electrolytes with variable proportions are measured, and the optimal electrolyte of PEO-2%vol Li3PS4 presents a considerable ionic conductivity of 8.01 × 10-4 S cm-1 at 60 °C and an electrochemical window up to 5.1 V. The tests of DSC and EDXS reveal that the Li3PS4 nanoparticles with better distribution, as active fillers scattering in the PEO, exhibit a positive effect on the transference of lithium ion and electrochemical interfacial stabilities. Finally, the assembled solid-state LiFePO4/Li battery presents a decent cycling performance (80.9% retention rate after 325 cycles at 60 °C) and excellent rate capacities with 153, 143, 139 and 127 mAh g-1 at the discharging rate of 0.1 C, 0.2 C, 0.5 C and 1 C at 60 °C. It is fully proved that it is an advanced strategy to preparing the new organic/inorganic hybrid electrolytes for lithium-ion batteries applications.

  18. Comparison of LiVPO4F to Li4Ti5O12 as anode materials for lithium-ion batteries.

    Science.gov (United States)

    Ma, Rui; Shao, Lianyi; Wu, Kaiqiang; Shui, Miao; Wang, Dongjie; Pan, Jianguo; Long, Nengbing; Ren, Yuanlong; Shu, Jie

    2013-09-11

    In this paper, we reported on a comparison of LiVPO4F to Li4Ti5O12 as anode materials for lithium-ion batteries. Combined with powder X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, galvanostatic discharge/charge tests and in situ X-ray diffraction technologies, we explore and compare the insertion/extraction mechanisms of LiVPO4F based on the V3+/V2+/V+ redox couples and Li4Ti5O12 based on the Ti4+/Ti3+ redox couple cycled in 1.0-3.0 V and 0.0-3.0 V. The electrochemical results indicate that both LiVPO4F and Li4Ti5O12 are solid electrolyte interphase free materials in 1.0-3.0 V. The insertion/extraction mechanisms of LiVPO4F and Li4Ti5O12 are similar with each other in 1.0-3.0 V as proved by in situ X-ray diffraction. It also demonstrates that both samples possess stable structure in 0.0-3.0 V. Additionally, the electrochemical performance tests of LiVPO4F and Li4Ti5O12 indicate that both samples cycled in 0.0-3.0 V exhibit much higher capacities than those cycled in 1.0-3.0 V but display worse cycle performance. The rate performance of Li4Ti5O12 far exceeds that of LiVPO4F in the same electrochemical potential window. In particular, the capacity retention of Li4Ti5O12 cycled in 1.0-3.0 V is as high as 98.2% after 20 cycles. By contrast, Li4Ti5O12 is expected to be a candidate anode material considering its high working potential, structural zero-strain property, and excellent cycle stability and rate performance.

  19. A novel UV-emitting phosphor: LiSr4(BO3)3: Pb2+

    International Nuclear Information System (INIS)

    Pekgözlü, İlhan

    2013-01-01

    Pure and Pb 2+ doped LiSr 4 (BO 3 ) 3 materials were prepared by a solution combustion synthesis method. The phase analysis of all synthesized materials were determined using the powder XRD. The synthesized materials were investigated using spectrofluorometer at room temperature. The excitation and emission bands of LiSr 4 (BO 3 ) 3 : Pb 2+ were observed at 284 and 328 nm, respectively. The dependence of the emission intensity on the Pb 2+ concentration for the LiSr 4 (BO 3 ) 3 were studied in detail. It was observed that the concentration quenching of Pb 2+ in LiSr 4 (BO 3 ) 3 is 0.005 mol. The Stokes shifts of LiSr 4 (BO 3 ) 3 : Pb 2+ phosphor was calculated to be 4723 cm –1 . -- Highlights: • A novel UV-emitting phosphor: LiSr 4 (BO 3 ) 3 : Pb 2+ ” synthesized for the first time. • The emission band of LiSr 4 (BO 3 ) 3 : Pb 2+ was observed at 328 nm upon excitation with 284 nm. • LiSr 4 (BO 3 ) 3 : Pb 2+ is a good phosphor for broadband UV application

  20. Effect of synthesis methods on luminescence properties of LiCaPO{sub 4}:Ce phosphor for radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Palan, C.B., E-mail: chetupalan@rediffmail.com; Omanwar, S.K.

    2016-10-15

    The polycrystalline doped and un-doped LiCaPO{sub 4} phosphors were successfully prepared via solid state diffusion [SSD] and sol–gel [SG] methods. The sol–gel method was implied to decrease the processing time and heating temperature. The prepared un-doped and doped LiCaPO{sub 4} phosphors were characterized through X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Additionally photoluminescence (PL), thermoluminescence (TL) and optically stimulated luminescence (OSL) properties were studied. The XRD patterns of prepared LiCaPO{sub 4} and LiCaPO{sub 4}:Ce phosphors were well matched with the ICDD file. The average particles size of LiCaPO{sub 4} and LiCaPO{sub 4}:Ce phosphors were found to be in the range 2–10 μm by SSD method and 2-5 μm by SG method. The excitation spectra of LiCaPO{sub 4} and LiCaPO{sub 4}:Ce phosphors consist of broad band in the range 200–330 nm and maximum intensity was observed at 314 nm. Also emission spectra consist of broad band in range from 330–500 nm and maximum intensity was observed at 369 nm. With the increase of Ce{sup 3+} ions concentration, the emission spectra of LiCaPO{sub 4}:Ce{sup 3+} phosphors shifted to a longer wavelength. The prepared phosphors were showed excellent TL properties under β irradiation. The OSL sensitivity of the LiCaPO{sub 4}:Ce phosphor synthesized by the SSD method was the nearly same as compared with the OSL sensitivity of LiCaPO{sub 4}:Ce phosphor synthesized by the SG method.

  1. A chemically activated graphene-encapsulated LiFePO4 composite for high-performance lithium ion batteries.

    Science.gov (United States)

    Ha, Jeonghyun; Park, Seung-Keun; Yu, Seung-Ho; Jin, Aihua; Jang, Byungchul; Bong, Sungyool; Kim, In; Sung, Yung-Eun; Piao, Yuanzhe

    2013-09-21

    A composite of modified graphene and LiFePO4 has been developed to improve the speed of charging-discharging and the cycling stability of lithium ion batteries using LiFePO4 as a cathode material. Chemically activated graphene (CA-graphene) has been successfully synthesized via activation by KOH. The as-prepared CA-graphene was mixed with LiFePO4 to prepare the composite. Microscopic observation and nitrogen sorption analysis have revealed the surface morphologies of CA-graphene and the CA-graphene/LiFePO4 composite. Electrochemical properties have also been investigated after assembling coin cells with the CA-graphene/LiFePO4 composite as a cathode active material. Interestingly, the CA-graphene/LiFePO4 composite has exhibited better electrochemical properties than the conventional graphene/LiFePO4 composite as well as bare LiFePO4, including exceptional speed of charging-discharging and excellent cycle stability. That is because the CA-graphene in the composite provides abundant porous channels for the diffusion of lithium ions. Moreover, it acts as a conducting network for easy charge transfer and as a divider, preventing the aggregation of LiFePO4 particles. Owing to these properties of CA-graphene, LiFePO4 could demonstrate enhanced and stably long-lasting electrochemical performance.

  2. LiCa{sub 4}Si{sub 4}N{sub 8}F and LiSr{sub 4}Si{sub 4}N{sub 8}F. Nitridosilicate fluorides with a BCT-zeolite-type network structure

    Energy Technology Data Exchange (ETDEWEB)

    Horky, Katrin; Schnick, Wolfgang [Department of Chemistry, Inorganic Solid-State, Chemistry, University of Munich (LMU), Butenandtstrasse 5-13, 81377, Munich (Germany)

    2017-02-17

    LiCa{sub 4}Si{sub 4}N{sub 8}F and LiSr{sub 4}Si{sub 4}N{sub 8}F were synthesized from Si{sub 3}N{sub 4}, LiNH{sub 2}, CaH{sub 2}/SrH{sub 2}, and LiF through a metathesis reaction in a radiofrequency furnace. The crystal structures of both compounds were solved and refined on the basis of single-crystal X-ray diffraction data [LiCa{sub 4}Si{sub 4}N{sub 8}F: P2{sub 1}/c (no. 14), a = 10.5108(3), b = 9.0217(3), c = 10.3574(3) Aa, β = 117.0152(10) , R{sub 1} = 0.0422, wR{sub 2} = 0.0724, Z = 4; LiSr{sub 4}Si{sub 4}N{sub 8}F: P4nc (no. 104), a = 9.3118(4), b = 9.3118(4), c = 5.5216(2) Aa, R{sub 1} = 0.0160, wR{sub 2} = 0.0388, Z = 2]. The silicate substructure of both compounds is built up of vertex-sharing SiN{sub 4} tetrahedra, thereby forming a structure analogous to the BCT zeolite with Ca{sup 2+}/Sr{sup 2+}, Li{sup +}, and F{sup -} ions filling the voids. The crystal structure of LiSr{sub 4}Si{sub 4}N{sub 8}F is homeotypic with that of Li{sub 2}Sr{sub 4}Si{sub 4}N{sub 8}O as it exhibits the same zeolite-type [SiN{sub 2}]{sup 2-} framework, but incorporates LiF instead of Li{sub 2}O. In contrast to the respective Sr compound, LiCa{sub 4}Si{sub 4}N{sub 8}F shows a distortion of the BCT-zeolite-type network as well as an additional site for F. Both F sites in LiCa{sub 4}Si{sub 4}N{sub 8}F exhibit different coordination spheres to LiSr{sub 4}Si{sub 4}N{sub 8}F. The title compounds are the first reported lithium alkaline-earth nitridosilicates containing fluorine. The crystal structures were confirmed by lattice-energy calculations (MAPLE), energy-dispersive X-ray spectroscopy (EDX) measurements, and powder X-ray diffraction. IR spectra confirmed the absence of N-H bonds. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Three-dimensional graphene/LiFePO4 nanostructures as cathode materials for flexible lithium-ion batteries

    International Nuclear Information System (INIS)

    Ding, Y.H.; Ren, H.M.; Huang, Y.Y.; Chang, F.H.; Zhang, P.

    2013-01-01

    Graphical abstract: Graphene/LiFePO 4 composites as a high-performance cathode material for flexible lithium-ion batteries have been prepared by using a co-precipitation method to synthesize graphene/LiFePO4 powders as precursors and then followed by a solvent evaporation process. - Highlights: • Flexible LiFePO 4 /graphene films were prepared first time by a solvent evaporation process. • The flexible electrode exhibited a high discharge capacity without conductive additives. • Graphene network offers the electrode adequate strength to withstand repeated flexing. - Abstract: Three-dimensional graphene/LiFePO 4 nanostructures for flexible lithium-ion batteries were successfully prepared by solvent evaporation method. Structural characteristics of flexible electrodes were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrochemical performance of graphene/LiFePO 4 was examined by a variety of electrochemical testing techniques. The graphene/LiFePO 4 nanostructures showed high electrochemical properties and significant flexibility. The composites with low graphene content exhibited a high capacity of 163.7 mAh g −1 at 0.1 C and 114 mAh g −1 at 5 C without further incorporation of conductive agents

  4. Ag-Decorated Fe3O4@SiO2 Nanorods: Synthesis, Characterization, and Applications in Degradation of Organic Dyes

    Directory of Open Access Journals (Sweden)

    Chao Li

    2016-01-01

    Full Text Available Well-dispersed Ag nanoparticles (NPs are successfully decorated on Fe3O4@SiO2 nanorods (NRs via a facile step-by-step strategy. This method involves coating α-Fe2O3 NRs with uniform silica layer, reduction in 10% H2/Ar atmosphere at 450°C to obtain Fe3O4@SiO2 NRs, and then depositing Ag NPs on the surface of Fe3O4@SiO2 NRs through a sonochemical step. It was found that the as-prepared Ag-decorated magnetic Fe3O4@SiO2 NRs (Ag-MNRs exhibited a higher catalytic efficiency than bare Ag NPs in the degradation of organic dye and could be easily recovered by convenient magnetic separation, which show great application potential for environmental protection applications.

  5. Preparation and characterization of SnO2 and Carbon Co-coated LiFePO4 cathode materials.

    Science.gov (United States)

    Wang, Haibin; Liu, Shuxin; Huang, Yongmao

    2014-04-01

    The SnO2 and carbon co-coated LiFePO4 cathode materials were successfully synthesized by solid state method. The microstructure and morphology of LiFePO4 composites were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscope. The results showed that the SnO2 and carbon co-coated LiFePO4 cathode materials exhibited more uniform particle size distribution. Compared with the uncoated LiFePO4/C, the structure of LiFePO4 with SnO2 and carbon coating had no change. The existence of SnO2 and carbon coating layer effectively enhanced the initial discharge capacity. Among the investigated samples, the one with DBTDL:LiFePO4 molar ratios of 7:100 exhibited the best electrochemical performance.

  6. Synthesis and electrochemical properties of Ti4+ doped Li3-xFe2-xTix(PO4)3/C cathode materials

    International Nuclear Information System (INIS)

    Liu Zhanqiang; Huang Fuqiang; Sun Junkang

    2011-01-01

    Highlights: → Li 3-x Fe 2-x Ti x (PO 4 ) 3 /C composite cathodes were prepared by ball-milling method. Ti-doping can improve the electrochemical property of Li 3 Fe 2 (PO 4 ) 3 . → The optimized doping level was found to be x = 0.2. → The second phase of LiTi 2 (PO 4 ) 3 will emerge if the doping level higher than 0.2. - Abstract: Li 3-x Fe 2-x Ti x (PO 4 ) 3 /C (x = 0-0.4) cathodes designed with Fe doped by Ti was studied. Both Li 3 Fe 2 (PO 4 ) 3 /C (x = 0) and Li 2.8 Fe 1.8 Ti 0.2 (PO 4 ) 3 /C (x = 0.2) possess two plateau potentials of Fe 3+ /Fe 2+ couple (around 2.8 V and 2.7 V vs. Li + /Li) upon discharge observed from galvanostatic charge/discharge and cyclic voltammetry. Li 2.8 Fe 1.8 Ti 0.2 (PO 4 ) 3 /C has higher reversibility and better capacity retention than that of the undoped Li 3 Fe 2 (PO 4 ) 3 /C. A much higher specific capacity of 122.3 mAh/g was obtained at C/20 in the first cycle, approaching the theoretical capacity of 128 mAh/g, and a capacity of 100.1 mAh/g was held at C/2 after the 20th cycle.

  7. Study of the structure and ferroelectric behavior of BaBi4-xLaxTi4O15 ceramics

    Science.gov (United States)

    Khokhar, Anita; Goyal, Parveen K.; Thakur, O. P.; Sreenivas, K.

    2015-06-01

    The structure and ferroelectric properties of Lanthanum substituted barium bismuth titanate BaBi4-xLaxTi4O15 (0 ≤ x ≤ 0.5) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material. The distribution of lanthanum into the perovskite layers and (Bi2O2)2+ layers of BaBi4Ti4O15 ceramics have been revealed through Raman spectroscopy. At lower value of x, it is seen that La3+ ions prefer to substitute A-site Bi3+ ions in the perovskite layers while for higher x values, La3+ ions get incorporated into the (Bi2O2)2+ layers. A critical La content of x ˜ 0.2 in BaBi4-xLaxTi4O15 is seen to exhibit a large remnant polarization (Pr) with low coercive field (Ec). The improvement in the ferroelectric properties of La substituted BaBi4Ti4O15 ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of lanthanum ion.

  8. Dehydriding and rehydriding reactions of LiBH4

    International Nuclear Information System (INIS)

    Orimo, S.; Nakamori, Y.; Kitahara, G.; Miwa, K.; Ohba, N.; Towata, S.; Zuettel, A.

    2005-01-01

    Structural differences in LiBH 4 before and after the melting reaction at approximately 550-bar K were investigated to clarify the experimental method for the confirmation of reversible dehydriding and rehydriding reactions. Since the long-range order of LiBH 4 begins to disappear after the melting reaction was achieved, investigation of the atomistic vibrations of the [BH 4 ]-anion in LiBH 4 was found to be effective for the confirmation of the reversibility. In the present study, LiBH 4 was successively dehydrided (decomposed) into LiH and B under 1-bar MPa of hydrogen at 873-bar K, and then rehydrided (recombined) into LiBH 4 under 35-bar MPa of hydrogen at the same temperature (873-bar K). The temperatures at the beginning and ending of the dehydriding reaction are lowered, by approximately 30-bar K, for LiBH 4 substituted (or mixed) with Mg (atomic ratio of Li:Mg=9:1) as compared to those for LiBH 4 alone. This is similar to the tendency exhibited by LiNH 2

  9. High ion conductive Sb2O5-doped β-Li3PS4 with excellent stability against Li for all-solid-state lithium batteries

    Science.gov (United States)

    Xie, Dongjiu; Chen, Shaojie; Zhang, Zhihua; Ren, Jie; Yao, Lili; Wu, Linbin; Yao, Xiayin; Xu, Xiaoxiong

    2018-06-01

    The combination of high conductivity and good stability against Li is not easy to achieve for solid electrolytes, hindering the development of high energy solid-state batteries. In this study, doped electrolytes of Li3P1-xSbxS4-2.5xO2.5x are successfully prepared via the high energy ball milling and subsequent heat treatment. Plenty of techniques like XRD, Raman, SEM, EDS and TEM are utilized to characterize the crystal structures, particle sizes, and morphologies of the glass-ceramic electrolytes. Among them, the Li3P0.98Sb0.02S3.95O0.05 (x = 0.02) exhibits the highest ionic conductivity (∼1.08 mS cm-1) at room temperature with an excellent stability against lithium. In addition, all-solid-state lithium batteries are assembled with LiCoO2 as cathode, Li10GeP2S12/Li3P0.98Sb0.02S3.95O0.05 as the bi-layer electrolyte, and lithium as anode. The constructed solid-state batteries delivers a high initial discharge capacity of 133 mAh g-1 at 0.1C in the range of 3.0-4.3 V vs. Li/Li+ at room temperature, and shows a capacity retention of 78.6% after 50 cycles. Most importantly, the all-solid-state lithium batteries with the Li10GeP2S12/Li3P0.98Sb0.02S3.95O0.05 electrolyte can be workable even at -10 °C. This study provides a promising electrolyte with the improved conductivity and stability against Li for the application of all-solid-state lithium batteries.

  10. Modeling Li-ion conductivity in LiLa(PO3)4 powder

    International Nuclear Information System (INIS)

    Mounir, Ferhi; Karima, Horchani-Naifer; Khaled, Ben Saad; Mokhtar, Férid

    2012-01-01

    Polycrystalline powder and single-crystal of LiLa(PO 3 ) 4 are synthesized by solid state reaction and flux technique, respectively. A morphological description of the obtained product was made based on scanning electron microscopy micrographs. The obtained powder was characterized by X-ray powder diffraction, FTIR and Raman spectroscopies. Ionic conductivity of the LiLa(PO 3 ) 4 powder was measured and evaluated over a temperature range from 553 to 913 K. Single crystals of LiLa(PO 3 ) 4 are characterized by single-crystal X-ray diffraction. The LiLa(PO 3 ) 4 structure was found to be isotypic with LiNd(PO 3 ) 4 . It crystallizes in the monoclinic system with space group C2/c and cell parameters: a=16.635(6) Å, b=7.130(3) Å, c=9.913(3) Å, β=126.37(4)°, V=946.72(6) Å 3 and Z=4. The LiLa(PO 3 ) 4 structure was described as an alternation between spiraling chains (PO 3 ) n and (La 3+ , Li + ) cations along the b direction. The small Li + ions, coordinated to four oxygen atoms, were located in the large connected cavities created between the LaO 8 polyhedra and the polyphosphate chains. The jumping of Li + through tunnels of the crystalline network was investigated using complex impedance spectroscopy. The close value of the activation energies calculated through the analysis of conductivity data and loss spectra indicate that the transport in the investigated system is through hopping mechanism. The correlation between ionic conductivity of LiLa(PO 3 ) 4 and its crystallographic structure was investigated and the most probably transport pathway model was determined.

  11. Kinetic Monte Carlo Study of Li Intercalation in LiFePO4.

    Science.gov (United States)

    Xiao, Penghao; Henkelman, Graeme

    2018-01-23

    Even as a commercial cathode material, LiFePO 4 remains of tremendous research interest for understanding Li intercalation dynamics. The partially lithiated material spontaneously separates into Li-poor and Li-rich phases at equilibrium. Phase segregation is a surprising property of LiFePO 4 given its high measured rate capability. Previous theoretical studies, aiming to describe Li intercalation in LiFePO 4 , include both atomic-scale density functional theory (DFT) calculations of static Li distributions and entire-particle-scale phase field models, based upon empirical parameters, studying the dynamics of the phase separation. Little effort has been made to bridge the gap between these two scales. In this work, DFT calculations are used to fit a cluster expansion for the basis of kinetic Monte Carlo calculations, which enables long time scale simulations with accurate atomic interactions. This atomistic model shows how the phases evolve in Li x FePO 4 without parameters from experiments. Our simulations reveal that an ordered Li 0.5 FePO4 phase with alternating Li-rich and Li-poor planes along the ac direction forms between the LiFePO 4 and FePO 4 phases, which is consistent with recent X-ray diffraction experiments showing peaks associated with an intermediate-Li phase. The calculations also help to explain a recent puzzling experiment showing that LiFePO 4 particles with high aspect ratios that are narrower along the [100] direction, perpendicular to the [010] Li diffusion channels, actually have better rate capabilities. Our calculations show that lateral surfaces parallel to the Li diffusion channels, as well as other preexisting sites that bind Li weakly, are important for phase nucleation and rapid cycling performance.

  12. Synthesis and characterization of PVA blended LiClO4 as electrolyte material for battery Li-ion

    Science.gov (United States)

    Gunawan, I.; Deswita; Sugeng, B.; Sudaryanto

    2017-07-01

    It have been synthesized the materials for Li ion battery electrolytes, namely PVA with the addition of LiClO4 salt were varied 0, 5, 10, 15 and 20% by weight respectively. The objective of this study is to control the ionic conductivity in traditional polymer electrolytes, to improve ionic conductivity with the addition of lithium perchlorat (LiClO4). These electrolyte materials prepared by PVA powder was dissolved into distilled water and added LiClO4 salt were varied. After drying the solution, PVA sheet blended LiClO4 salt as electrolyte material for Li ion battery obtained. PVA blended LiClO4 salt crystallite form was confirmed using X-Ray Difraction (XRD) equipment. Observation of the morphology done by using Scanning Electron Microscope (SEM). While the electrical conductivity of the material is measured using LCR meter. The results of XRD pattern of LiClO4 shows intense peaks at angles 2θ = 23.2, 32.99, and 36.58°, which represent the crystalline nature of the salt. Particles morphology of the sample revealed by scanning electron microscopy are irregular in shape and agglomerated, with mean size 200-300 nm. It can be concluded that polycrystalline particles are composed of large number of crystallites. The study of conductivity by using LCR meter shows that all the graphs represent the DC and AC conductivity phenomena.

  13. Li-ion batteries from LiFePO{sub 4} cathode and anatase/graphene composite anode for stationary energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Daiwon; Wang, Donghai; Viswanathan, Vish V.; Wang, Wei; Nie, Zimin; Zhang, Ji-Guang; Graff, Gordon L.; Liu, Jun; Yang, Zhenguo [Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352 (United States); Bae, In-Tae [Small Scale Systems Integration and Packaging Center, State University of New York at Binghamton, P.O. Box 6000, Binghamton, NY 13902 (United States); Duong, Tien [US Departments of Energy, 1000 Independence Ave., Washington, DC 20858 (United States)

    2010-03-15

    Li-ion batteries made from LiFePO{sub 4} cathode and anatase TiO{sub 2}/graphene composite anode were investigated for potential application in stationary energy storage. Fine-structured LiFePO{sub 4} was synthesized by a novel molten surfactant approach whereas anatase TiO{sub 2}/graphene nanocomposite was prepared via self-assembly method. The full cell that operated at 1.6 V demonstrated negligible fade even after more than 700 cycles at measured 1 C rate. While with relative lower energy density than traditional Li-ion chemistries interested for vehicle applications, the Li-ion batteries based on LiFePO{sub 4}/TiO{sub 2} combination potentially offers long life and low cost, along with safety, all which are critical to the stationary applications. (author)

  14. Ultralong Lifespan and Ultrafast Li Storage: Single-Crystal LiFePO4 Nanomeshes.

    Science.gov (United States)

    Zhang, Yan; Zhang, Hui Juan; Feng, Yang Yang; Fang, Ling; Wang, Yu

    2016-01-27

    A novel LiFePO4 material, in the shape of a nanomesh, has been rationally designed and synthesized based on the low crystal-mismatch strategy. The LiFePO4 nanomesh possesses several advantages in morphology and crystal structure, including a mesoporous structure, its crystal orientation that is along the [010] direction, and a shortened Li-ion diffusion path. These properties are favorable for their application as cathode in Li-ion batteries, as these will accelerate the Li-ion diffusion rate, improve the Li-ion exchange between the LiFePO4 nanomesh and the electrolyte, and reduce the Li-ion capacitive behavior during Li intercalation. So the LiFePO4 nanomesh exhibits a high specific capacity, enhanced rate capability, and strengthened cyclability. The method developed here can also be extended to other similar systems, for instance, LiMnPO4 , LiCoPO4 , and LiNiPO4 , and may find more applications in the designed synthesis of functional materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Compaction of LiBH4-LiAlH4 nanoconfined in activated carbon nanofibers: Dehydrogenation kinetics, reversibility, and mechanical stability during cycling

    DEFF Research Database (Denmark)

    Plerdsranoy, Praohatsorn; Javadian-Deylami, Seyd Payam; Jensen, Nicholai Daugaard

    2017-01-01

    To enhance volumetric hydrogen capacity for on-board fuel cells, compaction of LiAlH4-LiBH4 nanoconfined in activated carbon nanofibers (ACNF) is for the first time proposed. Loose powders of milled and nanoconfined LiAlH4-LiBH4 samples are compacted under 976 MPa to obtain the pellet samples...... with thickness and diameter of ∼1.20–1.30 and 8.0 mm, respectively. Dehydrogenation temperature of milled LiAlH4-LiBH4 increases from 415 to 434 °C due to compaction, while those of both compacted and loose powder samples of nanoconfined LiAlH4-LiBH4 are lower at comparable temperature of 330–335 °C. Hydrogen...

  16. Surface Modification of LiMn2O4 for Lithium Batteries by Nanostructured LiFePO4 Phosphate

    Directory of Open Access Journals (Sweden)

    B. Sadeghi

    2012-01-01

    Full Text Available LiMn2O4 spinel cathode materials have been successfully synthesized by solid-state reaction. Surface of these particles was modified by nanostructured LiFePO4 via sol gel dip coating method. Synthesized products were characterized by thermally analyzed thermogravimetric and differential thermal analysis (TG/DTA, X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, and energy dispersive X-ray spectroscopy (EDX. The results of electrochemical tests showed that the charge/discharge capacities improved and charge retention of battery enhanced. This improved electrochemical performance is caused by LiFePO4 phosphate layer on surfaces of LiMn2O4 cathode particles.

  17. Physical and chemical properties of MgO ceramics treated in molten K2SO4 for a long period

    International Nuclear Information System (INIS)

    Iwasa, Mikio; Kose, Saburo; Korenaga, Sadayoshi; Furukawa, Mitsuhiko.

    1978-01-01

    The wall materials of MHD power generating channel are exposed to thermally, physically and chemically severe conditions, so that they have to withstand great damages, especially the attack of seed materials. Several kinds of ceramics proposed as the wall materials have been tested in the simulated MHD environment. In this paper, MgO ceramics were treated in molten K 2 SO 4 , a typical seed material, and the changes in their physical and chemical properties were investigated in comparison with those of Al 2 O 3 ceramics. four kinds of MgO ceramics, three sintered and one electric fused, were immersed in molten K 2 SO 4 at 1300 0 C for the periods up to 1000 h, and weight, volume, surface roughness, bending strength and hardness were measured. The changes in the microstructures and chemical compositions due to the K 2 SO 4 treatment were also investigated. MgO ceramics were attacked by molten K 2 SO 4 only at the grain boundaries on the surface, in contrast at Al 2 O 3 ceramics which were severely damaged to form β-Al 2 O 3 . It was found that SiO 2 and CaO in the grain boundaries had played important roles to the attack of K 2 SO 4 . Generally, the changes in the properties of MgO ceramics by the K 2 SO 4 treatment were very small compared with those of Al 2 O 3 ceramics. It was concluded that MgO ceramics are more stable than Al 2 O 3 ceramics in molten K 2 SO 4 and their properties do not show substantial drops for long periods. (author)

  18. Uniform second Li ion intercalation in solid state ϵ-LiVOPO4

    International Nuclear Information System (INIS)

    Wangoh, Linda W.; Quackenbush, Nicholas F.; Sallis, Shawn; Wiaderek, Kamila M.; Ma, Lu; Wu, Tianpin; Chapman, Karena W.; Lin, Yuh-Chieh; Ong, Shyue Ping; Wen, Bohua; Chernova, Natasha A.; Whittingham, M. Stanley; Guo, Jinghua; Lee, Tien-Lin; Schlueter, Christoph; Piper, Louis F. J.

    2016-01-01

    Full, reversible intercalation of two Li + has not yet been achieved in promising VOPO 4 electrodes. A pronounced Li + gradient has been reported in the low voltage window (i.e., second lithium reaction) that is thought to originate from disrupted kinetics in the high voltage regime (i.e., first lithium reaction). Here, we employ a combination of hard and soft x–ray photoelectron and absorption spectroscopy techniques to depth profile solid state synthesized LiVOPO 4 cycled within the low voltage window only. Analysis of the vanadium environment revealed no evidence of a Li + gradient, which combined with almost full theoretical capacity confirms that disrupted kinetics in the high voltage window are responsible for hindering full two lithium insertion. Furthermore, we argue that the uniform Li + intercalation is a prerequisite for the formation of intermediate phases Li 1.50 VOPO 4 and Li 1.75 VOPO 4 . The evolution from LiVOPO 4 to Li 2 VOPO 4 via the intermediate phases is confirmed by direct comparison between O K–edge absorption spectroscopy and density functional theory.

  19. Photoluminescence of the Mg2Al4Si5O18-Al2O3-MgAl2O4-SiO2 ceramic system containing Fe3+ and Cr3+ as impurity ions

    Science.gov (United States)

    Sosman, L. P.; López, A.; Pedro, S. S.; Papa, A. R. R.

    2018-02-01

    This work presents the results of photoluminescence, excitation and radiative decay time for a ceramic system containing Mg2Al4Si5O18-Al2O3-MgAl2O4-SiO2 with Fe3+ and Cr3+ as impurity ions. Emission data were obtained using several excitation wavelengths and the excitation data were acquired for the most intense emission bands. The optical results were analyzed according to the Tanabe-Sugano (TS) theory from which the crystalline field parameter Dq and Racah parameters B and C were obtained for the Fe3+ and Cr3+ sites. The results indicate that the Fe3+ and Cr3+ ions occupy tetrahedral and octahedral sites, respectively. The emission from Fe3+ and Cr3+ ions causes an intense and broad band ranging between 350 nm and 850 nm, showing that this material is a potential tunable radiation source at room temperature.

  20. Synthesis and characterization of LiFePO{sub 4} cathode preparation by low temperature method

    Energy Technology Data Exchange (ETDEWEB)

    Rajesh, Desapogu, E-mail: rajesh.desapogu@gmail.com; Srinivas Naik, V.; Sunandana, C.S., E-mail: sunandana@gmail.com

    2015-05-01

    We review in detail the physics and technology of the novel material LiFePO{sub 4}, a potential cathode material for Li-ion batteries. In the present work, nano crystalline LiFePO{sub 4} film has been synthesized in both powder and thin film forms from a non-aqueous sol–gel synthesis route based on oxalates of Li and Fe (II). Ferrous oxalate has been synthesized indigenously using a ferrous sulphate based chemical reaction and characterized. Nano powders and thin films of LiFePO{sub 4} have been fabricated and coated on stainless steel substrates with the aim of device development in future. The material has been characterized extensively by XRD for crystal structure, FESEM for microstructure, EDS for elemental analysis and FTIR for the internal modes of phosphate ion. Fe{sup 3+} impurity characterization has been done by using ESR.

  1. Microwave synthesis of molybdenum doped LiFePO4/C and its electrochemical studies.

    Science.gov (United States)

    Naik, Amol; P, Sajan C

    2016-05-10

    A Mo-doped LiFePO4 composite was prepared successfully from an iron carbonyl complex by adopting a facile and rapid microwave assisted solid state method. The evolution of gases from the iron precursor produces a highly porous product. The formation and substitution of Mo in LiFePO4 were confirmed by X-ray diffraction; surface analysis was carried out by scanning electron microscopy, field emission scanning electron microscopy, and transmission electron microscopy. The electrochemical properties of the substituted LiFePO4 were examined by cyclic voltammetry, electrochemical impedance spectroscopy and by recording charge-discharge cycles. It was observed that the as prepared composites consisted of a single phase orthorhombic olivine-type structure, where Mo(6+) was successfully introduced into the M2(Fe) sites. Incorporation of supervalent Mo(6+) introduced Li(+) ion vacancies in LiFePO4. The synthesized material facilitated lithium ion diffusion during charging/discharging due to the charge compensation effect and porosity. The battery performance studies showed that LiMo0.05Fe0.095PO4 exhibited a maximum capacity of 169.7 mA h g(-1) at 0.1 C current density, with admirable stability retention. Even at higher current densities, the retention of the specific capacity was exceptional.

  2. Improving thermal insulation of TC4 using YSZ-based coating and SiO2 aerogel

    Directory of Open Access Journals (Sweden)

    Lei Jin

    2015-04-01

    Full Text Available In this paper, air plasmas spray (APS was used to prepare YSZ and Sc2O3–YSZ (ScYSZ coating in order to improve the thermal insulation ability of TC4 alloy. SiO2 aerogel was also synthesized and affixed on TC4 titanium alloy to inhabit thermal flow. The microstructures, phase compositions and thermal insulation performance of three coatings were analyzed in detail. The results of thermal diffusivity test by a laser flash method showed that the thermal diffusivities of YSZ, Sc2O3–YSZ and SiO2 aerogel are 0.553, 0.539 and 0.2097×10−6 m2/s, respectively. Then, the thermal insulation performances of three kinds of coating were investigated from 20 °C to 400 °C using high infrared radiation heat flux technology. The experimental results indicated that the corresponding temperature difference between the top TC4 alloy (400 °C and the bottom surface of YSZ is 41.5 °C for 0.6 mm thickness coating. For 1 mm thickness coating, the corresponding temperature difference between the top TC4 alloys (400 °C and the bottom surface of YSZ, ScYSZ, SiO2 aerogel three specimens is 54, 54.6 and 208 °C, respectively. The coating thickness and species were found to influence the heat insulation ability. In these materials, YSZ and ScYSZ exhibited a little difference for heat insulation behavior. However, SiO2 aerogel was the best one among them and it can be taken as protection material on TC4 alloys. In outer space, SiO2 aerogel can meet the need of thermal insulation of TC4 of high-speed aircraft.

  3. Effects of carbon source and carbon content on electrochemical performances of Li{sub 4}Ti{sub 5}O{sub 12}/C prepared by one-step solid-state reaction

    Energy Technology Data Exchange (ETDEWEB)

    Hu Xuebu [College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, Sichuan 610066 (China); Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Lin Ziji [China National Quality Supervision and Inspection Center for Alcoholic Beverage Products and Processed Food, Luzhou, Sichuan 646100 (China); Yang Kerun [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Hua, Yongjian [China Aviation Lithium Battery Co. Ltd., Luoyang, Henan 471009 (China); Deng Zhenghua, E-mail: zhdeng@cioc.ac.cn [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China)

    2011-05-30

    Highlights: > A simple route to prepare the Li{sub 4}Ti{sub 5}O{sub 12}/C by one-step solid-state reaction. > Carbon source and carbon content are two important factors on the electrochemical performances of Li{sub 4}Ti{sub 5}O{sub 12}/C. > As-prepared Li{sub 4}Ti{sub 5}O{sub 12}/C under optimized conditions shows excellent electrochemical performances. - Abstract: Li{sub 4}Ti{sub 5}O{sub 12}/C composites were synthesized by one-step solid-state reaction method using four commonly used organic compounds or organic polymers as carbon source, i.e., polyacrylate acid (PAA), citric acid (CA), maleic acid (MA) and polyvinyl alcohol (PVA). The physical characteristics of Li{sub 4}Ti{sub 5}O{sub 12}/C composites were investigated by X-ray diffraction, electron microscopy, Raman spectroscopy, particle size distribution and thermogravimetry-derivative thermogravimetry techniques. Their electrochemical properties were characterized by cyclic voltammograms, electrochemical impedance spectra, constant current charge-discharge and rate charge-discharge. These analyses indicated that the carbon source and carbon content have a great effect on the physical and electrochemical performances of Li{sub 4}Ti{sub 5}O{sub 12}/C composites. An ideal carbon source and appropriate carbon content effectively improved the electrical contact between the Li{sub 4}Ti{sub 5}O{sub 12} particles, which enhanced the discharge capacity and rate capability of Li{sub 4}Ti{sub 5}O{sub 12}/C composites. PAA was the best carbon source for the synthesis of Li{sub 4}Ti{sub 5}O{sub 12}/C composites. When the carbon content was 3.49 wt.% (LiOH.H{sub 2}O/PAA molar ratio of 1), as-prepared Li{sub 4}Ti{sub 5}O{sub 12}/C showed the maximum discharge capacity. At 0.2 C, initial capacity of the optimized sample was 168.6 mAh g{sup -1} with capacity loss of 2.8% after 50 cycles. At 8 and 10 C, it showed discharge capacities of 143.5 and 132.7 mAh g{sup -1}, with capacity loss of 8.7 and 9.9% after 50 cycles

  4. Preparation and electrochemical properties of LiFePO 4 /C ...

    Indian Academy of Sciences (India)

    A network structure, LiFePO4/C composite, was obtained using phenolic resin as carbon source. It possessed the highest specific surface area of 115.65 m2/g, exhibited the highest discharge capacity of 164.89 and 149.12 mAh/g at 0.1 C and 1 C rates, respectively. The discharge capacity was completely recovered when ...

  5. Synthesis and electrochemical properties of xLiMn0.9Fe0.1PO4·yLi3V2(PO4)3/C composite cathode materials for lithium–ion batteries

    International Nuclear Information System (INIS)

    Wu, Ling; Lu, JiaJia; Wei, Gui; Wang, Pengfei; Ding, Hao; Zheng, Junwei; Li, Xiaowei; Zhong, Shengkui

    2014-01-01

    Highlights: • xLiMn 0.9 Fe 0.1 PO4·yLi 3 V 2 (PO 4 ) 3 /C composites are prepared by a solid-state method. • The addition of Li 3 V 2 (PO 4 ) 3 can improve the properties of LiMn 0.9 Fe 0.1 PO 4 . • Mutual doping occurrs between the LiMn 0.9 Fe 0.1 PO 4 and Li 3 V 2 (PO 4 ) 3 phases. • 5LiMn 0.9 Fe 0.1 PO 4 ·Li 3 V 2 (PO 4 ) 3 /C shows the best electrochemical properties. - Abstract: The xLiMn 0.9 Fe 0.1 PO 4 ·yLi 3 V 2 (PO 4 ) 3 /C (x:y=1:0, 9:1 5:1, 3:1, 1:1 and 0:1) cathode materials are synthesized by a ball–milling and post–calcination method. XRD results reveal that the xLiMn 0.9 Fe 0.1 PO 4 ·yLi 3 V 2 (PO 4 ) 3 /C (x,y≠0) composites are composed of LiMn 0.9 Fe 0.1 PO 4 and Li 3 V 2 (PO 4 ) 3 phases, and no impurities are detected. In LiMn 0.9 Fe 0.1 PO 4Li 3 V 2 (PO 4 ) 3 system, most of the manganese, iron and vanadium elements in the raw materials tend to form the two major phases, and only small amounts of V, Mn and Fe as dopants enter into the lattice of LiMn 0.9 Fe 0.1 PO 4 and Li 3 V 2 (PO 4 ) 3 . Electrochemical tests show that the xLiMn 0.9 Fe 0.1 PO 4 ·yLi 3 V 2 (PO 4 ) 3 /C (x,y≠0) composites exhibit much better performance than the single LiMn 0.9 Fe 0.1 PO 4 /C. Among the samples, 5LiMn 0.9 Fe 0.1 PO 4 ·Li 3 V 2 (PO 4 ) 3 /C shows the best electrochemical performance. The sample delivers the specific capacities of 158.1, 140.7 and 100.2 mAh g −1 at 0.05, 1 and 4 C rates in the potential range of 2.5–4.5 V, and exhibits very long and flat discharge plateau around 4.0 V up to 1 C rate. The sample also shows good cycling performance at various C–rates

  6. Study of the structure, dielectric and ferroelectric behavior of BaBi{sub 4+δ}Ti{sub 4}O{sub 15} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Khokhar, Anita, E-mail: mails4anita@gmail.com, E-mail: goyalphy@gmail.com; Goyal, Parveen K., E-mail: mails4anita@gmail.com, E-mail: goyalphy@gmail.com; Sreenivas, K. [Department of Physics & Astrophysics, University of Delhi, Delhi-110 007 (India); Thakur, O. P. [Electroceramics Group, Solid State Physics Laboratory, Lucknow Road, Delhi 110 054 (India)

    2016-05-23

    The structure and ferroelectric properties of excess bismuth doped barium bismuth titanate BaBi{sub 4+δ}Ti{sub 4}O{sub 15} (δ = 2 - 10 wt.%)) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material with a change in the orthorhombic distortion with varying excess of bismuth content. There is no change in the phase transition temperature (T{sub m}) while the relaxor behaviour has been modified significantly with excess of bismuth doping. Saturated hysteresis loops with high remnant polarization (P{sub r} ~ 12.5  µC/cm{sup 2}), low coercive fields (E{sub c} ~ 26 kV/cm) are measured and a high piezoelectric coefficient (d{sub 33} ~ 29 pC/N) is achieved in poled BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics prepared with up to 8 wt.% of excess bismuth oxide. The improvement in the ferroelectric properties with increase in the excess bismuth content in BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of excess bismuth.

  7. Effects of Surface Morphology ZnAl2O4 of Ceramic Materials on Osteoblastic Cells Responses

    International Nuclear Information System (INIS)

    Suarez-Franco, J.L.; Fernandez-Pedrero, J.A.; Ivarez-Perez, M.A.; Garcia-Hipolito, M.; Surarez-Rosales, M.; Fregoso, O.; Juarez-Islas, J.A.; Ivarez-Perez, M.A.

    2013-01-01

    Ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. The purpose of this study was to investigate the effect of surface morphology of nano structure thin films of ZnAl 2 O 4 prepared by spray pyrolysis and bulk pellets of polycrystalline ZnAl 2 O 4 prepared by chemical coprecipitation reaction on the in vitro cell adhesion, viability, and cell-material interactions of osteoblastic cells. Our result showed that cell attachment was significantly enhanced from 60 to 80% on the ZnAl 2 O 4 nano structured material surface when compared with bulk ceramic surfaces. Moreover, our results showed that the balance of morphological properties of the thin film nano structure ceramic improves cell-material interaction with enhanced spreading and filopodia with multiple cellular extensions on the surface of the ceramic and enhancing cell viability/proliferation in comparison with bulk ceramic surfaces used as control. Altogether, these results suggest that zinc aluminate nano structured materials have a great potential to be used in dental implant and bone substitute applications.Ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. The purpose of this study was to investigate the effect of surface morphology of nano structure thin films of ZnAl 2 O 4 prepared by spray pyrolysis and bulk pellets of polycrystalline ZnAl 2 O 4 prepared by chemical coprecipitation reaction on the in vitro cell adhesion, viability, and cell-material interactions of osteoblastic cells. Our result showed that cell attachment was significantly enhanced from 60 to 80% on the ZnAl 2 O 4 nano structured material surface when compared with bulk ceramic surfaces. Moreover, our results showed that the balance of morphological properties of the thin film nano structure ceramic improves

  8. In situ carbon coated LiFePO4/C microrods with improved lithium intercalation behavior.

    Science.gov (United States)

    Bhuvaneswari, D; Kalaiselvi, N

    2014-01-28

    LiFePO4/C microrods consisting of building blocks of interconnected nanoparticles surrounded by a thin and amorphous coating of carbon have been prepared by a customized hydrothermal method. Appreciable discharge capacity values of 168 mA h g(-1) at 0.1 C and 130 mA h g(-1) at 5 C rates have been exhibited by the currently synthesized LiFePO4/C cathode. The study enumerates the feasibility of exploiting the hydrothermal method to prepare an in situ carbon coated LiFePO4/C compound with tunable morphological properties and desirable electrochemical properties observed for up to 100 cycles at a 5 C rate.

  9. The effect of heat preservation time on the electrochemical properties of LiFePO4

    Science.gov (United States)

    He, Rui; Zhang, Lihui; Bai, Xue; Liu, Zhenfa

    2017-12-01

    LiFePO4 was prepared via high temperature solid-state method at different heat preservation time. XRD and SEM was used to test the structure and morphology of LiFePO4. Land 2001 was used to test the electrochemical performance of LiFePO4. The results illustrated that well-crystallized LiFePO4 composite with homogeneous small particles was obtained by XRD and SEM. And the optimum heat preservation time was 4 hour. From charge/discharge test, it can be seen that at 0.2C, LiFePO4 has initial discharge capacities of 159.1mAh/g at the heat preservation time 4 hour. From the rate capacity, it can be seen that the discharge capacity was of optimum sample remains above 99% after 200 cycles.

  10. Effect of orthorhombic distortion on dielectric and piezoelectric properties of CaBi4Ti4O15 ceramics

    International Nuclear Information System (INIS)

    Tanwar, Amit; Sreenivas, K.; Gupta, Vinay

    2009-01-01

    High temperature bismuth layered piezoelectric and ferroelectric ceramics of CaBi 4 Ti 4 O 15 (CBT) have been prepared using the solid state route. The formation of single phase material with orthorhombic structure was verified from x-ray diffraction and Raman spectroscopy. The orthorhombic distortion present in the CBT ceramic sintered at 1200 deg. C was found to be maximum. A sharp phase transition from ferroelectric to paraelectric was observed in the temperature dependent dielectric studies of all CBT ceramics. The Curie's temperature (T c =790 deg. C) was found to be independent of measured frequency. The behavior of ac conductivity as a function of frequency (100 Hz-1 MHz) at low temperatures ( 33 ). The observed results indicate the important role of orthorhombic distortion in determining the improved property of multicomponent ferroelectric material.

  11. In-situ generation of Li2FeSiO4/C nanocomposite as cathode material for lithium ion battery

    International Nuclear Information System (INIS)

    Yi, Jin; Hou, Meng-yan; Bao, Hong-liang; Wang, Cong-xiao; Wang, Jian-qiang; Xia, Yong-yao

    2014-01-01

    Highlights: • A Li 2 FeSiO 4 /C nanocomposite is prepared via thermal vapor deposition technology. • The Li 2 FeSiO 4 /C nanocomposite is free from impurity and coated with carbon layer. • The Li 2 FeSiO 4 /C nanocomposite exhibits good rate capability and cycling stability. • Lithium benzoate serves as both lithium and carbon sources. - Abstract: A Li 2 FeSiO 4 /C nanocomposite is prepared via solvothermal method in combination with carbon coating technology. The as-prepared Li 2 FeSiO 4 /C nanocomposite is a single phase Li 2 FeSiO 4 with nano-tickness coated carbon layer and connected by the mutual cross-linked carbon conductive matrix. As cathode material for lithium ion battery, the composite delivers a discharge capacity of 154 mAh g −1 at 1 C and exhibits good rate capability with a discharge capacity of 106 mAh g −1 at the rate of 10 C, which is ascribed to the small particle size and enhanced electronic conductivity using carbon coating technology. The as-prepared Li 2 FeSiO 4 /C nanocomposite also behaves a good cycling stability with capacity retention of over 100 cycles

  12. Dual-band LTCC antenna based on 0.95Zn2SiO4-0.05CaTiO3 ceramics for GPS/UMTS applications

    Science.gov (United States)

    Dou, Gang; Li, Yu-Xia; Guo, Mei

    2015-10-01

    In this paper, we present a compact low-temperature co-fired ceramic (LTCC) dual-band antenna by using the electromagnetic coupling effect concept for global positioning system (GPS) and universal mobile telecommunication system (UMTS) applications. The overall dimension of the antenna is 8.6 mm × 13.0 mm × 1.1 mm. It consists of double meander lines and a via hole line. The top meander line operates at the upper band, and the bottom radiating patch is designed for the lower band. The via-hole line is employed to connect the double meander lines. Because of the effect of the coupled line, total dimension of the proposed antenna is greatly reduced. With the 2.5: voltage standing wave ratio (VSWR) impedance bandwidth definition, the lower and upper bands have the bandwidths of 110 MHz and 150 MHz, respectively. The proposed antenna is successfully designed, simulated, and analyzed by a high frequency structure simulator (HFSS). And the antenna is manufactured by using the 0.95Zn2SiO4-0.05CaTiO3 ceramics (εr = 7.1, tanδ = 0.00038) that is prepared by ourselves. The results show that the antenna is compact, efficient, and of near omnidirectional radiation pattern. Project supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20133718120009), the Natural Science Foundation of Shandong Provence, China (Grant Nos. ZR2013FQ002 and ZR2014FQ006), the China Postdoctoral Science Foundation (Grant No. 2014M551935), the Qingdao Municipality Postdoctoral Science Foundation, China, and the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents, China (Grant Nos. 2013RCJJ042 and 2014RCJJ052).

  13. Revision of the Li13Si4 structure.

    Science.gov (United States)

    Zeilinger, Michael; Fässler, Thomas F

    2013-11-06

    Besides Li17Si4, Li16.42Si4, and Li15Si4, another lithium-rich representative in the Li-Si system is the phase Li13Si4 (trideca-lithium tetra-silicide), the structure of which has been determined previously [Frank et al. (1975 ▶). Z. Naturforsch. Teil B, 30, 10-13]. A careful analysis of X-ray diffraction patterns of Li13Si4 revealed discrepancies between experimentally observed and calculated Bragg positions. Therefore, we redetermined the structure of Li13Si4 on the basis of single-crystal X-ray diffraction data. Compared to the previous structure report, decisive differences are (i) the introduction of a split position for one Li site [occupancy ratio 0.838 (7):0.162 (7)], (ii) the anisotropic refinement of atomic displacement parameters for all atoms, and (iii) a high accuracy of atom positions and unit-cell parameters. The asymmetric unit of Li13Si4 contains two Si and seven Li atoms. Except for one Li atom situated on a site with symmetry 2/m, all other atoms are on mirror planes. The structure consists of isolated Si atoms as well as Si-Si dumbbells surrounded by Li atoms. Each Si atom is either 12- or 13-coordinated. The isolated Si atoms are situated in the ab plane at z = 0 and are strictly separated from the Si-Si dumbbells at z = 0.5.

  14. Ionic conductivity and the formation of cubic CaH2 in the LiBH4-Ca(BH4)2 composite

    DEFF Research Database (Denmark)

    Sveinbjörnsson, Dadi Þorsteinn; Blanchard, Didier; Mýrdal, Jón Steinar Garðarsson

    2014-01-01

    LiBH4–Ca(BH4)2 composites were prepared by ball milling. Their crystal structures and phase composition were investigated using synchrotron X-ray diffraction and Rietveld refinement, and their ionic conductivity was measured using impedance spectroscopy. The materials were found to form a physical...... treatment. Concurrent formation of elemental boron may also occur. The ionic conductivity of the composites was measured using impedance spectroscopy, and was found to be lower than that of ball milled LiBH4. Electronic band structure calculations indicate that cubic CaH2 with hydrogen defects...... is electronically conducting. Its formation along with the possible precipitation of boron therefore has an effect on the measured conductivity of the LiBH4–Ca(BH4)2 composites and may increase the risk of an internal short-circuit in the cells....

  15. Bi4Sr3Ca3Cu4O16 galss and superconducting glass ceramics

    International Nuclear Information System (INIS)

    Zheng, H.; Mackenzie, J.D.

    1988-01-01

    Bi 4 Sr 3 Ca 3 Cu 4 O 16 glass has been successfully fabricated by the melting process. Glass transition temperature, crystallization temperature, and liquid temperature of the glass are 434, 478, and 833 0 C, respectively. After the glass is heat treated at 800 0 C, a glass ceramic is formed. A comparison of the x-ray-diffraction pattern of the superconducting Bi 4 Sr 3 Ca 3 Cu 4 O/sub 16+//sub x/ ceramic to the Bi 4 Sr 3 Ca 3 Cu 4 O 16 glass ceramic revealed preferred orientation in the glass ceramic crystals. The superconducting transition temperatures T/sub c//sub (onset)/ and T/sub c//sub (zero)/ of the glass ceramics are 100 and 45 K, respectively

  16. Radiation-disorder and aperiodicity in irradiated ceramics

    International Nuclear Information System (INIS)

    Hobbs, L.W.

    1992-01-01

    This final technical report documents the accomplishments of the program of research entitled ''Radiation Disorder and Aperiodicity in Irradiated Ceramics'' for the period June 22, 1989--June 21, 1992. This research forms the latest part on an on-going program, begun at MIT in 1983 under DOE support, which has had as its objectives investigation of the responses in radiation environments of ceramics heavily-irradiated with electrons, neutrons and ions, with potential applications to fusion energy technology and high-level nuclear waste storage. Materials investigated have included SiO 2 , MgAl 2 O 4 , Al 23 O 27 N 5 , SiC, BeO, LiAlO 2 , Li 2 ZrO 3 , CaTiO 3 KTaO 3 and Ca(Zr, Pu)Ti 2 O 7 . The program initially proposed for 1989 had as its major objectives two main thrusts: (1) research on defect aggregation in irradiated non-oxide ceramics, and (2) research on irradiation-induced amorphization of network silicas and phosphates

  17. Graphene Modified LiFePO4 Cathode Materials for High Power Lithium ion Batteries

    International Nuclear Information System (INIS)

    Zhou, X.; Wang, F.; Zhu, Y.; Liu, Z.

    2011-01-01

    Graphene-modified LiFePO 4 composite has been developed as a Li-ion battery cathode material with excellent high-rate capability and cycling stability. The composite was prepared with LiFePO 4 nanoparticles and graphene oxide nanosheets by spray-drying and annealing processes. The LiFePO 4 primary nanoparticles embedded in micro-sized spherical secondary particles were wrapped homogeneously and loosely with a graphene 3D network. Such a special nanostructure facilitated electron migration throughout the secondary particles, while the presence of abundant voids between the LiFePO 4 nanoparticles and graphene sheets was beneficial for Li + diffusion. The composite cathode material could deliver a capacity of 70 mAh g -1 at 60C discharge rate and showed a capacity decay rate of <15% when cycled under 10C charging and 20C discharging for 1000 times.

  18. Rechargable xLi{sub 2}MnO{sub 3}·(1 − x)Li{sub 4/3}Mn{sub 5/3}O{sub 4} electrode nanocomposite material as a modification product of chemical manganese dioxide by lithium additives

    Energy Technology Data Exchange (ETDEWEB)

    Sokolsky, Georgii V., E-mail: gvsokol@rambler.ru [National University of Food Technologies, Volodymyrska st., 70, 01033 Kyiv (Ukraine); National Aviation University, Cosmonaut Komarov Avenue 1, 04058 Kiev 58 (Ukraine); Ivanov, Sergiy V. [National University of Food Technologies, Volodymyrska st., 70, 01033 Kyiv (Ukraine); Boldyrev, Eudgene I.; Ivanova, Natalya D. [Institute of General and Inorganic Chemistry of Ukrainian National Academy of Science, Palladin Avenue 32-34, 252680 Kiev 142 (Ukraine); Kiporenko, Oksana Ya. [The Ukrainian Physics and Mathematics Lyceum, Akademika Glushkova Avenue 6, 03680, Kyiv (Ukraine)

    2015-12-15

    Highlights: • Li-ion battery cathode preparation procedure included MnO{sub 2} modification by Li-salts with subsequent heat treatment. • Li{sub 4}Mn{sub 5}O{sub 12}, Li{sub 2}MnO{sub 3,} and Li-rich phases form active nanocomposite cathode. • Heat treatment mode is of crucial importance for rechargeability. • Cathode material capacity is 150 mA h g{sup −1} within 2.5–4.5 V. - Abstract: Relatively simple preparation procedure of rechargeable Li-ion battery cathode material via manganese dioxide treatment with Li-containing additive and subsequent calcination has been demonstrated. X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and atomic force microscopy study were characterisation methods of modification products. Pyrolusite, Li{sub 0.3}MnO{sub 2}, layered Li{sub 2}MnO{sub 3}, and spinel Li{sub 4}Mn{sub 5}O{sub 12} phases were revealed as products of initial ramsdellite phase transformations at temperatures of heat treatment ranging from 360 °C to 600 °C. Optimal temperature of final heat treatment from the point of view of rechargeability and discharge characteristics was 450 °C. Samples heat-treated at 450 °C are characterized by the unique combination of Li{sub 4/3}Mn{sub 5/3}O{sub 4} and Li{sub 2}MnO{sub 3} phase components due to their structural integration, a significant degree of disordering, and sizes of nanocrystallites with Li diffusion path, which is the most favourable for reversibility. The prepared nanocomposite cathode material delivers a capacity of 150 mA h g{sup −1} within 2.5–4.5 V at 0.1 mA discharge.

  19. Transport property of novel sono-catalysed LiCF sub 3 SO sub 3 doped SiO sub 2 -PEG ormolyte

    CERN Document Server

    Jung, H Y; Wi, C J; Whang, C M

    2003-01-01

    Transport property of a novel sono-catalysed LiCF sub 3 SO sub 3 doped SiO sub 2 -10 wt% PEG ormolyte is reported. The ormolyte was synthesized by sol-gel method by varying the LiCF sub 3 SO sub 3 concentration [Li/O] from 0 to 0.1 in mole. The composition with [Li/O] = 0.05 exhibited the highest conductivity (sigma sub 2 sub 5 sub d eg sub C = 2.4x10 sup - sup 4 S cm sup - sup 1) with an enhancement of 10 sup 3 from that of the host matrix: SiO sub 2 -10 wt% PEG sono gel and has been referred to as 'optimum conducting composition (OCC)'. The direct determination of Li sup + ion mobility (mu)/mobile ion concentration (n) indicated that the enhancement was due to the increase in mu and n both. The temperature dependence of sigma, mu and n were carried out for the OCC samples in order to evaluate the respective energies involved in different thermally activated processes and to understand the ion transport mechanism. The ion transference number (t sub i sub o sub n) measurement inferred the ions as the sole cha...

  20. Comparison of inventory of tritium in various ceramic breeder blankets

    International Nuclear Information System (INIS)

    Nishikawa, M.; Beloglazov, S.; Nakashima, N.; Hashimoto, K.; Enoeda, M.

    2002-01-01

    It has been pointed out by the present authors that it is essential to understand such mass transfer steps as diffusion of tritium in the grain of breeder material, absorption of water vapor into bulk of the grain, and adsorption of water on surface of the grain, together with the isotope exchange reaction between hydrogen in purge gas and tritium on surface of breeder material and the isotope exchange reaction between water vapor in purge gas and tritium on surface, for estimation of the tritium inventory in a uniform ceramic breeder blanket under the steady-state condition. It has been also pointed out by the present authors that the water formation reaction on the surface of ceramic breeder materials at introduction of hydrogen can give effect on behavior of bred tritium and lithium transfer in blanket. The tritium inventory for various ceramic breeder blankets are compared in this study basing on adsorption capacity, absorption capacity, isotope exchange capacity, and isotope exchange reactions on the Li 2 O, LiAlO 2 , Li 2 ZrO 3 , Li 4 SiO 4 and Li 2 TiO 3 surface experimentally obtained by the present authors. Effect of each mass transfer steps on the shape of release curve of bred tritium at change of the operational conditions is also discussed from the observation at out pile experiment in KUR. (orig.)

  1. Revision of the Li13Si4 structure

    Directory of Open Access Journals (Sweden)

    Thomas F. Fässler

    2013-12-01

    Full Text Available Besides Li17Si4, Li16.42Si4, and Li15Si4, another lithium-rich representative in the Li–Si system is the phase Li13Si4 (tridecalithium tetrasilicide, the structure of which has been determined previously [Frank et al. (1975. Z. Naturforsch. Teil B, 30, 10–13]. A careful analysis of X-ray diffraction patterns of Li13Si4 revealed discrepancies between experimentally observed and calculated Bragg positions. Therefore, we redetermined the structure of Li13Si4 on the basis of single-crystal X-ray diffraction data. Compared to the previous structure report, decisive differences are (i the introduction of a split position for one Li site [occupancy ratio 0.838 (7:0.162 (7], (ii the anisotropic refinement of atomic displacement parameters for all atoms, and (iii a high accuracy of atom positions and unit-cell parameters. The asymmetric unit of Li13Si4 contains two Si and seven Li atoms. Except for one Li atom situated on a site with symmetry 2/m, all other atoms are on mirror planes. The structure consists of isolated Si atoms as well as Si–Si dumbbells surrounded by Li atoms. Each Si atom is either 12- or 13-coordinated. The isolated Si atoms are situated in the ab plane at z = 0 and are strictly separated from the Si–Si dumbbells at z = 0.5.

  2. Synthesis, structures and properties of the new lithium cobalt(II) phosphate Li4Co(PO4)2

    International Nuclear Information System (INIS)

    Glaum, R.; Gerber, K.; Schulz-Dobrick, M.; Herklotz, M.; Scheiba, F.; Ehrenberg, H.

    2012-01-01

    α-Li 4 Co(PO 4 ) 2 has been synthesized and crystallized by solid-state reactions. The new phosphate crystallizes in the monoclinic system (P2 1 /a, Z=4, a=8.117(3) Å, b=10.303(8) Å, c=8.118(8) Å, β=104.36(8) Å) and is isotypic to α-Li 4 Zn(PO 4 ) 2 . The structure of α-Li 4 Co(PO 4 ) 2 has been determined from single-crystal X-ray diffraction data {R 1 =0.040, wR 2 =0.135, 2278 unique reflections with F o >4σ(F o )}. The crystal structure, which might be regarded as a superstructure of the wurtzite structure type, is build of layers of regular CoO 4 , PO 4 and Li1O 4 tetrahedra. Lithium atoms Li2, Li3 and Li4 are located between these layers. Thermal investigations by in-situ XRPD, DTA/TG and quenching experiments suggest decomposition followed by formation and phase transformation of Li 4 Co(PO 4 ) 2 : α-Li 4 Co(PO 4 ) 2 ⟹ 442°C β-Li 3 PO 4 +LiCoPO 4 ⇌ 773°C β-Li 4 Co(PO 4 ) 2 ⟹ quenchingto25°C α-Li 4 Co(PO 4 ) 2 According to HT-XRPD at θ=850°Cβ-Li 4 Co(PO 4 ) 2 (Pnma, Z=2, 10.3341(8) Å, b=6.5829(5) Å, c=5.0428(3) Å) is isostructural to γ-Li 3 PO 4 . The powder reflectance spectrum of α-Li 4 Co(PO 4 ) 2 shows the typical absorption bands for the tetrahedral chromophore [Co II O 4 ]. - Graphical abstract: The complex formation and decomposition behavior of Li 4 Co(PO 4 ) 2 with temperature has been elucidated. The crystal structure of its α-phase was determined from single crystal data, HT-XRPD allowed derivation of a structure model for the β-phase. Both modifications belong to the Li 3 PO 4 structure family. Highlights: ► Li 4 Co(PO 4 ) 2 exhibits complex thermal behavior. ► The new phosphate belongs to the Li 3 PO 4 structure family. ► A single-crystal structure analysis is provided for the metastable α-Li 4 Co(PO 4 ) 2 . ► From HT-XRPD data a cation distribution model is developed for β-Li 4 Co(PO 4 ) 2 . ► No electrochemical delithiation is observed up to 5 V.

  3. Structural and Electrochemical Characterization of Pure LiFePO4 and Nanocomposite C-LiFePO4 Cathodes for Lithium Ion Rechargeable Batteries

    Directory of Open Access Journals (Sweden)

    Arun Kumar

    2009-01-01

    Full Text Available Pure lithium iron phosphate (LiFePO4 and carbon-coated LiFePO4 (C-LiFePO4 cathode materials were synthesized for Li-ion batteries. Structural and electrochemical properties of these materials were compared. X-ray diffraction revealed orthorhombic olivine structure. Micro-Raman scattering analysis indicates amorphous carbon, and TEM micrographs show carbon coating on LiFePO4 particles. Ex situ Raman spectrum of C-LiFePO4 at various stages of charging and discharging showed reversibility upon electrochemical cycling. The cyclic voltammograms of LiFePO4 and C-LiFePO4 showed only a pair of peaks corresponding to the anodic and cathodic reactions. The first discharge capacities were 63, 43, and 13 mAh/g for C/5, C/3, and C/2, respectively for LiFePO4 where as in case of C-LiFePO4 that were 163, 144, 118, and 70 mAh/g for C/5, C/3, C/2, and 1C, respectively. The capacity retention of pure LiFePO4 was 69% after 25 cycles where as that of C-LiFePO4 was around 97% after 50 cycles. These results indicate that the capacity and the rate capability improved significantly upon carbon coating.

  4. MW-assisted synthesis of LiFePO 4 for high power applications

    Science.gov (United States)

    Beninati, Sabina; Damen, Libero; Mastragostino, Marina

    LiFePO 4/C was prepared by solid-state reaction from Li 3PO 4, Fe 3(PO 4) 2·8H 2O, carbon and glucose in a few minutes in a scientific MW (microwave) oven with temperature and power control. The material was characterized by X-ray diffraction, scanning electron microscopy and by TGA analysis to evaluate carbon content. The electrochemical characterization as positive electrode in EC (ethylene carbonate)-DMC (dimethylcarbonate) 1 M LiPF 6 was performed by galvanostatic charge-discharge cycles at C/10 to evaluate specific capacity and by sequences of 10 s discharge-charge pulses, at different high C-rates (5-45C) to evaluate pulse-specific power in simulate operative conditions for full-HEV application. The maximum pulse-specific power and, particularly, pulse efficiency values are quite high and make MW synthesis a very promising route for mass production of LiFePO 4/C for full-HEV batteries at low energy costs.

  5. Effect of Cr-sources on performance of Li1.05Cr0.04Mn1.96O4 cathode materials prepared by slurry spray drying method

    International Nuclear Information System (INIS)

    Peng, Z.D.; Jiang, Q.L.; Du, K.; Wang, W.G.; Hu, G.R.; Liu, Y.X.

    2010-01-01

    The effect of Cr-sources on the performance of Li 1.05 Cr 0.04 Mn 1.96 O 4 prepared by slurry spray drying method was studied by adopting three different chromic compounds, Cr 2 O 3 , Cr 2 (SO 4 ) 3 and Cr(CH 3 COO) 3 , respectively. The prepared powder materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), laser particle size analyzer and Brunauer-Emmett-Teller (BET) specific surface area test. Electrochemical performances of these cathode materials were investigated by electrochemical impedance spectroscopy (EIS) and charge-discharge tests with Li/LiCr x Mn 2-x O 4 coin-type batteries. The results indicate that porous spherical particles with average particle size of about 24 μm can be obtained by slurry spray drying process. Using Cr(CH 3 COO) 3 as Cr-source resulted in the better mixing properties, which can make the as-prepared CA-Li 1.05 Cr 0.04 Mn 1.96 O 4 having smaller lattice parameter, smaller grain size and better structure stability, and consequently the obtained sample showed low charge transfer impedance and electrochemical polarization, and exhibited good electrochemical performance at elevated temperature.

  6. Triple carbon coated LiFePO4 composite with hierarchical conductive architecture as high-performance cathode for Li-ion batteries

    International Nuclear Information System (INIS)

    Mei, Riguo; Yang, Yanfeng; Song, Xiaorui; An, Zhenguo; Zhang, Jingjie

    2015-01-01

    Triple carbon coated LiFePO 4 composite is prepared by spray drying-carbothermal reduction (SD-CTR) method. The triple carbon sources (viz. graphene oxide, thermoplastic phenolic resin and water-solubility starch) play different roles in constructing the hierarchical conductive architecture. The structure, component and morphology of the as-obtained LiFePO 4 composites are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. The results indicate that, compared with double carbon coated LiFePO 4 counterparts, the triple carbon coated LiFePO 4 composite possesses smaller crystallite and high-efficiency of carbon coating such as more complete coating, lower I D /I G ratio, and better conductive architecture. Benefited from the above mentioned superiority, the triple carbon coated LiFePO 4 composite exhibits outstanding electrochemical performance, especially for high-rate capability, which reaches up to 120 mA h g −1 at 10 C

  7. Dosimetric characteristics of Li2B4O7:Cu,Ag,P solid TL detectors

    International Nuclear Information System (INIS)

    Proki, M.

    2002-01-01

    The main dosimetric characteristics are presented of newly prepared tissue-equivalent, highly sensitive thermoluminescent detector, Li 2 B 4 O 7 :Cu,Ag,P in the form of sintered pellets, developed at the Institute of Nuclear Sciences, Vin a . As a result of an advancement in the preparation procedure by the sensitising of basic copper activated lithium borate TL material, significant improvement in the TL sensitivity of Li 2 B 4 O 7 :Cu,Ag,P was gained. The glow curve of Li 2 B 4 O 7 :Cu,Ag,P consists of well defined main dosimetric peak situated at about 185-190 deg. C with the TL sensitivity which is about four to five times higher than that of LiF:Mg,Ti (TLD-100). From the experimental results a very wide linear dose response range, up to 10 3 Gy is evident. Dosimetric characteristics make sintered solid Li 2 B 4 O 7 :Cu,Ag,P TL detectors very promising for different dosimetry applications particularly in medical dosimetry and also for individual monitoring. (author)

  8. Synthesis and magnetic properties of LiFePO4 substitution magnesium

    Science.gov (United States)

    Choi, Hyunkyung; Kim, Min Ji; Hahn, Eun Joo; Kim, Sam Jin; Kim, Chul Sung

    2017-06-01

    LiFe0.9Mg0.1PO4 sample was prepared by using a solid-state reaction method, and the temperature-dependent magnetic properties of the sample were studied. The X-ray diffraction (XRD) pattern showed an olivine-type orthorhombic structure with space group Pnma based on Rietveld refinement method. The effect of Mg substitution in antiferromagnetic LiFe0.9Mg0.1PO4 was investigated using a vibrating sample magnetometer (VSM) and Mössbauer spectroscopy. The temperature-dependence of the magnetization curves of LiFe0.9Mg0.1PO4 shows abnormal antiferromagnetic behavior with ordering temperature. Sudden changes in both the magnetic hyperfine field (Hhf) and its slope below 15 K suggest that magnetic phase transition associated to the abrupt occurrence of spin-reorientation. The Néel temperature (TN) and spin-reorientation temperature (TS) of LiFe0.9Mg0.1PO4 are lower than those of pure LiFePO4 (TN = 51 K, TS = 23 K). This is due to the Fe-O-Fe superexchange interaction being larger than that of the Fe-O-Mg link. Also, we have confirmed a change in the electric quadrupole splitting (ΔEQ) by the spin-orbit coupling effect and the shape of Mössbauer spectrum has provided the evidence for TS and a strong crystalline field. We have found that Mg ions in LiFe0.9Mg0.1PO4 induce an asymmetric charge density due to the presence of Mg2+ ions at the FeO6 octahedral sites.

  9. Preparation of V-Doped LiFePO4/C as the Optimized Cathode Material for Lithium Ion Batteries.

    Science.gov (United States)

    Sun, Pingping; Zhang, Haiyang; Shen, Kai; Fan, Qi; Xu, Qingyu

    2015-04-01

    LiFe1-x,Vx,PO4/C composites were synthesized by solid state reaction. The effect of carbon coating and V doping on the performance of LiFePO4 has been systematically investigated by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), charge/discharge and cyclic voltammetry (CV) measurement. The results show that carbon coating and proper amount of V incorporation do not significantly change the host crystal structure of LiFePO4, while the electrochemical performance of LiFePO4 can be significantly improved. Particularly, the LiFe0.96V0.04PO4/C exhibits the best performance with a specific discharge capacity of 105.5 mA h/g at 5.0 C, 90.3 mA h/g at 10 C and 66.7 mA h/g at 30 C with stable cycle performance, which is significantly improved compared with the pure LiFePO4/C. The cyclic voltammograms result reveals that V doping could decrease the resistance of LiFePO4/C composite electrode drastically and improve its reversibility.

  10. Electrical characteristics of Li(Ni7/10Fe3/10)VO4 ceramics

    International Nuclear Information System (INIS)

    Ram, Moti

    2011-01-01

    Graphical abstract: Display Omitted Research highlights: → The compound [Li(Ni 7/10 Fe 3/10 )VO 4 ] was synthesized by a solution-based chemical method. → Structural, microstructural and electrical properties are studied using X-ray diffraction, field emission scanning electron microscopy and complex impedance spectroscopy techniques, respectively. → Electrical conductivity study indicates that electrical conduction in the material is a thermally activated process. - Abstract: The compound [Li(Ni 7/10 Fe 3/10 )VO 4 ] was produced by a solution-based chemical route whose electrical properties were investigated using complex impedance spectroscopy technique. X-ray diffraction study reveals an orthorhombic unit cell structure of the compound. Complex electrical impedance analysis exhibits: (i) grain interior, grain boundary and electrode-material interface contributions to electrical response and (ii) the presence of temperature dependent electrical relaxation phenomena in the material. Electrical conductivity study indicates that electrical conduction in the material is a thermally activated process.

  11. Synthesis and characterization of metastable, 20 nm-sized Pna21-LiCoPO4 nanospheres

    International Nuclear Information System (INIS)

    Ludwig, Jennifer; Nordlund, Dennis; Doeff, Marca M.; Nilges, Tom

    2017-01-01

    The majority of research activities on LiCoPO 4 are focused on the phospho-olivine (space group Pnma), which is a promising high-voltage cathode material for Li-ion batteries. In contrast, comparably little is known about its metastable Pna2 1 modification. Herein, we present a comprehensive study on the structure–property relationships of 15–20 nm Pna2 1 -LiCoPO 4 nanospheres prepared by a simple microwave-assisted solvothermal process. Unlike previous reports, the results indicate that the compound is non-stoichiometric and shows cation-mixing with Co ions on the Li sites, which provides an explanation for the poor electrochemical performance. Co L 2,3 -edge X-ray absorption spectroscopic data confirm the local tetrahedral symmetry of Co 2+ . Comprehensive studies on the thermal stability using thermogravimetric analysis, differential scanning calorimetry, and in situ powder X-ray diffraction show an exothermic phase transition to olivine Pnma-LiCoPO 4 at 527 °C. The influence of the atmosphere and the particle size on the thermal stability is also investigated. - Graphical abstract: Blue nano-sized Pna2 1 -LiCoPO 4, featuring tetrahedrally-coordinated Co 2+ , was synthesized in a rapid one-step microwave-assisted solvothermal process. The phase relation between this metastable and the stable polymorph was analyzed and electrochemical properties are discussed. - Highlights: • Preparation of uniform 15–20 nm nanospheres of metastable Pna2 1 -LiCoPO 4 polymorph. • Structure redetermination shows cation-mixing (Co blocking Li sites). • In situ investigation of phase transformation to olivine Pnma-LiCoPO 4 at 527 °C. • Pna2 1 -LiCoPO 4 reemerges as a stable high-temperature phase above 800 °C. • X-ray absorption spectroscopy confirms local tetrahedral symmetry (T d Co 2+ ).

  12. Preparation of LiMn{sub 2}O{sub 4} cathode thin films for thin film lithium secondary batteries by a mist CVD process

    Energy Technology Data Exchange (ETDEWEB)

    Tadanaga, Kiyoharu, E-mail: tadanaga@chem.osakafu-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka, 599-8531 (Japan); Yamaguchi, Akihiro; Sakuda, Atsushi; Hayashi, Akitoshi; Tatsumisago, Masahiro [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka, 599-8531 (Japan); Duran, Alicia; Aparacio, Mario [Instituto de Cerámica y Vidrio, Consejo Superior de Investigaciones Científicas, Kelsen 5 (Campus de Cantoblanco), Madrid, 28049 (Spain)

    2014-05-01

    Highlights: • LiMn{sub 2}O{sub 4} thin films were prepared by using the mist CVD process. • An aqueous solution of lithium and manganese acetates is used for the precursor solution. • The cell with the LiMn{sub 2}O{sub 4} thin films exhibited a capacity of about 80 mAh/g. • The cell showed good cycling performance during 10 cycles. - Abstract: LiMn{sub 2}O{sub 4} cathode thin films for thin film lithium secondary batteries were prepared by using so-called the “mist CVD process”, employing an aqueous solution of lithium acetate and manganese acetate, as the source of Li and Mn, respectively. The aqueous solution of starting materials was ultrasonically atomized to form mist particles, and mists were transferred by nitrogen gas to silica glass substrate to form thin films. FE-SEM observation revealed that thin films obtained by this process were dense and smooth, and thin films with a thickness of about 750 nm were obtained. The electrochemical cell with the thin films obtained by sintering at 700 °C exhibited a capacity of about 80 mAh/g, and the cell showed good cycling performance during 10 cycles.

  13. Properties–structure relationship research on LiCaPO4:Eu2+ as blue phosphor for NUV LED application

    International Nuclear Information System (INIS)

    Zhang, Xinguo; Mo, Fuwang; Zhou, Liya; Gong, Menglian

    2013-01-01

    Graphical abstract: The graphical abstract shows the excitation and emission spectrum of LiCaPO 4 :Eu 2+ , and the CIE coordinates of LiCaPO 4 :Eu 2+ . The inset shows the photo of blue LED prepared by LiCaPO 4 :Eu 2+ and NUV chip. It indicates that this phosphor can be excited by UV light and emit strong greenish-blue light. Highlights: •Pure phase blue phosphors of LiCaPO 4 :Eu 2+ with a hexagonal structure were first prepared via solid-state method. •The crystallographic site of Eu 2+ ion in the LiCaPO 4 lattice was identified as 8-fold Ca 2+ site. •The phosphor exhibits excellent thermal stability and the corresponding mechanism was thermal assisted ionization. •Bright and high color purity blue LED prototype based on LiCaPO 4 :Eu 2+ phosphor was fabricated. -- Abstract: Blue-emitting phosphors of Eu 2+ -activated LiCaPO 4 with a hexagonal structure were prepared via a conventional solid-state method. The XRD, PL spectra and thermal quenching were applied to characterize the phosphors. The crystallographic site of Eu 2+ ion in the LiCaPO 4 lattice was identified and discussed. The optimized LiCaPO 4 :0.03Eu 2+ exhibits the bright greenish-blue emission with CIE coordinates of (0.119, 0.155) and a quantum efficiency of 52%. The critical energy-transfer distance was confirmed as ∼18 Å by both calculated crystal structure method and experimental spectral method. The thermal stability of LiCaPO 4 :Eu 2+ was evaluated by temperature-dependent PL spectra, and the thermal quenching mechanism was found to be thermal assisted ionization. Prototype blue LEDs with high color purity and good current stability were fabricated

  14. In Situ Studies of Fe4+ Stability in β-Li3Fe2(PO4)3 Cathodes for Li Ion Batteries

    DEFF Research Database (Denmark)

    Christiansen, Ane Sælland; Johnsen, Rune E.; Norby, Poul

    2015-01-01

    In commercial Fe-based batteries the Fe2+/Fe3+ oxidation states are used, however by also utilizing the Fe4+ oxidation state, intercalation of up to two Li ions per Fe ion could be possible. In this study, we investigate whether Fe4+ can be formed and stabilized in β-Li3Fe2(PO4)3. The work includes...... of Fe4+ formation. Oxidation of the organic electrolyte is inevitable at 4.5 V but this alone cannot explain the volume change. Instead, a reversible oxygen redox process (O2− → O−) could possibly explain and charge compensate for the reversible extraction of lithium ions from β-Li3Fe2(PO4)3....... in situ synchrotron X-ray powder diffraction studies (XRPD) during charging of β-Li3Fe2(PO4)3 up to 5.0 V vs. Li/Li+. A novel capillary-based micro battery cell for in situ XRPD has been designed for this. During charge, a plateau at 4.5 V was found and a small contraction in volume was observed...

  15. Crystal structure of a Zn-doped derivative of the Li17Ge4 compound

    International Nuclear Information System (INIS)

    Lacroix-Orio, L.; Tillard, M.; Belin, C.

    2008-01-01

    The compound Li 17-ε Zn ε Ge 4 has been obtained as a side product during the preparation of the intermetallic compound Li 8 Zn 2 Ge 3 from the elements. Its structure has been determined from single crystal X-ray diffraction intensities measured at 173 K. It crystallizes in the cubic system, F4-bar3m space group, a = 18.842(1) A, Z = 20. Its crystal structure is slightly different from those so far reported in the literature for the Zn-free phase Li 17 Ge 4 , particularly concerned are the positions and the site occupations of Li atoms. Most likely, these structural variations result from the presence of a small Zn concentration in the compound. The Zn doping atom has been found only at the specific Li 4d site (about 3 at.% Zn)

  16. LiFePO4/polymer/natural graphite: low cost Li-ion batteries

    International Nuclear Information System (INIS)

    Zaghib, K.; Striebel, K.; Guerfi, A.; Shim, J.; Armand, M.; Gauthier, M

    2004-01-01

    The aging and performance of natural graphite/PEO-based gel electrolyte/LiFePO 4 cells are reported. The gel polymer electrolytes were produced by electron-beam irradiation and then soaked in a liquid electrolyte. The natural graphite anode in gel electrolyte containing LiBF4-EC/GBL exhibited high reversible capacity (345 mAh/g) and high coulombic efficiency (91%). The LiFePO 4 cathode in the same gel-polymer exhibited a reversible capacity of 160 mAh/g and 93% coulombic efficiency. Better performance was obtained at high-rate discharge with 6% carbon additive in the cathode, however the graphite anode performance suffers at high rate. The Li-ion gel polymer battery shows a capacity fade of 13% after 180 cycles and has poor performance at low temperature due to low diffusion of the lithium to the graphite in the GBL system. The LiFePO 4 /gel/Li system has an excellent rate capacity. LiFePO 4 cathode material is suitable for HEV application

  17. In-pile Tritium Permeation through F82H Steel with and without a Ceramic Coating of Cr2O3-SiO2 Including CrPO4

    International Nuclear Information System (INIS)

    Nakamichi, M.; Hayashi, K.; Kulsartov, T.V.; Afanasyev, S.E.; Shestakov, V.P.; Chikhray, Y.V.; Kenzhin, E.A.; Kolbaenkov, A.N.

    2006-01-01

    Development of coating on blanket structural materials with significant reduction capability of tritium permeation is highly required in order to realize a reasonable design of a tritium recovery and processing system of demonstration (DEMO) fusion reactors. An effective coating has been developed in Japan Atomic Energy Agency (JAEA) using a ceramic material of Cr 2 O 3 -SiO 2 including CrPO 4 . In previous out-of-pile deuterium permeation experiments at 600 o C [T.V. Kulsartov et al., Fusion Eng. Des. 81 (2006) 701], a significant permeation reduction factor (PFR) of about 300 was obtained for the coating on the inner-side surface of tubular diffusion cells made by ferritic steel (F82H). In the present study, in-pile experiments on tritium permeation were conducted for F82H steel with and without the same coating, using a testing reactor IGV-1M in Kazakhstan. The tritium source used was liquid lithium-lead eutectics, Pb17Li, which was poured into a space around a tubular diffusion cell (specimen) of F82H steel with or without the coating on the inner side the cell. The irradiation time was about 4 hours, which corresponds to a fast-neuron fluence of about 2x10 21 m -2 (E > 1.1 MeV). The permeation reduction factor (PRF) was obtained by comparison of kinetics curves of tritium permeation through the diffusion cell of F82H steel with and without the coating. The PRFs at 600 and 500 o C were 292 and 30, respectively. These values are close to corresponding PRF values of 307 and 45, which had been obtained at 600 and 500 o C, respectively, in the previous out-of-pile experiments [T.V. Kulsartov et al., Fusion Eng. Des. 81 (2006) 701]. (author)

  18. 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.

  19. Structural and Mössbauer studies of nanocrystalline Mn{sup 4+}-doped Li{sub 0.5}Fe{sub 2.5}O{sub 4} particles prepared by mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Widatallah, H. M., E-mail: hishammw@squ.edu.om; Al-Mabsali, F. N.; Al-Hajri, F. S. [Sultan Qaboos University, Physics Department, College of Science (Oman); Khalifa, N. O. [University of Khartoum, Physics Department, Faculty of Science (Sudan); Gismelseed, A. M.; Al-Rawas, A. D.; Elzain, M.; Yousif, A. [Sultan Qaboos University, Physics Department, College of Science (Oman)

    2016-12-15

    The structure and magnetic properties of spinel-related Mn{sup 4+}-doped Li{sub 0.5}Fe{sub 2.5}O{sub 4} nanocrystalline particles of the composition Li{sub 0.5}Fe{sub 2.25}Mn{sub 0.1875}O{sub 4}, prepared by milling a pristine sample for different times, were investigated. The average crystallite and particle size, respectively, decreased form ∼40 nm to ∼10 nm and ∼2.5 μm to ∼10 nm with increasing milling time from 0 h to 70 h. Rietveld refinement of the XRD data of the non-milled sample show the Mn{sup 4+} dopant ions to substitute for Fe{sup 3+} at the octahedral B-sites of the spinel-related structure. The Mössbauer spectra of the milled ferrites indicate that more particles turn superparamagnetic with increasing milling time. The Mössbauer data collected at 78 K suggest that while in the non-milled sample the Mn{sup 4+} ions substitute for Fe{sup 3+} at the octahedral B-sites, this is reversed as milling proceeds with doped Mn{sup 4+} ions, balancing Fe{sup 3+} vacancies and possibly Li{sup +} ions progressively migrate to the tetrahedral A-sites. This is supported by the slight increase observed in the magnetization of the milled samples relative to that of the non-milled one. The magnetic data suggest that in addition to the increasing superparamagentic component of the milled particles, thermal spin reversal and/or spin canting effects are possible at the surface layers of the nanoparticles.

  20. A facile approach to fabricate Au nanoparticles loaded SiO2 microspheres for catalytic reduction of 4-nitrophenol

    International Nuclear Information System (INIS)

    Tang, Mingyi; Huang, Guanbo; Li, Xianxian; Pang, Xiaobo; Qiu, Haixia

    2015-01-01

    Hydrophilic and biocompatible macromolecules were used to improve and simplify the process for the fabrication of core/shell SiO 2 @Au composite particles. The influence of polymers on the morphology of SiO 2 @Au particles with different size of SiO 2 cores was analyzed by transmission electron microscopy and scanning electron microscopy. The optical property of the SiO 2 @Au particles was studied with UV–Vis spectroscopy. The results indicate that the structure and composition of macromolecules affect the morphology of Au layers on SiO 2 microspheres. The SiO 2 @Au particles prepared in the presence of polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) have thin and complete Au nanoshells owing to their inducing act in preferential growth of Au nanoparticles along the surface of SiO 2 microspheres. SiO 2 @Au particles can be also prepared from SiO 2 microspheres modified with 3-aminopropyltrimethoxysilane in the presence of PVA or PVP. This offers a simple way to fabricate a Au layer on SiO 2 or other microspheres. The SiO 2 @Au particles demonstrated high catalytic activity in the reduction of 4-nitrophenol. - Highlights: • Facile direct deposition method for Au nanoparticles on silica microspheres. • Influence of different types of macromolecule on the formation of Au shell. • High catalytic performance of Au nanoparticles on silica microspheres

  1. Structural study of caesium-based britholites Sr7La2Cs(PO4)5(SiO4)F2

    International Nuclear Information System (INIS)

    Boughzala, K.; Gmati, N.; Bouzouita, K.; Ben Cherifa, A.; Gravereau, P.

    2010-01-01

    Several studies demonstrated the ability of britholites to retain radionuclides such as the caesium and actinides. Therefore, three compounds with formulas Sr 8 LaCs(PO 4 ) 6 F 2 , Sr 7 La 2 Cs(PO 4 ) 5 (SiO 4 )F 2 and Sr 2 La 7 Cs(SiO 4 ) 6 F 2 , were prepared by solid state reaction. However, it seems that only the mono-silicated composition was obtained in a pure state. In this present work, the X-ray diffraction and magnetic nuclear resonance have been used to investigate the structure for this composition. The results showed that in fact this phase was not pure, but it was mixed with a secondary phase, SrLaCs(PO 4 ) 2 . The refinement by the Rietveld method allowed also to precise the distribution of La 3+ and Cs + ions between the two cationic sites of the apatite. (authors)

  2. Mesoporous Spinel Li4Ti5O12 Nanoparticles for High Rate Lithium-ion Battery Anodes

    International Nuclear Information System (INIS)

    Liu, Weijian; Shao, Dan; Luo, Guoen; Gao, Qiongzhi; Yan, Guangjie; He, Jiarong; Chen, Dongyang; Yu, Xiaoyuan; Fang, Yueping

    2014-01-01

    Graphical abstract: - Highlights: • Mesoporous Li 4 Ti 5 O 12 nanoparticles were prepared by a simple hydrothermal method. • The mesoporous Li 4 Ti 5 O 12 nanoparticles exhibited a diameter of 40 ± 5 nm and a pore-size distribution of 6 - 8 nm. • Cells with the mesoporous Li 4 Ti 5 O 12 anode showed excellent high rate electrochemical properties. - Abstract: Mesoporous spinel lithium titanate (Li 4 Ti 5 O 12 ) nanoparticles with the diameter of 40 ± 5 nm and the pore-size distribution of 6 - 8 nm were prepared by a simple hydrothermal method. As an anode material for lithium-ion batteries, these spinel Li 4 Ti 5 O 12 mesoporous nanoparticles exhibited desirable lithium storage properties with an initial discharge capacity of 176 mAh g −1 at 1 C rate and a capacity of approximately 145 mAh g −1 after 200 cycles at a high rate of 20 C. These excellent electrochemical properties at high charge/discharge rates are due to the mesoporous nano-scale structures with small size particles, uniform mesopores and larger electrode/electrolyte contact area, which shortens the diffusion path for both electrons and Li + ions, and offers more active sites for Li + insertion-extraction process

  3. Ag-decorated Fe_3O_4@SiO_2 core-shell nanospheres: Seed-mediated growth preparation and their antibacterial activity during the consecutive recycling

    International Nuclear Information System (INIS)

    Li, Miaomiao; Wu, Wenjie; Qiao, Ru; Tan, Linxiang; Li, Zhengquan; Zhang, Yong

    2016-01-01

    We demonstrated a seed-mediated growth approach to synthesize Ag nanoparticles-decorated Fe_3O_4@SiO_2 core-shell nanospheres without use of surface functionalization. The particle size and decoration density of the immobilized Ag nanoparticles on SiO_2 surface were tunable by adjusting the added AgNO_3 concentration and the alternating repetition times in seed-mediated growth procedure. The as-prepared Ag-decorated Fe_3O_4@SiO_2 nanospheres exhibited excellent antibacterial activities against Escherichia coli, Bacillus subtilis and Candida albicans, in which the minimum inhibitory concentration were 12.5 μg mL"−"1, 50 μg mL"−"1 and 50 μg mL"−"1, respectively. It is speculated that their antibacterial activity is attributed to both the interaction of released Ag ions with the functional groups of vital enzymes and proteins and the strong oxidation of reactive oxygen species generated under the action of photoinduced electrons in Ag nanoparticles. Besides studying their antibacterial mechanism, we also investigated the variation of antibacterial activity of these heterostructured nanospheres during the consecutive magnetic separation and recycling. It shows that the magnetic antibacterial agent could be reused and its activity remained stable even after nine cycles, which enable it to be promisingly applied in biomedical areas. - Highlights: • Ag-decorated Fe_3O_4@SiO_2 were synthesized via a seed-mediated growth method. • The core-shell heterostructures exhibited excellent antibacterial activity. • The activity was attributed to the effect of released Ag"+ with ROS oxidation. • The antibacterial agent was reused during magnetic separation and recycling.

  4. Uniform second Li ion intercalation in solid state ϵ-LiVOPO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Wangoh, Linda W.; Quackenbush, Nicholas F. [Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Sallis, Shawn [Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States); Wiaderek, Kamila M.; Ma, Lu; Wu, Tianpin; Chapman, Karena W. [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Lin, Yuh-Chieh; Ong, Shyue Ping [Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive 0448, La Jolla, California 92093 (United States); Wen, Bohua; Chernova, Natasha A.; Whittingham, M. Stanley [NECCES, Binghamton University, Binghamton, New York 13902 (United States); Guo, Jinghua [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Lee, Tien-Lin; Schlueter, Christoph [Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Piper, Louis F. J., E-mail: lpiper@binghamton.edu [Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States)

    2016-08-01

    Full, reversible intercalation of two Li{sup +} has not yet been achieved in promising VOPO{sub 4} electrodes. A pronounced Li{sup +} gradient has been reported in the low voltage window (i.e., second lithium reaction) that is thought to originate from disrupted kinetics in the high voltage regime (i.e., first lithium reaction). Here, we employ a combination of hard and soft x–ray photoelectron and absorption spectroscopy techniques to depth profile solid state synthesized LiVOPO{sub 4} cycled within the low voltage window only. Analysis of the vanadium environment revealed no evidence of a Li{sup +} gradient, which combined with almost full theoretical capacity confirms that disrupted kinetics in the high voltage window are responsible for hindering full two lithium insertion. Furthermore, we argue that the uniform Li{sup +} intercalation is a prerequisite for the formation of intermediate phases Li{sub 1.50}VOPO{sub 4} and Li{sub 1.75}VOPO{sub 4}. The evolution from LiVOPO{sub 4} to Li{sub 2}VOPO{sub 4} via the intermediate phases is confirmed by direct comparison between O K–edge absorption spectroscopy and density functional theory.

  5. Controlled synthesis and relationship between luminescent properties and shape/crystal structure of Zn2SiO4:MN2+ phosphor

    International Nuclear Information System (INIS)

    Wan Junxi; Wang Zhenghua; Chen Xiangying; Mu Li; Yu Weichao; Qian Yitai

    2006-01-01

    Mn-doped Zn 2 SiO 4 phosphors with different morphology and crystal structure, which show different luminescence and photoluminescence intensity, were synthesized via a low-temperature hydrothermal route without further calcining treatment. As-synthesized zinc silicate nanostructures show green or yellow luminescence depending on their different crystal structure obtained under different preparation conditions. The yellow peak occurring at 575 nm comes from the β-phase zinc silicate, while the green peak centering at 525 nm results from the usual α-phase zinc silicate. From photoluminescence spectra, it is found that Zn 2 SiO 4 nanorods have higher photoluminescence intensity than Zn 2 SiO 4 nanoparticles. It can be ascribed to reduced surface-damaged region and high crystallinity of nanorods

  6. Improving low-temperature performance of spinel LiNi0.5Mn1.5O4 electrode and LiNi0.5Mn1.5O4/Li4Ti5O12 full-cell by coating solid-state electrolyte Li-Al-Ti-P-O

    Science.gov (United States)

    Bi, Kun; Zhao, Shi-Xi; Huang, Chao; Nan, Ce-Wen

    2018-06-01

    Octahedral cathode materials LiNi0.5Mn1.5O4 (LNMO), with primary particles size of 300-600 nm are prepared through one-step co-precipitation. Then solid-state electrolyte Li2O-Al2O3-TiO2-P2O5 (LATP) was coated on LNMO to form continuous surface-modification layer. There is no obviously difference of structure, morphology between coated LATP LiNi0.5Mn1.5O4 (LATP-LNMO) and pristine LiNi0.5Mn1.5O4 (P-LNMO). Low-temperature electrochemical performance of P-LNMO and LATP-LNMO electrodes, including charge-discharge capacity, cycle performance, middle discharge voltage and electrochemical impedance spectra (EIS), were measured systematically with three electrode. The results reveal that LATP-LNMO electrode presents superior electrochemical performance at low temperature, compared to P-LNMO electrode. At -20 °C, the capacity retention of LATP-LNMO (61%) is much higher than that of P-LNMO (39%). According to EIS, the enhancement of performance of LATP-LNMO cathode at low temperature can be attribute to LATP coating, which not only promotes lithium-ion diffusion at electrode/electrolyte interface but also decreases the charge transfer resistance. Finally, the electrochemical performances of full cell of LATP-LNMO or P-LNMO cathode vs Li4Ti5O12 anode are investigated. The energy density can be achieved to 270 Wh·Kg-1 at -20 °C if using LATP-LNMO, which is much better than that of P-LNMO.

  7. Manufacturing Technology of Ceramic Pebbles for Breeding Blanket

    Directory of Open Access Journals (Sweden)

    Rosa Lo Frano

    2018-05-01

    Full Text Available An open issue for the fusion power reactor is the choice of breeding blanket material. The possible use of Helium-Cooled Pebble Breeder ceramic material in the form of pebble beds is of great interest worldwide as demonstrated by the numerous studies and research on this subject. Lithium orthosilicate (Li4SiO4 is a promising breeding material investigated in this present study because the neutron capture of Li-6 allows the production of tritium, 6Li (n, t 4He. Furthermore, lithium orthosilicate has the advantages of low activation characteristics, low thermal expansion coefficient, high thermal conductivity, high density and stability. Even if they are far from the industrial standard, a variety of industrial processes have been proposed for making orthosilicate pebbles with diameters of 0.1–1 mm. However, some manufacturing problems have been observed, such as in the chemical stability (agglomeration phenomena. The aim of this study is to provide a new methodology for the production of pebbles based on the drip casting method, which was jointly developed by the DICI-University of Pisa and Industrie Bitossi. Using this new (and alternative manufacturing technology, in the field of fusion reactors, appropriately sized ceramic pebbles could be produced for use as tritium breeders.

  8. Pb3O4 type antimony oxides MSb2O4 (M = Co, Ni) as anode for Li-ion batteries

    International Nuclear Information System (INIS)

    Jibin, A.K.; Reddy, M.V.; Subba Rao, G.V.; Varadaraju, U.V.; Chowdari, B.V.R.

    2012-01-01

    Graphical abstract: Isostructural Pb 3 O 4 type MSb 2 O 4 (M = Co, Ni) compounds were investigated as possible anodes for lithium ion batteries. The reversible capacity is due to electrochemically active Sb and the transition metal and Li 2 O form an inactive matrix which buffers volume variations associated with alloying-de-alloying of antimony. Highlights: ► Isostructural MSb 2 O 4 (M = Co, Ni) were studied as anode for LIBs for first time. ► Li/MSb 2 O 4 (M = Co, Ni) cells displayed reversibility due to electrochemically active Sb. ► CoSb 2 O 4 showed good reversibility compared to NiSb 2 O 4 . - Abstract: Polycrystalline samples of isostructural MSb 2 O 4 (M = Co, Ni) have been prepared by solid state synthesis and lithium-storage is investigated as possible anode materials for lithium-ion batteries. The reaction mechanism of lithium with MSb 2 O 4 (M = Co, Ni) is explored by galvanostatic cycling, cyclic voltammogram and ex situ studies. Both CoSb 2 O 4 and NiSb 2 O 4 exhibit similar electrochemical behavior and show reversible capacity of 490 and 412 mAh g −1 respectively in the first cycle. Reversible alloying de-alloying of Li x Sb takes place in an amorphous matrix of M (Co, Ni) and Li 2 O during electrochemical cycling.

  9. Core-shell Li2S@Li3PS4 nanoparticles incorporated into graphene aerogel for lithium-sulfur batteries with low potential barrier and overpotential

    Science.gov (United States)

    Jiao, Zheng; Chen, Lu; Si, Jian; Xu, Chuxiong; Jiang, Yong; Zhu, Ying; Yang, Yaqing; Zhao, Bing

    2017-06-01

    Lithium sulfide as a promising cathode material not only have a high theoretical specific capacity, but also can be paired with Li-free anode material to avoid potential safety issues. However, how to prepare high electrochemical performance material is still challenge. Herein, we present a facile way to obtain high crystal quality Li2S nanomaterials with average particle size of about 55 nm and coated with Li3PS4 to form the nano-scaled core-shell Li2S@Li3PS4 composite. Then nano-Li2S@Li3PS4/graphene aerogel is prepared by a simple liquid infiltration-evaporation coating process and used directly as a composite cathode without metal substrate for lithium-sulfur batteries. Electrochemical tests demonstrate that the composite delivers a high discharge capacity of 934.4 mAh g-1 in the initial cycle and retains 485.5 mAh g-1 after 100 cycles at 0.1 C rate. In addition, the composite exhibits much lower potential barrier (∼2.40 V) and overpotential compared with previous reports, indicating that Li2S needs only a little energy to be activated. The excellent electrochemical performances could be attributed to the tiny particle size of Li2S and the superionic conducting Li3PS4 coating layer, which can shorten Li-ion and electron diffusion paths, improve the ionic conductivity, as well as retarding polysulfides dissolution into the electrolyte to some extent.

  10. Synthesis, structure and electrochemistry of Ag-modified LiMn2O4 cathode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhou Wenjia; He Benlin; Li Hulin

    2008-01-01

    Spinel lithium manganese oxide was prepared by sol-gel method and a series of Ag/LiMn 2 O 4 composites with different Ag additive contents were prepared by thermal decomposition of AgNO 3 added to the pure LiMn 2 O 4 powders. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDAX) and various electrochemical measurement methods were used to examine the structural and electrochemical characteristics of the Ag/LiMn 2 O 4 composite powders. Phase analysis showed that Ag particles were dispersed on the surface of LiMn 2 O 4 instead of entering the spinel structure. According to the electrochemical tests results, it is clearly to see that Ag additives efficiently improved the cycling stability, reversibility and high-rate discharge capacity of pristine LiMn 2 O 4 by increasing the electrical conductivity between LiMn 2 O 4 particles, decreasing the polarization of cathode and reducing the dissolution of Mn. Meanwhile the influence of the Ag additive contents on the electrochemical properties of the Ag/LiMn 2 O 4 composites is also investigated in detail

  11. Dehydration of glucose to 5-hydroxymethylfurfural by a core-shell Fe3O4@SiO2-SO3H magnetic nanoparticle catalyst

    Science.gov (United States)

    This paper discusses the potential use of (Fe3O4@SiO2-SO3H) nanoparticle catalyst for the dehydration of glucose into 5-hydroxymethylfurfural (HMF). A magnetically recoverable (Fe3O4@SiO2-SO3H) nanoparticle catalyst was successfully prepared by supporting sulfonic acid groups (SO3H) on the surface o...

  12. Effect of orthorhombic distortion on dielectric and piezoelectric properties of CaBi4Ti4O15 ceramics

    Science.gov (United States)

    Tanwar, Amit; Sreenivas, K.; Gupta, Vinay

    2009-04-01

    High temperature bismuth layered piezoelectric and ferroelectric ceramics of CaBi4Ti4O15 (CBT) have been prepared using the solid state route. The formation of single phase material with orthorhombic structure was verified from x-ray diffraction and Raman spectroscopy. The orthorhombic distortion present in the CBT ceramic sintered at 1200 °C was found to be maximum. A sharp phase transition from ferroelectric to paraelectric was observed in the temperature dependent dielectric studies of all CBT ceramics. The Curie's temperature (Tc=790 °C) was found to be independent of measured frequency. The behavior of ac conductivity as a function of frequency (100 Hz-1 MHz) at low temperatures (<500 °C) follows the power law and is attributed to hopping conduction. The presence of large orthorhombic distortion in the CBT ceramic sintered at 1200 °C results in high dielectric constant, low dielectric loss, and high piezoelectric coefficient (d33). The observed results indicate the important role of orthorhombic distortion in determining the improved property of multicomponent ferroelectric material.

  13. Microwave-assisted preparation of Li3V2(PO4)3/C composite with high-rate capacity

    International Nuclear Information System (INIS)

    Yan, Ji; Mao, Wen-feng; Xie, Hui; Tang, Zhi-yuan; Yuan, Wei; Chen, Xue-cheng; Xu, Qiang; Ma, Li

    2012-01-01

    Highlights: ► High-rate Li 3 V 2 (PO 4 ) 3 /C is firstly reported via a microwave-assisted method. ► The reduced particle size is responsible for the improved high-rate performance. ► A discharge capacity of 100 mAh g −1 is obtained at 20 C charge–discharge rate. -- Abstract: A fast sol–gel assisted microwave heating approach has been developed for the synthesis of high-rate Li 3 V 2 (PO 4 ) 3 /C cathode material. This approach can synthesize Li 3 V 2 (PO 4 ) 3 /C particles with high purity and good crystallinity in 12 min at a low microwave power of 320 W. In the voltage range of 3.0–4.3 V, the obtained Li 3 V 2 (PO 4 ) 3 /C delivers a reversible discharge capacity of 100 mAh g −1 after 100 cycles at 20 °C, exhibiting excellent rate capability and cycling performance. The rate-recovery performance also suggests that the Li 3 V 2 (PO 4 ) 3 /C material possesses excellent structure stability after high-rate cycles, presenting excellent application value in high-power lithium ion batteries.

  14. Effects of helical GNF on improving the dehydrogenation behavior of LiMg(AlH{sub 4}){sub 3} and LiAlH{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Leo Hudson, M. Sterlin; Raghubanshi, Himanshu; Pukazhselvan, D.; Srivastava, O.N. [Hydrogen Energy Center, Department of Physics, Banaras Hindu University, Varanasi-221005 (India)

    2010-03-15

    The present paper reports the effect of graphitic nanofibres (GNFs) for improving the desorption kinetics of LiMg(AlH{sub 4}){sub 3} and LiAlH{sub 4}. LiMg(AlH{sub 4}){sub 3} has been synthesized by mechano-chemical metathesis reaction involving LiAlH{sub 4} and MgCl{sub 2}. The enhancement in dehydrogenation characteristics of LiMg(AlH{sub 4}){sub 3} has been shown to be higher when graphitic nanofibres (GNFs) were used as catalyst. Out of two different types of nanofibres namely planar graphitic nanofibre (PGNF) and helical graphitic nanofibre (HGNF), the latter has been found to act as better catalyst. We observed that helical morphology of fibres improves the desorption kinetics and decreases the desorption temperature of both LiMg(AlH{sub 4}){sub 3} and LiAlH{sub 4}. The desorption temperature for 8 mol% HGNF admixed LiAlH{sub 4} gets lowered from 159 C to 128 C with significantly faster kinetics. In 8 mol% HGNF admixed LiMg(AlH{sub 4}){sub 3} sample, the desorption temperature gets lowered from 105 C to {proportional_to}70 C. The activation energy calculated for the first step decomposition of LiAlH{sub 4} admixed with 8 mol% HGNF is {proportional_to}68 kJ/mol, where as that for pristine LiAlH{sub 4} it is 107 kJ/mol. The activation energy calculated for as synthesized LiMg(AlH{sub 4}){sub 3} is {proportional_to}66 kJ/mol. Since the first step decomposition of LiMg(AlH{sub 4}){sub 3} occurs during GNF admixing, the activation energy for initial step decomposition of GNF admixed LiMg(AlH{sub 4}){sub 3} could not be estimated. (author)

  15. Raman and infrared investigations of glass and glass-ceramics with composition 2Na2O·1CaO·3SiO2

    OpenAIRE

    Ziemath, Ervino C.; Aegerter, Michel A.

    1994-01-01

    Precursor glass and glass-ceramics with molar composition 2Na2O·1CaO·3SiO2 are studied by infrared, conventional, and microprobe Raman techniques. The Gaussian deconvoluted Raman spectrum of the glass presents bands at 625 and 660 cm-1, attributed to bending vibrations of Si-O-Si bonds, and at 860, 920, 975 and 1030 cm-1, attributed to symmetric stretching vibrations of SiO4 tetrahedra with 4, 3, 2, and 1 nonbridging oxygens, respectively. The Raman microprobe spectrum of a highly crystalliz...

  16. Biomimetic synthesis and characterization of the positive electrode material LiFePO4

    International Nuclear Information System (INIS)

    Li Peng; He Wen; Zhao Hongshi; Wang Shaopeng

    2009-01-01

    The biosurfactant is used as the template to synthesize lithium iron phosphate (LiFePO 4 ) precursor with the co-precipitation method and the microwave sintering method is used to prepare positive electrode material LiFePO 4 for the lithium ion battery. By using the Brunauer-Emmett-Teller (BET) surface areas, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and conductometer, the authors explored the influence of the microwave power on the structure and performance of the materials. The results the authors got have proved that good crystal and high conductivity values can be obtained from the LiFePO 4 powders which are processed 10 min under the microwave power of 300 W

  17. Impact of incorporation of chromium on electrochemical properties of LiFePO4/C for Li-ion batteries

    Directory of Open Access Journals (Sweden)

    Naik Amol

    2015-12-01

    Full Text Available LiFe0.95Cr0.05PO4/C was successfully synthesized by one-step solid-state reaction using a single mode microwave reactor. The effect of incorporation of chromium on LiFePO4 lattice parameters was systematically investigated by X-ray diffraction. Surface analysis was done by scanning electron microscopy and transmission electron microscopy. The ratio of amorphous to graphitic carbon was determined from Raman spectroscopic data. The influence of chromium incorporation on electrochemical properties was studied by recording charge/discharge cycles combined with electrochemical impedance spectroscopy (EIS and cyclic voltammetry. It was found that Cr incorporation significantly enhanced the electrochemical performance of LiFePO4 at all current densities up to 10 C. LiFe0.95Cr0.05PO4/C prepared exhibited the best performance with an initial specific discharge capacity of 157.7, 144.8, 138.3, 131.0, 124.1 and 111.1 mAh·g−1 at 0.1 C, 0.5 C, 1.0 C, 2.0 C, 5 C and 10 C, respectively. The doped sample displayed excellent capacity retention, which was substantially superior than that of pristine LiFePO4/C at a higher current rate.

  18. Effects of Na2WO4 and Na2SiO3 additives in electrolytes on microstructure and properties of PEO coatings on Q235 carbon steel

    International Nuclear Information System (INIS)

    Wang Yunlong; Jiang Zhaohua; Yao Zhongping

    2009-01-01

    Ceramic coatings were achieved on Q235 carbon steel by plasma electrolytic oxidation in aluminate system with and without Na 2 WO 4 and Na 2 SiO 3 additives in electrolyte. Influence of Na 2 WO 4 and Na 2 SiO 3 on surface morphology, phase and elemental composition of PEO coatings were examined by means of scanning electron microscope (SEM), thin-film X-ray diffraction (TF-XRD) and energy dispersive X-ray spectroscopy (EDS). Effects of the two additives on the properties of the coatings including surface roughness, surface micro hardness and friction coefficient were studied. The results showed that W from Na 2 WO 4 and Si from Na 2 SiO 3 in electrolytes entered into the coatings. Na 2 WO 4 additive had no evident effect on phase composition of the coating, while Na 2 SiO 3 additive resulted in the coating changing from crystalline state to amorphous state and increased the content of P in the coating. Both additives reduced the surface roughness of the coatings. With Na 2 WO 4 or Na 2 SiO 3 into the electrolytes, the surface micro hardness of the coating was enhanced to 1433 and 1478, respectively, and the friction coefficients were also decreased to below 0.1.

  19. Etched colloidal LiFePO4 nanoplatelets toward high-rate capable Li-ion battery electrodes.

    Science.gov (United States)

    Paolella, Andrea; Bertoni, Giovanni; Marras, Sergio; Dilena, Enrico; Colombo, Massimo; Prato, Mirko; Riedinger, Andreas; Povia, Mauro; Ansaldo, Alberto; Zaghib, Karim; Manna, Liberato; George, Chandramohan

    2014-12-10

    LiFePO4 has been intensively investigated as a cathode material in Li-ion batteries, as it can in principle enable the development of high power electrodes. LiFePO4, on the other hand, is inherently "plagued" by poor electronic and ionic conductivity. While the problems with low electron conductivity are partially solved by carbon coating and further by doping or by downsizing the active particles to nanoscale dimensions, poor ionic conductivity is still an issue. To develop colloidally synthesized LiFePO4 nanocrystals (NCs) optimized for high rate applications, we propose here a surface treatment of the NCs. The particles as delivered from the synthesis have a surface passivated with long chain organic surfactants, and therefore can be dispersed only in aprotic solvents such as chloroform or toluene. Glucose that is commonly used as carbon source for carbon-coating procedure is not soluble in these solvents, but it can be dissolved in water. In order to make the NCs hydrophilic, we treated them with lithium hexafluorophosphate (LiPF6), which removes the surfactant ligand shell while preserving the structural and morphological properties of the NCs. Only a roughening of the edges of NCs was observed due to a partial etching of their surface. Electrodes prepared from these platelet NCs (after carbon coating) delivered a capacity of ∼ 155 mAh/g, ∼ 135 mAh/g, and ∼ 125 mAh/g, at 1 C, 5 C, and 10 C, respectively, with significant capacity retention and remarkable rate capability. For example, at 61 C (10.3 A/g), a capacity of ∼ 70 mAh/g was obtained, and at 122 C (20.7 A/g), the capacity was ∼ 30 mAh/g. The rate capability and the ease of scalability in the preparation of these surface-treated nanoplatelets make them highly suitable as electrodes in Li-ion batteries.

  20. Magnetic properties of lithium rare-earth fluorides: Ferromagnetism in LiErF4 and LiHoF4 and crystal-field parameters at the rare-earth and Li sites

    DEFF Research Database (Denmark)

    Hansen, P. E.; Johansson, Torben; Nevald, Rolf

    1975-01-01

    Single crystals of LiErF4 and LiHoF4 have been grown and their magnetic properties measured from 1.3 K to 300 K. LiHoF4 turned out to be a nearly ideal Ising ferromagnet with TC=1.30±0.05 K and a saturation magnetization along the crystalline c axis of (6.98±0.02)μB. In LiErF4 no ordering...... was observed, but extrapolation indicates that below 0.5 K it will be ferromagnetic with the magnetic moments in the crytalline ab plane. From the susceptibilities the crystal-field parameters Bnm with (n, m)=(2, 0), (4, 0), (4, 4), (6, 0), (6, 4) have been extracted giving for Er3+ in LiErF4: 430., -985......., 1185., -5., 740.+i135. (cm-1) and for Ho3+ in LiHoF4: 470., -825., 1050., -10., 760.+i150 (cm-1). The exchange constants were found to be small compared to the dipole interactions. Furthermore the 7Li NMR spectra have been obtained in these materials as well as in LiTbF4 thereby determining the second...

  1. Electrochemical properties of Li2 FeSiO4 /C nanocomposites prepared by sol-gel and hydrothermal methods

    Science.gov (United States)

    Kumar, Ajay; Jayakumar, O. D.; Naik, Vaman M.; Nazri, Gholam A.; Naik, Ratna

    Li2FeSiO4 is considered as potential cathode material for next generation lithium ion batteries because of its high specific theoretical capacity, low cost, and safety. However, it suffers from poor electronic conductivity and slow lithium ion diffusion in the solid phase. To address these issues, we have studied mesoporous Li2FeSiO4/C composites synthesized by sol-gel (SG) and hydrothermal (HT) methods using tri-block copolymer (P123) as carbon source and structure directing agent. The structure and morphology of the composites were characterized by XRD, SEM and TEM and the surface area and pore size distribution were measured by using N2 adsorption/desorption. Galvanostatic cycling, electrochemical impedance spectroscopy, and cyclic voltammetry were used to evaluate the electrochemical performance of the Li2FeSiO4/C composites. The Li2FeSiO4/C (HT) composites show a superior electrochemical performance compared to Li2FeSiO4/C (SG). At C/30 rate, the discharge capacity of Li2FeSiO4/C (HT) reached ~276 mAh/g in the 1.5-4.6 V window and shows better rate capability and stability at high rates. We attribute the improved electrochemical performance of Li2FeSiO4/C (HT) to its large surface area and reduced particle size. The details of the study will be presented.

  2. Complex phosphates in the Li(Na)3PO4-InPO4 systems

    International Nuclear Information System (INIS)

    Potapova, A.M.; Zimina, G.V.; Smirnova, I.N.; Novoselov, A.V.; Spiridonov, F.M.; Stefanovich, S.Yu.

    2008-01-01

    Subsolidus sections in the systems Li 3 PO 4 -InPO 4 (950 deg C) and Na 3 PO 4 -InPO 4 (800, 900, and 1000 deg C) have been studied by X-ray powder diffraction. The compound Li 3 In(PO 4 ) 2 has been synthesized, and the NASICON-type solid solution Li 3(1-x) In 2+x (PO 4 ) 3 (0.67 ≤ x ≤ 0.80) has been found to exist. In the system Na 3 PO 4 -InPO 4 , the solid solution Na 3(1-x) In x/3 PO 4 (0 ≤ x ≤ 0.2) and two complex phosphates exist: Na 3 In(PO 4 ) 2 and Na 3 In 2 (PO 4 ) 3 . These complex phosphates are dimorphic, with the irreversible-transition temperature equal to 675 and 820 deg C, respectively. Na 3 In(PO 4 ) 2 degrades at 920 deg C. Ionic conductivity has been measured in some phases in the system [ru

  3. Single Nanorod Devices for Battery Diagnostics: A Case Study on LiMn 2 O 4

    KAUST Repository

    Yang, Yuan

    2009-12-09

    This paper presents single nanostructure devices as a powerful new diagnostic tool for batteries with LiMn2O4 nanorod materials as an example. LiMn2O4 and Al-doped LiMn2O4 nanorods were synthesized by a two-step method that combines hydrothermal synthesis of β-MnO2 nanorods and a solid state reaction to convert them to LiMn2O4 nanorods. λ-MnO2 nanorods were also prepared by acid treatment of LiMn2O4 nanorods. The effect of electrolyte etching on these LiMn2O 4-related nanorods is investigated by both SEM and single-nanorod transport measurement, and this is the first time that the transport properties of this material have been studied at the level of an individual singlecrystalline particle. Experiments show that Al dopants reduce the dissolution of Mn3+ ions significantly and make the LiAl 0.1Mn1.9O4 nanorods much more stable than LiMn2O4 against electrolyte etching, which is reflected by the magnification of both size shrinkage and conductance decrease. These results correlate well with the better cycling performance of Al-doped LiMn 2O4 in our Li-ion battery tests: LiAl0.1Mn 1.9O4 nanorods achieve 96% capacity retention after 100 cycles at 1C rate at room temperature, and 80% at 60 °C, whereas LiMn 2O4 shows worse retention of 91% at room temperature, and 69% at 60 °C. Moreover, temperature-dependent I - V measurements indicate that the sharp electronic resistance increase due to charge ordering transition at 290 K does not appear in our LiMn2O4 nanorod samples, suggesting good battery performance at low temperature. © 2009 American Chemical Society.

  4. Synthesis, characterization and electroanalytical application of a new SiO2/SnO2 carbon ceramic electrode

    International Nuclear Information System (INIS)

    Arguello, Jacqueline; Magosso, Herica A.; Landers, Richard; Pimentel, Vinicius L.; Gushikem, Yoshitaka

    2010-01-01

    A new SiO 2 /SnO 2 carbon ceramic composite was prepared by the sol-gel method, and its potential application in electrochemistry as a novel electrode material has been studied. The prepared xerogel was structurally and electrochemically characterized by scanning electron microscopy coupled to energy dispersive spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and cyclic voltammetry. The composite was pressed in a rigid disk-shape and used as a conductive substrate to immobilize a water-soluble organic-inorganic hybrid polymer, 3-n-propyl-4-picolinium chloride silsesquioxane. The oxidation of nitrite was studied on this polymer film coated electrode in aqueous solution using cyclic voltammetry and differential pulse voltammetry. This modified electrode exhibited a better defined voltammetric peak shifted negatively about 60 mV. The linear detection limit found for nitrite was from 1.3 x 10 -5 to 1.3 x 10 -3 mol l -1 and the detection limit was 3.3 x 10 -6 mol l -1 .

  5. Impedance spectroscopy and morphology of SrBi{sub 4}Ti{sub 4}O{sub 15} ceramics prepared by soft chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Rout, S.K. [Department of Chemical and Biomolecular Engineering, KAIST (Korea, Republic of); Department of Applied Physics, BIT, Mesra, Ranchi (India)], E-mail: drskrout@gmail.com; Hussian, Ali; Lee, J.S. [School of Materials Science and Engineering University of Ulsan (Korea, Republic of); Kim, I.W. [Department of Physics, University of Ulsan (Korea, Republic of); Woo, S.I. [Department of Chemical and Biomolecular Engineering, KAIST (Korea, Republic of)], E-mail: siwoo@kaist.ac.kr

    2009-05-27

    In this work, we have synthesized polycrystalline SrBi{sub 4}Ti{sub 4}O{sub 15} (SBiT) ceramics by soft chemical method. These ceramics were structurally characterized by analysis of X-ray diffraction (XRD) patterns, indicates that SBiT ceramics present an orthorhombic structure. Scanning electron micrograph shows that the grains exhibit a plate like morphology. Dielectric relaxations of the SBiT ceramics were investigated in the temperature range 100-700 deg. C. Using the Cole-Cole model, an analysis of the dielectric loss with frequency was performed, assuming a distribution of relaxation time. The presence of the peaks in temperature dependent dielectric loss indicates that the hoping of charge carriers is responsible for the relaxation. Impedance studies shows a non-Debye type relaxation, and relaxation frequency shift to higher side with increase in temperature. A significant shift in impedance loss peaks towards higher frequency side indicates conduction in material and favoring the long range motion of mobile charge carriers. The Nyquist plot shows overlapping semicircles, for grain and grain boundary of SBiT ceramics. The frequency dependent ac conductivity at different temperatures indicates that the conduction process is thermally activated process and the spectra follow the universal power law. The hopping frequency shifts towards higher frequency side with increase of temperature, below which the conductivity is frequency independent. The variation of dc conductivity confirms that the SBiT ceramics exhibits negative temperature coefficient of resistance behavior in high temperature.

  6. Structural Evolution and Electrochemical Performance of Li2MnSiO4/C Nanocomposite as Cathode Material for Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Min Wang

    2014-01-01

    Full Text Available High capacity Li2MnSiO4/C nanocomposite with good rate performance was prepared via a facile sol-gel method using ascorbic acid as carbon source. It had a uniform distribution on particle size of approximately 20 nm and a thin outlayer of carbon. The galvanostatic charge-discharge measurement showed that the Li2MnSiO4/C electrode could deliver an initial discharge capacity of 257.1 mA h g−1 (corresponding to 1.56 Li+ at a current density of 10 mA g−1 at 30°C, while the Li2MnSiO4 electrode possessed a low capacity of 25.6 mA h g−1. Structural amorphization resulting from excessive extraction of Li+ during the first charge was the main reason for the drastic capacity fading. Controlling extraction of Li+ could inhibit the amorphization of Li2MnSiO4/C during the delithiation, contributing to a reversible structural change and good cycling performance.

  7. Low sintering temperature and high piezoelectric properties of Li-doped (Ba,Ca)(Ti,Zr)O3 lead-free ceramics

    International Nuclear Information System (INIS)

    Chen, Xiaoming; Ruan, Xuezheng; Zhao, Kunyun; He, Xueqing; Zeng, Jiangtao; Li, Yongsheng; Zheng, Liaoying; Park, Chul Hong; Li, Guorong

    2015-01-01

    Highlights: • Li-doped Ba 0.85 Ca 0.15 Ti 0.9 Zr 0.1 O 3 (BCZT) lead-free piezoceramics were prepared by the two-step synthesis and solid-state reaction method. • Their sintering temperature decreases from about 1540 °C down to about 1400 °C. • With the proper addition of Li, the densities and grain sizes of ceramics increase. • The ceramics not only have the characteristics of hard piezoceramics but also possesses the features of soft piezoceramics at low sintering temperature. - Abstract: Li-doped Ba 0.85 Ca 0.15 Ti 0.9 Zr 0.1 O 3 (BCZT) lead-free piezoelectric ceramics were prepared by the two-step synthesis and the solid-state reaction method. The density and grain size of ceramics sufficiently increases by Li-doped sintering aid, and their sintering temperature decreases from about 1540 °C down to about 1400 °C. X-ray diffraction reveals that the phase structure of Li-doped BCTZ ceramics is changed with the sintering temperature, which is consistent with their phase transition observed by the temperature-dependent dielectric curves. The well-poled Li-doped BCZT ceramics show a high piezoelectric constant d 33 (512 pC/N) and a planar electromechanical coupling factor k p (0.49), which have the characteristics of soft Pb(Zr,Ti)O 3 (PZT) piezoceramic, on the other hand, the mechanical quality factor Q m is about 190, which possesses the features of hard PZT piezoceramics. The enhanced properties of the Li-doped BCZT are explained by the combination of Li-doped effect and sintering effect on the microstructure and the phase transition around room temperature

  8. Modeling Li-ion conductivity in LiLa(PO{sub 3}){sub 4} powder

    Energy Technology Data Exchange (ETDEWEB)

    Mounir, Ferhi, E-mail: ferhi.mounir@gmail.com [Laboratoire de Physicochimie des Materiaux Mineraux et leurs Applications, Centre National des Recherches en Sciences des Materiaux, BP No. 73, 8027 Soliman (Tunisia); Karima, Horchani-Naifer [Laboratoire de Physicochimie des Materiaux Mineraux et leurs Applications, Centre National des Recherches en Sciences des Materiaux, BP No. 73, 8027 Soliman (Tunisia); Khaled, Ben Saad [Laboratoire de Photovoltaieque, Centre des Recherches et des Technologies de l' Energie, Technopole Borj Cedria, BP No. 95, 2050 Hammam Lif (Tunisia); Mokhtar, Ferid [Laboratoire de Physicochimie des Materiaux Mineraux et leurs Applications, Centre National des Recherches en Sciences des Materiaux, BP No. 73, 8027 Soliman (Tunisia)

    2012-07-01

    Polycrystalline powder and single-crystal of LiLa(PO{sub 3}){sub 4} are synthesized by solid state reaction and flux technique, respectively. A morphological description of the obtained product was made based on scanning electron microscopy micrographs. The obtained powder was characterized by X-ray powder diffraction, FTIR and Raman spectroscopies. Ionic conductivity of the LiLa(PO{sub 3}){sub 4} powder was measured and evaluated over a temperature range from 553 to 913 K. Single crystals of LiLa(PO{sub 3}){sub 4} are characterized by single-crystal X-ray diffraction. The LiLa(PO{sub 3}){sub 4} structure was found to be isotypic with LiNd(PO{sub 3}){sub 4}. It crystallizes in the monoclinic system with space group C2/c and cell parameters: a=16.635(6) A, b=7.130(3) A, c=9.913(3) A, {beta}=126.37(4) Degree-Sign , V=946.72(6) A{sup 3} and Z=4. The LiLa(PO{sub 3}){sub 4} structure was described as an alternation between spiraling chains (PO{sub 3}){sub n} and (La{sup 3+}, Li{sup +}) cations along the b direction. The small Li{sup +} ions, coordinated to four oxygen atoms, were located in the large connected cavities created between the LaO{sub 8} polyhedra and the polyphosphate chains. The jumping of Li{sup +} through tunnels of the crystalline network was investigated using complex impedance spectroscopy. The close value of the activation energies calculated through the analysis of conductivity data and loss spectra indicate that the transport in the investigated system is through hopping mechanism. The correlation between ionic conductivity of LiLa(PO{sub 3}){sub 4} and its crystallographic structure was investigated and the most probably transport pathway model was determined.

  9. Promotional role of Li4Ti5O12 as polysulfide adsorbent and fast Li+ conductor on electrochemical performances of sulfur cathode

    Science.gov (United States)

    Zeng, Tianbiao; Hu, Xuebu; Ji, Penghui; Shang, Biao; Peng, Qimeng; Zhang, Yaoyao; Song, Ruiqiang

    2017-08-01

    Lithium-sulfur (Li-S) batteries attract much attention due to its high specific capacity and energy density compared to lithium-ion batteries (LiBs). Herein, a novel composite named as (void/nano-Li4Ti5O12 pieces)@C [(v/n-L)@C] was designed and prepared as a sulfur host. Spinel Li4Ti5O12 here as a multifunctional additive played as polysulfide adsorbent agent and fast Li+ conductor, and carbon shell was designed as electronic conductor, as well as volume barrier to limit the volume expansion caused by sulfur. As-prepared (S/nano-Li4Ti5O12 pieces)@C [(S/n-L)@C] are core-shell spheres, which are about 200 nm in size. Nano-Li4Ti5O12 and sulfur were coated by the outer carbon shell with a thickness of about 20 nm. The experimental results show that electrochemical performances of (S/n-L)@C cathode were enhanced effectively compared to S@C cathode. At 0.5C and 1C, the discharge capacity of (S/n-L)@C was 33.5% and 40.1% higher than that of S@C at 500th cycle. Even at 2C, its capacity reached 600.9 mAh g-1 at 1000th cycle. Li+ conductivity of (S/n-L)@C was one order of magnitude higher than that of S@C, which was reach to 2.55 × 10-8 S cm-1. The experiment results indicate Li4Ti5O12 plays a promotional role on electrochemical performances of sulfur cathode, especially for stable cycling performance and high rate performance.

  10. Solvothermal synthesis and electrochemical performance of hollow LiFePO{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Zhenmiao [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Pang, Wei Kong [Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia); Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Tang, Xincun, E-mail: tangxincun@163.com [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Jia, Dianzeng; Huang, Yudai [Institute of Applied Chemistry, Xinjiang University, Urumqi 840046 (China); Guo, Zaiping [Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia)

    2015-08-15

    Highlights: • Hollow LiFePO{sub 4} nanoparticles were successfully synthesized via solvothermal method. • The shorter b lattice parameter allows the shorter diffusion path of lithium ion. • Hollow LiFePO{sub 4} nanoparticles show better rate capability than solid LiFePO{sub 4}. - Abstract: Hollow LiFePO{sub 4} nanoparticles were synthesized via a solvothermal technique, using ammonium tartrate as additive and carbon source, and ethylene glycol/water as solvent. The as-prepared samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning and transmission electron microscopies, and Brunauer–Emmett–Teller specific surface area measurements. The electrochemical properties of the LiFePO{sub 4} cathode were examined in coin-type cell configuration and the cathode exhibited excellent rate capability (i.e., discharge capacity of 120.9 mA h g{sup −1} at 10 C) and cycling performance (i.e., >98% of capacity retention rate after 50 cycles). It is believed that the enhanced performance is correlated to the hollow structure, small crystallite and particle sizes, and relatively shorter lattice parameter b.

  11. Comparison of electrospun and conventional LiFePO{sub 4}/C composite cathodes for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Bachtin, Krystyna, E-mail: krystyna.bachtin@kit.edu [Institute for Applied Materials – Energy Storage Systems (IAM-ESS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Helmholtz Institute Ulm for Electrochemical Energy Storage (HIU), Albert-Einstein-Allee 11, 89081 Ulm (Germany); Kaus, Maximilian [Institute for Applied Materials – Energy Storage Systems (IAM-ESS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Helmholtz Institute Ulm for Electrochemical Energy Storage (HIU), Albert-Einstein-Allee 11, 89081 Ulm (Germany); Pfaffmann, Lukas [Institute for Applied Materials – Energy Storage Systems (IAM-ESS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Indris, Sylvio; Knapp, Michael [Institute for Applied Materials – Energy Storage Systems (IAM-ESS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Helmholtz Institute Ulm for Electrochemical Energy Storage (HIU), Albert-Einstein-Allee 11, 89081 Ulm (Germany); Roth, Christina [Freie Universität Berlin (FUB), Physical Chemistry, Takustraße 3, 14195 Berlin (Germany); Ehrenberg, Helmut [Institute for Applied Materials – Energy Storage Systems (IAM-ESS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Helmholtz Institute Ulm for Electrochemical Energy Storage (HIU), Albert-Einstein-Allee 11, 89081 Ulm (Germany)

    2016-11-15

    In order to apply low conductive materials, such as LiFePO{sub 4}, in lithium-ion batteries, a conductive additive like carbon black is commonly used to build an electronic transport path between the active particles. The connection between active phase and conductive media has a dominant influence on electrochemical properties and lifetime of batteries. We compare the performance and properties of electrodes which were prepared in two different ways with the same LiFePO{sub 4} nanopowder as the active phase. The electrodes were prepared in a conventional route, based on the commonly used powder-suspension coating on metallic foils and in an alternative route, based on the electrospinning method. As a result, the obtained electrodes have different structures and connections between the active and conductive phase, which has an influence on the electrode behavior during cycling. The accessible high thickness and variable density of the electrodes are the main advantages of the electrodes prepared by electrospinning.

  12. Studi Electrochemical Impedance Spectroscopy dari Lembaran Polyvinyl Alcohol dengan Penambahan Liclo4 sebagai Bahan Elektolit Baterai Li-ion

    OpenAIRE

    Gunawan, Indra; Wahyudianingsih, Wahyudianingsih; Sudaryanto, Sudaryanto

    2016-01-01

    ELECTROCHEMICALIMPEDANCE SPECTROSCOPY STUDY OF POLYVINYL ALCOHOL SHEETWITHADDITION OFLiClO4AS ELECTROLYTE MATERIAL OF Li-ION BATTERAY. Solid polymer electrolyte materials for Li ion battery have been prepared using polyvinyl alcohol (PVA) added by lithium perchlorate (LiClO4) salt with various concentration. Electrochemical Impedance Spectroscopy (EIS) study of the material was done by making a Nyquist plot of the measurement with a LCR meter. These electrolyte materials prepared by using PVA...

  13. Internal Friction in L.A.S. Type Glass and Glass-Ceramics

    OpenAIRE

    Arnault , L.; RiviÈre , A.

    1996-01-01

    Internal friction measurements have been performed on glass and glass-ceramics of the Li2O-Al2O3-SiO2 type by isothermal mechanical spectroscopy. Experiments were carried out over a large frequency range (10-4Hz - 31.6 Hz) for various temperatures between 260K and 850K. For the glass, a relaxation peak is observed at low temperature (276K for 1Hz). This peak does not appear in the glass-ceramics ; however, for each of them, two other peaks were observed : the first one at about 343K (1Hz) and...

  14. Bending strength of glass-ceramics based on 3CaO.P2O5-SiO2-MgO glass system

    International Nuclear Information System (INIS)

    Daguano, J.K.M.F.; Suzuki, P.A.; Santos, C.; Fernandes, M.H.V.; Elias, C.N.

    2009-01-01

    In this work, the Modulus of Rupture of bioactive glass-ceramic based on 3CaO.P 2 O 5 -SiO 2 -MgO system was investigated, aiming its use in bone-restorations. The mechanical property was correlated with microstructural and crystallographic features of this material. High-purity starting-powders, CaCO 3 , SiO 2 , MgO, Ca (H 2 PO 4 ).H 2 O, were used in this study. The powders were mixed in a stoichiometric ratio, using planetary ball-mill. The suspensions were dried, sieved and melted at 1600 deg C, for 4h. The casting ones were cooled quickly until annealing temperature 700 deg C, in which remained for 2h, with controlled cooling-rate until ambient temperature. Bulks of glass were heat-treated with temperatures varying between 700 deg C and 1100 deg C, for 4h, being after that, cooled at 3 deg C/min. Bioactive glass and glass-ceramic were characterized by HRXRD (high resolution X-ray diffraction), where whitlockite was main phase. The microstructure was analyzed by scanning electronic microscopy. Modulus of Rupture was determined by four-point bending testing using specimens of 1.5 x 2 x 25 mm and glasses presented strength near to 70MPa, while glass ceramics treated at 975 deg C-4h, presented bending strength of 120MPa. (author)

  15. Rapid Polyol-Assisted Microwave Synthesis of Nanocrystalline LiFePO4/C Cathode for Lithium-Ion Batteries.

    Science.gov (United States)

    Paul, Baboo Joseph; Gim, Jihyeon; Baek, Sora; Kang, Jungwon; Song, Jinju; Kim, Sungjin; Kim, Jaekook

    2015-08-01

    Nanocrystalline LiFePO4/C has been synthesized under a very short period of time (90 sec) using a polyol-assisted microwave heating synthesis technique. The X-ray diffraction (XRD) data indicates that the rapidly synthesized materials correspond to phase pure olivine. Post-annealing of the as-prepared sample at 600 °C in argon atmosphere yields highly crystalline LiFePO4/C. The morphology of the samples studied using scanning electron microscopy (SEM) reveals the presence of secondary particles formed from aggregation of primary particles in the range of 30-50 nm. Transmission electron microscopy (TEM) images reveal a thin carbon layer coating on the surface of the primary particle. The charge/discharge studies indicate that the as-prepared and annealed LiFePO4/C samples delivered initial discharge capacities of 126 and 160 mA h g-1, respectively, with good capacity retentions at 0.05 mA cm-2 current densities. The post-annealing process indeed improves the crystallinity of the LiFePO4 nanocrystals, which enhances the electrode performance of LiFePO4/C.

  16. Study of LiFePO{sub 4} cathode materials coated with high surface area carbon

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Cheng-Zhang; Fey, George Ting-Kuo [Department of Chemical and Materials Engineering, National Central University, Chung-Li 32054 (China); Kao, Hsien-Ming [Department of Chemistry, National Central University, Chung-Li 32054 (China)

    2009-04-01

    LiFePO{sub 4} is a potential cathode material for 4 V lithium-ion batteries. Carbon-coated lithium iron phosphates were prepared using a high surface area carbon to react precursors through a solid-state process, during which LiFePO{sub 4} particles were embedded in amorphous carbon. The carbonaceous materials were synthesized by the pyrolysis of peanut shells under argon, where they were carbonized in a two-step process that occurred between 573 and 873 K. The shells were also treated with a proprietary porogenic agent with the goal of altering the pore structure and surface area of the pyrolysis products. The electrochemical properties of the as-prepared LiFePO{sub 4}/C composite cathode materials were systematically characterized by X-ray diffraction, scanning electron microscope, element mapping, energy dispersive spectroscopy, Raman spectroscopy, and total organic carbon (TOC) analysis. In LiFePO{sub 4}/C composites, the carbon not only increases rate capability, but also stabilizes capacity. In fact, the capacity of the composites increased with the specific surface area of carbon. The best result was observed with a composite made of 8.0 wt.% with a specific surface area of 2099 m{sup 2} g{sup -1}. When high surface area carbon was used as a carbon source to produce LiFePO{sub 4}, overall conductivity increased from 10{sup -8} to 10{sup -4} S cm{sup -1}, because the inhibition of particle growth during the final sintering process led to greater specific capacity, improved cycling properties and better rate capability compared to a pure olivine LiFePO{sub 4} material. (author)

  17. Magnetic phase investigations on fluorine (F) doped LiFePO4

    Science.gov (United States)

    Radhamani, A. V.

    2018-03-01

    LiFePO4 (LFP) is a very promising cathode material for Li-ion batteries due to its high thermal stability, less toxicity and high theoretical capacity (170 mAh g-1). Anion doping, especially fluorine (F) at the oxygen site is one way to improve the low electronic conductivity of the material. In this line, fluorine doped LFP was prepared at different fluorine concentrations (1 to 40 mol%) to study the structural, spectroscopic and magnetic properties in view of the material property optimization for battery applications. The investigation of the magnetic properties was found to be successful for the determination of small amounts of magnetic impurities which were not noticeably observed from structural characterizations. Determination of conducting magnetic impurities has its own relevance in the current scenario of Li-ion based battery applications. Systematic characterization studies along with the implications of magnetic phases on the material activity of fluorine doped LiFePO4 nanoparticles will be discussed in detail.

  18. Mechanistic insights of Li+ diffusion within doped LiFePO4 from Muon Spectroscopy.

    Science.gov (United States)

    Johnson, Ian D; Ashton, Thomas E; Blagovidova, Ekaterina; Smales, Glen J; Lübke, Mechthild; Baker, Peter J; Corr, Serena A; Darr, Jawwad A

    2018-03-07

    The Li + ion diffusion characteristics of V- and Nb-doped LiFePO 4 were examined with respect to undoped LiFePO 4 using muon spectroscopy (µSR) as a local probe. As little difference in diffusion coefficient between the pure and doped samples was observed, offering D Li values in the range 1.8-2.3 × 10 -10  cm 2 s -1 , this implied the improvement in electrochemical performance observed within doped LiFePO 4 was not a result of increased local Li + diffusion. This unexpected observation was made possible with the µSR technique, which can measure Li + self-diffusion within LiFePO 4 , and therefore negated the effect of the LiFePO 4 two-phase delithiation mechanism, which has previously prevented accurate Li + diffusion comparison between the doped and undoped materials. Therefore, the authors suggest that µSR is an excellent technique for analysing materials on a local scale to elucidate the effects of dopants on solid-state diffusion behaviour.

  19. Effect of microstructure on low temperature electrochemical properties of LiFePO4/C cathode material

    International Nuclear Information System (INIS)

    Zhao, Nannan; Zhi, Xiaoke; Wang, Li; Liu, Yanhui; Liang, Guangchuan

    2015-01-01

    Graphical abstract: The low temperature performance of Li-ion batteries and LiFePO 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 2 O 4 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 and LiFePO 4 /C as cathode materials. The low temperature performance results indicate the LiFePO 4 /C microstructure is the main factor influencing the low temperature performance of LiFePO 4 . A new LiFePO 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 4 /C composite was discussed. • Cathode material mainly decided the low temperature performance of Li-ion battery. • LiFePO 4 /C microstructure mainly affects its low temperature performance. • Pomegranate-like spherical structure LiFePO 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 2 O 4 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 , and LiFePO 4 /C as the cathode, respectively, at −20 °C. LiFePO 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 indicate that the microstructure of LiFePO 4 /C is a key factor determining the low

  20. LiFePO4 Nanostructures Fabricated from Iron(III) Phosphate (FePO4 x 2H2O) by Hydrothermal Method.

    Science.gov (United States)

    Saji, Viswanathan S; Song, Hyun-Kon

    2015-01-01

    Electrode materials having nanometer scale dimensions are expected to have property enhancements due to enhanced surface area and mass/charge transport kinetics. This is particularly relevant to intrinsically low electronically conductive materials such as lithium iron phosphate (LiFePO4), which is of recent research interest as a high performance intercalation electrode material for Li-ion batteries. Many of the reported works on LiFePO4 synthesis are unattractive either due to the high cost of raw materials or due to the complex synthesis technique. In this direction, synthesis of LiFePO4 directly from inexpensive FePO4 shows promise.The present study reports LiFePO4 nanostructures prepared from iron (III) phosphate (FePO4 x 2H2O) by precipitation-hydrothermal method. The sintered powder was characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Inductive coupled plasma-optical emission spectroscopy (ICP-OES), and Electron microscopy (SEM and TEM). Two synthesis methods, viz. bulk synthesis and anodized aluminum oxide (AAO) template-assisted synthesis are reported. By bulk synthesis, micro-sized particles having peculiar surface nanostructuring were formed at precipitation pH of 6.0 to 7.5 whereas typical nanosized LiFePO4 resulted at pH ≥ 8.0. An in-situ precipitation strategy inside the pores of AAO utilizing the spin coating was utilized for the AAO-template-assisted synthesis. The template with pores filled with the precipitate was subsequently subjected to hydrothermal process and high temperature sintering to fabricate compact rod-like structures.

  1. Mesoporous LiMnPO4/C nanoparticles as high performance cathode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Wen, Fang; Shu, Hongbo; Zhang, Yuanyuan; Wan, Jiajia; Huang, Weihua; Yang, Xiukang; Yu, Ruizhi; Liu, Li; Wang, Xianyou

    2016-01-01

    LiMnPO 4 has been considered as one of the most promising high voltage cathode materials for next-generation lithium ion batteries. However, LiMnPO 4 suffers from intrinsic drawbacks of extremely low electronic conductivity and ionic diffusivity between LiMnPO 4 /MnPO 4 . In this paper, mesoporous LiMnPO 4 nanoparticles are synthesized successfully via a facile glycine-assisted solvothermal rout. The as-prepared mesoporous LiMnPO 4 /C nanoparticles present well-defined abundant mesoporous structure (diameter of 3 ∼ 10 nm), uniform carbon layer (thickness of 3 ∼ 4 nm), high specific surface area (90.1 m 2 /g). As a result, the mesoporous LiMnPO 4 /C nanoparticles achieve excellent electrochemical performance as cathode materials for lithium ion batteries. It demonstrates a high discharge capacity of 167.7, 161.6, 156.4, 148.4 and 128.7 mAh/g at 0.1, 0.5, 1, 2 and 5C, and maintains a discharge capacity of 130.0 mAh/g after 100 cycles at 1C. The good electrochemical performance is attributed to its special interpenetrating mesoporous structure in LiMnPO 4 nanoparticles, which significantly enhances the ionic and electronic transport and additional capacitive behavior to compensate the sluggish kinetics.

  2. 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

  3. Fast-Rate Capable Electrode Material with Higher Energy Density than LiFePO4: 4.2V LiVPO4F Synthesized by Scalable Single-Step Solid-State Reaction.

    Science.gov (United States)

    Kim, Minkyung; Lee, Seongsu; Kang, Byoungwoo

    2016-03-01

    Use of compounds that contain fluorine (F) as electrode materials in lithium ion batteries has been considered, but synthesizing single-phase samples of these compounds is a difficult task. Here, it is demonstrated that a simple scalable single-step solid-state process with additional fluorine source can obtain highly pure LiVPO 4 F. The resulting material with submicron particles achieves very high rate capability ≈100 mAh g -1 at 60 C-rate (1-min discharge) and even at 200 C-rate (18 s discharge). It retains superior capacity, ≈120 mAh g -1 at 10 C charge/10 C discharge rate (6-min) for 500 cycles with >95% retention efficiency. Furthermore, LiVPO 4 F shows low polarization even at high rates leading to higher operating potential >3.45 V (≈3.6 V at 60 C-rate), so it achieves high energy density. It is demonstrated for the first time that highly pure LiVPO 4 F can achieve high power capability comparable to LiFePO 4 and much higher energy density (≈521 Wh g -1 at 20 C-rate) than LiFePO 4 even without nanostructured particles. LiVPO 4 F can be a real substitute of LiFePO 4.

  4. LiFePO4 mesocrystals for lithium-ion batteries.

    Science.gov (United States)

    Popovic, Jelena; Demir-Cakan, Rezan; Tornow, Julian; Morcrette, Mathieu; Su, Dang Sheng; Schlögl, Robert; Antonietti, Markus; Titirici, Maria-Magdalena

    2011-04-18

    Olivine LiFePO(4) is considered one of the most promising cathode materials for Li-ion batteries. A simple one-step, template-free, low-temperature solvothermal method is developed for the synthesis of urchinlike hierarchical mesocrystals of pristine LiFePO(4) as well as carbon-coated LiFePO(4) composites. Each urchinlike mesocrystal consists of LiFePO(4) sheets self-assembled via a dipolar field in spheres during a solvothermal process under the influence of Cl(-) anions. The obtained primary sheets of LiFePO(4) are single crystalline in nature and can be coated in situ with an amorphous nitrogen-doped carbonaceous layer several nanometers in thickness. To increase the conductivity of the carbon coating, the materials are subjected to further temperature treatment (700 °C) under an inert atmosphere. The lithium storage performance of the pure LiFePO(4) is compared with that of its carbon-coated counterparts. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. LiV2O4: A heavy fermion transition metal oxide

    International Nuclear Information System (INIS)

    Shinichiro, Kondo

    1999-01-01

    The format of this dissertation is as follows. In the remainder of Chapter 1, brief introductions and reviews are given to the topics of frustration, heavy fermions and spinels including the precedent work of LiV 2 O 4 . In Chapter 2, as a general overview of this work the important publication in Physical Review Letters by the author of this dissertation and collaborators regarding the discovery of the heavy fermion behavior in LiV 2 O 4 is introduced [removed for separate processing]. The preparation methods employed by the author for nine LiV 2 O 4 and two Li 1+x Ti 2-x O 4 (x = 0 and 1/3) polycrystalline samples are introduced in Chapter 3. The subsequent structural characterization of the LiV 2 O 4 and Li 1+x Ti 2-x O 4 samples was done by the author using thermogravimetric analysis (TGA), x-ray diffraction measurements and their structural refinements by the Rietveld analysis. The results of the characterization are detailed in Chapter 3. In Chapter 4 magnetization measurements carried out by the author are detailed. In Chapter 5, after briefly discussing the resistivity measurement results including the single-crystal work by Rogers et al., for the purpose of clear characterization of LiV 2 O 4 it is of great importance to introduce in the following chapters the experiments and subsequent data analyses done by his collaborators. Heat capacity measurements (Chapter 6) were carried out and analyzed by Dr. C.A. Swenson, and modeled theoretically by Dr. D.C. Johnston. In Chapter 7 a thermal expansion study using neutron diffraction by Dr. O. Chmaissem et al. and capacitance dilatometry measurements by Dr. C.A. Swenson are introduced. The data analyses for the thermal expansion study were mainly done by Dr. O. Chmaissem (for neutron diffraction) and Dr. C.A. Swendon (for dilatometry), with assistances by Dr. J.D. Jorgensen, Dr. D.C. Johnston, and S. Kondo the author of this dissertation. Chapter 8 describes nuclear magnetic resonance (NMR) measurements and

  6. Combustion synthesized nanocrystalline Li3V2(PO4)3/C cathode for lithium-ion batteries

    International Nuclear Information System (INIS)

    Nathiya, K.; Bhuvaneswari, D.; Gangulibabu; Kalaiselvi, N.

    2012-01-01

    Graphical abstract: Nanocrystalline Li 3 V 2 (PO 4 ) 3 /C compound has been synthesized using a novel corn assisted combustion (CAC) method, wherein the composite prepared at 850 °C is found to exhibit superior physical and electrochemical properties than the one synthesized at 800 °C (Fig. 1). Despite the charge disproportionation of V 4+ and a possible solid solution behavior of Li 3 V 2 (PO 4 ) 3 cathode upon insertion and de-insertion of Li + ions, the structural stability of the same is appreciable, even with the extraction of third lithium at 4.6 V (Fig. 2). An appreciable specific capacity of 174 mAh g −1 with an excellent columbic efficiency (99%) and better capacity retention upon high rate applications have been exhibited by Li 3 V 2 (PO 4 ) 3 /C cathode, thus demonstrating the feasibility of CAC method in preparing the title compound to best suit with the needs of lithium battery applications. Display Omitted Highlights: ► Novel corn assisted combustion method has been used to synthesize Li 3 V 2 (PO 4 ) 3 /C. ► Corn is a cheap and eco benign combustible fuel to facilitate CAC synthesis. ► Li 3 V 2 (PO 4 ) 3 /C exhibits an appreciable specific capacity of 174 mAh g −1 (C/10 rate). ► Currently observed columbic efficiency of 99% is better than the reported behavior. ► Suitability of Li 3 V 2 (PO 4 ) 3 /C cathode up to 10C rate is demonstrated. -- Abstract: Nanocrystalline Li 3 V 2 (PO 4 ) 3 /C composite synthesized using a novel corn assisted combustion method at 850 °C exhibits superior physical and electrochemical properties than the one synthesized at 800 °C. Despite the charge disproportionation of V 4+ and a possible solid solution behavior of Li 3 V 2 (PO 4 ) 3 cathode upon insertion and extraction of Li + ions, the structural stability of the same is appreciable, even with the extraction of third lithium at 4.6 V. An appreciable specific capacity of 174 mAh g −1 and better capacity retention upon high rate applications have been

  7. Ab initio identification of the Li-rich phase in LiFePO4.

    Science.gov (United States)

    Zeng, Hua; Gu, Yue; Teng, Gaofeng; Liu, Yimeng; Zheng, Jiaxin; Pan, Feng

    2018-06-27

    A recent discovery of anionic redox activity in Li-rich layered compounds opens a new direction for the design of high-capacity cathode materials for lithium-ion batteries. Here using extensive ab initio calculations, the thermodynamic existence of the Li-rich phase in LiFePO4 to form Li1+xFe1-xPO4 with x not exceeding 12.5% has been proved. Anionic redox activity and structural stability during delithiation are further investigated. Interestingly, it is found that Li1+xFe1-xPO4 cannot be delithiated completely and thus cannot achieve extra capacity by anionic redox activity, because the local oxygen-ion redox will cause the fracture of the rigid framework formed by phosphate tetrahedral polyanions. Although an extra capacity cannot be realized, the excess Li-ions at Fe sites can enhance the Li-ion diffusivity along the adjacent [010] channel and contribute to the shift from 1D to 2D/3D diffusion. This study provides a fresh perspective on olivine-type LiFePO4 and offers some important clues on designing Li-rich cathode materials with high energy density.

  8. Improved electrochemical properties of Li{sub 4}Ti{sub 5}O{sub 12}–Li{sub 0.33}La{sub 0.56}TiO{sub 3} composite anodes prepared by a solid-state synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yan-Rong; Yuan, Jing; Zhu, Min [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan, Anhui 243002 (China); Hao, Guodong [College of Chemistry and Chemical Engineering, Mudanjiang Normal University, Mudanjiang, Heilongjiang 157012 (China); Yi, Ting-Feng, E-mail: tfyihit@163.com [School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan, Anhui 243002 (China); Xie, Ying, E-mail: xieying@hlju.edu.cn [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin, Heilongjiang 150080 (China)

    2015-10-15

    Li{sub 4}Ti{sub 5}O{sub 12}–Li{sub 0.33}La{sub 0.56}TiO{sub 3} composite anodes are successfully prepared by a facile solid state route. The structure, morphology and electrochemical performance of all samples are characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge–discharge tests, respectively. XRD reveals that the little La{sup 3+} ions enter into the lattice, and then make the crystal lattice of Li{sub 4}Ti{sub 5}O{sub 12} expand. SEM shows that all samples are composed of 1–2 μm primary particles with irregular shapes. CV and EIS imply that Li{sub 4}Ti{sub 5}O{sub 12}–Li{sub 0.33}La{sub 0.56}TiO{sub 3} composites have lower polarization, larger lithium-ion diffusion coefficient and smaller charge transfer resistance corresponding to a much higher conductivity than those of Li{sub 4}Ti{sub 5}O{sub 12} corresponding to the extraction of Li{sup +} ions. The improved electrochemical performance of Li{sub 4}Ti{sub 5}O{sub 12}–Li{sub 0.33}La{sub 0.56}TiO{sub 3} composites can be attributed to the enhanced transfer kinetics of both the lithium ions and electrons. Particularly, Li{sub 4}Ti{sub 5}O{sub 12}–Li{sub 0.33}La{sub 0.56}TiO{sub 3} (5 wt.%) composite shows a excellent high-rate capability and cycling stability. Therefore, the present Li{sub 4}Ti{sub 5}O{sub 12}–Li{sub 0.33}La{sub 0.56}TiO{sub 3} (5 wt.%) composite anode is capable of large-scale applications, such as electric vehicles and hybrid electric vehicles, requiring high energy, long life and excellent safety. - Highlights: • The electrochemical property of Li{sub 4}Ti{sub 5}O{sub 12}–Li{sub 0.33}La{sub 0.56}TiO{sub 3} down to 0 V is first reported. • Li{sub 0.33}La{sub 0.56}TiO{sub 3} modifying results in fast lithium insertion/extraction kinetics. • Li{sub 4}Ti{sub 5}O{sub 12}–Li{sub 0.33}La{sub 0.56}TiO{sub 3} (5 wt.%) exhibits a good fast charge

  9. Preparation of rod-like β-Si3N4 single crystal particles

    International Nuclear Information System (INIS)

    Hirao, K.; Tsuge, A.; Brito, M.E.; Kanzaki, S.

    1994-01-01

    The use of β-Si 3 N 4 particles as a seed material has been demonstrated to be effective for development of a self-reinforcing microstructure in sintered silicon nitride ceramics. We have confirmed the seeding effect and arrived at a concept that seed particles should consist of rod-like single crystals free from defects and with a large diameter. The present work describes our attempts to produce such particles with a controlled morphology and in high amount. β-Si 3 N 4 particles with a diameter of 1μm and length of 5μm were obtained by heating a mixture of α-Si 3 N 4 , SiO 2 and Y 2 O 3 , followed by acid rinse treatments to remove residual glassy phase. (orig.)

  10. Effects of the co-addition of LiSbO3-LiTaO3 on the densification of (Na1/2K1/2)NbO3 lead free ceramics by atmosphere sintering

    International Nuclear Information System (INIS)

    Jiang Na; Fang Bijun; Wu Jian; Du Qingbo

    2011-01-01

    Research highlights: → This manuscript shows a synthesis method that can easily obtain excellent lead-free samples, which is valuable for industrial production. → Pure phase perovskite 0.94(Na 1/2 K 1/2 )NbO 3 -0.03LiSbO 3 -0.03LiTaO 3 (0.94NKN-0.03LS-0.03LT) lead-free piezoelectric ceramics with high relative density, being 94.73%, and excellent integral electrical properties, piezoelectric constant d 33 being 228 pC/N, were prepared by atmosphere sintering method. Which can be attributed to the co-doping of LiSbO 3 -LiTaO 3 . - Abstract: Pure phase perovskite 0.94(Na 1/2 K 1/2 )NbO 3 -0.03LiSbO 3 -0.03LiTaO 3 (0.94NKN-0.03LS-0.03LT) lead-free piezoelectric ceramics were prepared by the conventional solid-state reaction method. Due to the co-addition of LiSbO 3 -LiTaO 3 , the 0.94NKN-0.03LS-0.03LT ceramics prepared by atmosphere sintering at 1040 deg. C exhibit high relative density, being 94.73%, and rather homogenous microstructure. X-ray diffraction (XRD) measurement confirmed that the sintered ceramics exhibit pure tetragonal perovskite structure. The 0.94NKN-0.03LS-0.03LT ceramics exhibit excellent integral electrical properties, in which the value of piezoelectric constant d 33 is 228 pC/N, the electromechanical coupling factors K p and K t are 0.220 and 0.230, respectively, the mechanical quality factor Q m is 32.19, and the remnant polarization P r is 23.06 μC/cm 2 . Such excellent electrical properties are considered as correlating with the high relative density of the synthesized ceramics induced by the co-doping of LiSbO 3 -LiTaO 3 .

  11. Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres

    Indian Academy of Sciences (India)

    Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres. K C BARICK and D BAHADUR*. Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay,. Mumbai 400 076, India. Abstract. The assembly of superparamagnetic Fe3O4 nanoparticles on submicroscopic SiO2 ...

  12. Structural and electrochemical studies of PPy/PEG-LiFePO4 cathode material for Li-ion batteries

    International Nuclear Information System (INIS)

    Fedorkova, Andrea; Nacher-Alejos, Ana; Gomez-Romero, Pedro; Orinakova, Renata; Kaniansky, Dusan

    2010-01-01

    A simple chemical oxidative polymerization of pyrrole (Py) directly onto the surface of LiFePO 4 particles was applied to the synthesis of polypyrrole-LiFePO 4 (PPy-LiFePO 4 ) powder. The LiFePO 4 sample without carbon coating was synthesized by a solvothermal method. The polyethylene glycol (PEG) was used as additive during Py polymerization for increasing the PPy-LiFePO 4 conductivity. Properties of resulting LiFePO 4 , PPy-LiFePO 4 and PPy/PEG-LiFePO 4 samples were characterized by XRD, SEM, TGA and galvanostatic charge-discharge measurements. These methods confirmed the presence of polypyrrole on LiFePO 4 particles and its homogeneous distribution in the resulting powder material. The PPy/PEG-LiFePO 4 composites show higher discharge capacity than pure LiFePO 4 , as PPy/PEG network improves the electron conductivity. It presents specific discharge capacity of 153 mAh/g at C/5 rate.

  13. Effect of Carbon Coating on Li4TiO12 of Anode Material for Hybrid Capacitor.

    Science.gov (United States)

    Lee, Jong-Kyu; Lee, Byung-Gwan; Yoon, Jung-Rag

    2015-11-01

    The carbon-coated Li4Ti5O12 of anode material for hybrid capacitor was prepared by controlling carbonization time at 700 degrees C in nitrogen. With increasing of carbonization time, the discharge capacity and capacitance were decreased, while the equivalent series resistance was not changed remarkably. The rate capability and cycle performance of carbon-coated Li4Ti5O12 were larger than that of Li4Ti5O12. Carbon coating improved conductivity as well as Li-ion diffusion, and thus also resulted in good rate capabilities and cycle stability. The effects of carbon coating on the gas generation of hybrid capacitor were also discussed.

  14. TiO2/SiO2 prepared via facile sol-gel method as an ideal support for green synthesis of Ag nanoparticles using Oenothera biennis extract and their excellent catalytic performance in the reduction of 4-nitrophenol

    Directory of Open Access Journals (Sweden)

    Bahar Khodadadi

    2017-01-01

    Full Text Available In the present study, the extract of the plant of Oenothera biennis was used to green synthesis of silver nanoparticles (Ag NPs as an environmentally friendly, simple and low cost method. And Additionally, TiO2/SiO2 was prepared via facile sol-gel method using starch as an important, naturally abundant organic polymer as an ideal support. The Ag NPs/TiO2/SiO2 as an effective catalyst was prepared through reduction of Ag+ ions using Oenothera biennis extract as the reducing and stabilizing agent and Ag NPs immobilization on TiO2/SiO2 surface in the absence of any stabilizer or surfactant. Several techniques such as FT-IR spectroscopy, UV-Vis spectroscopy, X-ray Diffraction (XRD, sScanning eElectron mMicroscopy (FE-SEM, Eenergy dDispersive X-ray sSpectroscopy (EDS, and Ttransmission Eelectron Mmicroscopy (TEM were used to characterize TiO2/SiO2, silver nanoparticles (Ag NPs, and Ag NPs/TiO2/SiO2. Moreover, the catalytic activity of the Ag NPs/ TiO2/SiO2 was investigated in the reduction of 4-nitrophenol (4-NP at room temperature. On the basis of the results, the Ag NPs/TiO2/SiO2 was found to be high catalytic activity highly active catalyst according to the experimental results in this study. In addition, Ag NPs/TiO2/SiO2 can be recovered and reused several times in the reduction of 4-NP with no significant loss of catalytic activity.

  15. Fast neutron irradiation results on Li2O, Li4SiO4, Li2ZrO3 and LiA102

    International Nuclear Information System (INIS)

    Hollenberg, G.W.

    1983-04-01

    Several ceramic solid breeder materials were irradiated in the fast neutron flux of EBR-II to a burnup of 3 x 10 20 captures/cm 3 in the 500 0 C to 900 0 C temperature range. Performance data were obtained on structural integrity, lithium transport, pellet swelling, and grain growth. The data provide a basis for more accurately forecasting the feasibility and performance limitations for these materials

  16. Total Ionizing Dose Effects of Si Vertical Diffused MOSFET with SiO2 and Si3N4/SiO2 Gate Dielectrics

    Directory of Open Access Journals (Sweden)

    Jiongjiong Mo

    2017-01-01

    Full Text Available The total ionizing dose irradiation effects are investigated in Si vertical diffused MOSFETs (VDMOSs with different gate dielectrics including single SiO2 layer and double Si3N4/SiO2 layer. Radiation-induced holes trapping is greater for single SiO2 layer than for double Si3N4/SiO2 layer. Dielectric oxidation temperature dependent TID effects are also studied. Holes trapping induced negative threshold voltage shift is smaller for SiO2 at lower oxidation temperature. Gate bias during irradiation leads to different VTH shift for different gate dielectrics. Single SiO2 layer shows the worst negative VTH at VG=0 V, while double Si3N4/SiO2 shows negative VTH shift at VG=-5 V, positive VTH shift at VG=10 V, and negligible VTH shift at VG=0 V.

  17. Electrochemical Characteristics and Li+ Ion Intercalation Kinetics of Dual-phase Li4Ti5O12/Li2TiO3 Composite in Voltage Range of 0−3 V

    KAUST Repository

    Bhatti, Humaira S

    2016-04-20

    Li4Ti5O12, Li2TiO3 and dual-phase Li4Ti5O12/Li2TiO3 composite were prepared by sol-gel method with average particle size of 1 µm, 0.3 µm and 0.4 µm, respectively. Though Li2TiO3 is electrochemically inactive, the rate capability of Li4Ti5O12/Li2TiO3 is comparable to Li4Ti5O12 at different current rates. Li4Ti5O12/Li2TiO3 also shows good rate performance of 90 mA h g-1 at high rate of 10 C in voltage range of 1−3 V, attributable to increased interfaces in the composite. While Li4Ti5O12 delivers capacity retention of 88.6 % at 0.2 C over 50 cycles, Li4Ti5O12/Li2TiO3 exhibits no capacity fading at 0.2 C (40 cycles) and capacity retention of 98.45 % at 0.5 C (50 cycles). This highly stable cycling performance is attributed to the contribution of Li2TiO3 in preventing undesirable reaction of Li4Ti5O12 with the electrolyte during cycling. CV curves of Li4Ti5O12/Li2TiO3 in 0−3 V range exhibit two anodic peaks at 1.51 V and 0.7−0.0 V, indicating two modes of lithium intercalation into the lattice sites of active material. Owing to enhanced intercalation/de-intercalation kinetics in 0−3 V, composite electrode delivers superior rate performance of 203 mAh/g at 2.85 C and 140 mAh/g at 5.7 C with good reversible capacity retention over 100 cycles.

  18. Electrochemical Characteristics and Li+ Ion Intercalation Kinetics of Dual-phase Li4Ti5O12/Li2TiO3 Composite in Voltage Range of 0−3 V

    KAUST Repository

    Bhatti, Humaira S; Anjum, Dalaver H.; Ullah, Shafiq; Ahmed, Bilal; Habib, Amir; Karim, Altaf; Hasanain, Syed Khurshid

    2016-01-01

    Li4Ti5O12, Li2TiO3 and dual-phase Li4Ti5O12/Li2TiO3 composite were prepared by sol-gel method with average particle size of 1 µm, 0.3 µm and 0.4 µm, respectively. Though Li2TiO3 is electrochemically inactive, the rate capability of Li4Ti5O12/Li2TiO3 is comparable to Li4Ti5O12 at different current rates. Li4Ti5O12/Li2TiO3 also shows good rate performance of 90 mA h g-1 at high rate of 10 C in voltage range of 1−3 V, attributable to increased interfaces in the composite. While Li4Ti5O12 delivers capacity retention of 88.6 % at 0.2 C over 50 cycles, Li4Ti5O12/Li2TiO3 exhibits no capacity fading at 0.2 C (40 cycles) and capacity retention of 98.45 % at 0.5 C (50 cycles). This highly stable cycling performance is attributed to the contribution of Li2TiO3 in preventing undesirable reaction of Li4Ti5O12 with the electrolyte during cycling. CV curves of Li4Ti5O12/Li2TiO3 in 0−3 V range exhibit two anodic peaks at 1.51 V and 0.7−0.0 V, indicating two modes of lithium intercalation into the lattice sites of active material. Owing to enhanced intercalation/de-intercalation kinetics in 0−3 V, composite electrode delivers superior rate performance of 203 mAh/g at 2.85 C and 140 mAh/g at 5.7 C with good reversible capacity retention over 100 cycles.

  19. Quantum-Chemical Approach to NMR Chemical Shifts in Paramagnetic Solids Applied to LiFePO4 and LiCoPO4.

    Science.gov (United States)

    Mondal, Arobendo; Kaupp, Martin

    2018-04-05

    A novel protocol to compute and analyze NMR chemical shifts for extended paramagnetic solids, accounting comprehensively for Fermi-contact (FC), pseudocontact (PC), and orbital shifts, is reported and applied to the important lithium ion battery cathode materials LiFePO 4 and LiCoPO 4 . Using an EPR-parameter-based ansatz, the approach combines periodic (hybrid) DFT computation of hyperfine and orbital-shielding tensors with an incremental cluster model for g- and zero-field-splitting (ZFS) D-tensors. The cluster model allows the use of advanced multireference wave function methods (such as CASSCF or NEVPT2). Application of this protocol shows that the 7 Li shifts in the high-voltage cathode material LiCoPO 4 are dominated by spin-orbit-induced PC contributions, in contrast with previous assumptions, fundamentally changing interpretations of the shifts in terms of covalency. PC contributions are smaller for the 7 Li shifts of the related LiFePO 4 , where FC and orbital shifts dominate. The 31 P shifts of both materials finally are almost pure FC shifts. Nevertheless, large ZFS contributions can give rise to non-Curie temperature dependences for both 7 Li and 31 P shifts.

  20. Destabilized LiBH4-NaAlH4 Mixtures Doped with Titanium Based Catalysts

    DEFF Research Database (Denmark)

    Shi, Qing; Yu, Xuebin; Feidenhans'l, Robert

    2008-01-01

    We investigate the hydrogen storage properties of the mixed complex hydride LiBH4-NaAlH4 system, both undoped and doped with a TiCl3 additive. The mixed system is found to initiate a transformation to LiBH4-NaAlH4 after ball-milling, and the doped system is found to have a significant lower hydro...

  1. Luminescence characteristics and glow curves analysis of Cu"+ doped Li_3PO_4 phosphor

    International Nuclear Information System (INIS)

    Aghalte, G.A.; Dhoble, S.J.; Pawar, N.R.

    2016-01-01

    Li_3PO_4:Cu exhibits useful TL properties in personnel dosimetry of ionizing radiations. Cu is known to be one of the most efficient activator. The PL intensity is found to increase consistently with the increasing quenching temperature. Cu"+ doped Li_3PO_4 phosphor was synthesized by the wet chemical co-precipitation method. The crystal structure and particle morphology of the phosphor was investigated by using X-ray diffraction and scanning electron microscopy. Li_3PO_4:Cu is excellent phosphor for TL dosimetry. For the synthesis of Li_3PO_4:Cu phosphor the stoichiometric amounts of LiOH·H_2O and CuSO_4·"5H_2O were dissolved separately and then the solutions were mixed together. It was precipitated by using concentrated H_3PO_4. The precipitate was filtered out immediately and kept 12 hours below IR lamp. Prepared dry Li_3PO_4:Cu powder was then put on 2.5 wt% NH_4Cl in graphite crucible in preheated furnace at 800°C and was kept for 1 hour. It was then rapidly quenched to room temperature. Thermoluminescence (TL) glow curves were recorded on Nucleonix TL Reader with a heating rate of 2°C per second in the temperature range of 50-250°C. The PMT voltage was 750 volts. Photoluminescence (PL) studies were carried out by Hitachi F-4000 spectrophotometer with a spectral slit width of 1.5 nm

  2. Phase structure and piezoelectric properties of Li-modified NKLN lead-free piezoelectric ceramics

    International Nuclear Information System (INIS)

    Kim, Sin-Woong; Lee, Sung-Chan; Kim, Min-Soo; Jeong, Soon-Jong; Kim, In-Sung; Song, Jae-Sung

    2012-01-01

    Through the low-temperature sintering method, a sintered body with excellent characteristics was produced in an eco-friendly niobate-based piezoelectric ceramic, whose application was low in expectation due to poor sinterability. Li 2 CO 3 was added in excess to (Na 0.49 K 0.45 Li 0.06 )NbO 3 , and ceramics were manufactured using a commercial sintering method. Then, the sinterability and the piezoelectric properties of the specimens containing varying amounts of Li 2 CO 3 were investigated. The microstructure demonstrated the typical abnormal grain growth tendencies with the addition of Li 2 CO 3 , and this was explained through changes in the critical driving force in the interface reaction-controlled nucleation and growth theory. When the specimen had been sintered at 1000 .deg. C for 4 hours in air after the addition of 1.5 mol% Li 2 CO 3 , the sintered body showed outstanding characteristics with a piezoelectric coefficient of 180 pC/N, an electromechanical coupling coefficient of 0.32, and a dielectric constant of 975. These results showed that eco-friendly niobate-based ceramics, whose use in applications was expected to be difficult in spite of their excellent properties, could be used to produce piezoelectric materials with outstanding properties through a commercial low-temperature sintering method using additives.

  3. Phase structure and piezoelectric properties of Li-modified NKLN lead-free piezoelectric ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sin-Woong; Lee, Sung-Chan; Kim, Min-Soo; Jeong, Soon-Jong; Kim, In-Sung; Song, Jae-Sung [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

    2012-09-15

    Through the low-temperature sintering method, a sintered body with excellent characteristics was produced in an eco-friendly niobate-based piezoelectric ceramic, whose application was low in expectation due to poor sinterability. Li{sub 2}CO{sub 3} was added in excess to (Na{sub 0.49}K{sub 0.45}Li{sub 0.06})NbO{sub 3}, and ceramics were manufactured using a commercial sintering method. Then, the sinterability and the piezoelectric properties of the specimens containing varying amounts of Li{sub 2}CO{sub 3} were investigated. The microstructure demonstrated the typical abnormal grain growth tendencies with the addition of Li{sub 2}CO{sub 3}, and this was explained through changes in the critical driving force in the interface reaction-controlled nucleation and growth theory. When the specimen had been sintered at 1000 .deg. C for 4 hours in air after the addition of 1.5 mol% Li{sub 2}CO{sub 3}, the sintered body showed outstanding characteristics with a piezoelectric coefficient of 180 pC/N, an electromechanical coupling coefficient of 0.32, and a dielectric constant of 975. These results showed that eco-friendly niobate-based ceramics, whose use in applications was expected to be difficult in spite of their excellent properties, could be used to produce piezoelectric materials with outstanding properties through a commercial low-temperature sintering method using additives.

  4. Synthesis of Highly Uniform and Compact Lithium Zinc Ferrite Ceramics via an Efficient Low Temperature Approach.

    Science.gov (United States)

    Xu, Fang; Liao, Yulong; Zhang, Dainan; Zhou, Tingchuan; Li, Jie; Gan, Gongwen; Zhang, Huaiwu

    2017-04-17

    LiZn ferrite ceramics with high saturation magnetization (4πM s ) and low ferromagnetic resonance line widths (ΔH) represent a very critical class of material for microwave ferrite devices. Many existing approaches emphasize promotion of the grain growth (average size is 10-50 μm) of ferrite ceramics to improve the gyromagnetic properties at relatively low sintering temperatures. This paper describes a new strategy for obtaining uniform and compact LiZn ferrite ceramics (average grains size is ∼2 μm) with enhanced magnetic performance by suppressing grain growth in great detail. The LiZn ferrites with a formula of Li 0.415 Zn 0.27 Mn 0.06 Ti 0.1 Fe 2.155 O 4 were prepared by solid reaction routes with two new sintering strategies. Interestingly, results show that uniform, compact, and pure spinel ferrite ceramics were synthesized at a low temperature (∼850 °C) without obvious grain growth. We also find that a fast second sintering treatment (FSST) can further improve their gyromagnetic properties, such as higher 4πM s and lower ΔH. The two new strategies are facile and efficient for densification of LiZn ferrite ceramics via suppressing grain growth at low temperatures. The sintering strategy reported in this study also provides a referential experience for other ceramics, such as soft magnetism ferrite ceramics or dielectric ceramics.

  5. Mechanical Properties and Fabrication of Nanostructured Mg_2SiO_4-MgAl_2O_4 Composites by High-Frequency Induction Heated Combustion

    International Nuclear Information System (INIS)

    Shon, In-Jin; Kang, Hyun-Su; Hong, Kyung-Tae; Doh, Jung-Mann; Yoon, Jin-Kook

    2011-01-01

    Nanopowders of MgO, Al_2O_3 and SiO_2 were made by high energy ball milling. The rapid sintering of nanostructured MgAl_2O_4-Mg_2SiO_4 composites was investigated by a high-frequency induction heating sintering process. The advantage of this process is that it allows very quick densification to near theoretical density and inhibition of grain growth. Nanocrystalline materials have received much attention as advanced engineering materials with improved physical and mechanical properties. As nanomaterials possess high strength, high hardness, excellent ductility and toughness, undoubtedly, more attention has been paid for the application of nanomaterials. Highly dense nanostructured MgAl_2O_4-Mg_2SiO_4 composites were produced with simultaneous application of 80 MPa pressure and induced output current of total power capacity (15 kW) within 2 min. The sintering behavior, gain size and mechanical properties of MgAl_2O_4-Mg_2SiO_4 composites were investigated.

  6. Magnetic signature of charge ordering in Li[Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 and Li sub 0 sub . sub 2 [Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4

    CERN Document Server

    Verhoeven, V W J; Mulder, F M

    2002-01-01

    The stoichiometric compound LiMn sub 2 O sub 4 is known to show charge ordering with well-defined Mn sup 3 sup + and Mn sup 4 sup + sites just below room temperature (RT). Above RT the electrons are hopping rapidly between sites. For lithium-ion batteries the material Li[Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 is technologically relevant. Due to the small amount of Li on the Mn site, the low-T regular ordering of the Mn charge appears to be destroyed completely, as is evidenced by neutron diffraction in the magnetically ordered state. However, the charges are still fixed in an irregular fashion, as can also be deduced from sup 7 Li nuclear magnetic resonance measurements. In the lithium-extracted compound Li sub 0 sub . sub 2 [Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 , predominantly Mn sup 4 sup + is present. Neutron diffraction in the magnetically ordered state shows a well-defined antiferromagnetic ordering, with doubling of the unit cell in three directions. Clear...

  7. Structural and Electrical Properties of Lithium-Ion Rechargeable Battery Using the LiFePO4/Carbon Cathode Material.

    Science.gov (United States)

    Kim, Young-Sung; Jeoung, Tae-Hoon; Nam, Sung-Pill; Lee, Seung-Hwan; Kim, Jea-Chul; Lee, Sung-Gap

    2015-03-01

    LiFePO4/C composite powder as cathode material and graphite powder as anode material for Li-ion batteries were synthesized by using the sol-gel method. An electrochemical improvement of LiFePO4 materials has been achieved by adding polyvinyl alcohol as a carbon source into as-prepared materials. The samples were characterized by elemental analysis (EA), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-EM). The chemical composition of LiFePO4/C powders was in a good agreement with that of the starting solution. The capacity loss after 500 cycles of LiFePO4/C cell is 11.1% in room temperature. These superior electrochemical properties show that LiFePO4/C composite materials are promising candidates as cathode materials.

  8. Fluorocarbon based atomic layer etching of Si_3N_4 and etching selectivity of SiO_2 over Si_3N_4

    International Nuclear Information System (INIS)

    Li, Chen; Metzler, Dominik; Oehrlein, Gottlieb S.; Lai, Chiukin Steven; Hudson, Eric A.

    2016-01-01

    Angstrom-level plasma etching precision is required for semiconductor manufacturing of sub-10 nm critical dimension features. Atomic layer etching (ALE), achieved by a series of self-limited cycles, can precisely control etching depths by limiting the amount of chemical reactant available at the surface. Recently, SiO_2 ALE has been achieved by deposition of a thin (several Angstroms) reactive fluorocarbon (FC) layer on the material surface using controlled FC precursor flow and subsequent low energy Ar"+ ion bombardment in a cyclic fashion. Low energy ion bombardment is used to remove the FC layer along with a limited amount of SiO_2 from the surface. In the present article, the authors describe controlled etching of Si_3N_4 and SiO_2 layers of one to several Angstroms using this cyclic ALE approach. Si_3N_4 etching and etching selectivity of SiO_2 over Si_3N_4 were studied and evaluated with regard to the dependence on maximum ion energy, etching step length (ESL), FC surface coverage, and precursor selection. Surface chemistries of Si_3N_4 were investigated by x-ray photoelectron spectroscopy (XPS) after vacuum transfer at each stage of the ALE process. Since Si_3N_4 has a lower physical sputtering energy threshold than SiO_2, Si_3N_4 physical sputtering can take place after removal of chemical etchant at the end of each cycle for relatively high ion energies. Si_3N_4 to SiO_2 ALE etching selectivity was observed for these FC depleted conditions. By optimization of the ALE process parameters, e.g., low ion energies, short ESLs, and/or high FC film deposition per cycle, highly selective SiO_2 to Si_3N_4 etching can be achieved for FC accumulation conditions, where FC can be selectively accumulated on Si_3N_4 surfaces. This highly selective etching is explained by a lower carbon consumption of Si_3N_4 as compared to SiO_2. The comparison of C_4F_8 and CHF_3 only showed a difference in etching selectivity for FC depleted conditions. For FC accumulation conditions

  9. Phase formation in the Li2MoO4–Rb2MoO4–Fe2(MoO4)3 system and crystal structure of a novel triple molybdate LiRb2Fe(MoO4)3

    International Nuclear Information System (INIS)

    Khal'baeva, Klara M.; Solodovnikov, Sergey F.; Khaikina, Elena G.; Kadyrova, Yuliya M.; Solodovnikova, Zoya A.; Basovich, Olga M.

    2013-01-01

    X-ray investigation of solid state interaction of the components in the Li 2 MoO 4 –Rb 2 MoO 4 –Fe 2 (MoO 4 ) 3 system was carried out, and a subsolidus phase diagram of the said system was constructed. The subsystem Rb 2 MoO 4LiRbMoO 4 –RbFe(MoO 4 ) 2 was shown to be non-quasiternary. Formation of a novel triple molybdate LiRb 2 Fe(MoO 4 ) 3 was established, conditions of solid state synthesis and crystallization of the compound were found. Its crystal structure (orthorhombic, space group Pnma, Z=4, a=24.3956(6), b=5.8306(1), c=8.4368(2) Å) represents a new structure type and includes infinite two-row ribbons ([Fe(MoO 4 ) 3 ] 3− ) ∞ parallel to the b axis and composed of FeO 6 octahedra, terminal Mo(3)O 4 tetrahedra, and bridge Mo(1)O 4 and Mo(2)O 4 tetrahedra connecting two or three FeO 6 octahedra. The ribbons are connected to form 3D framework via corner-sharing LiO 4 tetrahedra. Rubidium cations are 11- and 13-coordinated and located in cavities of this heterogeneous polyhedral framework. - Graphical abstract: Exploring the Li 2 MoO 4 –Rb 2 MoO 4 –Fe 2 (MoO 4 ) 3 system showed its partial non-quasiternarity and revealed a new compound LiRb 2 Fe(MoO 4 ) 3 which was structurally studied. - Highlights: • The Li 2 MoO 4 –Rb 2 MoO 4 –Fe 2 (MoO 4 ) 3 system study revealed a new compound LiRb 2 Fe(MoO 4 ) 3 . • Its structure of a new type includes ribbons of FeO 6 octahedra and MoO 4 tetrahedra. • The ribbons are connected into a 3D framework via corner-sharing LiO 4 tetrahedra

  10. Low sintering temperature and high piezoelectric properties of Li-doped (Ba,Ca)(Ti,Zr)O{sub 3} lead-free ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaoming [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Ruan, Xuezheng; Zhao, Kunyun [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); He, Xueqing [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Zeng, Jiangtao, E-mail: zjt@mail.sic.ac.cn [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Li, Yongsheng [School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zheng, Liaoying [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Park, Chul Hong [Department of Physics Education, Pusan National University, Pusan 609735 (Korea, Republic of); Li, Guorong [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

    2015-05-25

    Highlights: • Li-doped Ba{sub 0.85}Ca{sub 0.15}Ti{sub 0.9}Zr{sub 0.1}O{sub 3} (BCZT) lead-free piezoceramics were prepared by the two-step synthesis and solid-state reaction method. • Their sintering temperature decreases from about 1540 °C down to about 1400 °C. • With the proper addition of Li, the densities and grain sizes of ceramics increase. • The ceramics not only have the characteristics of hard piezoceramics but also possesses the features of soft piezoceramics at low sintering temperature. - Abstract: Li-doped Ba{sub 0.85}Ca{sub 0.15}Ti{sub 0.9}Zr{sub 0.1}O{sub 3} (BCZT) lead-free piezoelectric ceramics were prepared by the two-step synthesis and the solid-state reaction method. The density and grain size of ceramics sufficiently increases by Li-doped sintering aid, and their sintering temperature decreases from about 1540 °C down to about 1400 °C. X-ray diffraction reveals that the phase structure of Li-doped BCTZ ceramics is changed with the sintering temperature, which is consistent with their phase transition observed by the temperature-dependent dielectric curves. The well-poled Li-doped BCZT ceramics show a high piezoelectric constant d{sub 33} (512 pC/N) and a planar electromechanical coupling factor k{sub p} (0.49), which have the characteristics of soft Pb(Zr,Ti)O{sub 3} (PZT) piezoceramic, on the other hand, the mechanical quality factor Q{sub m} is about 190, which possesses the features of hard PZT piezoceramics. The enhanced properties of the Li-doped BCZT are explained by the combination of Li-doped effect and sintering effect on the microstructure and the phase transition around room temperature.

  11. Ion exchange and electrochemical evaluation of the microporous phosphate Li9Fe7(PO4)10

    International Nuclear Information System (INIS)

    Becht, Gregory A.; Vaughey, John T.; Britt, Robin L.; Eagle, Cassandra T.; Hwu, Shiou-Jyh

    2008-01-01

    A new lithium iron(III) phosphate, Li 9 Fe 7 (PO 4 ) 10 , has been synthesized and is currently under electrochemical evaluation as an anode material for rechargeable lithium-ion battery applications. The sample was prepared via the ion exchange reaction of Cs 5 K 4 Fe 7 (PO 4 ) 10 1 in the 1 M LiNO 3 solution under hydrothermal conditions at 200 deg. C. The fully Li + -exchanged sample Li 9 Fe 7 (PO 4 ) 10 2 cannot yet be synthesized by conventional high-temperature, solid-state methods. The parent compound 1 is a member of the Cs 9-x K x Fe 7 (PO 4 ) 10 series that was previously isolated from a high-temperature (750 deg. C) reaction employing the eutectic CsCl/KCl molten salt. The polycrystalline solid 1 was first prepared in a stoichiometric reaction via conventional solid-state method then followed by ion exchange giving rise to 2. Both compounds adopt three-dimensional structures that consist of orthogonally interconnected channels where electropositive ions reside. It has been demonstrated that the Cs 9-x K x Fe 7 (PO 4 ) 10 series possesses versatile ion exchange capabilities with all the monovalent alkali metal and silver cations due to its facile pathways for ion transport. 1 and 2 were subject to electrochemical analysis and preliminary results suggest that the latter can be considered as an anode material. Electrochemical results indicate that Li 9 Fe 7 (PO 4 ) 10 is reduced below 1 V (vs. Li) to most likely form a Fe(0)/Li 3 PO 4 composite material, which can subsequently be cycled reversibly at relatively low potential. An initial capacity of 250 mAh/g was measured, which is equivalent to the insertion of thirteen Li atoms per Li 9+x Fe 7 (PO 4 ) 10 (x = 13) during the charge/discharge process (Fe 2+ + 2e → Fe 0 ). Furthermore, 2 shows a lower reduction potential (0.9 V), by approximately 200 mV, and much better electrochemical reversibility than iron(III) phosphate, FePO 4 , highlighting the value of improving the ionic conductivity of the sample

  12. Facile synthesis of aluminum-doped LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} hollow microspheres and their electrochemical performance for high-voltage Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaolin, E-mail: liu_x_l@sina.cn [College of Material Science and Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi (China); Li, Dan; Mo, Qiaoling; Guo, Xiaoyu; Yang, Xiaoxiao [College of Material Science and Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi (China); Chen, Guoxin, E-mail: gxchen@nimte.ac.cn [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, Zhejiang (China); Zhong, Shengwen [College of Material Science and Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi (China)

    2014-10-01

    Graphical abstract: LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} and Al doped LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} hollow microspheres as 5 V cathodes are prepared by templated transformation method using monodisperse MnCO{sub 3} microspheres as precursor. As a cathodic material for high voltage lithium ion batteries, the as-synthesized LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} and Al doped LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} hollow microspheres are investigated by galvanostatic cycling (GC) approach to evaluate their electrochemical properties in the range of 2.7–4.8 V vs. Li/Li{sup +} at the current rate 1 C. - Highlights: • LNMO and LANMO hollow microspheres are synthesized by template method. • The as-synthesized hollow microspheres have particle-size of 2 μm. • The hollow structure is responsible for improved electrochemical performance. - Abstract: This paper presents the preparation of LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} and aluminum (Al) doped LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} hollow microspheres as 5 V cathodes using monodisperse MnCO{sub 3} microspheres as precursor and template, which were synthesized using MnSO{sub 4}·H{sub 2}O, NaHCO{sub 3} and ethanol in water at room temperature. XRD and morphology characterization results indicated that the as-prepared LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} and Al doped LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} were both spinel structure, and have particle sizes of 2–3 μm. The cathode electrochemical properties of LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} and Al doped LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} hollow microspheres (as 5 V cathodes) were evaluated and compared by galvanostatic cycling (GC) vs. Li/Li{sup +} at the current rate 1 C in 2.7–4.8 V. The specific initial capacities of all samples were in the range of 70–120 mA h g{sup −1}. Compared to undoped LiNi{sub 0.5}Mn{sub 1.5}O{sub 4}, Al doped LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} hollow structures can effectively improve discharge capacity (up to 140 (±5) mA h g{sup −1}) and cycling stability (70

  13. Temperature stability of c-axis oriented LiNbO3/SiO2/Si thin film layered structures

    International Nuclear Information System (INIS)

    Tomar, Monika; Gupta, Vinay; Mansingh, Abhai; Sreenivas, K.

    2001-01-01

    Theoretical calculations have been performed for the temperature stability of the c-axis oriented LiNbO 3 thin film layered structures on passivated silicon (SiO 2 /Si) substrate with and without a non-piezoelectric SiO 2 overlayer. The phase velocity, electromechanical coupling coefficient and temperature coefficient of delay (TCD) have been calculated. The thicknesses of various layers have been determined for optimum SAW performance with zero TCD. The presence of a non-piezoelectric SiO 2 overlayer on LiNbO 3 film is found to significantly enhance the coupling coefficient. The optimized results reveal that a high coupling coefficient of K 2 =3.45% and a zero TCD can be obtained in the SiO 2 /LiNbO 3 /SiO 2 /Si structure with a 0.235λ thick LiNbO 3 layer sandwiched between 0.1λ thick SiO 2 layers. (author)

  14. Electrochemical studies on electrospun Li(Li1/3Ti5/3)O4 grains as an anode for Li-ion batteries

    International Nuclear Information System (INIS)

    Wu Yongzhi; Reddy, M.V.; Chowdari, B.V.R.; Ramakrishna, S.

    2012-01-01

    Highlights: ► We report (Li(Li 1/3 Ti 5/3 )O 4 ) (LTO) obtained via electrospinning and followed by heat treatment. ► Electrochemical studies on nano-LTO showed a reversible capacity of 165(±3) mAh g −1 and 78(±3) mAh g −1 at a current rate of 0.2 C and 10 C, respectively. ► Electrode kinetics studies of LTO were carried out the end of 380 cycle using GITT and EIS techniques. - Abstract: Li(Li 1/3 Ti 5/3 )O 4 or (Li 4 Ti 5 O 12 ) (LTO) grains are prepared via electrospinning a solution containing lithium acetate, titanium tetra(IV)-isopropoxide, polyvinyl acetate and acetic acid in N,N-dimethyl-formamide, followed by a subsequent sintering process. The structures and morphology were characterized by X-ray diffraction, scanning and transmission microscopy. Coin-type cells were assembled to test the electrochemical performance was evaluated using galvanostatic cycling at room temperature, in the cycling range, 1.0–2.8 V. The Li-cycling results showed characteristic discharge-charge plateaus at 1.55 and 1.8 V vs. Li/Li + , respectively. Electrospun LTO showed a reversible capacity of 165(±3) mAh g −1 at the end of 10th cycle at a current rate of 0.2 C. The later studies on rate capacities and cycling performance of LTO grains demonstrate good rate performance and long term cycling stability. Galvanostatic Intermittent Titration Technique (GITT) and Electrochemical Impedance Spectroscopy (EIS) studied were carried out at end of 381st and 382nd cycle to understand the electrode kinetics.

  15. Continuous flame aerosol synthesis of carbon-coated nano-LiFePO4 for Li-ion batteries

    Science.gov (United States)

    Waser, Oliver; Büchel, Robert; Hintennach, Andreas; Novák, Petr; Pratsinis, Sotiris E.

    2013-01-01

    Core-shell, nanosized LiFePO4-carbon particles were made in one step by scalable flame aerosol technology at 7 g/h. Core LiFePO4 particles were made in an enclosed flame spray pyrolysis (FSP) unit and were coated in-situ downstream by auto thermal carbonization (pyrolysis) of swirl-fed C2H2 in an O2-controlled atmosphere. The formation of acetylene carbon black (ACB) shell was investigated as a function of the process fuel-oxidant equivalence ratio (EQR). The core-shell morphology was obtained at slightly fuel-rich conditions (1.0 < EQR < 1.07) whereas segregated ACB and LiFePO4 particles were formed at fuel-lean conditions (0.8 < EQR < 1). Post-annealing of core-shell particles in reducing environment (5 vol% H2 in argon) at 700 °C for up to 4 hours established phase pure, monocrystalline LiFePO4 with a crystal size of 65 nm and 30 wt% ACB content. Uncoated LiFePO4 or segregated LiFePO4-ACB grew to 250 nm at these conditions. Annealing at 800 °C induced carbothermal reduction of LiFePO4 to Fe2P by ACB shell consumption that resulted in cavities between carbon shell and core LiFePO4 and even slight LiFePO4 crystal growth but better electrochemical performance. The present carbon-coated LiFePO4 showed superior cycle stability and higher rate capability than the benchmark, commercially available LiFePO4. PMID:23407817

  16. Preparation and Characterization of PVC-Al2O3-LiClO4 Composite Polymeric Electrolyte

    International Nuclear Information System (INIS)

    Azizan Ahmad; Mohd Yusri Abdul Rahman; Siti Aminah Mohd Noor; Mohd Reduan Abu Bakar

    2009-01-01

    Ionic conductivity of composite polymer electrolyte PVC-Al 2 O 3 -LiClO 4 as a function of Al 2 O 3 concentration has been studied. The electrolyte samples were prepared by solution casting technique. Their ionic conductivity was measured using impedance spectroscopy technique. It was observed that the conductivity of the electrolyte varies with Al 2 O 3 concentration. The highest room temperature conductivity of the electrolyte of 3.43 x 10 -10 S.cm -1 was obtain at 25 % by weight of Al 2 O 3 and that without Al 2 O 3 filler was found to be 2.43 x 10 -11 S.cm -1 . The glass transition temperature decreases with the increase of Al 2 O 3 percentage due to the increasing amorphous state, meanwhile the degradation temperature increases with the increase of Al 2 O 3 percentage. Both of these thermal properties influence the enhancement of the conductivity value. The morphology of the samples shows the even distribution of the Al 2 O 3 filler in the samples. However, the filler starts to agglomerate in the sample when high percentage of Al 2 O 3 is being used. In conclusion, the addition of Al 2 O 3 filler improves the ionic conductivity of PVC- Al 2 O 3 -LiCIO 4 solid polymer electrolyte. (author)

  17. Improving cylinder-type LiFePO4 battery performance via control of internal resistance

    Science.gov (United States)

    Purwanto, Agus; Jumari, Arif; Nizam, Muhammad; Widiyandari, Hendri; Sudaryanto; Deswita; Azmin Mohamad, Ahmad

    2018-04-01

    Strategies for controlling the internal resistance to improve battery performance were systematically investigated. Electrode densification of LiFePO4 cathodes significantly reduced the internal resistance of the prepared batteries. Densification by reduction to 31.25% of initial thickness resulted in optimal electrochemical performance of the prepared LiFePO4 batteries. The addition of KS 6 graphite material improved the conductivity of the cathodes, which was indicated by a lowering of the internal resistance. The internal resistance was decreased from 73 to 54 when the KS6/AB ratio was varied from 3 to 1. Another factor in controlling the internal resistance was the location of a welded aluminum tab in the cathode. The welding of an aluminum tab in a small gap in the cathode significantly reduced the internal resistance. Thus, three main factors can be performed during fabrication to reduce the internal resistance of a LiFePO4 battery: cathode densification, KS-6 graphite addition, and the arrangement of an aluminum tab welded to the cathode. By optimizing these factors, high-performance LFP batteries were produced.

  18. Li4Ti5O12 thin-film electrodes by in-situ synthesis of lithium alkoxide for Li-ion microbatteries

    International Nuclear Information System (INIS)

    Mosa, J.; Aparicio, M.; Tadanaga, K.; Hayashi, A.; Tatsumisago, M.

    2014-01-01

    Rechargeable thin-film batteries have recently become the topic of widespread research for use as efficient energy storage devices. Spinel Li 4 Ti 5 O 12 has been considered as one of the most prospective anode materials for Li-ion batteries because of its excellent reversibility and long cycle life. We report here the sol–gel synthesis and coating preparation of spinel thin-film Li 4 Ti 5 O 12 electrodes for Li-ion microbatteries using lithium ethoxide produced in situ that reacts with titanium alkoxide to produce the precursor solution without particle precipitation. This synthesis procedure reduces the thermal treatment to obtain a pure phase at only 700 °C and 15 minutes. The physical and structural characterization of the 300 nm Li 4 Ti 5 O 12 coatings shows a very homogeneous distribution of elements and a pure spinel phase. Galvanostatic discharge-charge tests indicate maximum discharge capacities of 152 mA h g −1 when the material is treated at 700 °C for 15 minutes

  19. Lithium ion conduction in sol-gel synthesized LiZr2(PO4)3 polymorphs

    Science.gov (United States)

    Kumar, Milind; Yadav, Arun Kumar; Anita, Sen, Somaditya; Kumar, Sunil

    2018-04-01

    Safety issue associated with the high flammability and volatility of organic electrolytes used in commercial rechargeable lithium ion batteries has led to significant attention to ceramic-based solid electrolytes. In the present study, lithium ion conduction in two polymorphs of LiZr2(PO4)3 synthesized via the sol-gel route has been investigated. Rietveld refinement of room temperature X-ray diffraction data of LiZr2(PO4)3 powders calcined at 900 °C and 1300 °C confirmed these to be the monoclinic phase with P21/n structure and rhombohedral phase with R3¯c structure, respectively. Increase in calcination temperature and resultant phase transformation improved the room temperature conductivity from 2.27×10-6 ohm-1m-1 for the monoclinic phase to 1.41×10-4 ohm-1m-1 for rhombohedral phase. Temperature dependence of conductivity was modeled using Arrhenius law and activation energy of ˜ 0.59 eV (for monoclinic phase) and ˜0.50 eV (for rhombohedral phase) were obtained.

  20. Chemical vs. electrochemical extraction of lithium from the Li-excess Li(1.10)Mn(1.90)O4 spinel followed by NMR and DRX techniques.

    Science.gov (United States)

    Martinez, S; Sobrados, I; Tonti, D; Amarilla, J M; Sanz, J

    2014-02-21

    Lithium extraction from the Li-excess Li1.10Mn1.90O4 spinel has been performed by chemical and electrochemical methods in aqueous and in organic media, respectively. De-lithiated samples have been investigated by XRD, SEM, TG, (7)Li and (1)H MAS-NMR techniques. The comparative study has allowed demonstrating that the intermediate de-intercalated samples prepared during the chemical extraction by acid titration are similar to those prepared by the electrochemical way in a non-aqueous electrolyte. LiMn2O4 based spinel with a tailored de-lithiation degree can be prepared as a single phase by controlling the pH used in chemical extraction. (7)Li MAS-NMR spectroscopy has been used to follow the influence of the manganese oxidation state on tetra and octahedral Li-signals detected in Li-extracted samples. The oxidation of Mn(III) ions goes parallel to the partial dissolution of the spinel, following Hunter's mechanism. Based on this mechanism, a generalized chemical reaction has been proposed to explain the formation of intermediate Li(+) de-intercalated samples during acid treatment in aqueous media. By the (1)H MAS NMR study, no evidence of Li-H topotactic exchange in the bulk of the acid treated material was found.

  1. Bare astrophysical S(E)-factor for the 6Li(d, α)4He and 7Li(p, α)4He reactions at astrophysical energies

    International Nuclear Information System (INIS)

    Pizzone, R.G.; Spitaleri, C.; Lattuada, M.; Musumarra, A.; Pellegriti, M.G.; Romano, S.; Tumino, A.; Cherubini, S.; Figuera, P.; Miljanic, D.; Rolfs, C.; Typel, S.; Wolter, H.H.; Castellani, V.; Degl'Innocenti, S.; Imperio, A.

    2003-01-01

    The Trojan Horse Method has been applied to study the 7 Li(p, α) 4 He and 6 (Li(d, α) 4 He reactions through the 7 Li(d, αα)n and 6 Li( 6 Li, αα) 4 He three body processes, respectively. The electron screening potential deduced from these experiments is much larger than the adiabatic approximation prediction for both cases; the systematic discrepancy between data and theoretical predictions is thus confirmed. Astrophysical implications of these measurements are also discussed

  2. Flexural strength and translucent characteristics of lithium disilicate glass-ceramics with different P2O5 content

    International Nuclear Information System (INIS)

    Wang, Fu; Gao, Jing; Wang, Hui; Chen, Ji-hua

    2010-01-01

    Lithium disilicate glass-ceramics derived from the SiO 2 -Li 2 O-K 2 O-Al 2 O 3 -ZrO 2 -P 2 O 5 system with different P 2 O 5 content (from 0.5 mol.% to 2.0 mol.% at a step of 0.5 mol.%) were prepared for dental restorative application. Flexural strength of final glass-ceramics and translucent characteristics expressed in term of contrast ratio (CR) were measured. The interrelations between P 2 O 5 content, microstructure and properties were discussed. Glass-ceramic with a P 2 O 5 content of 1.0 mol.%, in which elongated rod-like Li 2 Si 2 O 5 crystals formed an interlocking microstructure, showed the highest flexural strength and suitable contrast ratio for dental restorative application.

  3. Influence of CaCO3 and SiO2 additives on magnetic properties of M-type Sr ferrites

    Science.gov (United States)

    Huang, Ching-Chien; Jiang, Ai-Hua; Hung, Yung-Hsiung; Liou, Ching-Hsuan; Wang, Yi-Chen; Lee, Chi-Ping; Hung, Tong-Yin; Shaw, Chun-Chung; Kuo, Ming-Feng; Cheng, Chun-Hu

    2018-04-01

    An experiment was carried out to investigate the influence of CaCO3 and SiO2 additives on the magnetic and physical properties of M-type Sr ferrites by changing experimental parameters such as the additive composition and Ca/Si ratio. Specimens were prepared by conventional ceramic techniques. It was found that the magnetic properties (Br = 4.42 kG, iHc = 3.32 kOe and (BH)max = 4.863 MGOe) were considerably improved upon adding CaCO3 = 1.1% and SiO2 = 0.4 wt% together with Co3O4, and the mechanical properties thereof were acceptable for motor applications. It was revealed that CaCO3 and SiO2 additives led to an upswing in the magnetic properties via the enhancement of uniform grain growth, particle alignment, and the densification of Sr ferrite.

  4. Zr4+ doping in Li4Ti5O12 anode for lithium-ion batteries: open Li+ diffusion paths through structural imperfection.

    Science.gov (United States)

    Kim, Jae-Geun; Park, Min-Sik; Hwang, Soo Min; Heo, Yoon-Uk; Liao, Ting; Sun, Ziqi; Park, Jong Hwan; Kim, Ki Jae; Jeong, Goojin; Kim, Young-Jun; Kim, Jung Ho; Dou, Shi Xue

    2014-05-01

    One-dimensional nanomaterials have short Li(+) diffusion paths and promising structural stability, which results in a long cycle life during Li(+) insertion and extraction processes in lithium rechargeable batteries. In this study, we fabricated one-dimensional spinel Li4Ti5O12 (LTO) nanofibers using an electrospinning technique and studied the Zr(4+) doping effect on the lattice, electronic structure, and resultant electrochemical properties of Li-ion batteries (LIBs). Accommodating a small fraction of Zr(4+) ions in the Ti(4+) sites of the LTO structure gave rise to enhanced LIB performance, which was due to structural distortion through an increase in the average lattice constant and thereby enlarged Li(+) diffusion paths rather than changes to the electronic structure. Insulating ZrO2 nanoparticles present between the LTO grains due to the low Zr(4+) solubility had a negative effect on the Li(+) extraction capacity, however. These results could provide key design elements for LTO anodes based on atomic level insights that can pave the way to an optimal protocol to achieve particular functionalities. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. 3D inverse-opal structured Li4Ti5O12 Anode for fast Li-Ion storage capabilities

    Science.gov (United States)

    Kim, Dahye; Quang, Nguyen Duc; Hien, Truong Thi; Chinh, Nguyen Duc; Kim, Chunjoong; Kim, Dojin

    2017-11-01

    Since the demand for high power Li-ion batteries (LIBs) is increasing, spinel-structured lithium titanate, Li4Ti5O12 (LTO), as the anode material has attracted great attention because of its excellent cycle retention, good thermal stability, high rate capability, and so on. However, LTO shows relatively low conductivity due to empty 3 d orbital of Ti4+ state. Nanoscale architectures can shorten electron conduction path, thus such low electronic conductivity can be overcome while Li+ can be easily accessed due to large surface area. Herein, three dimensional bicontinuous LTO electrodes were prepared via close-packed self-assembly with polystyrene (PS) spheres followed by removal of them, which leads to no blockage of Li+ ion transportation pathways as well as fast electron conduction. 3D bicontinuous LTO electrodes showed high-rate lithium storage capability (103 mAh/g at 20 C), which is promising as the power sources that require rapid electrochemical response.[Figure not available: see fulltext.

  6. Improved battery performance using Pd nanoparticles synthesized on the surface of LiFePO4/C by ultrasound irradiation

    Science.gov (United States)

    Saliman, Muhammad Ali; Okawa, Hirokazu; Takai, Misaki; Ono, Yuki; Kato, Takahiro; Sugawara, Katsuyasu; Sato, Mineo

    2016-07-01

    LiFePO4 has been attracting interest as a cathode material for Li-ion batteries due to its high energy density, low cost, and eco-friendliness. The electrochemical performance of LiFePO4 is limited because it exhibits low Li-ion diffusivity and low electronic conductivity. Numerous solutions have been considered, such as carbon coating, which is widely known to improve the electronic conductivity of LiFePO4. The deposition of metal nanoparticles (NPs) on the surface of carbon-coated LiFePO4 further enhances the electronic conductivity. In this study, we deposited Pd NPs onto the surface of LiFePO4/C and investigated the resulting electrochemical performance. Sonochemical synthesis was used to prepare the metal NPs; the procedure did not require any surfactants and the reaction was rapid.

  7. Electrochemical performance of all-solid-state lithium batteries using inorganic lithium garnets particulate reinforced PEO/LiClO4 electrolyte

    International Nuclear Information System (INIS)

    Cheng, Samson Ho-Sum; He, Kang-Qiang; Liu, Ying; Zha, Jun-Wei; Kamruzzaman, Md; Ma, Robin Lok-Wang; Dang, Zhi-Min; Li, Robert K.Y.; Chung, C.Y.

    2017-01-01

    All-solid-state batteries are proposed to have ultimate safety and higher power and energy densities over conventional lithium ion batteries with liquid electrolytes. The Li ion conductivity and interfacial resistance between electrolyte and electrodes are the major bottleneck of the development of all-solid-state batteries for practical uses. Here, we reported a novel composite electrolyte which is composed of uniform distributed Li ion conducting Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) fillers in PEO/LiClO 4 matrix. The EO:Li + ratio of 15:1 is being used to achieve lower interfacial resistance between electrolyte and electrodes through the melting process. The composite electrolyte is fabricated by simple solution casting method, which is more advantageous comparing with high temperature sintering or sol-gel method used in the fabrication of ceramic electrolytes. The composite electrolyte exhibits good Li ion conductivity of 4.8 × 10 −4 Scm −1 at 60 °C and excellent interfacial stability against Li metal. The all-solid-state lithium battery using this composite electrolyte shows a specific capacity of 140mAhg −1 and an unprecedentedly high capacity retention of 83% after 500 cycles at 60 °C and the rate of 1C. It is concluded that good electrode/electrolyte interfacial stability and contact as well as fast Li ion conductivity obtained by the addition of active garnet particulates to PEO/LiClO 4 matrix are essential criteria for good charge/discharge performance of all-solid-state lithium batteries.

  8. Structural and dielectric properties of four - layer Aurivillius - type Ba0.25Sr0.75Bi4Ti4O15 ceramics

    International Nuclear Information System (INIS)

    Goyal, Parveen K.; Khokhar, Anita; Sreenivas, K.

    2013-01-01

    In the present study, a barium strontium bismuth titanate (Ba 0.25 Sr 0.75 Bi 4 Ti 4 O 15 , BSBT) ceramic composition has been prepared by conventional solid-state reaction. In order to study the structure of as synthesized BSBT ceramics, the X-ray powder diffraction (XRD), Raman and FTIR studies have been carried out on the powdered sample. X-ray diffraction analysis confirms the formation of a single phase four-layer Aurivillius-type ceramics that crystallizes in an orthorhombic structure with A2 1 am space group. The dielectric properties of the ceramics have been studied in the temperature range 30 - 600℃ temperature range at various frequencies (100 Hz to 1 MHz). A sharp dielectric anomaly was observed at ∼ 485℃ at all the frequencies corresponding to the ferroelectric to paraelectric phase transition. The ferroelectric behavior is confirmed from the Curie-Weiss law fitting of the dielectric data. (author)

  9. Improved high-rate charge/discharge performances of LiFePO{sub 4}/C via V-doping

    Energy Technology Data Exchange (ETDEWEB)

    Sun, C.S.; Zhou, Z.; Xu, Z.G.; Wang, D.G.; Wei, J.P.; Bian, X.K.; Yan, J. [Institute of New Energy Material Chemistry, Nankai University, Tianjin 300071 (China)

    2009-09-05

    V-doped LiFePO{sub 4}/C cathode materials were prepared through a carbothermal reduction route. The microstructure was characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The electrochemical Li{sup +} intercalation performances of V-doped LiFePO{sub 4}/C were compared with those of undoped one through galvanostatic intermittent titration technique, cyclic voltamperometry, and electrochemical impedance spectrum. V-doped LiFePO{sub 4}/C showed a high discharge capacity of {proportional_to}70 mAh g{sup -1} at the rate of 20 C (3400 mA g{sup -1}) at room temperature. The significantly improved high-rate charge/discharge capacity is attributed to the increase of Li{sup +} ion ''effective'' diffusion capability. (author)

  10. Enhancement of the Rate Capability of LiFePO4 by a New Highly Graphitic Carbon-Coating Method.

    Science.gov (United States)

    Song, Jianjun; Sun, Bing; Liu, Hao; Ma, Zhipeng; Chen, Zhouhao; Shao, Guangjie; Wang, Guoxiu

    2016-06-22

    Low lithium ion diffusivity and poor electronic conductivity are two major drawbacks for the wide application of LiFePO4 in high-power lithium ion batteries. In this work, we report a facile and efficient carbon-coating method to prepare LiFePO4/graphitic carbon composites by in situ carbonization of perylene-3,4,9,10-tetracarboxylic dianhydride during calcination. Perylene-3,4,9,10-tetracarboxylic dianhydride containing naphthalene rings can be easily converted to highly graphitic carbon during thermal treatment. The ultrathin layer of highly graphitic carbon coating drastically increased the electronic conductivity of LiFePO4. The short pathway along the [010] direction of LiFePO4 nanoplates could decrease the Li(+) ion diffusion path. In favor of the high electronic conductivity and short lithium ion diffusion distance, the LiFePO4/graphitic carbon composites exhibit an excellent cycling stability at high current rates at room temperature and superior performance at low temperature (-20 °C).

  11. Conductivity And Thermal Stability of Solid Acid Composites CsH2PO4 /NaH2PO4/ SiO2

    International Nuclear Information System (INIS)

    Norsyahida Mohammad; Abu Bakar Mohamad; Abu Bakar Mohamad; Abdul Amir Hassan Kadhum

    2016-01-01

    Solid acid composites CsH 2 PO 4 / NaH 2 PO 4 / SiO 2 with different mole ratios of CsH 2 PO 4 and NaH 2 PO 4 to SiO 2 were synthesized and characterized. Preliminary infrared measurements of CsH 2 PO 4 and its composites indicated that hydrogen bonds breaking and formation were detected between 1710 to 2710 cm -1 , while the rotation of phosphate tetrahedral anions occurred between 900 and 1200 cm -1 . The superprotonic transition of CsH 2 PO 4 / NaH 2 PO 4 / SiO 2 composite was identified at superprotonic temperatures between 230 and 260 degree Celcius, under atmospheric pressure. This study reveals higher conductivity values for composites with higher CsH 2 PO 4 (CDP) content. Solid acid composite CDP 613 appeared as the composite with the highest conductivity that is 7.2x10 -3 S cm -1 at 230 degree Celcius. Thermal stability of the solid acid composites such as temperature of dehydration, melting and decomposition were investigated. The addition of NaH 2 PO 4 lowers the dehydration temperature of the solid acid composites. (author)

  12. Fluoride substitution in LiBH4; destabilization and decomposition

    DEFF Research Database (Denmark)

    Richter, Bo; Ravnsbaek, Dorthe B.; Sharma, Manish

    2017-01-01

    Fluoride substitution in LiBH4 is studied by investigation of LiBH4-LiBF4 mixtures (9:1 and 3:1). Decomposition was followed by in situ synchrotron radiation X-ray diffraction (in situ SR-PXD), thermogravimetric analysis and differential scanning calorimetry with gas analysis (TGA/DSC-MS) and in ......Fluoride substitution in LiBH4 is studied by investigation of LiBH4-LiBF4 mixtures (9:1 and 3:1). Decomposition was followed by in situ synchrotron radiation X-ray diffraction (in situ SR-PXD), thermogravimetric analysis and differential scanning calorimetry with gas analysis (TGA...

  13. 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.

  14. Synthesis, Structure, and Li-Ion Conductivity of LiLa(BH4)3X, X = Cl, Br, I

    DEFF Research Database (Denmark)

    Payandeh GharibDoust, SeyedHosein; Brighi, Matteo; Sadikin, Yolanda

    2017-01-01

    In this work, a new type of addition reaction between La(BH4)3 and LiX, X = Cl, Br, I, is used to synthesize LiLa(BH4)3Cl and two new compounds LiLa(BH4)3X, X = Br, I. This method increases the amounts of LiLa(BH4)3X and the sample purity. The highest Li-ion conductivity is observed for LiLa(BH4)...

  15. Electrical behaviour of ceramic breeder blankets in pebble form after γ-radiation

    Directory of Open Access Journals (Sweden)

    E. Carella

    2015-07-01

    Full Text Available Lithium orthosilicate (Li4SiO4 ceramics in from of pebble bed is the European candidate for ITER testing HCPB (Helium Cooled Pebble Bed breeding modules. The breeder function and the shielding role of this material, represent the areas upon which attention is focused. Electrical measurements are proposed for monitoring the modification created by ionizing radiation and at the same time provide information on lithium movement in this ceramic structure. The electrical tests are performed on pebbles fabricated by Spray-dryer method before and after gamma-irradiation through a 60Co source to a fluence of 4.8 Gy/s till a total dose of 5 ∗ 105 Gy. The introduction of thermal annealing treatments during the electrical impedance spectroscopy (EIS measurements points out the recombination effect of the temperature on the γ-induced defects.

  16. Relaxation-Induced Memory Effect of LiFePO4 Electrodes in Li-Ion Batteries.

    Science.gov (United States)

    Jia, Jianfeng; Tan, Chuhao; Liu, Mengchuang; Li, De; Chen, Yong

    2017-07-26

    In Li-ion batteries, memory effect has been found in several commercial two-phase materials as a voltage bump and a step in the (dis)charging plateau, which delays the two-phase transition and influences the estimation of the state of charge. Although memory effect has been first discovered in olivine LiFePO 4 , the origination and dependence are still not clear and are critical for regulating the memory effect of LiFePO 4 . Herein, LiFePO 4 has been synthesized by a home-built spray drying instrument, of which the memory effect has been investigated in Li-ion batteries. For as-synthesized LiFePO 4 , the memory effect is significantly dependent on the relaxation time after phase transition. Besides, the voltage bump of memory effect is actually a delayed voltage overshooting that is overlaid at the edge of stepped (dis)charging plateau. Furthermore, we studied the kinetics of LiFePO 4 electrode with electrochemical impedance spectroscopy (EIS), which shows that the memory effect is related to the electrochemical kinetics. Thereby, the underlying mechanism has been revealed in memory effect, which would guide us to optimize two-phase electrode materials and improve Li-ion battery management systems.

  17. Crystallization characteristics and physico-chemical properties of glass–ceramics based on Li2O–ZnO–SiO2 system

    Directory of Open Access Journals (Sweden)

    Saad M. Salman

    2017-09-01

    Full Text Available Glass materials based on lithium zinc silicate system of the composition 24Li2O–20ZnO–56SiO2 LZS (mol% were prepared and converted to glass–ceramics using controlled heat-treatment schedules. The LZS base glass system was modified by addition of Al2O3 and MO/ZnO replacements where MO = CaO, CdO and SrO oxides. Several crystalline phases were developed, including lithium zinc orthosilicate, α-quartz, β-spodumene solid solution, lithium meta and disilicate, Ca-wollastonite, Cd or Sr metasilicate, and Sr-zinc silicate of hardystonite type. The effects of crystallization process on some properties, like thermal expansion coefficient (TEC, chemical stability, and density of glass–ceramics were evaluated. The TEC of crystalline samples varied from 72 × 10−7 to 149 × 10−7 K−1, 25–600 and density values in the range, 2.67–3.29 g/cm3. The addition of Al2O3 and MO/ZnO replacements in the base glass led to improve the chemical durability of the glass–ceramics samples. As a result of the thermal and physico-chemical properties of the studied glass–ceramic, the materials acquire excellent properties and can be used to seal a variety of different metals and alloys.

  18. Crystallization characteristics and physico-chemical properties of glass–ceramics based on Li2O–ZnO–SiO2 system

    International Nuclear Information System (INIS)

    Salman, Saad M.; Salama, Samia N.; Abo-Mosallam, Hany A.

    2017-01-01

    Glass materials based on lithium zinc silicate system of the composition 24Li2O–20ZnO–56SiO2 LZS (mol%) were prepared and converted to glass–ceramics using controlled heat-treatment schedules. The LZS base glass system was modified by addition of Al2O3 and MO/ZnO replacements where MO=CaO, CdO and SrO oxides. Several crystalline phases were developed, including lithium zinc orthosilicate, α-quartz, β-spodumene solid solution, lithium meta and disilicate, Ca-wollastonite, Cd or Sr metasilicate, and Sr-zinc silicate of hardystonite type. The effects of crystallization process on some properties, like thermal expansion coefficient (TEC), chemical stability, and density of glass–ceramics were evaluated. The TEC of crystalline samples varied from 72×10−7 to 149×10−7K−1, 25–600 and density values in the range, 2.67–3.29g/cm3. The addition of Al2O3 and MO/ZnO replacements in the base glass led to improve the chemical durability of the glass–ceramics samples. As a result of the thermal and physico-chemical properties of the studied glass–ceramic, the materials acquire excellent properties and can be used to seal a variety of different metals and alloys. [es

  19. Preparation of C-LiFePO{sub 4}/polypyrrole lithium rechargeable cathode by consecutive potential steps electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Boyano, Iker; Blazquez, J. Alberto; de Meatza, Iratxe; Bengoechea, Miguel; Miguel, Oscar; Grande, Hans [CIDETEC-IK4, P Miramon 196, 20009 Donostia, San Sebastian (Spain); Huang, Yunhui [School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 730074 (China); Goodenough, John B. [Texas Materials Institute, University of Texas at Austin, Austin, TX 78712 (United States)

    2010-08-15

    In this work carbon coated lithium iron phosphate (C-LiFePO{sub 4})/polypyrrole (PPy) composite preparation has been carried out using electrochemical techniques. This composite has been deposited on a stainless steel mesh in order to use it as a cathode in a lithium-ion battery. When an oxidation potential is applied to the working electrode, the pyrrole monomer is polymerized and the C-LiFePO{sub 4} particles are incorporated into the polymer matrix and bound to the polymer and mesh. An experimental procedure was performed in order to understand how the composite formation is carried out and what the oxidation state of the composite material is during the charge-discharge process. As the electrochemical method of synthesis has a big influence in the electrochemical properties of the polymer, the use of consecutive potential steps has been studied in order to improve the charge-storage capacity of the composite material. The influence on the final composite properties of the oxidation-deposition time and potential and the effect of the number of cycles has been analyzed. An improvement of about 20% has been achieved using short oxidation times (3 s) at 0.9 V vs. Ag/AgCl. The reasons for this improvement are discussed and analyzed using different experimental techniques. (author)

  20. Double Carbon Nano Coating of LiFePO4 Cathode Material for High Performance of Lithium Ion Batteries.

    Science.gov (United States)

    Ding, Yan-Hong; Huang, Guo-Long; Li, Huan-Huan; Xie, Hai-Ming; Sun, Hai-Zhu; Zhang, Jing-Ping

    2015-12-01

    Double carbon-coated LiFePO4 (D-LiFePO4/C) composite with sphere-like structure was synthesized through combination of co-precipitation and solid-state methods. Cetyl-trimethyl-ammonium bromide (CTAB) and citric acid served as two kinds of carbon sources in sequence. SEM images demonstrated that double carbon coating had certain influence on the morphology. The thickness of carbon coating on D-LiFePO4/C was about 1.7 nm and the content of carbon was 2.48 wt%, according to HRTEM and TG analysis. The electrochemical impedance spectroscopy analysis indicated that the D-LiFePO4/C composite presented the charge-transfer resistance of 68 Ω and Li ion diffusion coefficient of 2.68 x 10(-13) cm2 S(-1), while the single carbon-coated LiFePO4 (S-LiFePO4/C) exhibited 135.5Ω and 4.03 x 10(-14) cm2 S(-1). Especially, the prepared D-LiFePO4/C electrode showed discharge capacities of 102.9 (10C) and 87.1 (20C) mA h g(-1), respectively, with almost no capacity lost after 400 cycles at 10C, which were much better than those of S-LiFePO4/C composite.

  1. 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.

  2. LiFePO4/C nanocomposites for lithium-ion batteries

    Science.gov (United States)

    Eftekhari, Ali

    2017-03-01

    LiFePO4, as the most famous member of the family of olivine-type lithium transition metal phosphates, is one of the promising candidates for the cathodes of lithium-ion batteries. However, its battery performance is limited by its low electrical conductivity and slow Li solid-state diffusion. Various methods have been attempted to improve the battery performance of lithium iron phosphate. Among them, compositing the LiFePO4 with carbon nanomaterials seems to be the most promising, as it is facile and efficient. Carbon nanomaterials usually serve as a conductive agent to improve the electrical conductivity while increasing the material porosity in which the solid-state diffusion distances are significantly shortened. Owing to the popularity of various carbonaceous nanomaterials, there is no straightforward line of research for comparing the LiFePO4/C nanocomposites. This review aims to provide a general perspective based on the research achievements reported in the literature. While surveying the research findings reported in the literature, controversial issues are also discussed. The possible contribution of pseudocapacitance as a result of functionalized carbon or LiFePO4 lattice defects is described, since from a practical perspective, a LiFePO4/C electrode can be considered as a supercapacitor at high C rates (with a specific capacitance as large as 200 F g-1). The Li diffusion in LiFePO4 has not been well understood yet; while the Li diffusion within the LiFePO4 lattice seems to be quite fast, the peculiar interfacial electrochemistry of LiFePO4 slows down the diffusion within the entire electrode by a few orders of magnitude.

  3. Structural and thermodynamic similarities of phases in the Li-Tt (Tt = Si, Ge) systems: redetermination of the lithium-rich side of the Li-Ge phase diagram and crystal structures of Li17Si4.0-xGex for x = 2.3, 3.1, 3.5, and 4 as well as Li4.1Ge.

    Science.gov (United States)

    Zeilinger, Michael; Fässler, Thomas F

    2014-10-28

    A reinvestigation of the lithium-rich section of the Li-Ge phase diagram reveals the existence of two new phases, Li17Ge4 and Li4.10Ge (Li16.38Ge4). Their structures are determined by X-ray diffraction experiments of large single crystals obtained from equilibrated melts with compositions Li95Ge5 and Li85Ge15. Excess melt is subsequently removed through isothermal centrifugation at 400 °C and 530 °C, respectively. Li17Ge4 crystallizes in the space group F4[combining macron]3m (a = 18.8521(3) Å, V = 6700.1(2) Å(3), Z = 20, T = 298 K) and Li4.10Ge (Li16.38Ge4) in Cmcm (a = 4.5511(2) Å, b = 22.0862(7) Å, c = 13.2751(4) Å, V = 1334.37(8) Å(3), Z = 16, T = 123 K). Both phases are isotypic with their Si counterparts and are further representative of the Li17Pb4 and Li4.11Si structure types. Additionally, the solid solutions Li17Si4-xGex follows Vegard's law. A comparison of the GeLin coordination polyhedra shows that isolated Ge atoms are 13- and 14-coordinated in Li17Ge4, whereas in Li16.38Ge4 the Ge atoms possess coordination numbers 12 and 13. Regarding the thermodynamic stability, Li16.38Ge4 is assigned a high-temperature phase existing between ∼400 °C and 627 °C, whereas Li17Ge4 decomposes peritectically at 520-522 °C. Additionally, the decomposition of Li16.38Ge4 below ∼400 °C was found to be very sluggish. These findings are manifested by differential scanning calorimetry, long-term annealing experiments and the results from melt equilibration experiments. Interestingly, the thermodynamic properties of the lithium-rich tetrelides Li17Tt4 and Li4.1Tt (Li16.4Tt4) are very similar (Tt = Si, Ge). Besides Li15Tt4, Li14Tt6, Li12Tt7, and LiTt, the title compounds are further examples of isotypic tetrelides in the systems Li-Tt.

  4. Effects of titanium incorporation on phase and electrochemical performance in LiFePO4 cathode material

    International Nuclear Information System (INIS)

    Wang Zhaohui; Pang Quanquan; Deng Kejian; Yuan Lixia; Huang Fei; Peng Yunlong; Huang Yunhui

    2012-01-01

    Highlights: ► Nominal LiFe 1−x Ti x PO 4 cathode materials were synthesized via solid-state reaction. ► A clear feature of Ti-doped LiFePO 4 has been clarified. ► The formation of impurity phases strongly depends on Ti doping level. ► Appropriate amount of Ti in LiFePO 4 can enhance the electrochemical performance. - Abstract: Ti-incorporated LiFe 1−x Ti x PO 4 (0 ≤ x ≤ 0.2) samples have been prepared via a two-step solid-state reaction route. The samples have systematically been investigated with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), cyclic voltammetry (CV) and charge/discharge measurements. The incorporation of Ti in LiFePO 4 significantly enhances the electrochemical performance; the carbon-coated LiFe 0.9 Ti 0.1 PO 4 sample shows the best performance. It is confirmed that LiFe 1−x Ti x PO 4 with x ≤ 0.05 are of single phase while those with 0.07 ≤ x ≤ 0.2 contain impurity phases: LiTi 2 (PO 4 ) 3 and TiP 2 O 7 . The impurities influence not only the electronic conductivity, but also the total specific capacity. Appropriate amount of titanium incorporation is favorable for the improvement in electrochemical performance.

  5. Phase formation in the Li2MoO4–K2MoO4–In2(MoO4)3 system and crystal structures of new compounds K3InMo4O15 and LiK2In(MoO4)3

    International Nuclear Information System (INIS)

    Khal’baeva, Klara M.; Solodovnikov, Sergey F.; Khaikina, Elena G.; Kadyrova, Yuliya M.; Solodovnikova, Zoya A.; Basovich, Olga M.

    2012-01-01

    XRD study of solid-phase interaction in the Li 2 MoO 4 –K 2 MoO 4 –In 2 (MoO 4 ) 3 system was performed. The boundary K 2 MoO 4 –In 2 (MoO 4 ) 3 system is an non-quasibinary join of the K 2 O–In 2 O 3 –MoO 3 system where a new polymolybdate K 3 InMo 4 O 15 isotypic to K 3 FeMo 4 O 15 was found. In the structure (a=33.2905(8), b=5.8610(1), c=15.8967(4) Å, β=90.725(1)°, sp. gr. C2/c, Z=8, R(F)=0.0407), InO 6 octahedra, Mo 2 O 7 diortho groups and MoO 4 tetrahedra form infinite ribbons {[In(MoO 4 ) 2 (Mo 2 O 7 )] 3− } ∞ along the b-axis. Between the chains, 8- to 10-coordinate potassium cations are located. A subsolidus phase diagram of the Li 2 MoO 4 –K 2 MoO 4 –In 2 (MoO 4 ) 3 system was constructed and a novel triple molybdate LiK 2 In(MoO 4 ) 3 was revealed. Its crystal structure (a=7.0087(2), b=9.2269(3), c=10.1289(3) Å, β=107.401(1)°, sp. gr. P2 1 , Z=2, R(F)=0.0280) contains an open framework of vertex-shared MoO 4 tetrahedra, InO 6 octahedra and LiO 5 tetragonal pyramids with nine- and seven-coordinate potassium ions in the framework channels. - Graphical abstract: Exploring the Li 2 MoO 4 –K 2 MoO 4 –In 2 (MoO 4 ) 3 system showed its partial non-quasibinarity and revealed new compounds K 3 InMo 4 O 15 (isotypic to K 3 FeMo 4 O 15 ) and LiK 2 In(MoO 4 ) 3 which were structurally studied. An open framework of the latter is formed by vertex-shared MoO 4 tetrahedra, InO 6 octahedra and LiO 5 tetragonal pyramids. Highlights: ► Subsolidus phase relations in the Li 2 MoO 4 –K 2 MoO 4 –In 2 (MoO 4 ) 3 system were explored. ► The K 2 MoO 4 –In 2 (MoO 4 ) 3 system is a non-quasibinary join of the K 2 O–In 2 O 3 –MoO 3 system. ► New compounds K 3 InMo 4 O 15 and LiK 2 In(MoO 4 ) 3 were obtained and structurally studied. ► K 3 InMo 4 O 15 is isotypic to K 3 FeMo 4 O 15 and carries bands of InO 6 , MoO 4 and Mo 2 O 7 units. ► An open framework of LiK 2 In(MoO 4 ) 3 is formed by polyhedra MoO 4 , InO 6 and LiO 5 .

  6. Luminescence properties of LiPrxCe1-xP4O12

    International Nuclear Information System (INIS)

    Shalapska, T.; Stryganyuka, G.; Trotsc, D.; Demkiv, T.; Gektin, A.; Voloshinovskii, A.; Dorenbos, P.

    2010-01-01

    LiPr 1-x Ce x P 4 O 12 (x=0, 0.002, 0.02; 0.1) powder samples were prepared using the melt solution technique. Luminescent parameters of LiPr 1-x Ce x P 4 O 12 phosphors have been investigated under ultraviolet-vacuum ultraviolet (3-12 eV) synchrotron radiation and X-rays excitation at room and near liquid He temperatures. Excitation luminescence spectra of Ce 3+ emission, luminescent spectra and decay curves from the lower excited state levels of the 4f 1 5d 1 and 5d 1 electronic configuration of the Pr 3+ and Ce 3+ , respectively, clearly indicate energy transfer from Pr 3+ to Ce 3+ . Energy migration proceeds via the Pr-sublattice followed by nonradiation transfer from Pr 3+ to Ce 3+ ions.

  7. Development of all-solid lithium-ion battery using Li-ion conducting glass-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Inda, Yasushi [Research and Development Department, Ohara-inc, 1-15-30 Oyama, Sagamihara, Kanagawa 229-1186 (Japan); Graduate School of Engineering, Iwate University, 4-3-5 Ueda, Morioka, Iwate 020-8551 (Japan); Katoh, Takashi [Research and Development Department, Ohara-inc, 1-15-30 Oyama, Sagamihara, Kanagawa 229-1186 (Japan); Baba, Mamoru [Graduate School of Engineering, Iwate University, 4-3-5 Ueda, Morioka, Iwate 020-8551 (Japan)

    2007-12-06

    We have developed a high performance lithium-ion conducting glass-ceramics. This glass-ceramics has the crystalline form of Li{sub 1+x+y}Al{sub x}Ti{sub 2-x}Si{sub y}P{sub 3-y}O{sub 12} with a NASICON-type structure, and it exhibits a high lithium-ion conductivity of 10{sup -3} S cm{sup -1} or above at room temperature. Moreover, since this material is stable in the open atmosphere and even to exposure to moist air, it is expected to be applied for various uses. One of applications of this material is as a solid electrolyte for a lithium-ion battery. Batteries were developed by combining a LiCoO{sub 2} positive electrode, a Li{sub 4}Ti{sub 5}O{sub 12} negative electrode, and a composite electrolyte. The battery using the composite electrolyte with a higher conductivity exhibited a good charge-discharge characteristic. (author)

  8. First-principles calculated decomposition pathways for LiBH4 nanoclusters

    Science.gov (United States)

    Huang, Zhi-Quan; Chen, Wei-Chih; Chuang, Feng-Chuan; Majzoub, Eric H.; Ozoliņš, Vidvuds

    2016-05-01

    We analyze thermodynamic stability and decomposition pathways of LiBH4 nanoclusters using grand-canonical free-energy minimization based on total energies and vibrational frequencies obtained from density-functional theory (DFT) calculations. We consider (LiBH4)n nanoclusters with n = 2 to 12 as reactants, while the possible products include (Li)n, (B)n, (LiB)n, (LiH)n, and Li2BnHn; off-stoichiometric LinBnHm (m ≤ 4n) clusters were considered for n = 2, 3, and 6. Cluster ground-state configurations have been predicted using prototype electrostatic ground-state (PEGS) and genetic algorithm (GA) based structural optimizations. Free-energy calculations show hydrogen release pathways markedly differ from those in bulk LiBH4. While experiments have found that the bulk material decomposes into LiH and B, with Li2B12H12 as a kinetically inhibited intermediate phase, (LiBH4)n nanoclusters with n ≤ 12 are predicted to decompose into mixed LinBn clusters via a series of intermediate clusters of LinBnHm (m ≤ 4n). The calculated pressure-composition isotherms and temperature-pressure isobars exhibit sloping plateaus due to finite size effects on reaction thermodynamics. Generally, decomposition temperatures of free-standing clusters are found to increase with decreasing cluster size due to thermodynamic destabilization of reaction products.

  9. Li insertion into Li4Ti5O12 spinel prepared by low temperature solid state route: Charge capability vs surface area

    Czech Academy of Sciences Publication Activity Database

    Zukalová, Markéta; Fabián, M.; Klusáčková, Monika; Klementová, Mariana; Pitňa Lásková, Barbora; Danková, Z.; Senna, M.; Kavan, Ladislav

    2018-01-01

    Roč. 265 (2018), s. 480-487 ISSN 0013-4686 R&D Projects: GA ČR GA15-06511S; GA MŠk LM2015087; GA MŠk 8F15003 Institutional support: RVO:61388955 ; RVO:68378271 Keywords : Li4Ti5O12 * Charge capacity * Solid state * Li insertion * Surface area Subject RIV: CG - Electrochemistry OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) Impact factor: 4.798, year: 2016

  10. Synthesis of LiFePO4/C cathode material from ferric oxide and organic lithium salts

    International Nuclear Information System (INIS)

    Shi Zhongqi; Huang Ming; Huai Yongjian; Lin Ziji; Yang Kerun; Hu Xuebu; Deng Zhenghua

    2011-01-01

    Research highlights: → LiFePO 4 can be synthesized from Fe 2 O 3 by a sequence of free-radical reactions. → Organic lithium salts can avoid the composition segregation of the precursor. → Low cost ferric oxide and environmentally friendly distilled water are used. - Abstract: LiFePO 4 /C cathode material has been simply synthesized via a modified in situ solid-state reaction route using the raw materials of Fe 2 O 3 , NH 4 H 2 PO 4 , Li 2 C 2 O 4 and lithium polyacrylate (PAALi). The sintering temperature of LiFePO 4 /C precursor is studied by thermo-gravimetric (TG)/differential thermal analysis (DTA). The physical properties of LiFePO 4 /C are then investigated through analysis using by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and the electrochemical properties are investigated by electrochemical impedance spectra (EIS), cyclic voltammogram (CV) and constant current charge/discharge test. The LiFePO 4 /C composite with the particle size of ∼200 nm shows better discharge capacity (156.4 mAh g -1 ) than bare LiFePO 4 (52.3 mAh g -1 ) at 0.2 C due to the improved electronic conductivity which is demonstrated by EIS. The as-prepared LiFePO 4 /C through this method also shows excellent high-rate characteristic and cycle performance. The initial discharge capacity of the sample is 120.5 mAh g -1 and the capacity retention rate is 100.6% after 50 cycles at 5 C rate. The results prove that the using of organic lithium salts can obtain a high performance LiFePO 4 /C composite.

  11. [100]-Oriented LiFePO4 Nanoflakes toward High Rate Li-Ion Battery Cathode.

    Science.gov (United States)

    Li, Zhaojin; Peng, Zhenzhen; Zhang, Hui; Hu, Tao; Hu, Minmin; Zhu, Kongjun; Wang, Xiaohui

    2016-01-13

    [100] is believed to be a tough diffusion direction for Li(+) in LiFePO4, leading to the belief that the rate performance of [100]-oriented LiFePO4 is poor. Here we report the fabrication of 12 nm-thick [100]-oriented LiFePO4 nanoflakes by a simple one-pot solvothermal method. The nanoflakes exhibit unexpectedly excellent electrochemical performance, in stark contrast to what was previously believed. Such an exceptional result is attributed to a decreased thermodynamic transformation barrier height (Δμb) associated with increased active population.

  12. Hot deformation of particulate reinforced Al-4Li-1Mg-0.5Ge-0.2Zr

    International Nuclear Information System (INIS)

    Chanda, T.; Lavernia, E.J.; Wolfenstine, J.

    1991-01-01

    Lithium additions to aluminum give the greatest reduction in density and increase in elastic modulus per wt.% of any known alloying element. The potential for aluminum alloy density reduction through lithium additions is evident by comparing its atomic weight (6.94) to that of aluminum (26.98). Over the past decade, considerable research efforts have been directed towards developing aluminum-lithium alloys, with lithium contents of up to 2.5 wt.%, for aircraft applications, where their low density and increased stiffness can lead to significant improvements in payload capacity. A recent notable example has been the development of a quarternary aluminum-lithium alloy containing silver, (A1-(4.5-6.3) Cu-1.3Li-0.4Ag-0.4Mg-0.14Zr, in wt.%). In an effort to further decrease the density and increase the modulus of aluminum-lithium alloys, research efforts have progressively shifted towards alloys containing higher concentrations of lithium (>3.0 wt.%). Furthermore, aluminum-lithium alloys are being studied as potential candidate matrix materials in metal matrix composites (MMCs), as a result of the observation that lithium effectively enhances the ability of the aluminum matrix to wet the ceramic reinforcement. The extreme reactivity associated with high additions of lithium, and the difficulties associated with processing MMCs, have prompted the development of alternate synthesis approaches. One such approach, spray atomization and co-deposition, is actively being studied as a result of its ability to rapidly quench, reinforce, and consolidate in a single step, thus avoiding the difficulties associated with the handling of fine reactive particulates. The object of the paper is to provide insight into the elevated temperature deformation behavior of high lithium (4 wt.%) aluminum alloys reinforced with SiC particles prepared by spray atomization and co-deposition. The selection of the A1-4Li-1Mg-0.5Ge-0.2Zr wt

  13. Immobilization of glucose oxidase using CoFe2O4/SiO2 nanoparticles as carrier

    Science.gov (United States)

    Wang, Hai; Huang, Jun; Wang, Chao; Li, Dapeng; Ding, Liyun; Han, Yun

    2011-04-01

    Aminated-CoFe2O4/SiO2 magnetic nanoparticles (NPs) were prepared from primary silica particles using modified StÖber method. Glucose oxidase (GOD) was immobilized on CoFe2O4/SiO2 NPs via cross-linking with glutaraldehyde (GA). The optimal immobilization condition was achieved with 1% (v/v) GA, cross-linking time of 3 h, solution pH of 7.0 and 0.4 mg GOD (in 3.0 mg carrier). The immobilized GOD showed maximal catalytic activity at pH 6.5 and 40 °C. After immobilization, the GOD exhibited improved thermal, storage and operation stability. The immobilized GOD still maintained 80% of its initial activity after the incubation at 50 °C for 25 min, whereas free enzyme had only 20% of initial activity after the same incubation. After kept at 4 °C for 28 days, the immobilized and free enzyme retained 87% and 40% of initial activity, respectively. The immobilized GOD maintained approximately 57% of initial activity after reused 7 times. The KM (Michaelis-Menten constant) values for immobilized GOD and free GOD were 14.6 mM and 27.1 mM, respectively.

  14. Natural CaO-TiO2-SiO2 based ceramics

    Directory of Open Access Journals (Sweden)

    Jelena Pantić

    2011-06-01

    Full Text Available Lešnica river deposits consist of a large number of minerals of different grain sizes including sphene. Since it is very difficult to obtain pure monophase titanite by different synthetic routes (sol-gel, coprecipitation, combustion, spray pyrolysis and hydrothermal method, the aim of this work was to study the structure of the sphene from the Lešnica river deposits and possibility of using it as a natural precursor for CaO-TiO2-SiO2 based ceramics. The sphene from Lešnica was analyzed by different methods: tristimulus colorimetry, infrared spectroscopy, electron microprobe and X-ray single crystal diffraction. It was confirmed that Al, Fe, Mn and P are present in the sphene structure and proposed that corresponding structural formula could be: (Ca2+1.008 Mn2+0.0021.010(Ti4+0.901 Fe3+0.033 Al3+0.060 P5+0.0010.995 Si4+1.024 O2-5.

  15. LiFAP-based PVdF-HFP microporous membranes by phase-inversion technique with Li/LiFePO{sub 4} cell

    Energy Technology Data Exchange (ETDEWEB)

    Aravindan, V.; Vickraman, P. [Gandhigram Rural University, Department of Physics, Gandhigram (India); Sivashanmugam, A.; Thirunakaran, R.; Gopukumar, S. [Central Electrochemical Research Institute, Electrochemical Energy Systems Division, Karaikudi (India)

    2009-12-15

    Polyvinylidenefluoride-hexafluoropropylene-based (PVdF-HFP-based) gel and composite microporous membranes (GPMs and CPMs) were prepared by phase-inversion technique in the presence 10 wt% of AlO(OH){sub n} nanoparticles. The prepared membranes were gelled with 0.5-M LiPF{sub 3}(CF{sub 2}CF{sub 3}){sub 3} (lithium fluoroalkylphosphate, LiFAP) in EC:DEC (1:1 v/v) and subjected to various characterizations; the AC impedance study shows that CPMs exhibit higher conductivity than GPMs. Mechanical stability measurements on these systems reveal that CPMs exhibit Young's modulus higher than that of bare and GPMs and addition of nanoparticles drastically improves the elongation break was also noted. Transition of the host from {alpha} to {beta} phase after the loading of nanosized filler was confirmed by XRD and Raman studies. Physico-chemical properties, like liquid uptake, porosity, surface area, and activation energy, of the membranes were calculated and results are summarized. Cycling performance of Li/CPM/LiFePO{sub 4} coin cell was fabricated and evaluated at C/10 rate and delivered a discharge capacity of 157 and 148 mAh g {sup -1} respectively for first and tenth cycles. (orig.)

  16. In situ green synthesis of MnFe_2O_4/reduced graphene oxide nanocomposite and its usage for fabricating high-performance LiMn_1_/_3Fe_2_/_3PO_4/reduced graphene oxide/carbon cathode material for Li-ion batteries

    International Nuclear Information System (INIS)

    Wu, Kaipeng; Hu, Guorong; Peng, Zhongdong; Cao, Yanbing; Du, Ke

    2016-01-01

    Highlights: • MnFe_2O_4/rGO was prepared by an in situ green reduction-coprecipitation method. • LiMn_1_/_3Fe_2_/_3PO_4/rGO/C was synthesized by using MnFe_2O_4/rGO as precursor. • Both pyrolytic carbon and rGO could construct an interconnected conductive network. • LiMn_1_/_3Fe_2_/_3PO_4/rGO/C shows excellent electrochemical performance. - Abstract: MnFe_2O_4/reduced graphene oxide nanocomposite (MnFe_2O_4/rGO) has been synthesized via a green reduction-coprecipitation method for the first time, which involved in situ reduction of GO in presence of Fe"2"+ and the ensuing coprecipitation of Fe"3"+ and Mn"2"+ onto the surface of rGO. The resultant MnFe_2O_4/rGO was then employed as the precursor to fabricate LiMn_1_/_3Fe_2_/_3PO_4/reduced graphene oxide/carbon composite (LiMn_1_/_3Fe_2_/_3PO_4/rGO/C) cathode material for Li-ion batteries. The composite consists of homogeneous Mn-Fe distributed LiMn_1_/_3Fe_2_/_3PO_4 with its primary particles (∼200 nm) covered and connected by both pyrolytic carbon and rGO sheets, which could prevent the aggregation of the particles as well as construct an interconnected conductive network for rapid transmission of electrons during charging and discharging process. The fabricated LiMn_1_/_3Fe_2_/_3PO_4/rGO/C can deliver a discharge capacity of 94.8 mAh g"−"1 even at the high rate of 20C, and shows a capacity decay rate of only 6.25% after 900 long-term charge-discharge cycles. Moreover, the proposed synthesis strategy can also be applied to prepare other graphene-decorated multi-component cathode/anode materials for the Li-ion batteries.

  17. Li2FeSiO4 nanorod as high stability electrode for lithium-ion batteries

    International Nuclear Information System (INIS)

    Hsu, Chun-Han; Shen, Yu-Wen; Chien, Li-Hsuan; Kuo, Ping-Lin

    2015-01-01

    Li 2 FeSiO 4 (LFS) nanorods, with a diameter of 80–100 nm and length of 0.8–1.0 μm, were synthesized successfully from a mixture of LiOH, FeSO 4 , and SiO 2 nanoparticles via a simple hydrothermal process. The secondary structure with micro-sized bundles of nanorods was developed with high crystallinity under the hydrothermal condition of 180 °C for 72 h. Then, sucrose, as carbon source, was coated and carbonized on the surface of the LFS nanorods to fabricate LFS/C nanorod composite. The resulting LFS/C nanorod composite was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and surface area measurements. When used as the cathode materials for lithium-ion battery, the electrochemical performance of the LFS/C nanorod material delivers discharge capacities of 156 mAh g −1 in the voltage window of 1.8−4.7 V and also demonstrates good cycle stability when it is cycled between 1.8 and 4.1 V. In short, superior electrochemical properties could be caused by the short lithium-ion diffusion path of its nanorod structure

  18. Synthesis and electrochemical characterization of LiCo_1_/_3Fe_2_/_3PO_4/C composite using nano CoFe_2O_4 as precursor

    International Nuclear Information System (INIS)

    Wu, Kaipeng; Hu, Guorong; Du, Ke; Peng, Zhongdong; Cao, Yanbing

    2015-01-01

    LiCo_1_/_3Fe_2_/_3PO_4/C composite was synthesized by a solid state method with CoFe_2O_4 as the precursor and glucose as the carbon source. The composite consists of homogeneous Co–Fe distributed LiCo_1_/_3Fe_2_/_3PO_4 with its particles covered by nano-carbon layers, which could prevent the growth of the particles as well as form a fast path for electronic transmission during charging and discharging process. It shows excellent electrochemical performance as the cathode for lithium-ion batteries, which delivers discharge capacities of 154.6, 152.9, 135.4, 122.3, 105.2 and 91.3 mAh g"−"1 at 0.05, 0.1, 0.5, 1, 2 and 5 C, respectively, and retains 94.6% of its initial discharge capacity after 30 cycles at 5 C. - Highlights: • Nano CoFe_2O_4 was prepared by a co-precipitation method. • LiCo_1_/_3Fe_2_/_3PO_4/C composite was synthesized using nano CoFe_2O_4 as a precursor. • Homogeneous Co–Fe distributed LiCo_1_/_3Fe_2_/_3PO_4 is obtained. • LiCo_1_/_3Fe_2_/_3PO_4/C composite exhibits a quite good electrochemical performance.

  19. Structural characterization and optical properties of Eu"2"+ and Dy"2"+ doped Sr_2SiO_4 phosphor by solid state reaction method

    International Nuclear Information System (INIS)

    Verma, Durga; Verma, Mohan L.; Upma; Patel, R.P.

    2016-01-01

    Thermoluminescence, SEM, FTIR Divalent dysprosium and europium doped strontium silicate (Sr_2SiO_4) phosphors were synthesized with the high-temperature solid-state reaction technique. The obtained phosphor was well characterized by powder X-ray diffraction, scanning electron microscopy, FTIR, UV-visible spectroscopy and thermoluminescence. The crystal structure of the prepared phosphor has an orthorhombic structure with space group Pnma. From scanning electron microscopy (SEM), agglomerations of particles were observed due to the high temperature synthesis process. The chemical composition of the sintered Sr_2SiO_4:Dy"2"+ and Sr_2SiO_4: Eu"2"+ phosphor was confirmed by energy dispersive X-ray spectroscopy (EDX). The UV-VIS analysis can be thought as a good quality check for the optical behavior of materials. The Fourier transmission infrared spectroscopy (FTIR) confirms the present elements in phosphor. Thermoluminescence study was carried out for the phosphor with UV irradiation show one glow peak. The trapping parameters associated with the prominent glow peak of Sr_2SiO_4:Dy"2"+ and Sr_2SiO_4:Eu"2"+ are calculated using Chen's glow curve method. The release of holes/electrons from defect centers at the characteristic trap site initiates the luminescence process in this material. (author)

  20. Effects of magnesium doping on electronic conductivity and electrochemical properties of LiFePO{sub 4} prepared via hydrothermal route

    Energy Technology Data Exchange (ETDEWEB)

    Ou, Xiuqin; Liang, Guangchuan; Wang, Li; Xu, Shengzhao; Zhao, Xia [Institute of Power Source and Ecomaterials Science, Box 1055, Hebei University of Technology, Tianjin 300130 (China)

    2008-10-01

    Carbon free composites Li{sub 1-x}Mg{sub x}FePO{sub 4} (x=0.00,0.02) were synthesized from LiOH, H{sub 3}PO{sub 4}, FeSO{sub 4} and MgSO{sub 4} through hydrothermal route at 180 C for 6h followed by being fired at 750 C for 6 h. The samples were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), flame atomic absorption spectroscopy and electronic conductivity measurement. To investigate their electrochemical properties, the samples were mixed with glucose as carbon precursors, and fired at 750 C for 6 h. The charge-discharge curves and cycle life test were carried out at 23{+-}2 C. The Rietveid refinement results of lattice parameters of the samples indicate that the magnesium ion has been successfully doped into the M1 (Li) site of the phospho-olivine structure. With the same order of magnitude, there is no material difference in terms of the electronic conductivities between the doped and undoped composites. Conductivities of the doped and undoped samples are 10{sup -10}S cm{sup -1} before being fired, 10{sup -9} S cm{sup -1} after being fired at 750 C, and 10{sup -1}S cm{sup -1} after coated with carbon, respectively. Both the doped and undoped composites coated with carbon exhibit comparable specific capacities of 146 mAh g{sup -1} vs. 144 mAh g{sup -1} at 0.2C, 140 mAh g{sup -1} vs. 138 mAh g{sup -1} at 1C, and 124 mAh g{sup -1} vs. 123 mAh g{sup -1} at 5C, respectively. The capacity retention rates of both doped and undoped samples over 50 cycles at 5C are close to 100% (vs. the first-cycle corresponding C-rate capacity). Magnesium doping has little effects on electronic conductivity and electrochemical properties of LiFePO{sub 4} composites prepared via hydrothermal route. (author)

  1. Investigation of TL, OSL and PTTL properties of Mg2SiO4:Tb dosimeters

    International Nuclear Information System (INIS)

    Oguz, K. F.; Goekce, M.; Karali, T.; Harmansah, C.

    2010-01-01

    In this study thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of Mg 2 SiO 4 :Tb in the form of sintered pellets were investigated. Mg 2 SiO 4 :Tb is a recently developed dosimetric material which offers high sensitivity for TL and OSL in dosimetric applications. Thermoluminescence glow curve of Tb doped Mg 2 SiO 4 samples show a glow peak at about 200 degree Celsius with two small peaks at about 275 and 330 degree Celsius, respectively. OSL experiments showed that blue light (470 nm) is six times more efficient than green light (532 nm) to stimulate the OSL emission. The aim of this study was to determine the TL and OSL fading properties of Mg 2 SiO 4 : Tb using OSL and TL methods. In addition, PTTL properties of the Mg 2 SiO 4 : Tb was investigated by using blue LEDs, UV lamp and blue laser. Investigations on the fading properties also showed that the TL signal fades % 10 in a period of 1 month and OSL signal fades % 10 in a period of 3 month, which then the signal remains relatively stable for longer periods.

  2. Coating effect of LiFePO4 and Al2O3 on Li1.2Mn0.54Ni0.13Co0.13O2 cathode surface for lithium ion batteries

    CSIR Research Space (South Africa)

    Seteni, Bonani

    2017-06-01

    Full Text Available Lithium-manganese-rich cathode material Li1.2Mn0.54Ni0.13Co0.13O2 is prepared by combustion method, and then coated with nano-sized LiFePO4 and nano-sized Al2O3 particles via a wet chemical process. The as-prepared Li1.2Mn0.54Ni0.13Co0.13O2, LiFePO4...

  3. Ab initio studies of the electronic structure of the quaternary system LiBC4N4

    International Nuclear Information System (INIS)

    Matar, S.F.; Betranhandy, E.; Nakhl, M.

    2007-01-01

    Starting from experimental data on the synthesis of solid LiBC 4 N 4 , an ab initio study has been carried out within the DFT-LDA framework of its structure and completed by accounting for other potential cubic arrangements. The consideration of stabilization energies confirms the experimental phase as the most stable one but predicts some other potential arrangements. The system is found very compressible with a bulk modulus close to that of gypsum (B 0 = 35 GPa). The electronic structure characteristics are provided allowing to confirm an ionic behavior involving complex anionic species (Li + [B(China) 4 ] - ). The control of the crystal cell size by a stoichiometry modification, such as by a CN group substitution is also studied. The proposition of LiBX 4 and LiBS 4 N 4 stoichiometries leads to predict new materials

  4. Probing the failure mechanism of nanoscale LiFePO4 for Li-ion batteries

    International Nuclear Information System (INIS)

    Gu, Meng; Yan, Pengfei; Wang, Chongmin; Shi, Wei; Zheng, Jianming; Zhang, Ji-guang

    2015-01-01

    LiFePO 4 is a high power rate cathode material for lithium ion battery and shows remarkable capacity retention, featuring a 91% capacity retention after 3300 cycles. In this work, we use high-resolution transmission electron microscopy and electron energy loss spectroscopy to study the gradual capacity fading mechanism of LiFePO 4 materials. We found that upon prolonged electrochemical cycling of the battery, the LiFePO 4 cathode shows surface amorphization and loss of oxygen species, which directly contribute to the gradual capacity fading of the battery. The finding can guide the design and improvement of LiFePO 4 cathode for high-energy and high-power rechargeable battery for electric transportation

  5. Characterisation and radiolysis of modified lithium orthosilicate pebbles with noble metal impurities

    DEFF Research Database (Denmark)

    Tamulevičius, Sigitas; Zariņš, A.; Valtenbergs, O.

    2017-01-01

    Modified lithium orthosilicate (Li4SiO4) pebbles with additions of titanium dioxide (TiO2) are suggested as an alternative tritium breeding ceramic for the European solid breeder test blanket module. The noble metals – platinum (Pt), gold (Au) and rhodium (Rh), can be introduced into the modified...... Li4SiO4 pebbles during the melt-based process, due to the corrosion of Pt-Rh and Pt-Au alloy crucible components. In this study, the surface microstructure, chemical and phase composition of the modified Li4SiO4 pebbles with different contents of the noble metals was analysed. The influence...

  6. 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

  7. Evidence for nano-Si clusters in amorphous SiO anode materials for rechargeable Li-ion batteries

    International Nuclear Information System (INIS)

    Sepehri-Amin, H.; Ohkubo, T.; Kodzuka, M.; Yamamura, H.; Saito, T.; Iba, H.; Hono, K.

    2013-01-01

    Atom probe tomography and high resolution transmission electron microscopy have shown the presence of nano-sized amorphous Si clusters in non-disproportionated amorphous SiO powders are under consideration for anode materials in Li-ion batteries. After Li insertion/extraction, no change was found in the chemistry and structure of the Si clusters. However, Li atoms were found to be trapped at the amorphous SiO phase after Li insertion/extraction, which may be attributed to the large capacity fade after the first charge/discharge cycle

  8. Facile Synthesis of Bowl-Like LiFePO4/C Composite with High Rate-Performance

    Science.gov (United States)

    Jing, Peng; Yao, Lei; Xiang, Mingwu; Wang, Yan; Wu, Jinhua; Wang, Boya; Zhang, Yun; Wu, Hao; Liu, Heng

    2018-03-01

    Olivine-structured LiFePO4/C composites with high rate-performance were synthesized via an industrial spray-drying technique using a low cost Fe3O4 as iron source. The as-obtained LiFePO4/C exhibits a unique bowl-like morphology with a particle size of 2-5 μm in diameter. A continuous uniform carbon coating layer on the surface of LiFePO4/C cathodes promotes fast electron transport, whilst it guarantees the favorable electrochemical reaction. Especially the formation of porous structure leads to an average pore volume of 0.127 cm3 g-1 and a high specific surface area of 34.46 m2 g-1, which is conducive to facilitating the penetration of electrolyte and providing the more contact area of electrolyte with LiFePO4/C. As a result, the as-prepared LiFePO4/C cathode material delivers an outstanding discharge capacity of 102.1 mAh g-1, 94.2% of the initial capacity (108.3 mAh g-1), after 1000 cycles at 10 C. Even at an ultrahigh current rate of 50 C, it still shows an initial discharge capacity of 58 mAh g-1.

  9. Facile Synthesis of Bowl-Like LiFePO4/C Composite with High Rate-Performance

    Science.gov (United States)

    Jing, Peng; Yao, Lei; Xiang, Mingwu; Wang, Yan; Wu, Jinhua; Wang, Boya; Zhang, Yun; Wu, Hao; Liu, Heng

    2018-07-01

    Olivine-structured LiFePO4/C composites with high rate-performance were synthesized via an industrial spray-drying technique using a low cost Fe3O4 as iron source. The as-obtained LiFePO4/C exhibits a unique bowl-like morphology with a particle size of 2-5 μm in diameter. A continuous uniform carbon coating layer on the surface of LiFePO4/C cathodes promotes fast electron transport, whilst it guarantees the favorable electrochemical reaction. Especially the formation of porous structure leads to an average pore volume of 0.127 cm3 g-1 and a high specific surface area of 34.46 m2 g-1, which is conducive to facilitating the penetration of electrolyte and providing the more contact area of electrolyte with LiFePO4/C. As a result, the as-prepared LiFePO4/C cathode material delivers an outstanding discharge capacity of 102.1 mAh g-1, 94.2% of the initial capacity (108.3 mAh g-1), after 1000 cycles at 10 C. Even at an ultrahigh current rate of 50 C, it still shows an initial discharge capacity of 58 mAh g-1.

  10. Syntheses and characterizations of LiFePO4 powders

    OpenAIRE

    Jugović, Dragana; Kuzmanović, Maja; Mitrić, Miodrag; Cvjetićanin, Nikola; Uskoković, Dragan

    2011-01-01

    The olivine type compositions LiMPO4 (M = Fe, Mn, Co) are among the most attractive materials for the positive electrode of lithium-ion battery. The benefits of using LiFePO4 are excellent cycle life, high structural stability, low cost and environmental friendliness. Here will be presented our efforts to obtain LiFePO4 powders through several synthesis methods. The differences in phase purity, microstructure, morphology, and electrochemical performances of synthesized powders were investigat...

  11. Li_2ZrO_3-coated Li_4Ti_5O_1_2 with nanoscale interface for high performance lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhang, Han; Liu, Yang; Wang, Ting; Yang, Yang; Shi, Shaojun; Yang, Gang

    2016-01-01

    Graphical abstract: - Highlights: • Zr doped and Li_2ZrO_3 coated Li_4Ti_5O_1_2 are prepared by a solid-state method. • Zr-doping and LZO coating are positive in improving lithium diffusion ability. • Li_2ZrO_3 coated Li_4Ti_5O_1_2 deliver 168.1 mAh g"−"1 higher than 150.2 mAh g"−"1 of Li_4Ti_5O_1_2. • Li_2ZrO_3 coated Li_4Ti_5O_1_2 remains 162 mAh g"−"1 after 100 cycles. • The lowest D_L_i"+ is 5.97 × 10"−"1"7 and 1.85 × 10"−"1"5 cm"2 s"−"1 of Li_4Ti_5O_1_2 before and after coating. - Abstract: Zr doped sample of Li_4Ti_4_._9_9Zr_0_._0_1O_1_2 (LZTO) and Li_2ZrO_3 (LZO) coated Li_4Ti_5O_1_2 (LTO) are prepared by a solid-state method. The lattice structure of LTO is remained after doping element of Zr and coating layer of LZO. The crystal structure and electrochemical performance of the material are investigated by X-ray diffractometry (XRD), high-resolution transmission electron microscopy (HRTEM), cyclic voltammetry (CV), galvanostatic intermittent titration technique (GITT) and charge-discharge tests, respectively. Zr-doping and LZO coating play the positive role in improving the diffusion ability of lithium cations. LZTO and LZO-LTO show much improved specific capacity and rate capability compared with pristine sample of LTO. LZO-LTO has the smallest voltage differential (ΔV) of the redox peaks because the coating of Li_2ZrO_3 is helpful for the diffusion ability of lithium ions during charge/discharge processes. LZTO and LZO-LTO as electrode deliver the initial capacities of 164.8, 168.1 mAh g"−"1, respectively, which are much higher than 150.2 mAh g"−"1 of intrinsic sample of LTO. Even at the current density of 2 A g"−"1, LTZO and LZO-LTO offer capacity of 96 and 106 mAh g"−"1, which are much higher than 33 mAh g"−"1 of LTO. The improved electrochemical performance is attributed to the improved diffusion ability of lithium. During the whole discharge process, the lowest value of LTO is 5.97 × 10"−"1"7 cm"2 s"−"1 that is

  12. Design Of A Bi-Functional α-Fe2O3/Zn2SiO4:Mn2+ By Layer-By-Layer Assembly Method

    Directory of Open Access Journals (Sweden)

    Yu Ri

    2015-06-01

    Full Text Available This work describes the design of bi-functional α-Fe2O3/Zn2SiO4:Mn2+ using a two-step coating process. We propose a combination of pigments (α-Fe2O3 and phosphor (Zn2SiO4:Mn2+ glaze which is assembled using a layer-by-layer method. A silica-coated α-Fe2O3 pigment was obtained by a sol-gel method and a Zn2+ precursor was then added to the silica-coated α-Fe2O3 to create a ZnO layer. Finally, the Zn2SiO4:Mn2+ layer was prepared with the addition of Mn2+ ions to serve as a phosphor precursor in the multi-coated α-Fe2O3, followed by annealing at a temperature above 1000°C. Details of the phase structure, color and optical properties of the multi-functional α-Fe2O3/Zn2SiO4:Mn2+ were characterized by transmission electron microscopy and X-ray diffraction analyses.

  13. Solvothermal synthesis of LiFePO4 nanoplates with (010) plane and the uniform carbon coated on their surface by esterification reaction

    International Nuclear Information System (INIS)

    Ma, Zhipeng; Shao, Guangjie; Wang, Xu; Song, Jianjun; Wang, Guiling; Liu, Tingting

    2014-01-01

    A facile solvothermal synthesis and esterification reaction combined with a high temperature calcination technique has been developed to prepare the uniform carbon coating LiFePO 4 nanoplates. The carbon coating LiFePO 4 nanoplates are investigated by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), galvanostatic intermittent titration technique (GITT) and galvanostatic charge–discharge test. A reasonable growth mechanism of LiFePO 4 nanoplates is proposed on the basis of time dependent experimental results. The results show that each nanoplate is a LiFePO 4 single crystal with the large (010) plane. According to Raman spectroscopy analysis, carbon is uniformly coated on the surface of LiFePO 4 nanoplates. Electrochemical test results also indicate that the carbon coating LiFePO 4 nanoplates exhibit a high reversible specific capacity of 144.8 mAh g −1 at 0.5 C and 116.9 mAh g −1 under lower discharging rate at −20 °C. - Highlights: • LiFePO 4 nanoplates prepared by facile solvothermal synthesis expose large (010) plane. • The polyester network formed by the esterification reaction could entirely wrap LiFePO 4 . • The polyester wrapped on the surface of LiFePO 4 transformed into the uniform carbon layer after calcination. • LiFePO 4 /C nanoplates have good high-rate and low-temperature performance

  14. Grain growth behavior of Li{sub 4}SiO{sub 4} pebbles fabricated by agar method for tritium breeder

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Maoqiao [School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Zhang, Yingchun, E-mail: zycustb@126.com [School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Zhang, Yun; Wang, Chaofu; Liu, Wei [School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Yu, Yonghong [Department of Physics, Renmin University of China, Beijing, 100872 (China)

    2016-11-15

    Highlights: • Grain sizes of Li{sub 4}SiO{sub 4} were adjusted by different silicon sources. • Grain growth exponent of Li{sub 4}SiO{sub 4} was about 3. • Grain growth activation energy of Li{sub 4}SiO{sub 4} was about 125.54 kJ/mol. • Grain growth of Li{sub 4}SiO{sub 4} pebble was controlled by vapor transport. - Abstract: The Li{sub 4}SiO{sub 4} tritium breeding pebbles will be filled in the blanket and used for 2 years or more at high temperatures, which would increase the grain size and affect tritium release. Hence, grain sizes of the Li{sub 4}SiO{sub 4} pebbles fabricated by agar method were investigated, and two kinds of different silicon sources (crystal and amorphous SiO{sub 2}) with different particle sizes were used. The particle size of SiO{sub 2} could affect grain size and density of the Li{sub 4}SiO{sub 4} pebble. And the isothermal sintering was carried out to study the grain growth kinetics of Li{sub 4}SiO{sub 4}. The grain growth exponent (n) and the activation energy (Q) were calculated by the phenomenological kinetic equation. The calculated n values were 4.10, 3.98, 3.34 and 2.96, and corresponding Q values were 152.15, 147.99, 125.54 and 110.58 kJ/mol, respectively. At the higher sintering temperatures (950 and 1000 °C), the grain growth of Li{sub 4}SiO{sub 4} was controlled by vapor transport.

  15. Synthesis, Structure, and Li-Ion Conductivity of LiLa(BH4)3X, X = Cl, Br, I

    DEFF Research Database (Denmark)

    GharibDoust, Seyed Hosein Payandeh; Brighi, Matteo; Sadikin, Yolanda

    2017-01-01

    In this work, a new type of addition reaction between La(BH4)3 and LiX, X = Cl, Br, I, is used to synthesize LiLa(BH4)3Cl and two new compounds LiLa(BH4)3X, X = Br, I. This method increases the amounts of LiLa(BH4)3X and the sample purity. The highest Li-ion conductivity is observed for LiLa(BH4...... with increasing lattice parameter, that is, increasing size of the halide ion in the structure. Thus, we conclude that the sizes of both windows are important for the lithium ion conduction in LiLa(BH4)3X compounds. The lithium ion conductivity is measured over one to three heating cycles and with different...

  16. Preparation of carbon and oxide co-modified LiFePO{sub 4} cathode material for high performance lithium-ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chun-Chen, E-mail: ccyang@mail.mcut.edu.tw [Department of Chemical Engineering, Ming Chi University of Technology, New Taipei City 243, Taiwan (China); Battery Research Center of Green Energy, Ming Chi University of Technology, New Taipei City 243, Taiwan (China); Jang, Jer-Huan; Jiang, Jia-Rong [Department of Chemical Engineering, Ming Chi University of Technology, New Taipei City 243, Taiwan (China); Department of Mechanical Engineering, Ming Chi University of Technology, New Taipei City 243, Taiwan (China)

    2015-09-01

    In this study, a LiFePO{sub 4}/C (LFP/C) material was prepared using a spray dry method. The Li{sub 4}Ti{sub 5}O{sub 12} (LTO) surface modification on LFP/C composite was performed by a sol–gel method. The characteristic properties were examined using X-ray diffraction, micro-Raman spectroscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy, an AC impedance method, and the galvanostatic charge/discharge method. Pristine LFP/C powder and the 1–5 wt.% LTO-coated LFP/C composites were compared. The results revealed that the 3 wt.% LTO-coated LFP/C composite showed the best performance among LFP composite samples. It was found that the 3 wt.% LTO-coated LFP/C composite showed discharge capacities of 159 mAh g{sup −1}, 157 mAh g{sup −1}, 154 mAh g{sup −1}, 148 mAh g{sup −1}, 145 mAh g{sup −1}, and 138 mAh g{sup −1} at rates of 0.2C, 0.5C, 1C, 3C, 5C, and 10C, respectively at 55 °C. The long-term cycling performance of the LFP/C composite was greatly improved when the dual hybrid coating (carbon and oxide) was carried out. Moreover, the 3 wt.% LTO-coated LFP/C composite with the lowest fading rate maintained cycling stability at 3C rate at 55 °C after 300 cycles; by contrast, the bare LFP/C sample with the highest fading rate had an unfavorable lifecycle, and its discharge capacity decreased rapidly. A hybrid coating is a feasible method for improving the high temperature performance of LFP/C composites. - Highlights: • A spherical LiFePO{sub 4}/C (LFP/C) material is first prepared by a spray dry process. • Li{sub 4}Ti{sub 5}O{sub 12} (LTO) modified LFP/C composite was carried out by a sol–gel method. • The LFP/C with a hybrid coating showed good cycling performance at elevated temperature. • 3%LTO-LFP/C composite showed excellent cycling stability at 55 °C for 300 cycles test.

  17. LiVO/sub 3/-Li/sub 2/Mo(W)O/sub 4/ and NaVO/sub 3/-Na/sub 2/Cr(Mo)O/sub 4/ systems

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, I N; Lupeiko, T G; Vyalikova, V I [Rostovskij-na-Donu Gosudarstvennyj Univ. (USSR)

    1975-09-01

    The systems LiVO/sub 3/-Li/sub 2/MoO/sub 4/, LiVO/sub 3/-Li/sub 2/WO/sub 4/, NaNO/sub 3/-Na/sub 2/CrO/sub 4/, NaNO/sub 3/-Na/sub 2/MoO/sub 4/ were studied with thermographic and partially visual polythermal methods of physical and chemical analyses. Except NaVO/sub 3/-Na/sub 2/MoO/sub 4/ all investigated systems are eutectic ones with limited solid solutions on the basis of some component; the eutectics melt at 542, 544, 550/sup 0/C and contain 25, 20 and 26% of Li/sub 2/MoO/sub 4/, Li/sub 2/WO/sub 4/ and Na/sub 2/CrO/sub 4/ respectively. The system NaNO/sub 3/-Na/sub 2/MoO/sub 4/ contains compound 18 NaVO/sub 3/.11Na/sub 2/MoO/sub 4/ congruently melting at 570/sup 0/C. Two eutectics of the system have melting points at 542 and 548/sup 0/C and contain 47 and 67% of Na/sub 2/MoO/sub 4/.

  18. Study on lithium extraction from brines based on LiMn2O4/Li1-xMn2O4 by electrochemical method

    International Nuclear Information System (INIS)

    Zhao, Meng-Yao; Ji, Zhi-Yong; Zhang, Yong-Guang; Guo, Zhi-Yuan; Zhao, Ying-Ying; Liu, Jie; Yuan, Jun-Sheng

    2017-01-01

    Highlights: •A recovery system with LiMn 2 O 4 /Li 1-x Mn 2 O 4 as electrodes was used to extract lithium. •The influence sequence of coexisting ions on lithium extraction was Mg 2+ > Na + > Ca 2+ > K + . •The values of α Li-Na , α Li-Mg and α Li-Ca were more than 300, 70 and 110, respectively. •The specific energy consumption was between 18 and 19 W h·mol −1 . -- Abstract: Lithium rechargeable batteries have been used for lithium extraction in recent years. Here, we report on a highly selective lithium recovery system that consists of a LiMn 2 O 4 positive electrode, a Li 1-x Mn 2 O 4 negative electrode and a monovalent selective anion-exchange membrane. The effect of potential, temperature and coexisting ions on lithium extraction were investigated in this paper, and the lithium recovery system was applied to extract lithium from brine and concentrated seawater. The extraction capacity of Li + reached 34.31 mg· (1 g LiMn 2 O 4 ) −1 at 1.2 V. With higher reaction rate and lower energy consumption, 25 °C (room temperature) was considered as the appropriate temperature. The system still remained high selective for Li + even in the presence of impurity ions (K + , Na + , Mg 2+ , Ca 2+ ). With simulated brine and concentrated seawater as source solutions, the concentrations of Na + , Mg 2+ and Ca 2+ were reduced more than 300, 70 and 100 times, consuming 18–19 W h per mole of lithium recovered. And the electrodes still had high separation coefficients of Li + and Me n+ (Na + , Mg 2+ , Ca 2+ ) after five cycles although a slight drop was existing.

  19. A-site substitution effect of strontium on bismuth layered CaBi4Ti4O15 ceramics on electrical and piezoelectric properties

    International Nuclear Information System (INIS)

    Tanwar, Amit; Verma, Maya; Gupta, Vinay; Sreenivas, K.

    2011-01-01

    Strontium substituted CaBi 4 Ti 4 O 15 ceramics with the chemical formula Ca 1-x Sr x Bi 4 Ti 4 O 15 (CSBT) (x = 0.0-1.0) have been prepared through conventional solid state route. The formation of single phase material with orthorhombic structure was verified from X-ray diffraction with incorporation of Sr substitution. Decrease in a-axis displacement of Bi ion in the perovskite structure in the CSBT ceramics were observed from the relative changes in soft mode (20 cm -1 ) in the Raman spectra, and increase in Sr incorporation shows the shift in ferroelectric to paraelectric phase transition temperature. The dielectric properties for all the CSBT ceramic compositions are studied as a function of temperature over the frequency range of 100 Hz-1 MHz. Curie's temperature was found to be function of Sr substitution and with increase in the Sr concentration the phase transition becomes sharper and phase transition temperature gets shifted towards lower temperature (790-545 deg. C). The behavior of ac conductivity as a function of frequency (100 Hz-1 MHz) at low temperature ( 33 ) whereas piezoelectric charge coefficient values were found comparable to that of PZT at room temperature. Relative changes in soft modes due to Sr incorporation results in high piezoelectricity in the CSBT ceramics.

  20. A general solution-chemistry route to the synthesis LiMPO4 (M=Mn, Fe, and Co) nanocrystals with [010] orientation for lithium ion batteries

    International Nuclear Information System (INIS)

    Su Jing; Wei Bingqing; Rong Jiepeng; Yin Wenyan; Ye Zhixia; Tian Xianqing; Ren Ling; Cao Minhua; Hu Changwen

    2011-01-01

    A general and efficient solvothermal strategy has been developed for the preparation of lithium transition metal phosphate microstructures (LiMnPO 4 , LiFePO 4 , and LiCoPO 4 ), employing ethanol as the solvent, LiI as the Li source, metal salts as the M sources, H 3 PO 4 as the phosphorus source, and poly(vinyl pyrrolidone) (PVP) as the carbon source and template. This route features low cost, environmental benign, and one-step process for the cathode material production of Li-ion batteries without any complicated experimental setups and sophisticated operations. The as-synthesized LiMPO 4 microstructures exhibit unique, well-shaped and favorable structures, which are self-assembled from microplates or microrods. The b axis is the preferred crystal growth orientation of the products, resulting in a shorter lithium ion diffusion path. The LiFePO 4 microstructures show an excellent cycling stability without capacity fading up to 50 cycles when they are used as a cathode material in lithium-ion batteries. - Graphical abstract: A general and efficient solvothermal strategy has been developed for the preparation of lithium transition metal phosphate microstructures under solvothermal conditions in the presence of PVP. Highlights: → A general and efficient solvothermal strategy has been developed for the preparation of LiMPO 4 microstructures. → This route features low cost, environmental benign, and one-step process. → The LiMPO 4 microstructures exhibit unique, well-shaped, and favorable structures. → The LiFePO 4 microstructures show an excellent cycling stability up to 50 cycles as a cathode material of lithium-ion batteries.

  1. Unlocking the energy capabilities of micron-sized LiFePO4.

    Science.gov (United States)

    Guo, Limin; Zhang, Yelong; Wang, Jiawei; Ma, Lipo; Ma, Shunchao; Zhang, Yantao; Wang, Erkang; Bi, Yujing; Wang, Deyu; McKee, William C; Xu, Ye; Chen, Jitao; Zhang, Qinghua; Nan, Cewen; Gu, Lin; Bruce, Peter G; Peng, Zhangquan

    2015-08-03

    Utilization of LiFePO4 as a cathode material for Li-ion batteries often requires size nanonization coupled with calcination-based carbon coating to improve its electrochemical performance, which, however, is usually at the expense of tap density and may be environmentally problematic. Here we report the utilization of micron-sized LiFePO4, which has a higher tap density than its nano-sized siblings, by forming a conducting polymer coating on its surface with a greener diazonium chemistry. Specifically, micron-sized LiFePO4 particles have been uniformly coated with a thin polyphenylene film via the spontaneous reaction between LiFePO4 and an aromatic diazonium salt of benzenediazonium tetrafluoroborate. The coated micron-sized LiFePO4, compared with its pristine counterpart, has shown improved electrical conductivity, high rate capability and excellent cyclability when used as a 'carbon additive free' cathode material for rechargeable Li-ion batteries. The bonding mechanism of polyphenylene to LiFePO4/FePO4 has been understood with density functional theory calculations.

  2. Synthesis of LiFePO{sub 4}/polyacenes using iron oxyhydroxide as an iron source

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Guiling; Zhang, Xianfa; Liu, Jing; He, Xingguang; Wang, Jiawei; Xie, Haiming; Wang, Rongshun [Institute of Functional Materials, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China); LIB Engineering Laboratory, Materials Science and Technology Center, Changchun, Jilin 130024 (China)

    2010-02-15

    LiFePO{sub 4}/polyacenes (PAS) composite is synthesized by iron oxyhydroxide as a new raw material and phenol-formaldehyde resin as both reducing agent and carbon source. The mechanism of the reaction is outlined by the analysis of XRD, FTIR as well as TG/DSC. The results show that the formation of LiFePO{sub 4} is started at 300 C, and above 550 C, the product can be mainly ascribed to olivine LiFePO{sub 4}. The electrochemical properties of the synthesized composites are investigated by charge-discharge tests. It is found that the prepared sample at 750 C (S750) has a better electrochemical performance than samples prepared at other temperatures. A discharge capacity of 158 mAh g{sup -1} is delivered at 0.2 C. Under high discharge rate of 10 C, a discharge capacity of 145 mAh g{sup -1} and good capacity retention of 93% after 800 cycles are achieved. The morphology of S750 and PAS distribution in it are investigated by SEM and TEM. (author)

  3. Dielectric properties of BaBi4Ti4O15 ceramics produced by cost-effective chemical method

    International Nuclear Information System (INIS)

    Chakrabarti, A.; Bera, J.; Sinha, T.P.

    2009-01-01

    BaBi 4 Ti 4 O 15 , an Aurivillius compound, was synthesized by a cost-effective soft chemical route. The precursor was prepared by precipitating Bi- and Ba-oxalates inside a TiO 2 powder suspension. A phase pure orthorhombic BaBi 4 Ti 4 O 15 was synthesized by heating the precursor powder at 1000 deg. C. The phase formation behavior was investigated using TG-DSC and XRD. Densification behavior of the powder and microstructure development in sintered pellet was examined. Temperature dependent dielectric study of the ceramic has been investigated in the temperature range 300-780 K and frequency range of 1 kHz-1 MHz. The broad dielectric constant peaks at temperature T m was frequency dependent. The dielectric relaxation rate follows the Vogel-Fulcher relation with activation energy=0.2639 eV, relaxation frequency=4.95x10 21 Hz, and freezing temperature=620 K. All these parameters indicate that BaBi 4 Ti 4 O 15 is a relaxor ferroelectric.

  4. Advanced LiTi2(PO4)3@N-doped carbon anode for aqueous lithium ion batteries

    International Nuclear Information System (INIS)

    He, Zhangxing; Jiang, Yingqiao; Meng, Wei; Zhu, Jing; Liu, Yang; Dai, Lei; Wang, Ling

    2016-01-01

    Highlights: • LiTi 2 (PO 4 ) 3 @N-doped carbon anode was prepared by in-situ coating approach for aqueous lithium ion batteries. • The well-proportioned N-doped carbon layer and loose nanoporous structure was obtained using urea as nitrogen source and pore former. • LiTi 2 (PO 4 ) 3 @N-doped carbon demonstrates excellent rate performance and good cycling stability. - Abstract: In this paper, LiTi 2 (PO 4 ) 3 @N-doped carbon anode has been synthesized by in situ carbon coating approach. The well-proportioned N-doped carbon layer and loose nanoporous structure was obtained by using urea as nitrogen source and pore former. LiTi 2 (PO 4 ) 3 @N-doped carbon as anode demonstrates much better rate capability than LiTi 2 (PO 4 ) 3 @carbon in ALIBs. The optimized anode delivers the discharge capacity of 93.7 mAh g −1 and 74.2 mAh g −1 at rates of 10C and 20C, 22.5 mAh g −1 and 50.0 mAh g −1 larger than that of LiTi 2 (PO 4 ) 3 @carbon. Moreover, LiTi 2 (PO 4 ) 3 @N-doped carbon exhibits excellent cycling performance with capacity retention of 84.3% at 5C after 1000 cycles. As verified, the well-proportioned N-doped carbon layer could reduce charge transfer resistance and improve electrical conductivity. The loose nanoporous structure could shorten pathway and facilitate diffusion for Li ion. Therefore, LiTi 2 (PO 4 ) 3 @N-doped carbon gets the superior electrochemical properties benefiting from those two characteristics.

  5. Dehydrogenation mechanism of LiBH{sub 4} by Poly(methyl methacrylate)

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jianmei [School of Materials Science and Engineering, and Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Guangzhou 510641 (China); China-Australia Joint Laboratory for Energy & Environmental Materials, South China University of Technology, Guangzhou 510641 (China); Yan, Yurong [School of Materials Science and Engineering, and Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Guangzhou 510641 (China); Ouyang, Liuzhang, E-mail: meouyang@scut.edu.cn [School of Materials Science and Engineering, and Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Guangzhou 510641 (China); China-Australia Joint Laboratory for Energy & Environmental Materials, South China University of Technology, Guangzhou 510641 (China); Key Laboratory for Fuel Cell Technology in Guangdong Province, South China University of Technology, Guangzhou 510641 (China); Wang, Hui [School of Materials Science and Engineering, and Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Guangzhou 510641 (China); China-Australia Joint Laboratory for Energy & Environmental Materials, South China University of Technology, Guangzhou 510641 (China); Zhu, Min, E-mail: memzhu@scut.edu.cn [School of Materials Science and Engineering, and Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Guangzhou 510641 (China); China-Australia Joint Laboratory for Energy & Environmental Materials, South China University of Technology, Guangzhou 510641 (China)

    2015-10-05

    Highlights: • LiBH{sub 4} is amorphous after modified with PMMA. • Dehydrogenation temperature of LiBH{sub 4} decreases by 120 °C after modifying with PMMA. • The LiBH{sub 4}@PMMA composite releases 10 wt.% hydrogen at 360 °C within 1 h. • C=O group of PMMA weakens the B−H bonds to lower dehydrogenation temperature. - Abstract: We investigated the dehydrogenation properties and mechanism of Poly(methyl methacrylate) (PMMA) confined LiBH{sub 4}. Thermal stability of LiBH{sub 4} was reduced by PMMA, with a decrease in dehydrogenation temperature by 120 °C. At 360 °C, the composite showed fast dehydrogenation kinetics with 10 wt.% of hydrogen released within 1 h. The improved dehydrogenation performance was mainly attributed to the reaction between LiBH{sub 4} and PMMA forming Li{sub 3}BO{sub 3} as a final product. Furthermore, the presence of electrostatic interaction between B atom of LiBH{sub 4} and O atom in the carbonyl group of PMMA may weaken the B−H bonding of [BH{sub 4}]{sup −} and lower the hydrogen desorption temperature.

  6. Band structure analysis on olivine LiMPO4 and delithiated MPO4 (M = Fe, Mn) cathode materials

    International Nuclear Information System (INIS)

    Yi, Ting-Feng; Fang, Zi-Kui; Xie, Ying; Zhu, Yan-Rong; Dai, Changsong

    2014-01-01

    Highlights: • The conductivity of Li x MPO 4 were discussed relying on first principles technique. • Relationship between structure properties and microscopic bonding was addressed. • A mechanism responsible for the structural instability of MnPO 4 was proposed. - Abstract: Olivine compounds, i.e. Li x MPO 4 (M = Fe, Mn), are now regarded as the most competitive positive-electrode materials for future applications of large-scale rechargeable lithium batteries. There are significant interests in their electronic structures, because the microscopic information is very important for elucidating the structural stability, electrochemical performance, and electronic conductivity issues of batteries for high-rate applications. The structure stabilities of LiMPO 4 and MPO 4 (M = Fe, Mn) cathode materials are analyzed according to first principles calculations. The result shows that LiMPO 4 (M = Fe, Mn) materials exhibit good structure stability, which is mainly contributed to the extremely strong P-O covalent bonds. Furthermore, the introduction of P ions is also helpful for the chemical potential decrease of the materials. The band structure analysis reveals that the electronic conductance of LiFePO 4 , LiMnPO 4 , and FePO 4 is poor, while MnPO 4 possesses half metallic property. According to the electron distribution, it can be confirmed that Mn-O(II) bonds are weakened after Li + extractions, which is different from the variation trend of Fe-O(II) bonds. The decrease of Mn-O(II) bond strength is thus favorable for the phase transformation observed in experiments

  7. Improved capacity and rate capability of Ru-doped and carbon-coated Li4Ti5O12 anode material

    International Nuclear Information System (INIS)

    Lin, Chih-Yuan; Jhan, Yi-Ruei; Duh, Jenq-Gong

    2011-01-01

    Highlights: → By using a simple one-step solid-state reactions method synthesizes Li 4 Ru 0.01 Ti 4.99 O 12 /C anode material. → Combining the Ru-doped and carbon-coated techniques to fabricate Li 4 Ru 0.01 Ti 4.99 O 12 /C effectively enhance the diffusion rate of Li + and significantly reduce surface electronic resistance of Li 4 Ti 5 O 12 . → Li 4 Ru 0.01 Ti 4.99 O 12 /C delivers 120 and 110 mAh g -1 at 5 and 10 C charge/discharge rate, respectively, after 100 charge/discharge cycles. - Abstract: Pure Li 4 Ti 5 O 12 , modified Li 4 Ti 5 O 12 /C, Li 4 Ru 0.01 Ti 4.99 O 12 and Li 4 Ru 0.01 Ti 4.99 O 12 /C were successfully prepared by a modified solid-state method and its electrochemical properties were investigated. From the XRD patterns, the added sugar or doped Ru did not affect the spinel structure. The results of electrochemical properties revealed that Li 4 Ru 0.01 Ti 4.99 O 12 /C showed 120 and 110 mAh/g at 5 and 10 C rate after 100 charge/discharge cycles. Li 4 Ru 0.01 Ti 4.99 O 12 /C exhibited the best rate capability and the highest capacity at 5 and 10 C charge/discharge rate owing to the increase of electronic conductivity and the reduction of interface resistance between particles of Li 4 Ti 5 O 12 .It is expected that the Li 4 Ru 0.01 Ti 4.99 O 12 /C will be a promising anode material to be used in high-rate lithium ion battery.

  8. Mechanochemical transformations in Li(Na)AlH4-Li(Na)NH2 systems

    International Nuclear Information System (INIS)

    Dolotko, Oleksandr; Zhang Haiqiao; Ugurlu, Ozan; Wiench, Jerzy W.; Pruski, Marek; Scott Chumbley, L.; Pecharsky, Vitalij

    2007-01-01

    Mechanochemical transformations of tetrahydroaluminates and amides of lithium and sodium have been investigated using gas volumetric analysis, X-ray powder diffraction, solid-state nuclear magnetic resonance (NMR) and transmission electron microscopy. In a transformation of LiAlH 4 and LiNH 2 taken in an 1:1 molar ratio, the amount of released hydrogen (6.6 wt.% after 30 min ball milling) was higher than in any known one pot mechanochemical process involving a hydrogen-containing solid. A total of 4.3 wt.% of hydrogen is released by the NaAlH 4 -NaNH 2 system after 60 min ball milling; and 5.2 wt.% H 2 is released when LiAlH 4 and NaNH 2 or NaAlH 4 and LiNH 2 are ball milled for 90 min and 120 min, respectively. All transformations proceed at room temperature. The mechanism of the overall transformation MAlH 4 (s) + MNH 2 (s) → 2MH(s) + AlN(s) + 2H 2 (g) was identified based on detailed spectroscopic analysis of the intermediate (M 3 AlH 6 ) and final products of the ball milling process

  9. Hydrothermal synthesis of LiFePO4 nanorods composed of ...

    Indian Academy of Sciences (India)

    Administrator

    LiFePO4 nanorods composed of nanoparticles were synthesized from ... olivine structure; belongs to Pnma space group. ... LiFePO4 has one-dimensional (1D) channel along the ... phases of LiFePO4 ... Among the various synthesis techniques available, the .... Prosini P, Lisi M, Zane D and Pasquali M 2002 Solid State. Ion.

  10. Functionalization of Fe3O4/SiO2 with N-(2-Aminoethyl-3-aminopropyl for Sorption of [AuCl4]-

    Directory of Open Access Journals (Sweden)

    Nuryono Nuryono

    2016-08-01

    Full Text Available Synthesis of Fe3O4/SiO2 modified with N-(2-aminoethyl-3-aminopropyl group (Fe3O4/SiO2/ED via coating method and its application for adsorption-desorption of anionic gold in aqueous solution have been conducted. The synthesized product was characterized with an X-ray diffractometer (XRD, a Fourier transform infrared (FT-IR spectrophotometer and a transmission electron microscopy (TEM. Adsorption of Au(III was conducted in a batch system and the variables included pH, contact time, and initial concentration were investigated. Results showed that magnetite/silica has been successfully functionalized with N-(2-aminoethyl-3-aminopropyl in a homogeneous system. Kinetics study showed that adsorption of Au(III followed the pseudo-second order model with rate constant of 0.710 g mmol L-1min-1. Furthermore, the experimental data fitted well with the Langmuir isotherm model with the maximum adsorption capacity for Au(III of 142.9 mg g-1 and the energy of 25.0 kJ mol-1. Gold loaded on the Fe3O4/SiO2/ED could be easily desorbed with 0.2 mol L-1 HCl containing 2 wt.% of thiourea with recovery of 99.8%. Fe3O4/SiO2/ED was reusable and stable in 5 cycles of adsorption-desorption with recovery more than 90%. Fe3O4/SiO2/ED showed high selectivity towards Au(III in the multimetal system Au(III/Cu(II/Cr(VI with the coefficient selectivity for αAu-Cu of 227.5and for αAu-Cr of 12.3.

  11. Tailored surface structure of LiFePO4/C nanofibers by phosphidation and their electrochemical superiority for lithium rechargeable batteries.

    Science.gov (United States)

    Lee, Yoon Cheol; Han, Dong-Wook; Park, Mihui; Jo, Mi Ru; Kang, Seung Ho; Lee, Ju Kyung; Kang, Yong-Mook

    2014-06-25

    We offer a brand new strategy for enhancing Li ion transport at the surface of LiFePO4/C nanofibers through noble Li ion conducting pathways built along reduced carbon webs by phosphorus. Pristine LiFePO4/C nanofibers composed of 1-dimensional (1D) LiFePO4 nanofibers with thick carbon coating layers on the surfaces of the nanofibers were prepared by the electrospinning technique. These dense and thick carbon layers prevented not only electrolyte penetration into the inner LiFePO4 nanofibers but also facile Li ion transport at the electrode/electrolyte interface. In contrast, the existing strong interactions between the carbon and oxygen atoms on the surface of the pristine LiFePO4/C nanofibers were weakened or partly broken by the adhesion of phosphorus, thereby improving Li ion migration through the thick carbon layers on the surfaces of the LiFePO4 nanofibers. As a result, the phosphidated LiFePO4/C nanofibers have a higher initial discharge capacity and a greatly improved rate capability when compared with pristine LiFePO4/C nanofibers. Our findings of high Li ion transport induced by phosphidation can be widely applied to other carbon-coated electrode materials.

  12. Environmentally benign and scalable synthesis of LiFePO4 nanoplates with high capacity and excellent rate cycling performance for lithium ion batteries

    International Nuclear Information System (INIS)

    Zhao, Chunsong; Wang, Lu-Ning; Chen, Jitao; Gao, Min

    2017-01-01

    Highlights: •LiFePO 4 precursors were successfully prepared in pure water phase under atmosphere. •LiFePO 4 nanostructures were also regenerated by recycling filtrate. •LiFePO 4 /C delivers high discharge capacity of 160 mAh g −1 at 0.2 C and high rate capacity of 107 mAh g −1 at 20C. •LiFePO 4 /C delivers a capacity retention rate closed to 97% after 240 cycles at 20C. -- Abstract: An economical and scalable synthesis route of LiFePO 4 nanoplate precursors is successfully prepared in pure water phase under atmosphere without employing environmentally toxic surfactants or high temperature and high pressure compared with traditional hydrothermal or solvothermal methods, which also involves recycling the filtrate to regenerate LiFePO 4 nanoplate precursors and collecting by-product Na 2 SO 4 . The LiFePO 4 precursors present a plate-like morphology with mean thickness and length of 50–100 and 100–300 nm, respectively. After carbon coating, the LiFePO 4 /C nanoparticles with particle size around 200 nm can be observed which exhibit a high discharge capacity of 160 mAh g −1 at 0.2 C and 107 mAh g −1 at 20 C. A high capacity retention closed to 91% can be reached after 500 cycles even at a high current rate of 20C with coulombic efficiency of 99.5%. This work suggests a simple, economic and environmentally benign method in preparation of LiFePO 4 /C cathode material for power batteries that would be feasible for large scale industrial production.

  13. Influence of the cation substitution on the magnetic properties of LiCo2O4 and Li(Me,Co2O4 spinels

    Directory of Open Access Journals (Sweden)

    Gautier, J. L.

    2004-08-01

    Full Text Available Lithium-based cells LiCo2O4 have been characterized by magnetic techniques, looking at the influence of the partial substitution of cobalt by 3d or 4d transition metal elements (Fe, Ni, Cu, Cr, Mo. The non-substituted compound LiCo2O4 behaves as an antiferromagnet, with a Néel temperature TN of 30 K, although antiferromagnetic interactions are much more important, as suggested by a Weiss parameter Θ of the order of ‑225 K. In the solid solution Li(NixCo2‑xO4 the Weiss parameter Θ changes with x(Ni, reaching large positive values (e.g., Θ ~ +230 K, for x = 0.5. This phenomenon suggests the existence of a canted‑antiferromagnetic or ferrimagnetic structures with large ferromagnetic components. Substitution of cobalt by other 3d or 4d transition metals in the LiMe0.5Co1.5O4 series shows dramatic effects with respect to the non-substituted LiCo2O4 compound : copper completely suppresses the magnetic order, while iron increases TN to almost room temperature. No modifications are observed when molybdenum substitutes cobalt, while chromium transforms the AF order in a ferromagnetic one, with Tc of about 90 K.Se ha caracterizado por técnicas magnéticas, el efecto de la sustitución parcial de Co por elementos de transición 3d o 4d (Fe, Ni, Cu, Cr, Mo en celdas LiCo2O4 a base de litio. El compuesto no sustituído LiCo2O4, se comporta como un antiferromagneto de temperatura de Néel TN de 30 K, aunque existen interacciones antiferromagnéticas mucho más importantes, como lo indica un parámetro de Weiss Θ del orden de -225K. En la solución sólida Li(NixCo2‑xO4, el parámetro de Weiss Θ cambia con x(Ni, alcanzando valores positivos altos (e.g., Θ ~ +230K, para x=0.5. Este fenómeno sugiere la existencia de una estructura antiferromagnética inclinada (“AF-canted” o de una estructura ferrimagnética, donde predominan componentes ferromagnéticas importantes. La sustitución del cobalto por otros elementos de transición 3d o 4d en

  14. Experimental studies of collisions of excited Li(4p) atoms with C2H4, C2H6, C3H8 and theoretical interpretation of the Li-C2H4 system

    International Nuclear Information System (INIS)

    Semmineh, Natenael; Bililign, Solomon; Hagebaum-Reignier, Denis; Jeung, Gwang-Hi

    2009-01-01

    Collisions of excited Li(4p) states with C 2 H 4 , C 2 H 6 and C 3 H 8 are studied experimentally using far-wing scattering state spectroscopy techniques. High-level ab initio quantum mechanical studies of the Li-C 2 H 4 system are conducted to explain the results of the experiment for this system. The recent and present works indicate that knowledge of the internal structure of the perturber (C 2 H 4 , C 2 H 6 and C 3 H 8 ) is essential to fully understand the interaction between the metal and the hydrocarbon molecules. The ab initio calculation shows that the Li(4d) (with little probability under the experimental conditions) and the Li(4p) can be formed directly through the laser pumping. It also shows that the Li(4s) and Li(3d) states can be formed through an electronic diabatic coupling involving a radiationless process. However, the Li(3p), Li(3s) and Li(2p) states can only be formed through a secondary diabatic coupling which is a much less probable process than the primary one. The calculation limited to two C 2v sections of the potential energy surfaces (PESs) shows peculiar multi-state crossings that we have never seen in other lithium complexes we studied

  15. Effect of heat treatment time on microstructure and electrical conductivity in LATP glass ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sonigra, Dhiren, E-mail: somans@iitb.ac.in, E-mail: ajit.kulkarni@iitb.ac.in; Soman, Swati, E-mail: somans@iitb.ac.in, E-mail: ajit.kulkarni@iitb.ac.in; Kulkarni, Ajit R., E-mail: somans@iitb.ac.in, E-mail: ajit.kulkarni@iitb.ac.in [Dept. of Metallurgical Engineering and Materials Science, IIT Bombay, Mumbai-400076 (India)

    2014-04-24

    Glass-ceramic is prepared by heat treatment of melt quenched 14Li{sub 2}O−9Al{sub 2}O{sub 3}−38TiO{sub 2}−39P{sub 2}O{sub 5} glass in the vicinity of crystallization temperature. Growth of ceramic phase is controlled by tuning heat treatment time at fixed temperature. Ceramic phase was identified to be LiTi{sub 2}(PO{sub 4}){sub 3} from X Ray Diffraction analysis. Microstructural evolution of this phase with hold time was observed under high resolution Scanning Electron Microscope. DC conductivity is observed to increase by 4-5 orders of magnitude in this glass-ceramic compared to parent glass. However, formation of pores and cracks with very large heat treatment time seem to hinder further increase of conductivity.

  16. Study of the structure and ferroelectric behavior of BaBi{sub 4-x}La{sub x}Ti{sub 4}O{sub 15} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Khokhar, Anita, E-mail: mails4anita@gmail.com; Sreenivas, K. [Department of Physics & Astrophysics, University of Delhi, Delhi-110 007 (India); Goyal, Parveen K. [Department of Physics, ARSD College, University of Delhi, Dhaula Kuan, New Delhi-110 021 (India); Thakur, O. P. [Electroceramics Group, Solid State Physics Laboratory, Lucknow Road, Delhi 110 054 (India)

    2015-06-24

    The structure and ferroelectric properties of Lanthanum substituted barium bismuth titanate BaBi{sub 4-x}La{sub x}Ti{sub 4}O{sub 15} (0 ≤ x ≤ 0.5) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material. The distribution of lanthanum into the perovskite layers and (Bi{sub 2}O{sub 2}){sup 2+} layers of BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics have been revealed through Raman spectroscopy. At lower value of x, it is seen that La{sup 3+} ions prefer to substitute A-site Bi{sup 3+} ions in the perovskite layers while for higher x values, La{sup 3+} ions get incorporated into the (Bi{sub 2}O{sub 2}){sup 2+} layers. A critical La content of x ∼ 0.2 in BaBi{sub 4-x}La{sub x}Ti{sub 4}O{sub 15} is seen to exhibit a large remnant polarization (P{sub r}) with low coercive field (E{sub c}). The improvement in the ferroelectric properties of La substituted BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of lanthanum ion.

  17. Synthesis and Characterization of V2O5/SiO2 Nanoparticles as Efficient Catalyst for Aromatization 1,4 Dihydropyridines

    International Nuclear Information System (INIS)

    Farzaneh, F.; Zamanifar, E.; Jafari Foruzin, L.; Ghandi, M.

    2012-01-01

    V 2 O 5 /SiO 2 nanoparticles was prepared via an one-pot sol gel method from vanadyl- acetylacetonate and tetraethyl orthosilicate in refluxing MeOH, followed by calcination at 700 °C for 2 hours. The resultant nanoparticles was characterized by means of scanning electron microscopy, transmission electron microscopy, X-ray diffraction, TGA and FTIR techniques. Rapid and efficient aromatization of 1,4-dihydropyridines catalyzed by V 2 O 5 /SiO 2 nanoparticles is described in this presentation.

  18. Synthesis and characterization of metastable, 20 nm-sized Pna2{sub 1}-LiCoPO{sub 4} nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Jennifer [Technical University of Munich, Department of Chemistry, Synthesis and Characterization of Innovative Materials, Lichtenbergstr. 4, 85747 Garching (Germany); Nordlund, Dennis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Doeff, Marca M. [Lawrence Berkeley National Laboratory, Environmental Energy Technologies Division, 1 Cyclotron Rd, Berkeley, CA 94720 (United States); Nilges, Tom, E-mail: tom.nilges@lrz.tum.de [Technical University of Munich, Department of Chemistry, Synthesis and Characterization of Innovative Materials, Lichtenbergstr. 4, 85747 Garching (Germany)

    2017-04-15

    The majority of research activities on LiCoPO{sub 4} are focused on the phospho-olivine (space group Pnma), which is a promising high-voltage cathode material for Li-ion batteries. In contrast, comparably little is known about its metastable Pna2{sub 1} modification. Herein, we present a comprehensive study on the structure–property relationships of 15–20 nm Pna2{sub 1}-LiCoPO{sub 4} nanospheres prepared by a simple microwave-assisted solvothermal process. Unlike previous reports, the results indicate that the compound is non-stoichiometric and shows cation-mixing with Co ions on the Li sites, which provides an explanation for the poor electrochemical performance. Co L{sub 2,3}-edge X-ray absorption spectroscopic data confirm the local tetrahedral symmetry of Co{sup 2+}. Comprehensive studies on the thermal stability using thermogravimetric analysis, differential scanning calorimetry, and in situ powder X-ray diffraction show an exothermic phase transition to olivine Pnma-LiCoPO{sub 4} at 527 °C. The influence of the atmosphere and the particle size on the thermal stability is also investigated. - Graphical abstract: Blue nano-sized Pna2{sub 1}-LiCoPO{sub 4,} featuring tetrahedrally-coordinated Co{sup 2+}, was synthesized in a rapid one-step microwave-assisted solvothermal process. The phase relation between this metastable and the stable polymorph was analyzed and electrochemical properties are discussed. - Highlights: • Preparation of uniform 15–20 nm nanospheres of metastable Pna2{sub 1}-LiCoPO{sub 4} polymorph. • Structure redetermination shows cation-mixing (Co blocking Li sites). • In situ investigation of phase transformation to olivine Pnma-LiCoPO{sub 4} at 527 °C. • Pna2{sub 1}-LiCoPO{sub 4} reemerges as a stable high-temperature phase above 800 °C. • X-ray absorption spectroscopy confirms local tetrahedral symmetry (T{sub d} Co{sup 2+}).

  19. Photoluminescence properties of X5SiO4Cl6:Tb (X = Sr, Ba) green ...

    Indian Academy of Sciences (India)

    attracted more attention due to their potential applications ... materials were thoroughly mixed and ground in an agate mortar. ... Figure 2. Excitation spectra of Ba5SiO4Cl6:Tb3+ phosphor. spectrum of Tb3+ singly doped phosphor Ba5SiO4Cl6,.

  20. Preparation, Characterization and Thermal Degradation of Polyimide (4-APS/BTDA/SiO2 Composite Films

    Directory of Open Access Journals (Sweden)

    Arash Dehzangi

    2012-04-01

    Full Text Available Polyimide/SiO2 composite films were prepared from tetraethoxysilane (TEOS and poly(amic acid (PAA based on aromatic diamine (4-aminophenyl sulfone (4-APS and aromatic dianhydride (3,3,4,4-benzophenonetetracarboxylic dianhydride (BTDA via a sol-gel process in N-methyl-2-pyrrolidinone (NMP. The prepared polyimide/SiO2 composite films were characterized using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, scanning electron microscope (SEM and thermogravimetric analysis (TGA. The FTIR results confirmed the synthesis of polyimide (4-APS/BTDA and the formation of SiO2 particles in the polyimide matrix. Meanwhile, the SEM images showed that the SiO2 particles were well dispersed in the polyimide matrix. Thermal stability and kinetic parameters of the degradation processes for the prepared polyimide/SiO2 composite films were investigated using TGA in N2 atmosphere. The activation energy of the solid-state process was calculated using Flynn–Wall–Ozawa’s method without the knowledge of the reaction mechanism. The results indicated that thermal stability and the values of the calculated activation energies increased with the increase of the TEOS loading and the activation energy also varied with the percentage of weight loss for all compositions.

  1. Preparation, structure and analysis of the bonding in the molecular entity (OSO)2Li{[AlF(ORF)3]Li[Al(ORF)4]} (RF = C(CF3)3).

    Science.gov (United States)

    Cameron, T Stanley; Nikiforov, Grigory B; Passmore, Jack; Rautiainen, J Mikko

    2010-03-14

    The (SO(2))(2)Li[AlF(OR(F))(3)]Li[Al(OR(F))(4)] (1) (R(F) = C(CF(3))(3)) molecular entity was obtained by thermal decomposition of Li[Al(OR(F))(4)] followed by crystallization from liquid SO(2). 1, containing two SO(2) molecules eta(1)-O coordinated to Li(+), was structurally characterized by single crystal X-ray diffraction and NMR spectroscopy in SO(2)(l). Bonding analyses of 1 (bond valency units, AIM analysis, atomic charges, bond orders) show that 1 can be either considered as a Li(OSO)(2)(+) complex stabilized by the large WCA [AlF(OR(F))(3)](-)Li(+)[Al(OR(F))(4)](-) or as consisting of 2 SO(2), 2 Li(+), [AlF(OR(F))(3)](-), and [Al(OR(F))(4)](-) joined by electrostatic interactions into the discrete molecular entity 1. The bonding between Li(+) and SO(2) molecules is shown to be almost completely attributable to monopole-induced dipole electrostatic interactions. Theoretical gas phase lithium ion affinity of SO(2) is determined to be stronger than its silver(I) ion affinity owing largely to the shorter lithium SO(2) contacts in the calculated structures that increase the electrostatic interaction.

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

    OpenAIRE

    Zhang, Xinyi; Yang, Le; Hao, Feng; Chen, Haosen; Yang, Meng; Fang, Daining

    2015-01-01

    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 revea...

  3. Carbonate anion controlled growth of LiCoPO4/C nanorods and its improved electrochemical behavior

    International Nuclear Information System (INIS)

    Gangulibabu; Nallathamby, Kalaiselvi; Meyrick, Danielle; Minakshi, Manickam

    2013-01-01

    Highlights: ► Carbonate anion controlled growth of LiCoPO 4 nanorods has been prepared. ► Mixture of H 2 CO 3 + (NH 4 ) 2 CO 3 increases the CO 3 2− concentration and acts as an effective growth inhibitor. ► Heating the carbonate rich precursor in an inert atmosphere produces a Co 2 P phase that is conductive. ► Addition of super P carbon resulted in an amorphous carbon coating on LiCoPO 4 particles. ► LiCoPO 4 /C nanorods with a co-existence of Co 2 P exhibit excellent discharge capacity with retention on multiple cycling. -- Abstract: LiCoPO 4 /C nanocomposite with growth controlled by carbonate anions was synthesized via a unique solid-state fusion method. Carbonate anions in the form of H 2 CO 3 or a mixture of H 2 CO 3 + (NH 4 ) 2 CO 3 have been used as a growth inhibiting modifier to produce morphology controlled lithium cobalt phosphate. The presence of cobalt phosphide (Co 2 P) as a second phase improved the conductivity and electrochemical properties of the parent LiCoPO 4. The formation of Co 2 P is found to be achievable only in an inert atmosphere. Super P ® carbon (10 wt.%) provided an adherent carbon coating on pristine LiCoPO 4 resulting in the LiCoPO 4 /C composite cathode. This electrode exhibited enhanced electrochemical properties: capacity of 123 mAh g −1 with excellent capacity retention of 89% after 30 cycles, and reasonable rate capability of up to 5 C rate. The synergistic effect of carbonate anions and formation of Co 2 P under inert atmosphere has influenced the electrochemical behavior of LiCoPO 4 /C cathode through controlling the morphology and increasing the conductivity

  4. Synthesis of LiFePO{sub 4}/C cathode material from ferric oxide and organic lithium salts

    Energy Technology Data Exchange (ETDEWEB)

    Shi Zhongqi; Huang Ming [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); Huai Yongjian [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); China Aviation Lithium Battery Co., Ltd, Luoyang, Henan 471003 (China); Lin Ziji; Yang Kerun [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); Hu Xuebu [Department of Chemistry and Materials, Sichuan Normal University, Chengdu, Sichuan 610068 (China); Zhongke Laifang Power Science and Technology Co., Ltd., Chengdu, Sichuan 610041 (China); Deng Zhenghua, E-mail: zhdeng@cioc.ac.c [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); Zhongke Laifang Power Science and Technology Co., Ltd., Chengdu, Sichuan 610041 (China)

    2011-04-15

    Research highlights: {yields} LiFePO{sub 4} can be synthesized from Fe{sub 2}O{sub 3} by a sequence of free-radical reactions. {yields} Organic lithium salts can avoid the composition segregation of the precursor. {yields} Low cost ferric oxide and environmentally friendly distilled water are used. - Abstract: LiFePO{sub 4}/C cathode material has been simply synthesized via a modified in situ solid-state reaction route using the raw materials of Fe{sub 2}O{sub 3}, NH{sub 4}H{sub 2}PO{sub 4}, Li{sub 2}C{sub 2}O{sub 4} and lithium polyacrylate (PAALi). The sintering temperature of LiFePO{sub 4}/C precursor is studied by thermo-gravimetric (TG)/differential thermal analysis (DTA). The physical properties of LiFePO{sub 4}/C are then investigated through analysis using by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and the electrochemical properties are investigated by electrochemical impedance spectra (EIS), cyclic voltammogram (CV) and constant current charge/discharge test. The LiFePO{sub 4}/C composite with the particle size of {approx}200 nm shows better discharge capacity (156.4 mAh g{sup -1}) than bare LiFePO{sub 4} (52.3 mAh g{sup -1}) at 0.2 C due to the improved electronic conductivity which is demonstrated by EIS. The as-prepared LiFePO{sub 4}/C through this method also shows excellent high-rate characteristic and cycle performance. The initial discharge capacity of the sample is 120.5 mAh g{sup -1} and the capacity retention rate is 100.6% after 50 cycles at 5 C rate. The results prove that the using of organic lithium salts can obtain a high performance LiFePO{sub 4}/C composite.

  5. Synthesis and thermoluminescence of new Li2SO4:Eu and Li2SO4:Dy phosphors exposed to beta radiation

    International Nuclear Information System (INIS)

    Garcia H, A. R.; Bustamante L, G. A.; Castro C, A. I.; Bernal H, R.; Cruz V, C.; Burruel I, S. E.; Castano M, V. M.

    2015-10-01

    Full text: Li 2 SO 4 is systematically studied for the very first concerning their dosimetric capabilities. Pellet- shaped Eu and Dy doped Li 2 SO 4 phosphors were synthesized by sintering. Some samples were exposed to beta particle irradiation in order to investigate their thermoluminescence (Tl) features. Glow curves were obtained for 80 mg mass samples, showing that both, Tl sensitivity as well as the temperature at which the Tl maximum is recorded, depends upon the sample dopant. The glow curves of Li 2 SO 4 :Eu exhibit two maxima, located at 433 and 573 K, when a 5 K/s heating rate was used, being the most intense emission that observed at 573 K. The integrated Tl increases as the radiation dose was increased in the 0.25 - 5 Gy range, with no shift of the Tl maxima being observed, meaning that first order kinetics processes are involved in the Tl emission. The normalized sensitivity recorded in ten consecutive irradiation-Tl readout cycles shows a good reusability with only 5 % variability. The integrated Tl fades as a function of the elapsed time between irradiation and the corresponding Tl readout of Eu and Dy doped Li 2 SO 4 phosphors is obtained. From the obtained results, we conclude that Li 2 SO 4 is a promising phosphor material to develop high performance Tl dosimeters, and a long term research work focused to understand and to improve their Tl features is absolutely justified. (Author)

  6. Formation and accumulation of radiation-induced defects and radiolysis products in modified lithium orthosilicate pebbles with additions of titanium dioxide

    Science.gov (United States)

    Zarins, Arturs; Valtenbergs, Oskars; Kizane, Gunta; Supe, Arnis; Knitter, Regina; Kolb, Matthias H. H.; Leys, Oliver; Baumane, Larisa; Conka, Davis

    2016-03-01

    Lithium orthosilicate (Li4SiO4) pebbles with 2.5 wt.% excess of silicon dioxide (SiO2) are the European Union's designated reference tritium breeding ceramics for the Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM). However, the latest irradiation experiments showed that the reference Li4SiO4 pebbles may crack and form fragments under operation conditions as expected in the HCPB TBM. Therefore, it has been suggested to change the chemical composition of the reference Li4SiO4 pebbles and to add titanium dioxide (TiO2), to obtain lithium metatitanate (Li2TiO3) as a second phase. The aim of this research was to investigate the formation and accumulation of radiation-induced defects (RD) and radiolysis products (RP) in the modified Li4SiO4 pebbles with different contents of TiO2 for the first time, in order to estimate and compare radiation stability. The reference and the modified Li4SiO4 pebbles were irradiated with accelerated electrons (E = 5 MeV) up to 5000 MGy absorbed dose at 300-990 K in a dry argon atmosphere. By using electron spin resonance (ESR) spectroscopy it was determined that in the modified Li4SiO4 pebbles, several paramagnetic RD and RP are formed and accumulated, like, E' centres (SiO33-/TiO33-), HC2 centres (SiO43-/TiO3-) etc. On the basis of the obtained results, it is concluded that the modified Li4SiO4 pebbles with TiO2 additions have comparable radiation stability with the reference pebbles.

  7. Preparation and Characterization of PbO-SrO-Na2O-Nb2O5-SiO2 Glass Ceramics Thin Film for High-Energy Storage Application

    Science.gov (United States)

    Tan, Feihu; Zhang, Qingmeng; Zhao, Hongbin; Wei, Feng; Du, Jun

    2018-03-01

    PbO-SrO-Na2O-Nb2O5-SiO2 (PSNNS) glass ceramic thin films were prepared by pulsed laser deposition technology on heavily doped silicon substrates. The influence of annealing temperatures on microstructures, dielectric properties and energy storage performances of the as-prepared films were investigated in detail. X-ray diffraction studies indicate that Pb2Nb2O7 crystallizes at 800°C and disappears at 900°C, while NaNbO3 and PbNb2O6 are formed at the higher temperature of 900°C. The dielectric properties of the glass ceramics thin films have a strong dependence on the phase assemblages that are developed during heat treatment. The maximum dielectric constant value of 171 was obtained for the film annealed at 800°C, owing to the high electric breakdown field strength, The energy storage densities of the PSNNS films annealed at 800°C were as large as 36.9 J/cm3, These results suggest that PSNNS thin films are promising for energy storage applications.

  8. Highly efficient transparent Zn2SiO4:Mn2+ phosphor film on quartz glass

    International Nuclear Information System (INIS)

    Seo, K.I.; Park, J.H.; Kim, J.S.; Kim, G.C.; Yoo, J.H.

    2009-01-01

    Highly efficient transparent Zn 2 SiO 4 :Mn 2+ film phosphors on quartz substrates were deposited by the thermal diffusion of sputtered ZnO:Mn film. They show a textured structure with some preferred orientations. Our film phosphor shows, for the best photoluminescence (PL) brightness, a green PL brightness of about 20% of a commercial Zn 2 SiO 4 :Mn 2+ powder phosphor screen. The film shows a high transmittance of more than 10% at the red-color region. The excellence in PL brightness and transmittance can be explained in terms of the textured crystal growth with a continuous gradient of Zn 2 SiO 4 : Mn 2+ crystals.

  9. Synthesis of graphene supported Li2SiO3 as a high performance anode material for lithium-ion batteries

    Science.gov (United States)

    Yang, Shuai; Wang, Qiufen; Miao, Juan; Zhang, Jingyang; Zhang, Dafeng; Chen, Yumei; Yang, Hong

    2018-06-01

    The Li2SiO3-graphene composite is successfully synthesized through an easy hydrothermal method. The structures and morphologies of the produced samples are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectrum, Brunauer-Emmett-Teller formalism, scanning electron microscope, transmission electron microscope, and electrochemistry methods. The result shows a well crystalline of the Li2SiO3-GE composite. The existence of graphene doesn't change the crystalline of Li2SiO3. In addition, the Li2SiO3 compound with an average diameter of 20 nm can be seen on the surface of graphene with uniform distribution. After the composite with graphene, the composite displays large surface area which ensures the well electrochemistry of the composite. Finally, the Li2SiO3-graphene composite delivers a high initial capacity of 878.3 mAh g-1 at 1C as well as a high recovery capacity of 400 mAh g-1 after 200 cycles. When charged and discharged at high rate, the Li2SiO3-doping graphene composite still exhibits a high specific capacity of 748.3 mAh g-1 (at 2C, and 576 mAh g-1 at 5C) and well cycling performance. The well synthesized composite possesses well structure and well electrochemistry performance.

  10. Fabrication of lead-free piezoelectric Li2CO3-added (Ba,Ca)(Ti,Sn)O3 ceramics under controlled low oxygen partial pressure and their properties

    Science.gov (United States)

    Noritake, Kouta; Sakamoto, Wataru; Yuitoo, Isamu; Takeuchi, Teruaki; Hayashi, Koichiro; Yogo, Toshinobu

    2018-02-01

    Reduction-resistant lead-free (Ba,Ca)(Ti,Sn)O3 piezoceramics with high piezoelectric constants were fabricated by optimizing the amount of Li2CO3 added. Oxygen partial pressure was controlled during the sintering of (Ba,Ca)(Ti,Sn)O3 ceramics in a reducing atmosphere using H2-CO2 gas. Enhanced grain growth and a high-polarization state after poling treatment were achieved by adding Li2CO3. Optimizing the amount of Li2CO3 added to (Ba0.95Ca0.05)(Ti0.95Sn0.05)O3