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Sample records for carbon electrode materials

  1. Carbon-based electrode materials for DNA electroanalysis.

    Science.gov (United States)

    Kato, Dai; Niwa, Osamu

    2013-01-01

    This review addresses recent studies of newly developed carbon-based electrode materials and their use for DNA electroanalysis. Recently, new carbon materials including carbon nanotubes (CNT), graphene and diamond-based nanocarbon electrodes have been actively developed as sensing platforms for biomolecules, such as DNA and proteins. Electrochemical techniques using these new material-based electrodes can provide very simple and inexpensive sensing platforms, and so are expected to be used as one of the "post-light" DNA analysis methods, which include coulometric detection, amperometric detection with electroactive tags or intercalators, and potentiometric detection. DNA electroanalysis using these new carbon materials is summarized in view of recent advances on electrodes.

  2. Amorphous titania/carbon composite electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    Vaughey, John T.; Jansen, Andrew; Joyce, Christopher D.

    2017-05-09

    An isolated salt comprising a compound of formula (H.sub.2X)(TiO(Y).sub.2) or a hydrate thereof, wherein X is 1,4-diazabicyclo[2.2.2]octane (DABCO), and Y is oxalate anion (C.sub.2O.sub.4.sup.-2), when heated in an oxygen-containing atmosphere at a temperature in the range of at least about 275.degree. C. to less than about 400.degree. C., decomposes to form an amorphous titania/carbon composite material comprising about 40 to about 50 percent by weight titania and about 50 to about 60 percent by weight of a carbonaceous material coating the titania. Heating the composite material at a temperature of about 400 to 500.degree. C. crystallizes the titania component to anatase. The titania materials of the invention are useful as components of the cathode or anode of a lithium or lithium ion electrochemical cell.

  3. Towards Flexible Transparent Electrodes Based on Carbon and Metallic Materials

    Directory of Open Access Journals (Sweden)

    Minghui Luo

    2017-01-01

    Full Text Available Flexible transparent electrodes (FTEs with high stability and scalability are in high demand for the extremely widespread applications in flexible optoelectronic devices. Traditionally, thin films of indium thin oxide (ITO served the role of FTEs, but film brittleness and scarcity of materials limit its further application. This review provides a summary of recent advances in emerging transparent electrodes and related flexible devices (e.g., touch panels, organic light-emitting diodes, sensors, supercapacitors, and solar cells. Mainly focusing on the FTEs based on carbon nanomaterials (e.g., carbon nanotubes and graphene and metal materials (e.g., metal grid and metal nanowires, we discuss the fabrication techniques, the performance improvement, and the representative applications of these highly transparent and flexible electrodes. Finally, the challenges and prospects of flexible transparent electrodes will be summarized.

  4. Coaxial fiber supercapacitor using all-carbon material electrodes.

    Science.gov (United States)

    Le, Viet Thong; Kim, Heetae; Ghosh, Arunabha; Kim, Jaesu; Chang, Jian; Vu, Quoc An; Pham, Duy Tho; Lee, Ju-Hyuck; Kim, Sang-Woo; Lee, Young Hee

    2013-07-23

    We report a coaxial fiber supercapacitor, which consists of carbon microfiber bundles coated with multiwalled carbon nanotubes as a core electrode and carbon nanofiber paper as an outer electrode. The ratio of electrode volumes was determined by a half-cell test of each electrode. The capacitance reached 6.3 mF cm(-1) (86.8 mF cm(-2)) at a core electrode diameter of 230 μm and the measured energy density was 0.7 μWh cm(-1) (9.8 μWh cm(-2)) at a power density of 13.7 μW cm(-1) (189.4 μW cm(-2)), which were much higher than the previous reports. The change in the cyclic voltammetry characteristics was negligible at 180° bending, with excellent cycling performance. The high capacitance, high energy density, and power density of the coaxial fiber supercapacitor are attributed to not only high effective surface area due to its coaxial structure and bundle of the core electrode, but also all-carbon materials electrodes which have high conductivity. Our coaxial fiber supercapacitor can promote the development of textile electronics in near future.

  5. Effect of oxidation of carbon material on suspension electrodes for flow electrode capacitive deionization.

    Science.gov (United States)

    Hatzell, Kelsey B; Hatzell, Marta C; Cook, Kevin M; Boota, Muhammad; Housel, Gabrielle M; McBride, Alexander; Kumbur, E Caglan; Gogotsi, Yury

    2015-03-03

    Flow electrode deionization (FCDI) is an emerging area for continuous and scalable deionization, but the electrochemical and flow properties of the flow electrode need to be improved to minimize energy consumption. Chemical oxidation of granular activated carbon (AC) was examined here to study the role of surface heteroatoms on rheology and electrochemical performance of a flow electrode (carbon slurry) for deionization processes. Moreover, it was demonstrated that higher mass densities could be used without increasing energy for pumping when using oxidized active material. High mass-loaded flow electrodes (28% carbon content) based on oxidized AC displayed similar viscosities (∼21 Pa s) to lower mass-loaded flow electrodes (20% carbon content) based on nonoxidized AC. The 40% increased mass loading (from 20% to 28%) resulted in a 25% increase in flow electrode gravimetric capacitance (from 65 to 83 F g(-1)) without sacrificing flowability (viscosity). The electrical energy required to remove ∼18% of the ions (desalt) from of the feed solution was observed to be significantly dependent on the mass loading and decreased (∼60%) from 92 ± 7 to 28 ± 2.7 J with increased mass densities from 5 to 23 wt %. It is shown that the surface chemistry of the active material in a flow electrode effects the electrical and pumping energy requirements of a FCDI system.

  6. Single-walled Carbon Nanotubes as Electrode Materials for Supercapacitors

    Institute of Scientific and Technical Information of China (English)

    XU Bina; WU Feng; WANG Fang; CHEN Shi; CAO Gao-Ping; YANG Yu-Sheng

    2006-01-01

    Large-scale synthesized single-walled carbon nanotubes (SWNT) prepared by electric arc discharge method and a mixture of NiO and Y2O3 as catalyst have been used as electrode materials for supercapacitors. N2 adsorption/desorption measurement shows that the SWNT is a microporous and mesoporous material with specific surface area 435 m2g1.Thespecific capacitance of the nitric acid treated SWNT in aqueous electrolyte reaches as high as 105 F/g, which is a combination of electric double layer capacitance and pseudocapacitance. The SWNT-based capacitors also have good charge/discharge reversibility and cycling perdurability.

  7. Carbon nanotube prepared from carbon monoxide by CVD method and its application as electrode materials

    Institute of Scientific and Technical Information of China (English)

    AN Yuliang; YUAN Xia; CHENG Shinan; GEN Xin

    2006-01-01

    Carbon nanotubes with larger inner diameter were synthesized by the chemical vapor deposition of carbon monoxide (CO) on iron catalyst using H2S as promoting agent.It is found that the structure and morphology of carbon nanotubes can be tailored, to some degree, by varying the experimental conditions such as precursor components and process parameters.The results show that the presence of H2S may play key role for growing Y-branched carbon nanotubes.The products were characterized by SEM, TEM, and Raman spectroscopy, respectively.Furthermore, the obtained carbon nanotubes were explored as electrode materials for supercapacitor.

  8. Graphene-carbon nanotube hybrid materials and use as electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Tour, James M.; Zhu, Yu; Li, Lei; Yan, Zheng; Lin, Jian

    2016-09-27

    Provided are methods of making graphene-carbon nanotube hybrid materials. Such methods generally include: (1) associating a graphene film with a substrate; (2) applying a catalyst and a carbon source to the graphene film; and (3) growing carbon nanotubes on the graphene film. The grown carbon nanotubes become covalently linked to the graphene film through carbon-carbon bonds that are located at one or more junctions between the carbon nanotubes and the graphene film. In addition, the grown carbon nanotubes are in ohmic contact with the graphene film through the carbon-carbon bonds at the one or more junctions. The one or more junctions may include seven-membered carbon rings. Also provided are the formed graphene-carbon nanotube hybrid materials.

  9. Graphene-carbon nanotube hybrid materials and use as electrodes

    Science.gov (United States)

    Tour, James M.; Zhu, Yu; Li, Lei; Yan, Zheng; Lin, Jian

    2016-09-27

    Provided are methods of making graphene-carbon nanotube hybrid materials. Such methods generally include: (1) associating a graphene film with a substrate; (2) applying a catalyst and a carbon source to the graphene film; and (3) growing carbon nanotubes on the graphene film. The grown carbon nanotubes become covalently linked to the graphene film through carbon-carbon bonds that are located at one or more junctions between the carbon nanotubes and the graphene film. In addition, the grown carbon nanotubes are in ohmic contact with the graphene film through the carbon-carbon bonds at the one or more junctions. The one or more junctions may include seven-membered carbon rings. Also provided are the formed graphene-carbon nanotube hybrid materials.

  10. Electroanalysis with carbon paste electrodes

    CERN Document Server

    Svancara, Ivan; Walcarius, Alain; Vytras, Karel

    2011-01-01

    Introduction to Electrochemistry and Electroanalysis with Carbon Paste-Based ElectrodesHistorical Survey and GlossaryField in Publication Activities and LiteratureCarbon Pastes and Carbon Paste ElectrodesCarbon Paste as the Binary MixtureClassification of Carbon Pastes and Carbon Paste ElectrodesConstruction of Carbon Paste HoldersCarbon Paste as the Electrode MaterialPhysicochemical Properties of Carbon PastesElectrochemical Characteristics of Carbon PastesTesting of Unmodified CPEsIntera

  11. Recent development of carbon electrode materials and their bioanalytical and environmental applications.

    Science.gov (United States)

    Zhang, Wei; Zhu, Shuyun; Luque, Rafael; Han, Shuang; Hu, Lianzhe; Xu, Guobao

    2016-02-07

    Carbon materials have been extensively investigated due to their diversity, favorable properties, and active applications including electroanalytical chemistry. This critical review discusses new synthetic methods, novel carbon materials, new properties and electroanalytical applications of carbon materials particularly related to the preparation as well as bioanalytical and environmental applications of highly oriented pyrolytic graphite, graphene, carbon nanotubes, various carbon films (e.g. pyrolyzed carbon films, boron-doped diamond films and diamond-like carbon films) and screen printing carbon electrodes. Future perspectives in the field have also been discussed (366 references).

  12. Composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, S.T.; Pekala, R.W.; Kaschmitter, J.L.

    1997-05-06

    Carbon aerogels used as a binder for granulated materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy. 1 fig.

  13. Composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Steven T. (San Leandro, CA); Pekala, Richard W. (Pleasant Hill, CA); Kaschmitter, James L. (Pleasanton, CA)

    1997-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivty and power to system energy.

  14. Nitrogen Doped Macroporous Carbon as Electrode Materials for High Capacity of Supercapacitor

    Directory of Open Access Journals (Sweden)

    Yudong Li

    2017-01-01

    Full Text Available Nitrogen doped carbon materials as electrodes of supercapacitors have attracted abundant attention. Herein, we demonstrated a method to synthesize N-doped macroporous carbon materials (NMC with continuous channels and large size pores carbonized from polyaniline using multiporous silica beads as sacrificial templates to act as electrode materials in supercapacitors. By the nice carbonized process, i.e., pre-carbonization at 400 °C and then pyrolysis at 700/800/900/1000 °C, NMC replicas with high BET specific surface areas exhibit excellent stability and recyclability as well as superb capacitance behavior (~413 F ⋅ g−1 in alkaline electrolyte. This research may provide a method to synthesize macroporous materials with continuous channels and hierarchical pores to enhance the infiltration and mass transfer not only used as electrode, but also as catalyst somewhere micro- or mesopores do not work well.

  15. Grafted, cross-linked carbon black as a double-layer capacitor electrode material

    Energy Technology Data Exchange (ETDEWEB)

    Richner, R.; Mueller, S.; Wokaun, A.

    2001-03-01

    Isocyanate prepolymers readily react with oxidic functional groups on carbon black. On carbon black grafted with diisocyanates, reactive isocyanate groups are available for cross-linking to a polyurethane system. This cross-linked carbon black was considered as a new active material for electrochemical electrodes. Active material for electric double-layer capacitor electrodes was produced which had values of specific capacitance of up to 200 F/g. Cross-linking efficiencies of up to 58 % of the polymers utilised were achieved. (author)

  16. Carbon Paste Electrodes Made from Different Carbonaceous Materials: Application in the Study of Antioxidants

    Science.gov (United States)

    Apetrei, Constantin; Apetrei, Irina Mirela; De Saja, Jose Antonio; Rodriguez-Mendez, Maria Luz

    2011-01-01

    This work describes the sensing properties of carbon paste electrodes (CPEs) prepared from three different types of carbonaceous materials: graphite, carbon microspheres and carbon nanotubes. The electrochemical responses towards antioxidants including vanillic acid, catechol, gallic acid, l-ascorbic acid and l-glutathione have been analyzed and compared. It has been demonstrated that the electrodes based on carbon microspheres show the best performances in terms of kinetics and stability, whereas G-CPEs presented the smallest detection limit for all the antioxidants analyzed. An array of electrodes has been constructed using the three types of electrodes. As demonstrated by means of Principal Component Analysis, the system is able to discriminate among antioxidants as a function of their chemical structure and reactivity. PMID:22319354

  17. Carbonized chicken eggshell membranes with 3D architectures as high-performance electrode materials for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhi; Zhang, Li; Amirkhiz, Babak Shalchi; Tan, Xuehai; Xu, Zhanwei; Wang, Huanlei; Olsen, Brian C.; Holt, Chris M.B.; Mitlin, David [Chemical and Materials Engineering, University of Alberta, Edmonton, AB (Canada); National Institute for Nanotechnology (NINT), NRC, Edmonton, AB (Canada)

    2012-04-15

    Supercapacitor electrode materials are synthesized by carbonizing a common livestock biowaste in the form of chicken eggshell membranes. The carbonized eggshell membrane (CESM) is a three-dimensional macroporous carbon film composed of interwoven connected carbon fibers containing around 10 wt% oxygen and 8 wt% nitrogen. Despite a relatively low surface area of 221 m{sup 2} g{sup -1}, exceptional specific capacitances of 297 F g{sup -1} and 284 F g{sup -1} are achieved in basic and acidic electrolytes, respectively, in a 3-electrode system. Furthermore, the electrodes demonstrate excellent cycling stability: only 3% capacitance fading is observed after 10 000 cycles at a current density of 4 A g{sup -1}. These very attractive electrochemical properties are discussed in the context of the unique structure and chemistry of the material. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Novel air electrode for metal-air battery with new carbon material and method of making same

    Science.gov (United States)

    Ross, P.N. Jr.

    1988-06-21

    This invention relates to a rechargeable battery or fuel cell. More particularly, this invention relates to a novel air electrode comprising a new carbon electrode support material and a method of making same. 3 figs.

  19. Cooperation of micro- and meso-porous carbon electrode materials in electric double-layer capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Cheng [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, Jilin Province (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Qi, Li; Wang, Hongyu [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, Jilin Province (China); Yoshio, Masaki [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)

    2010-07-01

    The capacitive characteristics of micro- and meso-porous carbon materials have been compared in cyclic voltammetric studies and galvanostatic charge-discharge tests. Meso-porous carbon can keep certain high capacitance values at high scan rates, whereas micro-porous carbon possesses very high capacitance values at low scan rates but fades quickly as the scan rate rises up. For better performance of electric double-layer capacitors (EDLCs), the cooperative application of both kinds of carbon materials has been proposed in the following two ways: mixing both kinds of carbons in the same electrode or using the asymmetric configuration of carbon electrodes in the same EDLC. The cooperative effect on the electrochemical performance has also been addressed. (author)

  20. Characterisation of porous carbon electrode materials used in proton exchange membrane fuel cells via gas adsorption

    Science.gov (United States)

    Watt-Smith, M. J.; Rigby, S. P.; Ralph, T. R.; Walsh, F. C.

    Porous carbon materials are typically used in both the substrate (typically carbon paper) and the electrocatalyst supports (often platinised carbon) within proton exchange membrane fuel cells. Gravimetric nitrogen adsorption has been studied at a carbon paper substrate, two different Pt-loaded carbon paper electrodes and three particulate carbon blacks. N 2 BET surface areas and surface fractal dimensions were determined using the fractal BET and Frenkel-Halsey-Hill models for all but one of the materials studied. The fractal dimensions of the carbon blacks obtained from gas adsorption were compared with those obtained independently by small angle X-ray scattering and showed good agreement. Density functional theory was used to characterise one of the carbon blacks, as the standard BET model was not applicable.

  1. Comparison of carbon materials as electrodes for enzyme electrocatalysis: hydrogenase as a case study.

    Science.gov (United States)

    Quinson, Jonathan; Hidalgo, Ricardo; Ash, Philip A; Dillon, Frank; Grobert, Nicole; Vincent, Kylie A

    2014-01-01

    We present a study of electrocatalysis by an enzyme adsorbed on a range of carbon materials, with different size, surface area, morphology and graphitic structure, which are either commercially available or prepared via simple, established protocols. We choose as our model enzyme the hydrogenase I from E. coli (Hyd-1), which is an active catalyst for H2 oxidation, is relatively robust and has been demonstrated in H2 fuel cells and H2-driven chemical synthesis. The carbon materials were characterised according to their surface area, surface morphology and graphitic character, and we use the electrocatalytic H2 oxidation current for Hyd-1 adsorbed on these materials to evaluate their effectiveness as enzyme electrodes. Here, we show that a variety of carbon materials are suitable for adsorbing hydrogenases in an electroactive configuration. This unified study provides insight into selection and design of carbon materials for study of redox enzymes and different applications of enzyme electrocatalysis.

  2. Synthesis of mesoporous carbon as electrode material for supercapacitor by modified template method

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jia-chang; LAI Chun-yan; DAI Yang; XIE Jing-ying

    2005-01-01

    The pore structures and electrochemical performances of mesoporous carbons prepared by silica sol template method as electrode material for supercapacitor were investigated. The mean pore size and mass specific capacitance of the mesoporous carbons increase with the increase of mass ratio of silica sol to carbon source (glucose). A modified template method, combining silica sol template method and ZnCl2 chemical activation method, was proposed to improve the mass specific capacitance of the mesoporous carbon with an improved BET surface area. The correlation of rate capability and pore structure was studied by constant current discharge and electrochemical impedance spectroscopy. A commercially available microporous carbon was used for comparison. The result shows that mesoporous carbon with a larger pore size displays a higher rate capability. Mesoporous carbon synthesized by modified template method has both high mass specific capacitance and good rate capability.

  3. Morphological and Electrochemical Properties of the Lactose-derived Carbon Electrode Materials

    Directory of Open Access Journals (Sweden)

    I.F. Myronyuk

    2016-11-01

    Full Text Available The article explores the morphological and electrochemical properties of carbon electrode materials derived from D-lactose by mixing of carbon precursor with activating reagent selected from a number КОН, K2CO3, ZnCl2, SnCl2∙2H2O, and calcining the composite mixture at 800 °С. After dissolution and removal of K2O, ZnO or SnO from volume of prototypes specific surface of carbon materials increases in 1,7-4,2 times, and electrical conductivity - in 1,4-2,8 times. The activating reagents for effective influence on the properties of carbon structures can be placed in the following order: ZnCl2  КОН  K2CO3  SnCl2∙2H2O. It is set that the highest specific capacity as an electrode material for supercapacitor has a sample with the highest electrical conductivity (78 Оhm – 1∙m – 1 obtained using KOH activating reagent. The electrode material capacity was 176-157 F∙g – 1 at discharge currents of 10-100 mA. It was found that the difference in the values of capacitance of prototypes caused by different chemical state of their surface.

  4. Morphological and Electrochemical Properties of the Lactose-derived Carbon Electrode Materials

    Directory of Open Access Journals (Sweden)

    I.F. Myronyuk

    2016-10-01

    Full Text Available The article explores the morphological and electrochemical properties of carbon electrode materials derived from D-lactose by mixing of carbon precursor with activating reagent selected from a number КОН, K2CO3, ZnCl2, SnCl2∙2H2O, and calcining the composite mixture at 800 °С. After dissolution and removal of K2O, ZnO or SnO from volume of prototypes specific surface of carbon materials increases in 1,7-4,2 times, and electrical conductivity - in 1,4-2,8 times. The activating reagents for effective influence on the properties of carbon structures can be placed in the following order: ZnCl2 > КОН > K2CO3 > SnCl2∙2H2O. It is set that the highest specific capacity as an electrode material for supercapacitor has a sample with the highest electrical conductivity (78 Оhm – 1∙m – 1 obtained using KOH activating reagent. The electrode material capacity was 176-157 F∙g – 1 at discharge currents of 10-100 mA. It was found that the difference in the values of capacitance of prototypes caused by different chemical state of their surface.

  5. CO2 Activated Carbon Aerogel with Enhanced Electrochemical Performance as a Supercapacitor Electrode Material.

    Science.gov (United States)

    Lee, Eo Jin; Lee, Yoon Jae; Kim, Jeong Kwon; Hong, Ung Gi; Yi, Jongheop; Yoon, Jung Rag; Song, In Kyu

    2015-11-01

    Carbon aerogel (CA) was prepared by a sol-gel polymerization of resorcinol and formaldehyde in ambient conditions. A series of activated carbon aerogels (ACA-X, X = 1, 2, 3, 4, 5, and 6 h) were then prepared by CO2 activation of CA with a variation of activation time (X) for use as an electrode material for supercapacitor. Specific capacitances of CA and ACA-X electrodes were measured by cyclic voltammetry and galvanostatic charge/discharge methods in 6 M KOH electrolyte. Among the samples, ACA-5 h showed the highest BET surface area (2574 m2/g) and the highest specific capacitance (100 F/g). It was found that CO2 activation was a very efficient method for enhancing physicochemical property and supercapacitive electrochemical performance of activated carbon aerogel.

  6. Influence of KOH activation techniques on pore structure and electrochemical property of carbon electrode materials

    Institute of Scientific and Technical Information of China (English)

    LI Jing; LI Jie; LAI Yan-qing; SONG Hai-sheng; ZHANG Zhi-an; LIU Ye-xiang

    2006-01-01

    Taking the selection of coal-tar pitch as precursor and KOH as activated agent, the activated carbon electrode material was fabricated for supercapacitor. The surface area and the pore structure of activated carbon were analyzed by Nitro adsorption method. The electrochemical properties of the activated carbons were determined using two-electrode capacitors in 6 mol/L KOH aqueous electrolytes. The influences of activated temperature and mass ratio ofKOH to C on the pore structure and electrochemical property of porous activated carbon were investigated in detail. The reasons for the changes of pore structure and electrochemical performance of activated carbon prepared under different conditions were also discussed theoretically. The results indicate that the maximum specific capacitance of 240 F/g can be obtained in alkaline medium, and the surface area, the pore structure and the specific capacitance of activated carbon depend on the treatment methods; the capacitance variation of activated carbon cannot be interpreted only by the change of surface area and pore structure, the lattice order and the electrolyte wetting effect of the activated carbon should also be taken into account.

  7. Layered double hydroxide materials coated carbon electrode: New challenge to future electrochemical power devices

    Energy Technology Data Exchange (ETDEWEB)

    Djebbi, Mohamed Amine, E-mail: mohamed.djebbi@etu.univ-lyon1.fr [Institut des Sciences Analytiques UMR CNRS 5280, Université Claude Bernard-Lyon 1, 5 rue de la Doua, 69100 Villeurbanne (France); Laboratoire de Physique des Matériaux Lamellaires et Nano-Matériaux Hybrides, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Bizerte (Tunisia); Braiek, Mohamed [Institut des Sciences Analytiques UMR CNRS 5280, Université Claude Bernard-Lyon 1, 5 rue de la Doua, 69100 Villeurbanne (France); Namour, Philippe [Institut des Sciences Analytiques UMR CNRS 5280, Université Claude Bernard-Lyon 1, 5 rue de la Doua, 69100 Villeurbanne (France); Irstea, 5 rue de la Doua, 69100 Villeurbanne (France); Ben Haj Amara, Abdesslem [Laboratoire de Physique des Matériaux Lamellaires et Nano-Matériaux Hybrides, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Bizerte (Tunisia); Jaffrezic-Renault, Nicole [Institut des Sciences Analytiques UMR CNRS 5280, Université Claude Bernard-Lyon 1, 5 rue de la Doua, 69100 Villeurbanne (France)

    2016-11-15

    Highlights: • MgAl and ZnAl LDH nanosheets were chemically synthesized and deposited over carbon electrode materials. • Catalytic performance of both LDHs was investigated for Fe(II) reduction reaction. • Satisfactory results have been achieved with the MgAl LDH material. • MgAl and ZnAl LDH modified carbon felt were applied in MFC as an efficient anode catalyst. • The LDH-modified anode significantly increased power performance of MFC. - Abstract: Layered double hydroxides (LDHs) have been widely used in the past years due to their unique physicochemical properties and promising applications in electroanalytical chemistry. The present paper is going to focus exclusively on magnesium-aluminum and zinc-aluminum layered double hydroxides (MgAl & ZnAl LDHs) in order to investigate the property and structure of active cation sites located within the layer structure. The MgAl and ZnAl LDH nanosheets were prepared by the constant pH co-precipitation method and uniformly supported on carbon-based electrode materials to fabricate an LDH electrode. Characterization by powder x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy revealed the LDH form and well-crystallized materials. Wetting surface properties (hydrophilicity and hydrophobicity) of both prepared LDHs were recorded by contact angle measurement show hydrophilic character and basic property. The electrochemical performance of these hybrid materials was investigated by mainly cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry techniques to identify the oxidation/reduction processes at the electrode/electrolyte interface and the effect of the divalent metal cations in total reactivity. The hierarchy of the modified electrode proves that the electronic conductivity of the bulk material is considerably dependent on the divalent cation and affects the limiting parameter of the overall redox process. However

  8. Electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    Amine, Khalil; Abouimrane, Ali; Belharouak, Ilias

    2017-01-31

    A process for forming a surface-treatment layer on an electroactive material includes heating the electroactive material and exposing the electroactive material to a reducing gas to form a surface-treatment layer on the electroactive material, where the surface-treatment layer is a layer of partial reduction of the electroactive material.

  9. Poly(ethylene terephthalate)-based carbons as electrode material in supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Domingo-Garcia, M.; Almazan-Almazan, M.C.; Lopez-Garzon, F.J. [Dpto de Quimica Inorganica, Facultad de Ciencias, 18071 Granada (Spain); Fernandez, J.A.; Centeno, T.A. [Instituto Nacional del Carbon-CSIC, Apartado 73, 33080 Oviedo (Spain); Stoeckli, F. [Physics Department, University of Neuchatel, Rue Emile Argand 11, CH-2009 Neuchatel (Switzerland)

    2010-06-15

    A systematic study by complementary techniques shows that PET-waste from plastic vessels is a competitive precursor of carbon electrodes for supercapacitors. PET derived-activated carbons follow the general trends observed for highly porous carbons and display specific capacitances at low current density as high as 197 F g{sup -1} in 2 M H{sub 2}SO{sub 4} aqueous electrolyte and 98 F g{sup -1} in the aprotic medium 1 M (C{sub 2}H{sub 5}){sub 4}NBF{sub 4}/acetonitrile. Additionally, high performance has also been achieved at high current densities, which confirms the potential of this type of materials for electrical energy storage. A new method based on the basic solvolysis of PET-waste and the subsequent carbonization seems to be an interesting alternative to obtain porous carbons with enhanced properties for supercapacitors. (author)

  10. Layered double hydroxide materials coated carbon electrode: New challenge to future electrochemical power devices

    Science.gov (United States)

    Djebbi, Mohamed Amine; Braiek, Mohamed; Namour, Philippe; Ben Haj Amara, Abdesslem; Jaffrezic-Renault, Nicole

    2016-11-01

    Layered double hydroxides (LDHs) have been widely used in the past years due to their unique physicochemical properties and promising applications in electroanalytical chemistry. The present paper is going to focus exclusively on magnesium-aluminum and zinc-aluminum layered double hydroxides (MgAl & ZnAl LDHs) in order to investigate the property and structure of active cation sites located within the layer structure. The MgAl and ZnAl LDH nanosheets were prepared by the constant pH co-precipitation method and uniformly supported on carbon-based electrode materials to fabricate an LDH electrode. Characterization by powder x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy revealed the LDH form and well-crystallized materials. Wetting surface properties (hydrophilicity and hydrophobicity) of both prepared LDHs were recorded by contact angle measurement show hydrophilic character and basic property. The electrochemical performance of these hybrid materials was investigated by mainly cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry techniques to identify the oxidation/reduction processes at the electrode/electrolyte interface and the effect of the divalent metal cations in total reactivity. The hierarchy of the modified electrode proves that the electronic conductivity of the bulk material is considerably dependent on the divalent cation and affects the limiting parameter of the overall redox process. However, MgAl LDH shows better performance than ZnAl LDH, due to the presence of magnesium cations in the layers. Following the structural, morphological and electrochemical behavior studies of both synthesized LDHs, the prepared LDH modified electrodes were tested through microbial fuel cell configuration, revealing a remarkable, potential new pathway for high-performance and cost-effective electrode use in electrochemical power devices.

  11. Studies on supercapacitor electrode material from activated lignin-derived mesoporous carbon.

    Science.gov (United States)

    Saha, Dipendu; Li, Yunchao; Bi, Zhonghe; Chen, Jihua; Keum, Jong K; Hensley, Dale K; Grappe, Hippolyte A; Meyer, Harry M; Dai, Sheng; Paranthaman, M Parans; Naskar, A K

    2014-01-28

    We synthesized mesoporous carbon from pre-cross-linked lignin gel impregnated with a surfactant as the pore-forming agent and then activated the carbon through physical and chemical methods to obtain activated mesoporous carbon. The activated mesoporous carbons exhibited 1.5- to 6-fold increases in porosity with a maximum Brunauer-Emmett-Teller (BET) specific surface area of 1148 m(2)/g and a pore volume of 1.0 cm(3)/g. Both physical and chemical activation enhanced the mesoporosity along with significant microporosity. Plots of cyclic voltammetric data with the capacitor electrode made from these carbons showed an almost rectangular curve depicting the behavior of ideal double-layer capacitance. Although the pristine mesoporous carbon exhibited a range of surface-area-based capacitance similar to that of other known carbon-based supercapacitors, activation decreased the surface-area-based specific capacitance and enhanced the gravimetric specific capacitance of the mesoporous carbons. A vertical tail in the lower-frequency domain of the Nyquist plot provided additional evidence of good supercapacitor behavior for the activated mesoporous carbons. We have modeled the equivalent circuit of the Nyquist plot with the help of two constant phase elements (CPE). Our work demonstrated that biomass-derived mesoporous carbon materials continue to show potential for use in specific electrochemical applications.

  12. Studies on Supercapacitor Electrode Material from Activated Lignin-Derived Mesoporous Carbon

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Dipendu [ORNL; Li, Yunchao [ORNL; Bi, Zhonghe [ORNL; Chen, Jihua [ORNL; Keum, Jong Kahk [ORNL; Hensley, Dale K [ORNL; Grappe, Hippolyte A. [Oak Ridge Institute for Science and Education (ORISE); Meyer III, Harry M [ORNL; Dai, Sheng [ORNL; Paranthaman, Mariappan Parans [ORNL; Naskar, Amit K [ORNL

    2014-01-01

    We synthesized mesoporous carbon from pre-cross-linked lignin gel impregnated with a surfactant as the pore-forming agent, and then activated the carbon through physical and chemical methods to obtain activated mesoporous carbon. The activated mesoporous carbons exhibited 1.5- to 6-fold increases in porosity with a maximum BET specific surface area of 1148 m2/g and a pore volume of 1.0 cm3/g. Slow physical activation helped retain dominant mesoporosity; however, aggressive chemical activation caused some loss of the mesopore volume fraction. Plots of cyclic voltammetric data with the capacitor electrode made from these carbons showed an almost rectangular curve depicting the behavior of ideal double-layer capacitance. Although the pristine mesoporous carbon exhibited the same range of surface-area-based capacitance as that of other known carbon-based supercapacitors, activation decreased the surface-area-based specific capacitance and increased the gravimetric-specific capacitance of the mesoporous carbons. Surface activation lowered bulk density and electrical conductivity. Warburg impedance as a vertical tail in the lower frequency domain of Nyquist plots supported good supercapacitor behavior for the activated mesoporous carbons. Our work demonstrated that biomass-derived mesoporous carbon materials continue to show potential for use in specific electrochemical applications.

  13. Influence of carbon electrode material on energy recovery from winery wastewater using a dual-chamber microbial fuel cell.

    Science.gov (United States)

    Penteado, Eduardo D; Fernandez-Marchante, Carmen M; Zaiat, Marcelo; Gonzalez, Ernesto R; Rodrigo, Manuel A

    2017-06-01

    The aim of this work was to evaluate three carbon materials as anodes in microbial fuel cells (MFCs), clarifying their influence on the generation of electricity and on the treatability of winery wastewater, a highly organic-loaded waste. The electrode materials tested were carbon felt, carbon cloth and carbon paper and they were used at the same time as anode and cathode in the tests. The MFC equipped with carbon felt reached the highest voltage and power (72 mV and 420 mW m(-2), respectively), while the lowest values were observed when carbon paper was used as electrode (0.2 mV and 8.37·10(-6) mW m(-2), respectively). Chemical oxygen demand (COD) removal from the wastewater was observed to depend on the electrode material, as well. When carbon felt was used, the MFC showed the highest average organic matter consumption rate (650 mg COD L(-1) d(-1)), whereas by using carbon paper the rate decreased to 270 mg COD L(-1) d(-1). Therefore, both electricity generation and organic matter removal are strongly related not to the chemical composition of the electrode (which was graphite carbon in the three electrodes), but to its surface features and, consequently, to the amount of biomass adhered to the electrode surface.

  14. Improved Manufacturing Performance of Screen Printed Carbon Electrodes through Material Formulation.

    Science.gov (United States)

    Jewell, Eifion; Philip, Bruce; Greenwood, Peter

    2016-06-27

    Printed carbon graphite materials are the primary common component in the majority of screen printed sensors. Screen printing allows a scalable manufacturing solution, accelerating the means by which novel sensing materials can make the transition from laboratory material to commercial product. A common bottleneck in any thick film printing process is the controlled drying of the carbon paste material. A study has been undertaken which examines the interaction between material solvent, printed film conductivity and process consistency. The study illustrates that it is possible to reduce the solvent boiling point to significantly increase process productivity while maintaining process consistency. The lower boiling point solvent also has a beneficial effect on the conductivity of the film, reducing the sheet resistance. It is proposed that this is a result of greater film stressing increasing charge percolation through greater inter particle contact. Simulations of material performance and drying illustrate that a multi layered printing provides a more time efficient manufacturing method. The findings have implications for the volume manufacturing of the carbon sensor electrodes but also have implications for other applications where conductive carbon is used, such as electrical circuits and photovoltaic devices.

  15. Improved Manufacturing Performance of Screen Printed Carbon Electrodes through Material Formulation

    Directory of Open Access Journals (Sweden)

    Eifion Jewell

    2016-06-01

    Full Text Available Printed carbon graphite materials are the primary common component in the majority of screen printed sensors. Screen printing allows a scalable manufacturing solution, accelerating the means by which novel sensing materials can make the transition from laboratory material to commercial product. A common bottleneck in any thick film printing process is the controlled drying of the carbon paste material. A study has been undertaken which examines the interaction between material solvent, printed film conductivity and process consistency. The study illustrates that it is possible to reduce the solvent boiling point to significantly increase process productivity while maintaining process consistency. The lower boiling point solvent also has a beneficial effect on the conductivity of the film, reducing the sheet resistance. It is proposed that this is a result of greater film stressing increasing charge percolation through greater inter particle contact. Simulations of material performance and drying illustrate that a multi layered printing provides a more time efficient manufacturing method. The findings have implications for the volume manufacturing of the carbon sensor electrodes but also have implications for other applications where conductive carbon is used, such as electrical circuits and photovoltaic devices.

  16. High-Performance Supercapacitor Electrode Materials from Cellulose-Derived Carbon Nanofibers.

    Science.gov (United States)

    Cai, Jie; Niu, Haitao; Li, Zhenyu; Du, Yong; Cizek, Pavel; Xie, Zongli; Xiong, Hanguo; Lin, Tong

    2015-07-15

    Nitrogen-functionalized carbon nanofibers (N-CNFs) were prepared by carbonizing polypyrrole (PPy)-coated cellulose NFs, which were obtained by electrospinning, deacetylation of electrospun cellulose acetate NFs, and PPy polymerization. Supercapacitor electrodes prepared from N-CNFs and a mixture of N-CNFs and Ni(OH)2 showed specific capacitances of ∼236 and ∼1045 F g(-1), respectively. An asymmetric supercapacitor was further fabricated using N-CNFs/Ni(OH)2 and N-CNFs as positive and negative electrodes. The supercapacitor device had a working voltage of 1.6 V in aqueous KOH solution (6.0 M) with an energy density as high as ∼51 (W h) kg(-1) and a maximum power density of ∼117 kW kg(-1). The device had excellent cycle lifetime, which retained ∼84% specific capacitance after 5000 cycles of cyclic voltammetry scans. N-CNFs derived from electrospun cellulose may be useful as an electrode material for development of high-performance supercapacitors and other energy storage devices.

  17. FUEL CELL ELECTRODE MATERIALS

    Science.gov (United States)

    FUEL CELL ELECTRODE MATERIALS. RAW MATERIAL SELECTION INFLUENCES POLARIZATION BUT IS NOT A SINGLE CONTROLLING FACTOR. AVAILABLE...DATA INDICATES THAT AN INTERRELATIONSHIP OF POROSITY, AVERAGE PORE VOLUME, AND PERMEABILITY CONTRIBUTES TO ELECTRODE FUEL CELL BEHAVIOR.

  18. Impedance spectroscopic analysis of composite electrode from activated carbon/conductive materials/ruthenium oxide for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Taer, E.; Awitdrus,; Farma, R. [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Department of Physics, Faculty of Mathematics and Natural Sciences, University of Riau, 28293 Pekanbaru, Riau (Indonesia); Deraman, M., E-mail: madra@ukm.my; Talib, I. A.; Ishak, M. M.; Omar, R.; Dolah, B. N. M.; Basri, N. H.; Othman, M. A. R. [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Kanwal, S. [ICCBS, H.E.J. Research Institute of Chemistry, University of Karachi, 75270 Karachi (Pakistan)

    2015-04-16

    Activated carbon powders (ACP) were produced from the KOH treated pre-carbonized rubber wood sawdust. Different conductive materials (graphite, carbon black and carbon nanotubes (CNTs)) were added with a binder (polivinylidene fluoride (PVDF)) into ACP to improve the supercapacitive performance of the activated carbon (AC) electrodes. Symmetric supercapacitor cells, fabricated using these AC electrodes and 1 molar H{sub 2}SO{sub 4} electrolyte, were analyzed using a standard electrochemical impedance spectroscopy technique. The addition of graphite, carbon black and CNTs was found effective in reducing the cell resistance from 165 to 68, 23 and 49 Ohm respectively, and increasing the specific capacitance of the AC electrodes from 3 to 7, 17, 32 F g{sup −1} respectively. Since the addition of CNTs can produce the highest specific capacitance, CNTs were chosen as a conductive material to produce AC composite electrodes that were added with 2.5 %, 5 % and 10 % (by weight) electro-active material namely ruthenium oxide; PVDF binder and CNTs contents were kept at 5 % by weight in each AC composite produced. The highest specific capacitance of the cells obtained in this study was 86 F g{sup −1}, i.e. for the cell with the resistance of 15 Ohm and composite electrode consists of 5 % ruthenium oxide.

  19. Incorporating conjugated carbonyl compounds into carbon nanomaterials as electrode materials for electrochemical energy storage.

    Science.gov (United States)

    Yang, Guanhui; Zhang, Yu; Huang, Yanshan; Shakir, Muhammad Imran; Xu, Yuxi

    2016-11-23

    The increasing demand for energy and growing concerns for environmental issues are promoting the development of organic electrode materials. Among these, conjugated carbonyl compounds (CCCs) represent one of the most attractive and promising candidates for sustainable and eco-benign energy storage devices in the coming future. However, most of the current compounds suffer from dissolution in organic electrolytes and low electronic conductivity, which result in severe capacity decay and poor rate performance. Recently, researchers have achieved considerable progress by introducing electroactive carbonyl compounds into carbon nanomaterials. This perspective provides an overview of the up-to-date development of these nanocomposites in metal ion batteries (lithium-ion batteries or sodium-ion batteries) and supercapacitors (SCs), including the synthesis, performance improvement and applications. We mainly focus on carbon nanotubes (CNTs), graphene and mesoporous carbon (MC) as carbon nanomaterials because of their high specific surface area, good conductivity, electrochemical stability and favourable interaction with conjugated carbonyl compounds. This strategy opens up new possibilities to realize cost-effective, sustainable and versatile energy storage devices.

  20. Development of Novel Metal Hydride-Carbon Nanomaterial Based Nanocomposites as Anode Electrode Materials for Lithium Ion Battery

    Science.gov (United States)

    2014-06-30

    Final Progress Report (27-02-2012 To 26-02-2014) Project Title:- Development of novel metal hydride -carbon nanomaterial based nanocomposites as...anode electrode materials for Lithium ion battery Objectives:- The aim of this study is to develop metal hydride –carbon nanomaterial based...be as follows:- Milestone I • Synthesis of nanosized metal hydrides (NMH)-carbon nanotubes (CNT) hybridizing with G (NMH- CNT-G) nanocomposites

  1. Polyaniline nanofiber/large mesoporous carbon composites as electrode materials for supercapacitors

    Science.gov (United States)

    Liu, Huan; Xu, Bin; Jia, Mengqiu; Zhang, Mei; Cao, Bin; Zhao, Xiaonan; Wang, Yu

    2015-03-01

    A composite of polyaniline nanofiber/large mesoporous carbon (PANI-F/LMC) hybrid was prepared by an in situ chemical oxidative polymerization of aniline monomer with nano-CaCO3 templated LMC as host matrix for supercapacitors. The morphology, composition and electronic structure of the composites (PANI-F/LMC) together with pure PANI nanofibers and the LMC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found that the PANI nanofibers were incorporated into the large mesochannels of LMC with interpenetrating framework formed. Such unique structure endows the PANI-F/LMC composite with a high capacitance of 473 F g-1 at a current load of 0.1 A g-1 with good rate performance and cycling stability, suggesting its potential application in the electrode material for supercapacitors.

  2. Polyaniline nanofiber/large mesoporous carbon composites as electrode materials for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Huan; Xu, Bin; Jia, Mengqiu, E-mail: jiamq@mail.buct.edu.cn; Zhang, Mei; Cao, Bin; Zhao, Xiaonan; Wang, Yu

    2015-03-30

    Highlights: • The composites of polyaniline nanofiber and large mesoporous carbon were prepared for supercapacitors. • The large mesoporous carbons were simply prepared by nano-CaCO{sub 3} template method. • The composites exhibit high capacitance and good rate capability and cycle stability. - Abstract: A composite of polyaniline nanofiber/large mesoporous carbon (PANI-F/LMC) hybrid was prepared by an in situ chemical oxidative polymerization of aniline monomer with nano-CaCO{sub 3} templated LMC as host matrix for supercapacitors. The morphology, composition and electronic structure of the composites (PANI-F/LMC) together with pure PANI nanofibers and the LMC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found that the PANI nanofibers were incorporated into the large mesochannels of LMC with interpenetrating framework formed. Such unique structure endows the PANI-F/LMC composite with a high capacitance of 473 F g{sup −1} at a current load of 0.1 A g{sup −1} with good rate performance and cycling stability, suggesting its potential application in the electrode material for supercapacitors.

  3. Impedance spectroscopy study of a catechol-modified activated carbon electrode as active material in electrochemical capacitor

    Science.gov (United States)

    Cougnon, C.; Lebègue, E.; Pognon, G.

    2015-01-01

    Modified activated carbon (Norit S-50) electrodes with electrochemical double layer (EDL) capacitance and redox capacitance contributions to the electric charge storage were tested in 1 M H2SO4 to quantify the benefit and the limitation of the surface redox reactions on the electrochemical performances of the resulting pseudo-capacitive materials. The electrochemical performances of an electrochemically anodized carbon electrode and a catechol-modified carbon electrode, which make use both EDL capacitance of the porous structure of the carbon and redox capacitance, were compared to the performances obtained for the pristine carbon. Nitrogen gas adsorption measurements have been used for studying the impact of the grafting on the BET surface area, pore size distribution, pore volume and average pore diameter. The electrochemical behavior of carbon materials was studied by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The EIS data were discussed by using a complex capacitance model that allows defining the characteristic time constant, the global capacitance and the frequency at which the maximum charge stored is reached. The EIS measurements were achieved at different dc potential values where a redox activity occurs and the evolution of the capacitance and the capacitive relaxation time with the electrode potential are presented. Realistic galvanostatic charge/discharge measurements performed at different current rates corroborate the results obtained by impedance.

  4. Transition metal doped poly(aniline-co-pyrrole)/multi-walled carbon nanotubes nanocomposite for high performance supercapacitor electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    Dhibar, Saptarshi; Bhattacharya, Pallab; Hatui, Goutam; Das, C.K., E-mail: chapal12@yahoo.co.in

    2015-03-15

    Highlights: • The CuCl{sub 2} doped copolymer (PANI and PPy)/MWCNTs nanocomposite was prepared. • The nanocomposite achieved highest specific capacitance of 383 F/g at a 0.5 A/g. • Nanocomposite exhibits better energy density as well as power density. • The nanocomposite also showed better electrical conductivity at room temperature. • The nanocomposite can be used as promising electrode materials for supercapacitor. - Abstract: In this present communication, copolymer of polyaniline (PANI) and polypyrrole (PPy) that is poly(aniline-co-pyrrole) [poly(An-co-Py)], copper chloride (CuCl{sub 2}) doped poly(aniline-co-pyrrole) [poly(An-co-Py) Cu], and CuCl{sub 2} doped poly(aniline-co-pyrrole)/multi walled carbon nanotubes (MWCNTs) [poly(An-co-Py) Cu CNT] nanocomposite have been prepared by a simple and inexpensive in-situ chemical oxidative polymerization method, using ammonium persulfate (APS) as oxidant and hydrochloric acid (HCl) as dopant and investigated as high performance supercapacitor electrode materials. The possible interaction between CuCl{sub 2} with copolymers and MWCNTs was investigated by Fourier transform infrared spectroscopy (FTIR) and UV–visible spectroscopy analysis. The morphological characteristic of all the electrode materials were analyzed by Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) study. The electrochemical characterizations of all the electrode materials were carried out by three electrode probe method where, standard calomel electrode and platinum were used as reference and counter electrodes, respectively. Among all the electrode materials, poly(An-co-Py) Cu CNT nanocomposite achieved highest specific capacitance value of 383 F/g at 0.5 A/g scan rate. The nanocomposite showed better electrical conductivity at room temperature and also attained nonlinear current–voltage characteristic. Based on the superior electrochemical as well as other properties the as prepared

  5. Hybrid Multi-Walled Carbon Nanotube TiO2 Electrode Material for Next Generation Energy Storage Devices

    CERN Document Server

    Marler, Sydney

    2016-01-01

    Current supercapacitors present several distinct limitations that severely inhibit the efficiency, power, and electrical capacitance of energy storage devices. Supercapacitors present an exciting prospect that has countless applications in renewable energy storage and modern day electronic devices. In recent years the exciting development of carbon nanotubes (CNTs) has presented an advantage in electrode development. CNTs, however beneficial for their increased electrode surface area, have severe limitations regarding conductivity and electrode density. Creating a nanocomposite hybrid out of a transition metal-oxide and carbon nanotube array would help the current limitations of the modern supercapacitor. TiO2 was chosen for its common occurrence in everyday materials and promising capacitance levels. A multi-walled carbon nanotube array was grown on a SiO2 precursor via CCVD. The transition metal oxide was then deposited via RF Sputtering methods to a MWCNT array. Recharge tests and characterization were con...

  6. The Production and Characterization of Ceramic Carbon Electrode Materials for CuCl-HCl Electrolysis

    Science.gov (United States)

    Edge, Patrick

    Current H2 gas supplies are primarily produced through steam methane reforming and other fossil fuel based processes. This lack of viable large scale and environmentally friendly H2 gas production has hindered the wide spread adoption of H2 fuel cells. A potential solution to this problem is the Cu-Cl hybrid thermochemical cycle. The cycle captures waste heat to drive two thermochemical steps creating CuCl as well as O2 gas and HCl from CuCl2 and water. The CuCl is oxidized in HCl to produce H2 gas and regenerate CuCl2, this process occurs at potentials well below those required for water electrolysis. The electrolysis process occurs in a traditional PEM fuel-cell. In the aqueous anolyte media Cu(I) will form anionic complexes such as CuCl 2 - or CuCl32-. The slow transport of these species to the anode surface limits the overall electrolysis process. To improve this transport process we have produced ceramic carbon electrode (CCE) materials through a sol-gel method incorporating a selection of amine containing silanes with increasing numbers of primary and secondary amines. When protonated these amines allow for improved transport of anionic copper complexes. The electrochemical and physical characterization of these CCE materials in a half and full-cell electrolysis environment will be presented. Electrochemical analysis was performed using cell polarization, cyclic voltammetry, and electrochemical impedance spectroscopy.

  7. Preparation and Electrochemistry of Hydrous Ruthenium Oxide/Active Carbon Electrode materials for Supercapacitor

    Institute of Scientific and Technical Information of China (English)

    Zhang; Jianrong

    2001-01-01

    In this paper, we reported a new method to directly prepare the amorphous hydrous ruthenium oxide/active carbon powders. The relationship between the specific capacitance and ruthenium content in powders was studied in detail. Physical properties of the powders such as crystallinity、 particle size, and electrochemical characteristics of electrodes were reported along with the capacitor performance.  ……

  8. Preparation and Electrochemistry of Hydrous Ruthenium Oxide/Active Carbon Electrode materials for Supercapacitor

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ In this paper, we reported a new method to directly prepare the amorphous hydrous ruthenium oxide/active carbon powders. The relationship between the specific capacitance and ruthenium content in powders was studied in detail. Physical properties of the powders such as crystallinity、 particle size, and electrochemical characteristics of electrodes were reported along with the capacitor performance.

  9. Impulse space charge and dielectric characteristics of an Al2O3 nanoparticle suspension in propylene carbonate using various electrode materials

    Directory of Open Access Journals (Sweden)

    Qing Yang

    2016-09-01

    Full Text Available We tested the impulse breakdown voltage of Al2O3 “nano-modified” propylene carbonate between different electrode materials. At any given concentration, the breakdown voltage was highest with stainless steel electrodes, followed by copper, and then aluminum. The space charge and electric field distributions were measured too. Results show that less space charge was injected by the electrodes, and the electric field was less distorted, than in pure propylene carbonate. However, the hoped-for reduction of the influence of the electrodes did not take place. Substantial differences in the space charge density and electric field distortion remained between the different electrode materials.

  10. Porous carbon with a large surface area and an ultrahigh carbon purity via templating carbonization coupling with KOH activation as excellent supercapacitor electrode materials

    Science.gov (United States)

    Sun, Fei; Gao, Jihui; Liu, Xin; Pi, Xinxin; Yang, Yuqi; Wu, Shaohua

    2016-11-01

    Large surface area and good structural stability, for porous carbons, are two crucial requirements to enable the constructed supercapacitors with high capacitance and long cycling lifespan. Herein, we successfully prepare porous carbon with a large surface area (3175 m2 g-1) and an ultrahigh carbon purity (carbon atom ratio of 98.25%) via templating carbonization coupling with KOH activation. As-synthesized MTC-KOH exhibits excellent performances as supercapacitor electrode materials in terms of high specific capacitance and ultrahigh cycling stability. In a three electrode system, MTC-KOH delivers a high capacitance of 275 F g-1 at 0.5 A g-1 and still 120 F g-1 at a high rate of 30 A g-1. There is almost no capacitance decay even after 10,000 cycles, demonstrating outstanding cycling stability. In comparison, pre-activated MTC with a hierarchical pore structure shows a better rate capability than microporous MTC-KOH. Moreover, the constructed symmetric supercapacitor using MTC-KOH can achieve high energy densities of 8.68 Wh kg-1 and 4.03 Wh kg-1 with the corresponding power densities of 108 W kg-1 and 6.49 kW kg-1, respectively. Our work provides a simple design strategy to prepare highly porous carbons with high carbon purity for supercapacitors application.

  11. B4C as a stable non-carbon-based oxygen electrode material for lithium-oxygen batteries

    Energy Technology Data Exchange (ETDEWEB)

    Song, Shidong; Xu, Wu; Cao, Ruiguo; Luo, Langli; Engelhard, Mark H.; Bowden, Mark E.; Liu, Bin; Estevez, Luis; Wang, Chong-Min; Zhang, Ji-Guang

    2017-01-19

    Lithium-oxygen (Li-O2) batteries have extremely high theoretical specific capacities and energy densities when compared with Li-ion batteries. However, the instability of both electrolyte and carbon-based oxygen electrode related to the nucleophilic attack of reduced oxygen species during oxygen reduction reaction and the electrochemical oxidation during oxygen evolution reaction are recognized as the major challenges in this field. Here we report the application of boron carbide (B4C) as the non-carbon based oxygen electrode material for aprotic Li-O2 batteries. B4C has high resistance to chemical attack, good conductivity, excellent catalytic activity and low density that are suitable for battery applications. The electrochemical activity and chemical stability of B4C are systematically investigated in aprotic electrolyte. Li-O2 cells using B4C based air electrodes exhibit better cycling stability than those used TiC based air electrode in 1 M LiTf-Tetraglyme electrolyte. The degradation of B4C based electrode is mainly due to be the loss of active sites on B4C electrode during cycles as identified by the structure and composition characterizations. These results clearly demonstrate that B4C is a very promising alternative oxygen electrode material for aprotic Li-O2 batteries. It can also be used as a standard electrode to investigate the stability of electrolytes.

  12. Polyaniline integrated carbon nanohorn: A superior electrode materials for advanced energy storage

    Directory of Open Access Journals (Sweden)

    S. Maiti

    2014-12-01

    Full Text Available Fiber-like polyaniline (PANI/carbon nanohorn (CNH composites (PACN composites were prepared as electrode materials for supercapacitor by simple method that involves in-situ polymerization of aniline in the presence of CNH in acidic (HCl medium with noteworthy electrochemical performances. Thus, the prepared PACN composites show high specific capacitance value of ≈ 834 F/g at 5 mV/s scan rate compared to ≈ 231 F/g for pure PANI and CNH (≈ 145 F/g at same scan rate of 5 mV/s. CNHs are homogeneously dispersed throughout the matrix and coated successfully. Thus, it provides more active sites for nucleation and electron transfer path. In addition, the composites show high electrical conductivity in the order of ≈ 6.7•10–2 S•cm–1 which indicates the formation of continuous interconnected conducting network path in the PACN composites. Morphological study of the PACN composites was carried out by high resolution transmission electron microscopy (HRTEM and field emission scanning electron microscopy (FESEM.

  13. Fractals in several electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chunyong, E-mail: zhangchy@njau.edu.cn [Department of Chemistry, College of Science, Nanjing Agricultural University, Nanjing 210095 (China); Suzhou Key Laboratory of Environment and Biosafety, Suzhou Academy of Southeast University, Dushuhu lake higher education town, Suzhou 215123 (China); Wu, Jingyu [Department of Chemistry, College of Science, Nanjing Agricultural University, Nanjing 210095 (China); Fu, Degang [Suzhou Key Laboratory of Environment and Biosafety, Suzhou Academy of Southeast University, Dushuhu lake higher education town, Suzhou 215123 (China); State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096 (China)

    2014-09-15

    Highlights: • Fractal geometry was employed to characterize three important electrode materials. • The surfaces of all studied electrodes were proved to be very rough. • The fractal dimensions of BDD and ACF were scale dependent. • MMO film was more uniform than BDD and ACF in terms of fractal structures. - Abstract: In the present paper, the fractal properties of boron-doped diamond (BDD), mixed metal oxide (MMO) and activated carbon fiber (ACF) electrode have been studied by SEM imaging at different scales. Three materials are self-similar with mean fractal dimension in the range of 2.6–2.8, confirming that they all exhibit very rough surfaces. Specifically, it is found that MMO film is more uniform in terms of fractal structure than BDD and ACF. As a result, the intriguing characteristics make these electrodes as ideal candidates for high-performance decontamination processes.

  14. Nanostructured TiO2-coated activated carbon composite as an electrode material for asymmetric hybrid capacitors.

    Science.gov (United States)

    Kim, Sang-Ok; Lee, Joong Kee

    2012-02-01

    A nanostructured TiO2-coated activated carbon (TAC) composite was synthesized by a modified sol-gel reaction and employed it as a negative electrode active material for an asymmetric hybrid capacitor. The structural characterization showed that the TiO2 nano-layer was deposited on the surface of the activated carbon and the TAC composite has a highly mesoporous structure. The evaluation of electrochemical characteristics of the TAC electrode was carried out by galvanostatic charge/discharge cycling tests and electrochemical impedance spectroscopy. The obtained specific capacitance of the TAC composite was 42.87 F/g, which showed by 27.1% higher than that of the activated carbon (AC). The TAC composite also exhibited an excellent cycle performance and kept 95% of initial capacitance over 500 cycles.

  15. Amorphous carbon nitride as an alternative electrode material in electroanalysis: Simultaneous determination of dopamine and ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Roberta A., E-mail: roantigo@hotmail.com [Departamento de Química, Universidade Federal de São Carlos, C.P. 676, 13560-970 São Carlos, SP (Brazil); Matos, Roberto [Departamento de Química, Universidade Federal de São Carlos, C.P. 676, 13560-970 São Carlos, SP (Brazil); Benchikh, Abdelkader [LECVE, Faculté de la Technologie, Département de Génie des Procédés, Université Abderrahmane MIRA, Béjaïa (Algeria); LISE UPR 15 du CNRS, Université Pierre et Marie Curie, 4, Place Jussieu, 75005 Paris (France); Saidani, Boualem [LECVE, Faculté de la Technologie, Département de Génie des Procédés, Université Abderrahmane MIRA, Béjaïa (Algeria); Debiemme-Chouvy, Catherine [LISE UPR 15 du CNRS, Université Pierre et Marie Curie, 4, Place Jussieu, 75005 Paris (France); Deslouis, Claude, E-mail: claude.deslouis@upmc.fr [LISE UPR 15 du CNRS, Université Pierre et Marie Curie, 4, Place Jussieu, 75005 Paris (France); Rocha-Filho, Romeu C.; Fatibello-Filho, Orlando [Departamento de Química, Universidade Federal de São Carlos, C.P. 676, 13560-970 São Carlos, SP (Brazil)

    2013-10-03

    Graphical abstract: -- Highlights: •a-CN{sub x} films are a new class of electrodic carbon materials that present several properties similar to those of BDD films. •a-CN{sub x} and BDD were used as working electrodes for simultaneous determination of DA and AA. •Electrochemical pretreatments on a-CN{sub x} or BDD modified the nature of the surface terminations. •An anodic pretreatment in 0.1 mol L{sup −1} KOH was necessary to attain an adequate separation of the DA and AA oxidation potential peaks. •For the first time in the literature, the use of an a-CN{sub x} electrode in a complete electroanalytical procedure is reported. -- Abstract: Boron-doped diamond (BDD) films are excellent electrode materials, whose electrochemical activity for some analytes can be tuned by controlling their surface termination, most commonly either to predominantly hydrogen or oxygen. This tuning can be accomplished by e.g. suitable cathodic or anodic electrochemical pretreatments. Recently, it has been shown that amorphous carbon nitride (a-CN{sub x}) films may present electrochemical characteristics similar to those of BDD, including the influence of surface termination on their electrochemical activity toward some analytes. In this work, we report for the first time a complete electroanalytical method using an a-CN{sub x} electrode. Thus, an a-CN{sub x} film deposited on a stainless steel foil by DC magnetron sputtering is proposed as an alternative electrode for the simultaneous determination of dopamine (DA) and ascorbic acid (AA) in synthetic biological samples by square-wave voltammetry. The obtained results are compared with those attained using a BDD electrode. For both electrodes, a same anodic pretreatment in 0.1 mol L{sup −1} KOH was necessary to attain an adequate and equivalent separation of the DA and AA oxidation potential peaks of about 330 mV. The detection limits obtained for the simultaneous determination of these analytes using the a-CN{sub x

  16. Hierarchically ordered mesoporous carbon/graphene composites as supercapacitor electrode materials.

    Science.gov (United States)

    Song, Yanjie; Li, Zhu; Guo, Kunkun; Shao, Ting

    2016-08-25

    Hierarchically ordered mesoporous carbon/graphene (OMC/G) composites have been fabricated by means of a solvent-evaporation-induced self-assembly (EISA) method. The structures of these composites are characterized by X-ray diffraction, transmission electron microscopy, Raman spectroscopy and nitrogen adsorption-desorption at 77 K. These results indicate that OMC/G composites possess the hierarchically ordered hexagonal p6mm mesostructure with the lattice unit parameter and pore diameter close to 10 nm and 3 nm, respectively. The specific surface area of OMC/G composites after KOH activation is high up to 2109.2 m(2) g(-1), which is significantly greater than OMC after activation (1474.6 m(2) g(-1)). Subsequently, the resulting OMC/G composites as supercapacitor electrode materials exhibit an outstanding capacitance as high as 329.5 F g(-1) in 6 M KOH electrolyte at a current density of 0.5 A g(-1), which is much higher than both OMC (234.2 F g(-1)) and a sample made by mechanical mixing of OMC with graphene (217.7 F g(-1)). In addition, the obtained OMC/G composites display good cyclic stability, and the final capacitance retention is approximately 96% after 5000 cycles. These ordered mesopores in the OMC/G composites are beneficial to the accessibility and rapid diffusion of the electrolyte, while graphene in OMC/G composites can also facilitate the transport of electrons during the processes of charging and discharging owing to its high conductivity, thereby leading to an excellent energy storage performance. The method demonstrated in this work would open up a new route to design and develop graphene-based architectures for supercapacitor applications.

  17. Cerium oxide nanoparticles/multi-wall carbon nanotubes composites: Facile synthesis and electrochemical performances as supercapacitor electrode materials

    Science.gov (United States)

    Deng, Dongyang; Chen, Nan; Li, Yuxiu; Xing, Xinxin; Liu, Xu; Xiao, Xuechun; Wang, Yude

    2017-02-01

    Cerium oxide nanoparticles/multi-wall carbon nanotubes (MWCNTs) composites are synthesized by a facile hydrothermal method without any surfactant or template. The morphology and microstructure of samples are examined by scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray diffraction (XRD), Raman spectrum and X-ray photoelectron spectroscopy (XPS). Electrochemical properties of the MWCNTs, the pure CeO2, and the CeO2/MWCNTs nanocomposites electrodes are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge (GDC) and electrochemical impedance spectroscopy (EIS) measurements. The CeO2/MWCNTs nanocomposite (at the mole ratio of 1:1) electrode exhibits much larger specific capacitance compared with both the MWCNTs electrode and the pure CeO2 electrode and significantly improves cycling stability compared to the pure CeO2 electrode. The CeO2/MWCNTs nanocomposite (at the mole ratio of 1:1) achieves a specific capacitance of 455.6 F g-1 at the current density of 1 A g-1. Therefore, the as prepared CeO2/MWCNTs nanocomposite is a promising electrode material for high-performance supercapacitors.

  18. Capacitor with a composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, S.T.; Pekala, R.W.; Kaschmitter, J.L.

    1999-04-27

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy. 1 fig.

  19. Capacitor with a composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Steven T. (San Leandro, CA); Pekala, Richard W. (Pleasant Hill, CA); Kaschmitter, James L. (Pleasanton, CA)

    1999-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid partides being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy.

  20. Oxygen-rich hierarchical porous carbon made from pomelo peel fiber as electrode material for supercapacitor

    Science.gov (United States)

    Li, Jing; Liu, Wenlong; Xiao, Dan; Wang, Xinhui

    2017-09-01

    Oxygen-rich hierarchical porous carbon has been fabricated using pomelo peel fiber as a carbon source via an improved KOH activation method. The morphology and chemical composition of the obtained carbon materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), electron microscopy (EM), Raman spectra and elemental analysis. The unique porous structure with abundant oxygen functional groups is favorable to capacitive behavior, and the as-prepared carbon material exhibits high specific capacitance of 222.6 F g-1 at 0.5 A g-1 in 6 M KOH and superior stability over 5000 cycles. This work not only describes a simple way to prepare high-performance carbon material from the discarded pomelo peel, but also provides a strategy for its disposal issue and contributes to the environmental improvement.

  1. Hemi-ordered nanoporous carbon electrode material for highly selective determination of nitrite in physiological and environmental systems

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shenghai; Wu, Hongmin; Wu, Ying; Shi, Hongyan; Feng, Xun; Jiang, Shang; Chen, Jian; Song, Wenbo, E-mail: wbsong@jlu.edu.cn

    2014-08-01

    Hemi-ordered nanoporous carbon (HONC) was obtained from a mesoporous silica template through a nano-replication method using furfuryl alcohol as the carbon source. The structure and morphology of HONC were characterized and analyzed in detail by X-ray diffraction, N{sub 2}-sorption, Raman spectroscopy and transmission electron microscopy. HONC was then demonstrated as active electrode material for selective determination of nitrite in either physiological or environmental system. Well separated oxidation peaks of ascorbic acid, dopamine, uric acid and nitrite were observed in physiological system, and simultaneous discrimination of catechol, hydroquinone, resorcinol and nitrite in environmental system was also accomplished. Distinctly improved performances for selective determination of nitrite (such as significantly fast and sensitive current response with especially high selectivity) coexisted with ascorbic acid, dopamine and uric acid in the physiological system, as well as with catechol, hydroquinone and resorcinol in the environmental system were achieved at HONC electrode material. The excellent discriminating ability and high selectivity for NO{sub 2}{sup −} determination were ascribed to the good electronic conductivity, unique hemi-ordered porous structure, large surface area and large number of edge plane defect sites contained on the surface of nanopore walls of HONC. Results in this work demonstrated that HONC is one of the promising catalytic electrode materials for nitrite sensor fabrication. - Highlights: • Hemi-ordered nanoporous carbon as an active electrode material • Good discriminating ability towards NO{sub 2}{sup −} from physiological or environmental system • Highly selective determination of nitrite with fast and sensitive current response.

  2. Amorphous carbon nitride as an alternative electrode material in electroanalysis: simultaneous determination of dopamine and ascorbic acid.

    Science.gov (United States)

    Medeiros, Roberta A; Matos, Roberto; Benchikh, Abdelkader; Saidani, Boualem; Debiemme-Chouvy, Catherine; Deslouis, Claude; Rocha-Filho, Romeu C; Fatibello-Filho, Orlando

    2013-10-03

    Boron-doped diamond (BDD) films are excellent electrode materials, whose electrochemical activity for some analytes can be tuned by controlling their surface termination, most commonly either to predominantly hydrogen or oxygen. This tuning can be accomplished by e.g. suitable cathodic or anodic electrochemical pretreatments. Recently, it has been shown that amorphous carbon nitride (a-CNx) films may present electrochemical characteristics similar to those of BDD, including the influence of surface termination on their electrochemical activity toward some analytes. In this work, we report for the first time a complete electroanalytical method using an a-CNx electrode. Thus, an a-CNx film deposited on a stainless steel foil by DC magnetron sputtering is proposed as an alternative electrode for the simultaneous determination of dopamine (DA) and ascorbic acid (AA) in synthetic biological samples by square-wave voltammetry. The obtained results are compared with those attained using a BDD electrode. For both electrodes, a same anodic pretreatment in 0.1 mol L(-1) KOH was necessary to attain an adequate and equivalent separation of the DA and AA oxidation potential peaks of about 330 mV. The detection limits obtained for the simultaneous determination of these analytes using the a-CNx electrode were 0.0656 μmol L(-1) for DA and 1.05 μmol L(-1) for AA, whereas with the BDD electrode these values were 0.283 μmol L(-1) and 0.968 μmol L(-1), respectively. Furthermore, the results obtained in the analysis of the analytes in synthetic biological samples were satisfactory, attesting the potential application of the a-CNx electrode in electroanalysis.

  3. Nickel Sulfide/Graphene/Carbon Nanotube Composites as Electrode Material for the Supercapacitor Application in the Sea Flashing Signal System

    Institute of Scientific and Technical Information of China (English)

    Hailong Chen; Ji Li; Conglai Long; Tong Wei; Guoqing Ning; Jun Yan; Zhuangjun Fan

    2014-01-01

    This work presents NiS/graphene/carbon nanotube (NiS/GNS/CNT) composites as electrode material for the supercapacitor application in sea flashing signal systems. NiS nanosheets were closely anchored on the conductive GNS-CNT networks. As a result, the NiS/GNS/CNT electrode showed a high specific capacitance of 2 377 F·g-1 at 2 mV·s-1 and good cycling stability compared with the pure NiS (1 599 F·g-1 ). The enhanced electrochemical performances are attributed to the synergetic effect between the conductive carbon and the pseudo-capacitive NiS. The high performance supercapacitor may provide application in the sea flashing signal system.

  4. Evaluating biomass-derived hierarchically porous carbon as the positive electrode material for hybrid Na-ion capacitors

    Science.gov (United States)

    Chen, Jizhang; Zhou, Xiaoyan; Mei, Changtong; Xu, Junling; Zhou, Shuang; Wong, Ching-Ping

    2017-02-01

    As a promising renewable resource, biomass has several advantages such as wide availability, low cost, and versatility. In this study, we use peanut shell, wheat straw, rice straw, corn stalk, cotton stalk, and soybean stalk as the precursors to synthesize hierarchically porous carbon as the positive electrode material for hybrid Na-ion capacitors, aiming to establish a criterion of choosing suitable biomass precursors. The carbon derived from wood-like cotton stalk has abundant interconnected macropores, high surface area of 1994 m2 g-1, and large pore volume of 1.107 cm3 g-1, thanks to which it exhibits high reversible capacitance of 160.5 F g-1 at 0.2 A g-1 and great rate capability, along with excellent cyclability. The carbonaceous positive electrode material is combined with a Na2Ti2.97Nb0.03O7 negative electrode material to assemble a hybrid Na-ion capacitor, which delivers a high specific energy of 169.4 Wh kg-1 at 120.5 W kg-1, ranking among the best-performed hybrid ion capacitors.

  5. Structural and Optical Properties of Spray Coated Carbon Hybrid Materials Applied to Transparent and Flexible Electrodes

    Directory of Open Access Journals (Sweden)

    Grzegorz Wroblewski

    2017-01-01

    Full Text Available Transparent and flexible electrodes were fabricated with cost-effective spray coating technique on polyethylene terephthalate foil substrates. Particularly designed paint compositions contained mixtures of multiwalled carbon nanotubes and graphene platelets to achieve their desired rheology and electrooptical layers parameters. Electrodes were prepared in standard technological conditions without the need of clean rooms or high temperature processing. The sheet resistance and optical transmittance of fabricated layers were tuned with the number of coatings; then the most suitable relation of these parameters was designated through the figure of merit. Optical measurements were performed in the range of wavelengths from 250 to 2500 nm with a spectrophotometer with the integration sphere. Spectral dependence of total and diffusive optical transmission for thin films with graphene platelet covered by multiwalled carbon nanotubes was designated which allowed determining the relative absorbance. Layer parameters such as thickness, refractive index, energy gap, and effective reflectance coefficient show the correlation of electrooptical properties with the technological conditions. Moreover the structural properties of fabricated layers were examined by means of the X-ray diffraction.

  6. Simultaneous Electrochemical Determination of Hydroquinone, Catechol and Resorcinol at Nitrogen Doped Porous Carbon Nanopolyhedrons-multiwall Carbon Nanotubes Hybrid Materials Modified Glassy Carbon Electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei; Wu, Liang; Zhang, Xiaohua; Chen, Jinhua [Hunan Univ., Changsha (China)

    2014-01-15

    The nitrogen doped porous carbon nanopolyhedrons (N-PCNPs)-multi-walled carbon nanotubes (MWCNTs) hybrid materials were prepared for the first time. Combining the excellent catalytic activities, good electrical conductivities and high surface areas of N-PCNPs and MWCNTs, the simultaneous determination of hydroquinone (HQ), catechol (CC) and resorcinol (RE) with good analytical performance was achieved at the N-PCNPs-MWCNTs modified electrode. The linear response ranges for HQ, CC and RE are 0.2-455 μM, 0.7-440 μM and 3.0-365 μM, respectively, and the detection limits (S/N = 3) are 0.03 μM, 0.11 μM and 0.38 μM, respectively. These results are much better than that obtained on some graphene or CNTs-based materials modified electrodes. Furthermore, the developed sensor was successfully applied to simultaneously detect HQ, CC and RE in the local river water samples.

  7. Role of the Material Electrodes on Resistive Behaviour of Carbon Nanotube-Based Gas Sensors for H2S Detection

    Directory of Open Access Journals (Sweden)

    M. Lucci

    2012-01-01

    Full Text Available Miniaturized gas-sensing devices that use single-walled carbon nanotubes as active material have been fabricated using two different electrode materials, namely, Au/Cr and NbN. The resistive sensors have been assembled aligning by dielectrophoresis the nanotube bundles between 40 μm spaced Au/Cr or NbN multifinger electrodes. The sensing devices have been tested for detection of the H2S gas, in the concentration range 10–100 ppm, using N2 as carrier gas. No resistance changes were detected using sensor fabricated with NbN electrodes, whereas the response of the sensor fabricated with Au/Cr electrodes was characterized by an increase of the resistance upon gas exposure. The main performances of this sensor are a detection limit for H2S of 10 ppm and a recovery time of few minutes. The present study suggests that the mechanism involved in H2S gas detection is not a direct charge transfer between molecules and nanotubes. The hypothesis is that detection occurs through passivation of the Au surfaces by H2S molecules and modification of the contact resistance at the Au/nanotube interface.

  8. Synthesis of Polyaniline-Coated Ordered Mesoporous Carbon Composite Electrode Material for Supercapacitor and Its Enhanced Electrochemical Performance.

    Science.gov (United States)

    Li, Na; Xu, Jianxiong; Xu, Lijian; Du, Jingjing; Wang, Xianyou

    2015-07-01

    The polyaniline-coated ordered mesoporous carbon (PCOMC) material was prepared by chemical polymerization of aniline monomers on the ordered mesoporous carbon (OMC). The synthesized PCOMC materials were characterized by scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption isotherms and Fourier infrared spectroscopy. It was demonstrated that the polyaniline was successfully incorporated and well deposited on the external surface and inner pores of the OMC material. Furthermore, the electrochemical performance of the original OMC and PCOMC materials are compared by using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge tests. The results showed that the electrochemical performance of the OMC material was enhanced after the incorporation of polyaniline. The specific capacitance of PCOMC electrode (813.4 F/g) measured by cyclic voltammetry at the scan rate of 2 mV/s was much higher than that of the OMC electrode (200.9 F/g). The discharge specific capacitance of the PCOMC supercapacitor could be kept at 119.4 F/g when the current density was 5 A/g, indicating its good rate performance even at high charge/discharge current density. Moreover, the PCOMC supercapacitor exhibited long cycling stability with the capacitance retention remained 77% after 3500 cycles.

  9. Three-dimensional Hierarchical Metal oxide-Carbon Electrode Material for High Efficient Microbial Electrosynthesis

    DEFF Research Database (Denmark)

    Cui, Mengmeng; Nie, Huarong; Zhang, Tian

    2017-01-01

    pore structure in a microwave oven is demonstrated. Microwave pyrolysis of ferrocene using carbon felt as a microwave absorber, a method that is rapid (tens of seconds), does not require harsh conditions nor costly equipment is utilized, and can be readily scaled up. The produced material has a high...

  10. Ordered mesoporous carbide-derived carbon as new high performance electrode material in supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Korenblit, Yair; Yushin, Gleb [Georgia Inst. of Technology, Atlanta, GA (United States); Rose, Marcus; Kockrick, Emanuel; Borchardt, Lars; Kaskel, Stefan [Technische Univ. Dresden (Germany); Kvit, Alexander [Wisconsin Univ., Madison, WI (United States)

    2010-07-01

    The preparation and application of templated ordered mesoporous CDC overcome the present limitations of slow intraparticle ion transport and poor control over the biomodal pore size distribution in the carbons currently used, and shows a route for further performance enhancement. The ordered mesoporous channels in SiC CDC serve as ion-highways and allow for very fast ionic transport into the bulk of the CDC particles, thus leading to an excellent frequency response and outstanding capacitance retention at high current densities. The ordered mesopores in SiC allow for a greatly increased specific surface area and specific capacitance of SiC CDC, nearly doubling the previously reported values. The use of CDC produced from other carbides, including mesoporous TiC or VC is expected to further enhance the energy storage characteristics of EDLC electrodes, while optimization of the mesopore size is expected to enhance the power characteristics of EDLC. (orig.)

  11. Carbon Nanotube-based Nanohybrid Materials as Counter Electrode for Highly Efficient Dye-sensitized Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji-Soo; Sim, Eun-Ju; Dao, Van-Duong; Choi, Ho-Suk [Chungnam National University, Daejeon (Korea, Republic of)

    2016-04-15

    In this study, we present an excellent approach for easily and uniformly immobilizing Pt, Au and bimetallic PtAu nanoparticles (NPs) on a multi-walled carbon nanotube (MWNT)-coated layer through dry plasma reduction. The NPs are stably and uniformly immobilized on the surface of MWNTs and the nanohybrid materials are applied to counter electrode (CE) of dye-sensitized solar cells (DSCs). The electrochemical properties of CEs are examined through cyclic voltammogram, electrochemical impedance spectroscopy, and Tafel measurements. As a result, both electrochemical catalytic activity and electrical conductivity are highest for PtAu/MWNT electrode. The DSC employing PtAu/MWNT CE exhibits power conversion efficiency of 7.9%. The efficiency is better than those of devices with MWNT (2.6%), AuNP/MWNT (2.7%) and PtNP/MWNT (7.5%) CEs.

  12. Interconnecting Carbon Fibers with the In-situ Electrochemically Exfoliated Graphene as Advanced Binder-free Electrode Materials for Flexible Supercapacitor.

    Science.gov (United States)

    Zou, Yuqin; Wang, Shuangyin

    2015-07-07

    Flexible energy storage devices are highly demanded for various applications. Carbon cloth (CC) woven by carbon fibers (CFs) is typically used as electrode or current collector for flexible devices. The low surface area of CC and the presence of big gaps (ca. micro-size) between individual CFs lead to poor performance. Herein, we interconnect individual CFs through the in-situ exfoliated graphene with high surface area by the electrochemical intercalation method. The interconnected CFs are used as both current collector and electrode materials for flexible supercapacitors, in which the in-situ exfoliated graphene act as active materials and conductive "binders". The in-situ electrochemical intercalation technique ensures the low contact resistance between electrode (graphene) and current collector (carbon cloth) with enhanced conductivity. The as-prepared electrode materials show significantly improved performance for flexible supercapacitors.

  13. Redox electrode materials for supercapatteries

    Science.gov (United States)

    Yu, Linpo; Chen, George Z.

    2016-09-01

    Redox electrode materials, including transition metal oxides and electronically conducting polymers, are capable of faradaic charge transfer reactions, and play important roles in most electrochemical energy storage devices, such as supercapacitor, battery and supercapattery. Batteries are often based on redox materials with low power capability and safety concerns in some cases. Supercapacitors, particularly those based on redox inactive materials, e.g. activated carbon, can offer high power output, but have relatively low energy capacity. Combining the merits of supercapacitor and battery into a hybrid, the supercapattery can possess energy as much as the battery and output a power almost as high as the supercapacitor. Redox electrode materials are essential in the supercapattery design. However, it is hard to utilise these materials easily because of their intrinsic characteristics, such as the low conductivity of metal oxides and the poor mechanical strength of conducting polymers. This article offers a brief introduction of redox electrode materials, the basics of supercapattery and its relationship with pseudocapacitors, and reviews selectively some recent progresses in the relevant research and development.

  14. The preparation and performance of calcium carbide-derived carbon/polyaniline composite electrode material for supercapacitors

    Science.gov (United States)

    Zheng, Liping; Wang, Ying; Wang, Xianyou; Li, Na; An, Hongfang; Chen, Huajie; Guo, Jia

    Calcium carbide (CaC 2)-derived carbon (CCDC)/polyaniline (PANI) composite materials are prepared by in situ chemical oxidation polymerization of an aniline solution containing well-dispersed CCDC. The structure and morphology of CCDC/PANI composite are characterized by Fourier infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM) and N 2 sorption isotherms. It has been found that PANI was uniformly deposited on the surface and the inner pores of CCDC. The supercapacitive behaviors of the CCDC/PANI composite materials are investigated with cyclic voltammetry (CV), galvanostatic charge/discharge and cycle life measurements. The results show that the CCDC/PANI composite electrodes have higher specific capacitances than the as grown CCDC electrodes and higher stability than the conducting polymers. The capacitance of CCDC/PANI composite electrode is as high as 713.4 F g -1 measured by cyclic voltammetry at 1 mV s -1. Besides, the capacitance retention of coin supercapacitor remained 80.1% after 1000 cycles.

  15. The preparation and performance of calcium carbide-derived carbon/polyaniline composite electrode material for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Liping; Wang, Xianyou; Li, Na; An, Hongfang; Chen, Huajie [School of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Applications of Minister of Education, Xiangtan University, Hunan 411105 (China); Wang, Ying; Guo, Jia [School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Hubei 430073 (China)

    2010-03-15

    Calcium carbide (CaC{sub 2})-derived carbon (CCDC)/polyaniline (PANI) composite materials are prepared by in situ chemical oxidation polymerization of an aniline solution containing well-dispersed CCDC. The structure and morphology of CCDC/PANI composite are characterized by Fourier infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM) and N{sub 2} sorption isotherms. It has been found that PANI was uniformly deposited on the surface and the inner pores of CCDC. The supercapacitive behaviors of the CCDC/PANI composite materials are investigated with cyclic voltammetry (CV), galvanostatic charge/discharge and cycle life measurements. The results show that the CCDC/PANI composite electrodes have higher specific capacitances than the as grown CCDC electrodes and higher stability than the conducting polymers. The capacitance of CCDC/PANI composite electrode is as high as 713.4 F g{sup -1} measured by cyclic voltammetry at 1 mV s{sup -1}. Besides, the capacitance retention of coin supercapacitor remained 80.1% after 1000 cycles. (author)

  16. Dilute NiO/carbon nanofiber composites derived from metal organic framework fibers as electrode materials for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying; Yang, Feng; Hu, Hongru; Lee, Sungsik; Wang, Yue; Zhao, Hairui; Zeng, Dehong; Zhou, Biao; Hao, Shijie

    2017-01-01

    A new type of carbon nanofiber (CNF) dominated electrode materials decorated with dilute NiO particles (NiO/CNF) has been in situ fabricated by direct pyrolysis of Ni, Zn-containing metal organic framework fibers, which are skillfully constructed by assembling different proportional NiCl2·6H2O and Zn(Ac)2·2H2O with trimesic acid in the presence of N,N-dimethylformamide. With elegant combination of advantages of CNF and evenly dispersed NiO particles, as well as successful modulation of conductivity and porosity of final composites, our NiO/CNF composites display well-defined capacitive features. A high capacitance of 14926 F g–1 was obtained in 6 M KOH electrolyte when the contribution from 0.43 wt% NiO was considered alone, contributing to over 35% of the total capacitance (234 F g–1 ). This significantly exceeds its theoretical specific capacitance of 2584 F g–1. It has been established from the Ragone plot that a largest energy density of 33.4 Wh kg–1 was obtained at the current density of 0.25 A g–1. Furthermore, such composite electrode materials show good rate capability and outstanding cycling stability up to 5000 times (only 10% loss). The present study provides a brand-new approach to design a high capacitance and stable supercapacitor electrode and the concept is extendable to other composite materials. Keywords: Metal organic framework; Nickel oxide; Carbon nanofiber; In situ synthesis; Capacitance

  17. Graphene-like carbon nanosheets as a new electrode material for electrochemical determination of hydroquinone and catechol.

    Science.gov (United States)

    Jiang, Hongmei; Wang, Shuqin; Deng, Wenfang; Zhang, Youming; Tan, Yueming; Xie, Qingji; Ma, Ming

    2017-03-01

    We report here graphene-like carbon nanosheets (GCN) as a new electrode material for the electrochemical determination of hydroquinone (HQ) and catechol (CC). The GCN were prepared from maltose using ammonia chloride as a blowing agent and cobalt nitrate as a graphitization catalyst precursor. The as-prepared GCN material shows high graphitization degree, abundant porosity, and large specific surface area. Two well-separated anodic peaks for HQ and CC are obtained at GCN modified glassy carbon electrode (GCE) with a peak-to-peak separation of 118mV. The redox peak currents of HQ and CC at GCN/GCE were much higher than those at bare GCE and reduced graphene oxide modified GCE. For differential pulse voltammetric detection of HQ and CC, the GCN/GCE shows linear response ranges of 1×10(-7) ̶ 3×10(-5)M for HQ and 5×10(-7) ̶ 5×10(-5)M for CC, with detection limits of 2×10(-8)M for HQ, and 5×10(-8) M for CC. Satisfactory recoveries were achieved for the determination of HQ and CC in real water samples.

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

    Science.gov (United States)

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

    2016-10-01

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

  19. Low-power switching of phase-change materials with carbon nanotube electrodes.

    Science.gov (United States)

    Xiong, Feng; Liao, Albert D; Estrada, David; Pop, Eric

    2011-04-29

    Phase-change materials (PCMs) are promising candidates for nonvolatile data storage and reconfigurable electronics, but high programming currents have presented a challenge to realize low-power operation. We controlled PCM bits with single-wall and small-diameter multi-wall carbon nanotubes. This configuration achieves programming currents of 0.5 microampere (set) and 5 microamperes (reset), two orders of magnitude lower than present state-of-the-art devices. Pulsed measurements enable memory switching with very low energy consumption. Analysis of over 100 devices finds that the programming voltage and energy are highly scalable and could be below 1 volt and single femtojoules per bit, respectively.

  20. Hybrid nanostructured microporous carbon-mesoporous carbon doped titanium dioxide/sulfur composite positive electrode materials for rechargeable lithium-sulfur batteries

    Science.gov (United States)

    Zegeye, Tilahun Awoke; Kuo, Chung-Feng Jeffrey; Wotango, Aselefech Sorsa; Pan, Chun-Jern; Chen, Hung-Ming; Haregewoin, Atetegeb Meazah; Cheng, Ju-Hsiang; Su, Wei-Nien; Hwang, Bing-Joe

    2016-08-01

    Herein, we design hybrid nanostructured microporous carbon-mesoporous carbon doped titanium dioxide/sulfur composite (MC-Meso C-doped TiO2/S) as a positive electrode material for lithium-sulfur batteries. The hybrid MC-Meso C-doped TiO2 host material is produced by a low-cost, hydrothermal and annealing process. The resulting conductive material shows dual microporous and mesoporous behavior which enhances the effective trapping of sulfur and polysulfides. The hybrid MC-Meso C-doped TiO2/S composite material possesses rutile TiO2 nanotube structure with successful carbon doping while sulfur is uniformly distributed in the hybrid MC-Meso C-doped TiO2 composite materials after the melt-infusion process. The electrochemical measurement of the hybrid material also shows improved cycle stability and rate performance with high sulfur loading (61.04%). The material delivers an initial discharge capacity of 802 mAh g-1 and maintains it at 578 mAh g-1 with a columbic efficiency greater than 97.1% after 140 cycles at 0.1 C. This improvement is thought to be attributed to the unique hybrid nanostructure of the MC-Meso C-doped TiO2 host and the good dispersion of sulfur in the narrow pores of the MC spheres and the mesoporous C-doped TiO2 support.

  1. Porous carbon as electrode material in direct ethanol fuel cells (DEFCs) synthesized by the direct carbonization of MOF-5

    KAUST Repository

    Khan, Inayatali

    2014-01-12

    Porous carbon (PC-900) was prepared by direct carbonization of porous metal-organic framework (MOF)-5 (Zn4O(bdc)3, bdc=1,4-benzenedicarboxylate) at 900 °C. The carbon material was deposited with PtM (M=Fe, Ni, Co, and Cu (20 %) metal loading) nanoparticles using the polyol reduction method, and catalysts PtM/PC-900 were designed for direct ethanol fuel cells (DEFCs). However, herein, we are reporting PtFe/PC-900 catalyst combination which has exhibited superior performance among other options. This catalyst was characterized by powder XRD, high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and selected area electron diffraction (SAED) technique. The electrocatalytic capability of the catalyst for ethanol electrooxidation was investigated using cyclic voltammetry and direct ethanol single cell testing. The results were compared with those of PtFe and Pt supported on Vulcan XC72 carbon catalysts (PFe/CX-72 and Pt/XC-72) prepared via the same method. It has been observed that the catalyst PtFe/PC-900 developed in this work showed an outstanding normalized activity per gram of Pt (6.8 mA/g Pt) and superior power density (121 mW/cm2 at 90 °C) compared to commercially available carbon-supported catalysts. © Springer-Verlag Berlin Heidelberg 2014.

  2. Hierarchical micro- and mesoporous carbide-derived carbon as a high-performance electrode material in supercapacitors.

    Science.gov (United States)

    Rose, Marcus; Korenblit, Yair; Kockrick, Emanuel; Borchardt, Lars; Oschatz, Martin; Kaskel, Stefan; Yushin, Gleb

    2011-04-18

    Ordered mesoporous carbide-derived carbon (OM-CDC) materials produced by nanocasting of ordered mesoporous silica templates are characterized by a bimodal pore size distribution with a high ratio of micropores. The micropores result in outstanding adsorption capacities and the well-defined mesopores facilitate enhanced kinetics in adsorption processes. Here, for the first time, a systematic study is presented, in which the effects of synthesis temperature on the electrochemical performance of these materials in supercapacitors based on a 1 M aqueous solution of sulfuric acid and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid are reported. Cyclic voltammetry shows the specific capacitance of the OM-CDC materials exceeds 200 F g(-1) in the aqueous electrolyte and 185 F g(-1) in the ionic liquid, when measured in a symmetric configuration in voltage ranges of up to 0.6 and 2 V, respectively. The ordered mesoporous channels in the produced OM-CDC materials serve as ion-highways and allow for very fast ionic transport into the bulk of the OM-CDC particles. At room temperature the enhanced ion transport leads to 75% and 90% of the capacitance retention at current densities in excess of ∼10 A g(-1) in ionic liquid and aqueous electrolytes, respectively. The supercapacitors based on 250-300 μm OM-CDC electrodes demonstrate an operating frequency of up to 7 Hz in aqueous electrolyte. The combination of high specific capacitance and outstanding rate capabilities of the OM-CDC materials is unmatched by state-of-the art activated carbons and strictly microporous CDC materials.

  3. Effect of mesocelluar carbon foam electrode material on performance of vanadium redox flow battery

    Science.gov (United States)

    Jeong, Sanghyun; An, Sunhyung; Jeong, Jooyoung; Lee, Jinwoo; Kwon, Yongchai

    2015-03-01

    Languid reaction rate of VO2+/VO2+ redox couple is a problem to solve for improving performance of vanadium redox flow battery (VRFB). To facilitate the slow reaction materials including large pore sized mesocellular carbon foam (MSU-F-C and Pt/MSU-F-C) are used as new catalyst. Their catalytic activity and reaction reversibility are estimated and compared with other catalysts, while cycle tests of charge-discharge and polarization curve tests are implemented to evaluate energy efficiency (EE) and maximum power density (MPD). Their crystal structure, specific surface area and catalyst morphology are measured by XRD, BET and TEM. The new catalysts indicate high peak current ratio, small peak potential difference and high electron transfer rate constant, proving that their catalytic activity and reaction reversibility are superior. Regarding the charge-discharge and polarization curve tests, the VRFB single cells including new catalysts show high EE as well as low overpotential and internal resistance and high MPD. Such excellent results are due to mostly unique characteristics of MSU-F-C having large interconnected mesopores, high surface area and large contents of hydroxyl groups that serve as active sites for VO2+/VO2+ redox reaction and platinums (Pts) supporting the MSU-F-C. Indeed, employment of the catalysts including MSU-F-C leads to enhancement in performance of VRFB by facilitating the slow VO2+/VO2+ redox reaction.

  4. Ultra-small vanadium nitride quantum dots embedded in porous carbon as high performance electrode materials for capacitive energy storage

    Science.gov (United States)

    Yang, Yunlong; Zhao, Lei; Shen, Kuiwen; Liu, Ying; Zhao, Xiaoning; Wu, Yage; Wang, Yanqin; Ran, Fen

    2016-11-01

    Ultra-small vanadium nitride quantum dots embedded in porous carbon (VNQDs/PC) were fabricated by a thermal treatment process of NH4VO3/C3H6N6 under nitrogen atmosphere. The specific capacitance of VNQDs/PC was 1008 mF cm-2 at a current density of 0.004 A cm-2, whereas the VN/carbon hybrid material obtained by a solid-state blending of NH4VO3 and C3H6N6 just exhibited a capacitance of 432 mF cm-2 at the same current density. By mediating the ratio of NH4VO3 and C3H6N6, a maximum specific capacitance of 1124 mF cm-2 was achieved at a current density of 0.002 A cm-2 in aqueous 6 mol/L KOH electrolyte with the potential range from 0 to -1.15 V when it reached 1: 7 (wt./wt.). Additionally, symmetrical supercapacitor fabricated with synthesized VNQDs/PC presented a high specific capacitance of 215 mF cm-2 at 0.002 A cm-2 based on the entire cell, and exhibited a high capacitance retention of 86.6% with current density increased to 5 A g-1. The VNQDs/PC negative electrodes were combined with Ni(OH)2 positive electrodes for the fabrication of hybrid supercapacitors. Remarkably, at a power density of 828.7 W kg-1, the device delivered an ultrahigh energy density of 47.2 Wh kg-1.

  5. A facile approach for the synthesis of monolithic hierarchical porous carbons – high performance materials for amine based CO2 capture and supercapacitor electrode

    KAUST Repository

    Estevez, Luis

    2013-05-03

    An ice templating coupled with hard templating and physical activation approach is reported for the synthesis of hierarchically porous carbon monoliths with tunable porosities across all three length scales (macro- meso- and micro), with ultrahigh specific pore volumes [similar]11.4 cm3 g−1. The materials function well as amine impregnated supports for CO2 capture and as supercapacitor electrodes.

  6. Synthesis and characterization of natural dye and counter electrode thin films with different carbon materials for dye-sensitized solar cells.

    Science.gov (United States)

    Chang, Ho; Chen, Tien-Li; Kao, Mu-Jung; Chen, Chih-Hao; Chien, Shu-Hua; Jiang, Lii-Jenq

    2011-08-01

    This study aims to deal with the film of the counter electrode of dye-sensitized solar cells (DSSCs) and the preparation, structure and characteristics of the extract of natural dye. This study adopts different commercial carbon materials such as black lead, carbon black and self-made TiO2-MWCNT compound nanoparticle as the film of the counter electrodes. Moreover, for the preparation of natural dyes, anthocyanins and chlorophyll dyes are extracted from mulberry and pomegranate respectively. Furthermore, the extracted anthocyanins and chlorophyll are blended into cocktail dye to complete the preparation of natural dye. Results show that the photoelectric conversion efficiency of the single-layer TiO2-MWCNT counter electrode film and the cocktail dye of the DSSCs is 0.462%.

  7. Hierarchical composites of polyaniline-graphene nanoribbons-carbon nanotubes as electrode materials in all-solid-state supercapacitors.

    Science.gov (United States)

    Liu, Mingkai; Miao, Yue-E; Zhang, Chao; Tjiu, Weng Weei; Yang, Zhibin; Peng, Huisheng; Liu, Tianxi

    2013-08-21

    A three dimensional (3D) polyaniline (PANI)-graphene nanoribbon (GNR)-carbon nanotube (CNT) composite, PANI-GNR-CNT, has been prepared via in situ polymerization of an aniline monomer on the surface of a GNR-CNT hybrid. Here, the 3D GNR-CNT hybrid has been conveniently prepared by partially unzipping the pristine multi-walled CNTs, while the residual CNTs act as "bridges" connecting different GNRs. The morphology and structure of the resulting hybrid materials have been characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy and X-ray diffraction (XRD). Electrochemical tests reveal that the hierarchical PANI-GNR-CNT composite based on the two-electrode cell possesses much higher specific capacitance (890 F g(-1)) than the GNR-CNT hybrid (195 F g(-1)) and neat PANI (283 F g(-1)) at a discharge current density of 0.5 A g(-1). At the same time, the PANI-GNR-CNT composite displays good cycling stability with a retention ratio of 89% after 1000 cycles, suggesting that this novel PANI-GNR-CNT composite is a promising candidate for energy storage applications.

  8. A study on optimal pore development of modified commercial activated carbons for electrode materials of supercapacitors

    Science.gov (United States)

    Bang, Joon Hyuk; Lee, Hye-Min; An, Kay-Hyeok; Kim, Byung-Joo

    2017-09-01

    This study aimed to understand the impact of CO2 activation of commercial activated carbons (AC) on the changes in pore characteristics and the electrochemical property. The surface structure of manufactured AC was observed with a X-ray diffraction (XRD); the pore characteristics were analyzed at N2/77 K isothermal absorption using the Brunauer-Emmett-Teller (BET) and Dubinin-Radushkevich (DR) equations. In addition, the electrochemical characteristics were analyzed by means of an electrolyte of 1 M (C2H5)4NBF4/propylene carbonate, using a charge/discharge test, cyclic voltammetry (CV), and impedance. The N2/77 K isothermal absorption curve of the manufactured AC falls under Type I in the classification of the International Union of Pure and Applied Chemistry (IUPAC) and was found to largely comprise micropores. The specific surface area increased from 1690 m2/g to 2290 m2/g, and the pore volume grew from 0.80 cm3/g to 1.10 cm3/g. The analysis of electrochemical characteristics also found that the specific capacity increased from 17 F/g to 20 F/g (in a full cell condition). Based on these results, we were able to determine the pore characteristics of commercial AC through an additional activation process, which consequently allowed us to manufacture the AC with an advanced electrochemical property.

  9. Improved technology for manufacture of carbon electrodes

    Indian Academy of Sciences (India)

    A Platon; A Dumbrava; N Iutes-Petrescu; Luzia Simionescu

    2000-02-01

    Current industrial carbon electrodes are typically manufactured by blending petroleum coke particles (the filler) with molten coal tar pitch (the binder) and extruding the resultant mix to form the `green electrode’. This is then baked under controlled conditions. In case of usage as anodes in steel electric furnaces (or as other carbon and graphite products), the electrodes could undergo further processing like pitch impregnation or graphitization. During heat treatment, some of the organics are destructively distilled, vaporized or decomposed, resulting in carbon deposition in the electrode. As the vaporized materials exit the body of the electrode they cause porosity in the walls, which results in reduction in density, current carrying capacity and flexural strength. The paper presents investigations to improve some physico-chemical characteristics of these electrodes (such as coefficient of thermal expansion, mechanical strengths, density, pore volume, porosity etc.), obtained in different manufacture steps, by addition of varieties of coal tar pitch. These include attempts to improve the chemical compatibility of the coke-pitch system in the mixture and establish the method and the point of introduction of additive, the concentration required and appropriate analytical control during the entire manufacture. Methods of analysis used include thermogravimetry and porosimetry. The microstructure of the electrodes is investigated through a wide range and the data obtained include pore size and pore volume distribution, surface area, porosity, particle size distribution and type of pores. The overall results clearly indicate better characteristics and performance for electrodes with additives as against electrodes without them, such as lower porosity, lower thermal expansion coefficients and greater mechanical strength. These data are analyzed with respect to the process step and electrode type.

  10. Nitrogen-Doped Porous Carbon Nanosheets from Eco-Friendly Eucalyptus Leaves as High Performance Electrode Materials for Supercapacitors and Lithium Ion Batteries.

    Science.gov (United States)

    Mondal, Anjon Kumar; Kretschmer, Katja; Zhao, Yufei; Liu, Hao; Wang, Chengyin; Sun, Bing; Wang, Guoxiu

    2016-12-31

    Nitrogen-doped porous carbon nanosheets were prepared from eucalyptus tree leaves by simply mixing the leaf powders with KHCO3 and subsequent carbonisation. Porous carbon nanosheets with a high specific surface area of 2133 m(2)  g(-1) were obtained and applied as electrode materials for supercapacitors and lithium ion batteries. For supercapacitor applications, the porous carbon nanosheet electrode exhibited a supercapacitance of 372 F g(-1) at a current density of 500 mA g(-1) in 1 m H2 SO4 aqueous electrolyte and excellent cycling stability over 15 000 cycles. In organic electrolyte, the nanosheet electrode showed a specific capacitance of 71 F g(-1) at a current density of 2 Ag(-1) and stable cycling performance. When applied as the anode material for lithium ion batteries, the as-prepared porous carbon nanosheets also demonstrated a high specific capacity of 819 mA h g(-1) at a current density of 100 mA g(-1) , good rate capability, and stable cycling performance. The outstanding electrochemical performances for both supercapacitors and lithium ion batteries are derived from the large specific surface area, porous nanosheet structure and nitrogen doping effects. The strategy developed in this paper provides a novel route to utilise biomass-derived materials for low-cost energy storage systems.

  11. Carbon nanotube nanocomposite-modified paper electrodes for supercapacitor applications

    Science.gov (United States)

    Korivi, Naga S.; Vangari, Manisha; Jiang, Li

    2016-12-01

    This paper describes the evaluation of carbon paper electrodes for supercapacitor applications. The electrodes are based on carbon micro-fiber paper modified with active material consisting of layers of silver nano-particulate ink and a nanocomposite of multi-walled carbon nanotubes and silver nano-particulate ink. The electrodes were characterized microscopically and electrically. Current-voltage studies revealed a consistent Ohmic behavior of the electrode when modified with different nanostructured active material. Among the active materials incorporated into the electrode, a nanocomposite of carbon nanotubes and silver nano-particulate ink significantly improved capacitance. The paper electrodes can be used for lightweight and ultrathin supercapacitors and other portable energy applications.

  12. Carbon nanotube nanocomposite-modified paper electrodes for supercapacitor applications

    Science.gov (United States)

    Korivi, Naga S.; Vangari, Manisha; Jiang, Li

    2017-02-01

    This paper describes the evaluation of carbon paper electrodes for supercapacitor applications. The electrodes are based on carbon micro-fiber paper modified with active material consisting of layers of silver nano-particulate ink and a nanocomposite of multi-walled carbon nanotubes and silver nano-particulate ink. The electrodes were characterized microscopically and electrically. Current-voltage studies revealed a consistent Ohmic behavior of the electrode when modified with different nanostructured active material. Among the active materials incorporated into the electrode, a nanocomposite of carbon nanotubes and silver nano-particulate ink significantly improved capacitance. The paper electrodes can be used for lightweight and ultrathin supercapacitors and other portable energy applications.

  13. Symmetric supercapacitors using urea-modified lignin derived N-doped porous carbon as electrode materials in liquid and solid electrolytes

    Science.gov (United States)

    Wang, Keliang; Xu, Ming; Gu, Yan; Gu, Zhengrong; Fan, Qi Hua

    2016-11-01

    N-doped porous carbon materials derived from urea-modified lignin were prepared via efficient KOH activation under carbonization. The synthesized N-doped carbon materials, which displayed a well-developed porous morphology with high specific surface area of 3130 m2 g-1, were used as electrode materials in symmetric supercapacitors with aqueous and solid electrolytes. In consistent with the observed physical structures and properties, the supercapacitors exhibited specific capacitances of 273 and 306 F g-1, small resistances of 2.6 and 7.7 Ω, stable charge/discharge at different current densities for over 5000 cycles and comparable energy and power density in 6 mol L-1 KOH liquid and KOH-PVA solid electrolytes, respectively.

  14. Nitrogen-Doped Carbon Nanotube/Graphite Felts as Advanced Electrode Materials for Vanadium Redox Flow Batteries.

    Science.gov (United States)

    Wang, Shuangyin; Zhao, Xinsheng; Cochell, Thomas; Manthiram, Arumugam

    2012-08-16

    Nitrogen-doped carbon nanotubes have been grown, for the first time, on graphite felt (N-CNT/GF) by a chemical vapor deposition approach and examined as an advanced electrode for vanadium redox flow batteries (VRFBs). The unique porous structure and nitrogen doping of N-CNT/GF with increased surface area enhances the battery performance significantly. The enriched porous structure of N-CNTs on graphite felt could potentially facilitate the diffusion of electrolyte, while the N-doping could significantly contribute to the enhanced electrode performance. Specifically, the N-doping (i) modifies the electronic properties of CNT and thereby alters the chemisorption characteristics of the vanadium ions, (ii) generates defect sites that are electrochemically more active, (iii) increases the oxygen species on CNT surface, which is a key factor influencing the VRFB performance, and (iv) makes the N-CNT electrochemically more accessible than the CNT.

  15. Peltier effects in electrode carbon

    Science.gov (United States)

    Hansen, Ellen Marie; Egner, Espen; Kjelstrup, Signe

    1998-02-01

    The thermoelectric power of a cell with platinum electrodes and a carbon conductor was determined. The electromotive force (emf) was measured as a function of the temperature difference between the electrodes at temperatures varying from 310 °C to 970 °C. From these measurements, the transported entropy of electric charge in carbon was found to vary from -1.7 to -1.9 J/(K mole) at temperatures around 300 °C, from -2.0 to -2.3 J/(K mole) at temperatures around 550 °C, and from -3.4 to -3.7 J/(K mole) at temperatures around 950 °C. This transported entropy had not before been determined for temperatures above 550 °C. Also, it is shown how the previously neglected surface properties can be taken into account to interpret the measurements. In the Hall-Héroult cell, the anode is made of a similar kind of carbon. Hence, the transported entropy found above can be used to describe the often neglected coupling between transport of heat and electric charge in this electrode. It is shown that the calculated electric potential profile through a coal sample will change significantly if the coupling is neglected, but the calculated temperature profile is independent of whether the coupling is neglected. New equations are also developed that can be used to evaluate the importance of the coupling in other systems.

  16. Catalytic Graphitization for Preparation of Porous Carbon Material Derived from Bamboo Precursor and Performance as Electrode of Electrical Double-Layer Capacitor

    Science.gov (United States)

    Tsubota, Toshiki; Maguchi, Yuta; Kamimura, Sunao; Ohno, Teruhisa; Yasuoka, Takehiro; Nishida, Haruo

    2015-12-01

    The combination of addition of Fe (as a catalyst for graphitization) and CO2 activation (a kind of gaseous activation) was applied to prepare a porous carbon material from bamboo powder (a waste product of superheated steam treatment). Regardless of the heat treatment temperature, many macropores were successfully formed after the heating process by removal of Fe compounds. A turbostratic carbon structure was generated in the Fe-added sample heated at 850°C. It was confirmed that the added Fe acted as a template for pore formation. Moreover, it was confirmed that the added Fe acted as a catalyst for graphitization. The resulting electrochemical performance as the electrode of an electrical double-layer capacitor, as demonstrated by cyclic voltammetry, electrochemical impedance spectroscopy, and charge-discharge testing, could be explained based on the graphitization and activation effects. Addition of Fe could affect the electrical properties of carbon material derived from bamboo.

  17. Ultrasensitive and simultaneous detection of heavy metal ions based on three-dimensional graphene-carbon nanotubes hybrid electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hui; Chen, Ting [Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Liu, Xiuyu [Shandong Academy of Sciences, Jinan 250114 (China); Ma, Houyi, E-mail: hyma@sdu.edu.cn [Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2014-12-10

    Highlights: • Three-dimensional graphene-MWCNTs nanocomposites were prepared. • Graphene-MWCNTs based electrochemical sensor was used to detect heavy metal ions for the first time. • The proposed sensor was certified capable for real sample with satisfactory results. - Abstract: A green and facile method was developed to prepare a novel hybrid nanocomposite that consisted of one-dimensional multi-walled carbon nanotubes (MWCNTs) and two-dimensional graphene oxide (GO) sheets. The as-prepared three-dimensional GO–MWCNTs hybrid nanocomposites exhibit excellent water-solubility owing to the high hydrophilicity of GO components; meanwhile, a certain amount of MWCNTs loaded on the surface of GO sheets through π–π interaction seem to be “dissolved” in water. Moreover, the graphene(G)-MWCNTs nanocomposites with excellent conductivity were obtained conveniently by the direct electrochemical reduction of GO–MWCNTs nanocomposites. Seeing that there is a good synergistic effect between MWCNTs and graphene components in enhancing preconcentration efficiency of metal ions and accelerating electron transfer rate at G-MWCNTs/electrolyte interface, the G-MWCNTs nanocomposites possess fast, simultaneous and sensitive detection performance for trace amounts of heavy metal ions. The electrochemical results demonstrate that the G-MWCNTs nanocomposites can act as a kind of practical sensing material to simultaneously determine Pb{sup 2+} and Cd{sup 2+} ions in terms of anodic stripping voltammetry (ASV). The linear calibration plots for Pb{sup 2+} and Cd{sup 2+} ranged from 0.5 μg L{sup −1} to 30 μg L{sup −1}. The detection limits were determined to be 0.2 μg L{sup −1} (S/N = 3) for Pb{sup 2+} and 0.1 μg L{sup −1} (S/N = 3) for Cd{sup 2+} in the case of a deposition time of 180 s. It is worth mentioning that the G-MWCNTs modified electrodes were successfully applied to the simultaneous detection of Cd{sup 2+} and Pb{sup 2+} ions in real electroplating

  18. Low-temperature self-assembled vertically aligned carbon nanofibers as counter-electrode material for dye-sensitized solar cells

    Science.gov (United States)

    Mahpeykar, S. M.; Tabatabaei, M. K.; Ghafoori-fard, H.; Habibiyan, H.; Koohsorkhi, J.

    2013-11-01

    Low-temperature AC-DC PECVD is employed for direct growth of vertically aligned carbon nanofibers (VACNFs) on ordinary transparent conductive glass as counter-electrode material for dye-sensitized solar cells (DSSCs). To the best of our knowledge, this is the first report on utilization of VACNFs grown directly on ordinary FTO-coated glass as a cost-effective catalyst material in DSSCs. According to the FESEM images, the as-grown arrays are well aligned and dense, and offer uniform coverage on the surface of the substrate. In-plane and out-of-plane conductivity measurements reveal their good electrical conductivity, and Raman spectroscopy suggests a high number of electrocatalytic active sites, favoring charge transport at the electrolyte/electrode interface. Hybrid VACNF/Pt electrodes are also fabricated for performance comparison with Pt and VACNF electrodes. X-ray diffraction results verify the crystallization of Pt in hybrid electrodes and further confirm the vertical alignment of carbon nanofibers. Electrochemical characterization indicates that VACNFs provide both high catalytic and good charge transfer capability, which can be attributed to their high surface area, defect-rich and one-dimensional structure, vertical alignment and low contact resistance. As a result, VACNF cells can achieve a comparable performance (˜5.6%) to that of the reference Pt cells (˜6.5%). Moreover, by combination of the excellent charge transport and catalytic ability of VACNFs and the high conductivity of Pt nanoparticles, hybrid VACNF/Pt cells can deliver a performance superior to that of the Pt cells (˜7.2%), despite having a much smaller amount of Pt loading, which raises hopes for low-cost large-scale production of DSSCs in the future.

  19. Electrochemical storage of hydrogen on carbon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Jurewicz, K.; Frackowiak, E. [ICTE, Poznan University of Technology (Poland); Gautier, S.; Beguin, F. [CRMD, CNRS Universite, 45 - Orleans (France)

    2000-07-01

    Amount of hydrogen reversibly stored on an activated carbon electrode using electro-decomposition of 6 mol.l{sup -1} KOH aqueous solution has been investigated and compared data obtained under a high pressure of dihydrogen (70 bars) at 273 K. In the electrochemical method, 1.5 wt% of hydrogen was released from carbon during the oxidation process, with a well-defined plateau at ca. - 0.5 V vs Hg/HgO. Relatively smaller values were obtained for the sorption ability under a high pressure of gas. This means that the formation of nascent hydrogen during water reduction favours its easy penetration in the carbon nano-structure, even at ambient pressure and temperature. Our results show that not only carbon nano-tubes should be considered for hydrogen reservoir and that low cost materials such as activated carbons could be convenient in appropriate conditions.

  20. Enhanced electrochemical performance of porous activated carbon by forming composite with graphene as high-performance supercapacitor electrode material

    Science.gov (United States)

    Wang, Zhi-Hang; Yang, Jia-Ying; Wu, Xiong-Wei; Chen, Xiao-Qing; Yu, Jin-Gang; Wu, Yu-Ping

    2017-02-01

    In this work, a novel activated carbon containing graphene composite was developed using a fast, simple, and green ultrasonic-assisted method. Graphene is more likely a framework which provides support for activated carbon (AC) particles to form hierarchical microstructure of carbon composite. Scanning electron microscope (SEM), transmission electron microscope (TEM), Brunauer-Emmett-Teller (BET) surface area measurement, thermogravimetric analysis (TGA), Raman spectra analysis, XRD, and XPS were used to analyze the morphology and surface structure of the composite. The electrochemical properties of the supercapacitor electrode based on the as-prepared carbon composite were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), charge/discharge, and cycling performance measurements. It exhibited better electrochemical performance including higher specific capacitance (284 F g-1 at a current density of 0.5 A g-1), better rate behavior (70.7% retention), and more stable cycling performance (no capacitance fading even after 2000 cycles). It is easier for us to find that the composite produced by our method was superior to pristine AC in terms of electrochemical performance due to the unique conductive network between graphene and AC.

  1. Desalination with carbon aerogel electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J.C.; Richardson, J.H.; Fix, D.V.

    1996-10-21

    An electrically regenerated electrosorption process known as carbon aerogel CDI was developed for continuously removing ionic impurities from aqueous streams. A salt solution flows in a channel formed by pairs of parallel carbon aerogel electrodes. Each electrode has a very high BET surface area and very low resistivity. After polarization, anions and cations are removed from electrolyte by the electric field and electrosorbed onto the carbon aerogel. The solution is thus separated into two streams, brine and water. Based on this, carbon aerogel CDI appears to be an energy-efficient alternative to evaporation, electrodialysis, and reverse osmosis. The energy required by this process is about QV/2, plus losses. Estimated energy requirement for sea water desalination is 18-27 Wh gal{sup -1}, depending on cell voltage and flow rate. The requirement for brackish water desalination is less, 1.2-2.5 Wh gal{sup -1} at 1600 ppM. This is assuming that stored electrical energy is reclaimed during regeneration.

  2. Carbon nanotubes as electrode substrate material for PEM fuel cells; Kohlenstoff-Nanoroehrchen als Elektrodenmaterial fuer PEM-Brennstoffzellen

    Energy Technology Data Exchange (ETDEWEB)

    Soehn, Matthias

    2010-06-21

    This thesis reports an enhanced method to deposit nanoscaled noble metal catalysts (Pt/Ru) uniformly on carbon nanotubes based on wet chemical reduction of anorganic precursors via ethylene glycol. This well-known method is widely used to deposit noble metal catalyst particles on carbon black. Unfortunately, carbon nanotubes tend to agglomerate and therefore form bundles which cannot be penetrated by the precursor. Thus, effectiveness of the substrate is reduced. The new method prevents this by suspending the CNTs in butyl acetate by means of ultrasonic dispersion leading to a homogenous distribution. Because the butyl acetate is almost unpolar, it is nearly immiscible with the water-based ethylene glycol mixture. This problem has been solved by adding liquid Nafion {sup registered} which acts as an emulsifying agent. Thus an emulsion is created by ultrasonic treatment. This results in 30 {mu}m-sized droplets of butyl acetate with a layer of CNTs and Nafion {sup registered}. The large interface to the ethylene glycol phase yields a large surface for homogenous catalyst deposition. The prepared samples showed a narrow size distribution ({+-}0.5 nm) of small noble metal particles with loading up to 50% by weight and an average particle size of 3 nm. They are investigated using XRD, SEM, TEM, TGA-MS and CV. The added Nafion {sup registered} improves catalyst utilisation by establishing a proton conductive path to the catalyst particles. Furthermore, different manufacturing techniques for the CNT electrodes are evaluated. Thin layer Membrane-Electrode-Assemblies (MEAs) are prepared by the airbrush technique. Electrode thickness, composition and structure as well as membrane thickness is varied and the MEAs are tested in a single-cell hydrogen-oxygen-fed PEM fuel cell. The cells are characterised by cyclic IV curves which are recorded over an extended period of time, showing power densities up to 770mWcm-2 at a platinum loading of 0.3mgcm-2. Additionally, the MEAs are

  3. Investigation of the Characteristic Properties of Glacial Acetic Acid-Catalyzed Carbon Xerogels and Their Electrochemical Performance for Use as Electrode Materials in Electrical Double-Layer Capacitors

    Directory of Open Access Journals (Sweden)

    Nguyen Khanh Nguyen Quach

    2017-01-01

    Full Text Available Glacial acetic acid was used as a catalyst in the preparation process of carbon xerogels from the condensation of resorcinol and formaldehyde for shortening significantly the gelation time. The effect of the resorcinol/catalyst ratio over a large range of 2 to 500, the solvent exchange manner with acetone, and the pyrolysis temperature of 700 to 1000°C on the characteristic properties of the carbon xerogels were investigated. A resorcinol/catalyst ratio of 2 and a pyrolysis temperature at 800°C were found to be the optimal condition for the preparation of carbon xerogels with a well-balanced porosity between micro- and mesopores, high surface area (577.62 m2g−1, and large pore volume (0.97 cm3g−1, which are appropriate for use as electrode materials in an electrical double-layer capacitor. The carbon xerogel electrodes that were prepared under these optimal conditions exhibited a good electrochemical performance with the highest specific capacitance of 169 Fg−1 in 6 M KOH electrolyte at a scan rate of 5 mVs−1 from cyclic voltammetry.

  4. Electrode materials for rechargeable battery

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Christopher; Kang, Sun-Ho

    2015-09-08

    A positive electrode is disclosed for a non-aqueous electrolyte lithium rechargeable cell or battery. The electrode comprises a lithium containing material of the formula Na.sub.yLi.sub.xNi.sub.zMn.sub.1-z-z'M.sub.z'O.sub.d, wherein M is a metal cation, x+y>1, 0material preferably has a spinel or spinel-like component in its structure. The value of y preferably is less than about 0.2, and M comprises one or more metal cations selected preferably from one or more monovalent, divalent, trivalent or tetravalent cations, such as Mg.sup.2+, Co.sup.2+, Co.sup.3+, B.sup.3+, Ga.sup.3+, Fe.sup.2+, Fe.sup.3+, Al.sup.3+, and Ti.sup.4+. The electrode material can be synthesized using an ion-exchange reaction with a lithium salt in an organic-based solvent to partially replace sodium ions of a precursor material with lithium ions.

  5. Structure and Modification of Electrode Materials for Protein Electrochemistry.

    Science.gov (United States)

    Jeuken, Lars J C

    The interactions between proteins and electrode surfaces are of fundamental importance in bioelectrochemistry, including photobioelectrochemistry. In order to optimise the interaction between electrode and redox protein, either the electrode or the protein can be engineered, with the former being the most adopted approach. This tutorial review provides a basic description of the most commonly used electrode materials in bioelectrochemistry and discusses approaches to modify these surfaces. Carbon, gold and transparent electrodes (e.g. indium tin oxide) are covered, while approaches to form meso- and macroporous structured electrodes are also described. Electrode modifications include the chemical modification with (self-assembled) monolayers and the use of conducting polymers in which the protein is imbedded. The proteins themselves can either be in solution, electrostatically adsorbed on the surface or covalently bound to the electrode. Drawbacks and benefits of each material and its modifications are discussed. Where examples exist of applications in photobioelectrochemistry, these are highlighted.

  6. Electrochemical horseradish peroxidase biosensor based on dextran-ionic liquid-V{sub 2}O{sub 5} nanobelt composite material modified carbon ionic liquid electrode

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Zhihong [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China); Sun Xiaoying; Wang Yan [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, 53 Zhenzhou Road, Qingdao 266042 (China); Zeng Yan [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China); Sun Wei, E-mail: sunwei_1975@public.qd.sd.cn [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, 53 Zhenzhou Road, Qingdao 266042 (China); Huang Xintang [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China)

    2010-11-01

    Direct electrochemistry of horseradish peroxidase (HRP) was realized in a dextran (De), 1-ethyl-3-methylimidazolium ethylsulphate ([EMIM]EtOSO{sub 3}) and V{sub 2}O{sub 5} nanobelt composite material modified carbon ionic liquid electrode (CILE). Spectroscopic results indicated that HRP retained its native structure in the composite. A pair of well-defined redox peaks of HRP appeared in pH 3.0 phosphate buffer solution with the formal potential of -0.213 V (vs. SCE), which was the characteristic of HRP heme Fe(III)/Fe(II) redox couple. The result was attributed to the specific characteristics of De-IL-V{sub 2}O{sub 5} nanocomposite and CILE, which promoted the direct electron transfer rate of HRP with electrode. The electrochemical parameters of HRP on the composite modified electrode were calculated and the electrocatalysis of HRP to the reduction of trichloroacetic acid (TCA) was examined. Under the optimal conditions the reduction peak current increased with TCA concentration in the range from 0.4 to 16.0 mmol L{sup -1}. The proposed electrode is valuable for the third-generation electrochemical biosensor.

  7. Carbon aerogel electrodes for direct energy conversion

    Science.gov (United States)

    Mayer, Steven T.; Kaschmitter, James L.; Pekala, Richard W.

    1997-01-01

    A direct energy conversion device, such as a fuel cell, using carbon aerogel electrodes, wherein the carbon aerogel is loaded with a noble catalyst, such as platinum or rhodium and soaked with phosphoric acid, for example. A separator is located between the electrodes, which are placed in a cylinder having plate current collectors positioned adjacent the electrodes and connected to a power supply, and a pair of gas manifolds, containing hydrogen and oxygen positioned adjacent the current collectors. Due to the high surface area and excellent electrical conductivity of carbon aerogels, the problems relative to high polarization resistance of carbon composite electrodes conventionally used in fuel cells are overcome.

  8. Voltammetric Response of Epinephrine at Carbon Nanotube Modified Glassy Carbon Electrode and Activated Glassy Carbon Electrode

    Institute of Scientific and Technical Information of China (English)

    WANG Juan; TANG Ping; ZHAO Fa-qiong; ZENG Bai-zhao

    2005-01-01

    The electrochemical behavior of epinephrine at activated glassy carbon electrode and carbon nanotube-coated glassy carbon electrode was studied. Epinephrine could exhibit an anodic peak at about 0.2 V (vs. SCE) at bare glassy carbon electrode, but it was very small.However, when the electrode was activated at certain potential (i. e. 1.9V) or modified with carbon nanotube, the peak became more sensitive,resulting from the increase in electrode area in addition to the electrostatic attraction. Under the selected conditions, the anodic peak current was linear to epinephrine concentration in the range of 3.3 × 10-7-1.1 × 10-5mol/L at activated glassy carbon electrode and in the range of 1.0 × 10-6-5.0 × 10-5 mol/L at carbon nanotube-coated electrode. The correlation coefficients were 0. 998 and 0. 997, respectively. The determination limit was 1.0 × 10-7 mol/L. The two electrodes have been successfully applied for the determination of epinephrine in adrenaline hydrochloride injection with recovery of 95%-104%.

  9. Fabrication of 3D lawn-shaped N-doped porous carbon matrix/polyaniline nanocomposite as the electrode material for supercapacitors

    Science.gov (United States)

    Zhang, Xiuling; Ma, Li; Gan, Mengyu; Fu, Gang; Jin, Meng; Lei, Yao; Yang, Peishu; Yan, Maofa

    2017-02-01

    A facile approach to acquire electrode materials with prominent electrochemical property is pivotal to the progress of supercapacitors. 3D nitrogen-doped porous carbon matrix (PCM), with high specific surface area (SSA) up to 2720 m2 g-1, was obtained from the carbonization and activation of the nitrogen-enriched composite precursor (graphene/polyaniline). Then 3D lawn-shaped PCM/PANI composite was obtained by the simple in-situ polymerization. The morphology and structure of these resulting composites were characterized by combining SEM and TEM measurements, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) spectroscopy analyses and Raman spectroscope. The element content of all samples was evaluated using CHN analysis. The results of electrochemical testing indicated that the PCM/PANI composite displays a higher capacitance value of 527 F g-1 at 1 A g-1 compared to 338 F g-1 for pure PANI, and exhibits appreciable rate capability with a retention of 76% at 20 A g-1 as well as fine long-term cycling performance (with 88% retention of specific capacitance after 1000 cycles at 10 A g-1). Simultaneously, the excellent capacitance performance coupled with the facile synthesis of PCM/PANI indicates it is a promising electrode material for supercapacitors.

  10. Electrode materials for microbial fuel cells: nanomaterial approach

    KAUST Repository

    Mustakeem, Mustakeem

    2015-11-05

    Microbial fuel cell (MFC) technology has the potential to become a major renewable energy resource by degrading organic pollutants in wastewater. The performance of MFC directly depends on the kinetics of the electrode reactions within the fuel cell, with the performance of the electrodes heavily influenced by the materials they are made from. A wide range of materials have been tested to improve the performance of MFCs. In the past decade, carbon-based nanomaterials have emerged as promising materials for both anode and cathode construction. Composite materials have also shown to have the potential to become materials of choice for electrode manufacture. Various transition metal oxides have been investigated as alternatives to conventional expensive metals like platinum for oxygen reduction reaction. In this review, different carbon-based nanomaterials and composite materials are discussed for their potential use as MFC electrodes.

  11. A core–shell structured nanocomposite of NiO with carbon nanotubes as positive electrode material of high capacitance for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Z.B., E-mail: zbwen@jxnu.edu.cn [College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022 (China); Yu, F. [College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022 (China); College of Energy, Nanjing Tech University, Nanjing 211816, Jiangsu Province (China); New Energy and Material Laboratory (NEML), Department of Chemistry & Shanghai Key Laboratory of Molecular Catalysis and Innovative Material, Fudan University, Shanghai 200433 (China); You, T.; Zhu, L. [College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022 (China); Zhang, L., E-mail: lzhang@jxnu.edu.cn [College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022 (China); Wu, Y.P., E-mail: wuyp@fudan.edu.cn [College of Energy, Nanjing Tech University, Nanjing 211816, Jiangsu Province (China); New Energy and Material Laboratory (NEML), Department of Chemistry & Shanghai Key Laboratory of Molecular Catalysis and Innovative Material, Fudan University, Shanghai 200433 (China)

    2016-02-15

    Highlights: • A core–shell structured NiO@CNTs nanocomposite is synthesized by a simple hydrothermal method. • The CNTs core effectively improves the capacitance, rate and cycling performance of NiO. • A supercapacitor is assembled when activated carbon is used as the negative electrode. • The supercapacitor presents an energy density up to 52.6 Wh kg{sup −1}. - Abstract: A nanocomposite of carbon nanotubes coated with nickel oxide was prepared by a simple hydrothermal method. The structure, morphology and electrochemical performance of the nanocomposite were investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy, electrochemical tests including cyclic voltammogram, galvanostatic charge–discharge and electrochemical impedance spectroscopy, respectively. It presents the highest specific capacitance of 1844 F g{sup −1} at 1 A g{sup −1} and 1145 F g{sup −1} at current density of 10 A g{sup −1} with 88.9% (at 1 A g{sup −1}) capacitance retention after 1000 cycles. The specific capacitance of the nanocomposite is almost double of that of the virginal NiO (972 F g{sup −1} at 1 A g{sup −1}). Its cycling behavior is also very good. When combined with activated carbon as the negative electrode, the energy density can be up to 52.6 Wh kg{sup −1}. Such good electrochemical behavior indicates that the nanocomposite is a promising electrode material for supercapacitors.

  12. Microscopical characterization of carbon materials derived from coal and petroleum and their interaction phenomena in making steel electrodes, anodes and cathode blocks for the Microscopy of Carbon Materials Working Group of the ICCP

    Science.gov (United States)

    Predeanu, G.; Panaitescu, C.; Bălănescu, M.; Bieg, G.; Borrego, A.G.; Diez, M. A.; Hackley, Paul C.; Kwiecińska, B.; Marques, M.; Mastalerz, Maria; Misz-Kennan, M.; Pusz, S.; Suarez-Ruiz, I.; Rodrigues, S.; Singh, A. K.; Varma, A. K.; Zdravkov, A.; Zivotić, D.

    2015-01-01

    This paper describes the evaluation of petrographic textures representing the structural organization of the organic matter derived from coal and petroleum and their interaction phenomena in the making of steel electrodes, anodes and cathode blocks.This work represents the results of the Microscopy of Carbon Materials Working Group in Commission III of the International Committee for Coal and Organic Petrology between the years 2009 and 2013. The round robin exercises were run on photomicrograph samples. For textural characterization of carbon materials the existing ASTM classification system for metallurgical coke was applied.These round robin exercises involved 15 active participants from 12 laboratories who were asked to assess the coal and petroleum based carbons and to identify the morphological differences, as optical texture (isotropic/anisotropic), optical type (punctiform, mosaic, fibre, ribbon, domain), and size. Four sets of digital black and white microphotographs comprising 151 photos containing 372 fields of different types of organic matter were examined. Based on the unique ability of carbon to form a wide range of textures, the results showed an increased number of carbon occurrences which have crucial role in the chosen industrial applications.The statistical method used to evaluate the results was based on the “raw agreement indices”. It gave a new and original view on the analysts' opinion by not only counting the correct answers, but also all of the knowledge and experience of the participants. Comparative analyses of the average values of the level of overall agreement performed by each analyst in the exercises during 2009–2013 showed a great homogeneity in the results, the mean value being 90.36%, with a minimum value of 83% and a maximum value of 95%.

  13. Fabricating solid carbon porous electrodes from powders

    Energy Technology Data Exchange (ETDEWEB)

    Kaschmitter, James L. (Pleasanton, CA); Tran, Tri D. (Livermore, CA); Feikert, John H. (Livermore, CA); Mayer, Steven T. (San Leandro, CA)

    1997-01-01

    Fabrication of conductive solid porous carbon electrodes for use in batteries, double layer capacitors, fuel cells, capacitive dionization, and waste treatment. Electrodes fabricated from low surface area (<50 m.sup.2 /gm) graphite and cokes exhibit excellent reversible lithium intercalation characteristics, making them ideal for use as anodes in high voltage lithium insertion (lithium-ion) batteries. Electrodes having a higher surface area, fabricated from powdered carbon blacks, such as carbon aerogel powder, carbon aerogel microspheres, activated carbons, etc. yield high conductivity carbon compositives with excellent double layer capacity, and can be used in double layer capacitors, or for capacitive deionization and/or waste treatment of liquid streams. By adding metallic catalysts to be high surface area carbons, fuel cell electrodes can be produced.

  14. Fabricating solid carbon porous electrodes from powders

    Energy Technology Data Exchange (ETDEWEB)

    Kaschmitter, J.L.; Tran, T.D.; Feikert, J.H.; Mayer, S.T.

    1997-06-10

    Fabrication is described for conductive solid porous carbon electrodes for use in batteries, double layer capacitors, fuel cells, capacitive deionization, and waste treatment. Electrodes fabricated from low surface area (<50 m{sup 2}/gm) graphite and cokes exhibit excellent reversible lithium intercalation characteristics, making them ideal for use as anodes in high voltage lithium insertion (lithium-ion) batteries. Electrodes having a higher surface area, fabricated from powdered carbon blacks, such as carbon aerogel powder, carbon aerogel microspheres, activated carbons, etc. yield high conductivity carbon composites with excellent double layer capacity, and can be used in double layer capacitors, or for capacitive deionization and/or waste treatment of liquid streams. By adding metallic catalysts to high surface area carbons, fuel cell electrodes can be produced. 1 fig.

  15. Carbon Nanotube Electrodes for Effective Interfacing with Retinal Tissue

    OpenAIRE

    Shoval, Asaf; Adams, Christopher; David-Pur, Moshe; Shein, Mark; Hanein, Yael; Sernagor, Evelyne

    2009-01-01

    We have investigated the use of carbon nanotube coated microelectrodes as an interface material for retinal recording and stimulation applications. Test devices were micro-fabricated and consisted of 60, 30 μm diameter electrodes at spacing of 200 μm. These electrodes were coated via chemical vapor deposition of carbon nanotubes, resulting in conducting, three dimensional surfaces with a high interfacial area. These attributes are important both for the quality of the cell-surface coupling as...

  16. Hierarchically porous carbon nanosheets derived from Moringa oleifera stems as electrode material for high-performance electric double-layer capacitors

    Science.gov (United States)

    Cai, Yijin; Luo, Ying; Dong, Hanwu; Zhao, Xiao; Xiao, Yong; Liang, Yeru; Hu, Hang; Liu, Yingliang; Zheng, Mingtao

    2017-06-01

    A facile one-step pyrolysis route for the synthesis of hierarchically porous carbon nanosheets (PCNSs) derived from Moringa oleifera stems (MOSs) is reported, in which no post-activation-process in needed. The as-prepared PCNSs possesses unique porous nanosheet morphology with high specific surface area of ca. 2250 m2 g-1, large pore volume of ca. 2.3 cm3 g-1, appropriate porosity as well as heteroatom doping (N and O), endowing outstanding electrochemical properties as electrode material for high-performance supercapacitors. The PCNS-based electrodes are investigated in various aqueous electrolytes including 1.0 M Na2SO4, 1.0 M H2SO4, and 6.0 M KOH. The PCNSs exhibit a maximum specific capacitance of ca. 283 F g-1 (0.5 A g-1), excellent rate capability (ca. 72% of capacitance retention even at an ultrahigh current density of 50 A g-1), and a tremendous long-term cycling stability in the three-electrode system. Moreover, the as-assembled PCNS-based symmetric supercapacitor shows a high energy density of ca. 25.8 Wh kg-1 (in 1.0 M Na2SO4 electrolyte) and remarkable long-term cycling stability (almost no capacitance fade in aqueous electrolytes), indicating the promising of the as-prepared PCNSs for electrochemical energy storage and conversion.

  17. Carbon nanotube electrodes for effective interfacing with retinal tissue.

    Science.gov (United States)

    Shoval, Asaf; Adams, Christopher; David-Pur, Moshe; Shein, Mark; Hanein, Yael; Sernagor, Evelyne

    2009-01-01

    We have investigated the use of carbon nanotube coated microelectrodes as an interface material for retinal recording and stimulation applications. Test devices were micro-fabricated and consisted of 60, 30 mum diameter electrodes at spacing of 200 mum. These electrodes were coated via chemical vapor deposition of carbon nanotubes, resulting in conducting, three dimensional surfaces with a high interfacial area. These attributes are important both for the quality of the cell-surface coupling as well as for electro-chemical interfacing efficiency. The entire chip was packaged to fit a commercial multielectrode recording and stimulation system. Electrical recordings of spontaneous spikes from whole-mount neonatal mouse retinas were consistently obtained minutes after retinas were placed over the electrodes, exhibiting typical bursting and propagating waves. Most importantly, the signals obtained with carbon nanotube electrodes have exceptionally high signal to noise ratio, reaching values as high as 75. Moreover, spikes are marked by a conspicuous gradual increase in amplitude recorded over a period of minutes to hours, suggesting improvement in cell-electrode coupling. This phenomenon is not observed in conventional commercial electrodes. Electrical stimulation using carbon nanotube electrodes was also achieved. We attribute the superior performances of the carbon nanotube electrodes to their three dimensional nature and the strong neuro-carbon nanotube affinity. The results presented here show the great potential of carbon nanotube electrodes for retinal interfacing applications. Specifically, our results demonstrate a route to achieve a reduction of the electrode down to few micrometers in order to achieve high efficacy local stimulation needed in retinal prosthetic devices.

  18. Carbon nanotube electrodes for effective interfacing with retinal tissue

    Directory of Open Access Journals (Sweden)

    Asaf Shoval

    2009-04-01

    Full Text Available We have investigated the use of carbon nanotube microelectrodes as an interface material for retinal recording and stimulation applications. Test devices were micro-fabricated and consisted of 60 pristine 30 um electrodes coated with chemical vapor deposited carbon nanotubes, resulting in conducting, three dimensional surfaces with a high effective interfacial area. These attributes are important both for the quality of the cell-surface coupling as well as for electro-chemical interfacing efficiency. The entire chip was packaged to fit a commercial multielectrode recording and stimulation system. Electrical recordings of spontaneous spikes from whole-mount neonatal mouse retinas were consistently obtained minutes after retinas were placed over the electrodes, exhibiting typical bursting and propagating waves. Most importantly, the signals obtained with carbon nanotube electrodes have exceptionally high signal to noise ratio, reaching values as high as 75. Moreover, spikes are marked by a conspicuous gradual increase in amplitude recorded over a period of minutes to hours, suggesting improvement in cell-electrode coupling. This phenomenon is not observed in conventional commercial electrodes. Electrical stimulation using carbon nanotube electrodes was also achieved. We attribute the superior performances of the carbon nanotube electrodes to their three dimensional nature and the strong neuro-carbon nanotube affinity. The results presented here show the great potential of carbon nanotube electrodes for retinal interfacing applications. Specifically, our results demonstrate a route to achieve a reduction in the electrode size down to few micrometers in order to achieve high efficacy local stimulation needed in retinal prosthetic devices.

  19. Inkjet printing of carbon black electrodes for dielectric elastomer actuators

    Science.gov (United States)

    Schlatter, Samuel; Rosset, Samuel; Shea, Herbert

    2017-04-01

    Inkjet printing is an appealing technique to print electrodes for Dielectric Elastomer Actuators (DEAs). Here we present the preparation and ink-jet printing of a carbon black electrode mixture and characterise its properties. Carbon black has been used extensively in the past because it is very compliant; however, it has a high resistance and can be very dirty to work with. In this paper we show that carbon black remains an appropriate electrode material, and when inkjet printed can be used to fabricate devices meeting today's demanding requirements. DEAs are becoming thinner to decrease actuation voltages and are shrinking in size to match the scale of the devices in the biomedical field, tuneable optics, and microfluidics. Inkjet printing addresses both of these problems. Firstly, Inkjet printing is a non-contact technique and can print on very thin freestanding membranes. Secondly, the high precision of inkjet printers makes it possible to print complex electrode geometries in the millimetre scale. We demonstrate the advantages of inkjet printing and carbon black electrodes by conducting a full characterisation of the printed electrodes. The printed carbon black electrodes have resistances as low as 13kΩ/□, an elastic modulus of approximately 1MPa, and a cyclic resistance swing which increases by 7% over 1500 cycles at 50% stretch. We also demonstrate a DEA with printed carbon black electrodes with a diametral stretch of 8.8% at an electric field of approximately 94V/μm. Finally a qualitative test is conducted to show that the printed carbon black electrode is extremely hardwearing.

  20. Cupric Hexacyanoferrate Nanoparticle Modified Carbon Ceramic Composite Electrodes

    Institute of Scientific and Technical Information of China (English)

    WANG,Peng(王鹏); ZHU,Guo-Yi(朱果逸)

    2002-01-01

    Graphite powder-supported cupric hexacyanoferrate (CuHCF)nanoparticles were dispersed into methyltrimethoxysilane-based gels to produce a conducting carbon ceramic composite, which was used as electrode material to fabricate surface-renewable CuHCF-modified electrodes. Electrochemical behavior of the CuHCF-modified carbon ceramic composite electrodes was characterized using cyclic and square-wave voitammetry.Cyclic voltammograms at various scan rates indicated that peak currents were surface-confined at low scan rates. In the presence of glutathione, a clear electrocatalytic response was observed at the CuHCF-modified composite electrodes. In addition, the electrodes exhibited a distinct advantage of reproducible surface-renewal by simple mechanical polishing on emery paper, as well as ease of preparation, and good chemical and mechanical stability in a flowing stream.

  1. Cupric Hexacyanoferrate Nanoparticle Modified Carbon Ceramic Composite Electrodes

    Institute of Scientific and Technical Information of China (English)

    WANG,Peng; ZHU,Guo-Yi

    2002-01-01

    Graphite powder-supported cupric hexacyanoferrate(CuHCF) nanoparticles were dispersed into methyltrimethoxysilane-based gels to produce a conducting carbon ceramic composite,which was used as electrode materials to fabricate surface-renewable CuHCF-modified electrodes.Electrochemical behavior of the CuHCF-modified carbon ceramic composite electrodes was characterized using cyclic and square-wave voltammetry. Cyclinc voltammograms at various scan rates indicated that peak currents were suface-confined at low scan rates.In the presence of glutathione,a clear electrocatalytic response was observed at the CuHCF-modified composite electrodes.In addition,the electrodes exhibited a distinct advantage of reproducible surface-renewal by simple mechanical polishing on emery paper,as well as ease of preparation,and good chemical and mechanical stability in a flowing stream.

  2. A Reliable Reference Electrode in Molten Carbonate and Its Applications

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A Ag|AgCl reference electrode which can be used in molten carbonate media has been described in this paper.It consists of a silver wire immersed in a solution of AgCl(1mol%) in (Li0.62,K0.38)2CO3,with a zirconia junction.The main properties of reference electrode,such as reproducibility ,stability and reversibility, were checked.The results have demonstrated that the reference electrode is reliable.With such reference electrode catalysis of various electrode materials to oxygen reduction in molten alkali carbonate media was investigated.It is found that as catalysts for oxygen reduction oxidized nickel-niobium alloy is superior to nickel oxide.

  3. Thick electrodes including nanoparticles having electroactive materials and methods of making same

    Science.gov (United States)

    Xiao, Jie; Lu, Dongping; Liu, Jun; Zhang, Jiguang; Graff, Gordon L.

    2017-02-21

    Electrodes having nanostructure and/or utilizing nanoparticles of active materials and having high mass loadings of the active materials can be made to be physically robust and free of cracks and pinholes. The electrodes include nanoparticles having electroactive material, which nanoparticles are aggregated with carbon into larger secondary particles. The secondary particles can be bound with a binder to form the electrode.

  4. Thick electrodes including nanoparticles having electroactive materials and methods of making same

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Jie; Lu, Dongping; Liu, Jun; Zhang, Jiguang; Graff, Gordon L.

    2017-02-21

    Electrodes having nanostructure and/or utilizing nanoparticles of active materials and having high mass loadings of the active materials can be made to be physically robust and free of cracks and pinholes. The electrodes include nanoparticles having electroactive material, which nanoparticles are aggregated with carbon into larger secondary particles. The secondary particles can be bound with a binder to form the electrode.

  5. Functional materials in amperometric sensing polymeric, inorganic, and nanocomposite materials for modified electrodes

    CERN Document Server

    Seeber, Renato; Zanardi, Chiara

    2014-01-01

    Amperometric sensors, biosensors included, particularly rely on suitable electrode materials. Progress in material science has led to a wide variety of options that are available today. For the first time, these novel functional electrode coating materials are reviewed in this monograph, written by and for electroanalytical chemists. This includes intrinsically conducting, redox and ion-exchange polymers, metal and carbon nanostructures, silica based materials. Monolayers and relatively thick films are considered. The authors critically discuss preparation methods, in addition to chemical and

  6. Nanostructured Electrode Materials for Electrochemical Capacitor Applications

    Directory of Open Access Journals (Sweden)

    Hojin Choi

    2015-06-01

    Full Text Available The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication of electrochemical capacitor electrodes and also give a brief overview of electric double-layer capacitors, pseudocapacitors, and hybrid capacitors. From a materials point of view, the latest trends in electrochemical capacitor research are also discussed through extensive analysis of the literature and by highlighting notable research examples (published mostly since 2013. Finally, a perspective on next-generation capacitor technology is also given, including the challenges that lie ahead.

  7. Direct prediction of the desalination performance of porous carbon electrodes for capacitive deionization

    NARCIS (Netherlands)

    Porada, S.; Borchardt, D.; Oschatz, M.; Bryjak, M.; Atchison, J.S.; Keesman, K.J.; Kaskel, S.; Biesheuvel, P.M.; Presser, V.

    2013-01-01

    Desalination by capacitive deionization (CDI) is an emerging technology for the energy- and cost-efficient removal of ions from water by electrosorption in charged porous carbon electrodes. A variety of carbon materials, including activated carbons, templated carbons, carbon aerogels, and carbon nan

  8. Direct prediction of the desalination performance of porous carbon electrodes for capacitive deionization

    NARCIS (Netherlands)

    Porada, S.; Borchardt, D.; Oschatz, M.; Bryjak, M.; Atchison, J.S.; Keesman, K.J.; Kaskel, S.; Biesheuvel, P.M.; Presser, V.

    2013-01-01

    Desalination by capacitive deionization (CDI) is an emerging technology for the energy- and cost-efficient removal of ions from water by electrosorption in charged porous carbon electrodes. A variety of carbon materials, including activated carbons, templated carbons, carbon aerogels, and carbon

  9. Carbon paste electrodes in electroanalytical chemistry

    Directory of Open Access Journals (Sweden)

    KAREL VYTŘAS

    2009-09-01

    Full Text Available An overview is given dealing with the applications of carbon paste electrodes in equilibrium potentiometry as well as in electrochemical stripping analysis using both voltammetric and potentiometric modes. Various modifications of carbon pastes and carbon paste-based biosensors are also mentioned. The main emphasis in this article is directed at summarizing recent results of the authors’ research group during the past few years.

  10. Improved technology for manufacture of carbon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Platon, A.; Dumbrava, A.; Petrescu, N.I.; Simionescu, L.

    2000-07-01

    The paper presents investigations to improve some physico-chemical characteristics of carbon electrodes (such as coefficient of thermal expansion, mechanical strengths, density, pore volume, porosity etc.) obtained in different manufacture steps by addition of varieties of coal tar pitch. These include attempts to improve the chemical compatibility of the coke-pitch system in the mixture and establish the method and the point of introduction of additive, the concentration required and appropriate analytical control during the entire manufacture. Methods of analysis used include thermogravimetry and porosimetry. The microstructure of the electrodes is investigated through a wide range and the data obtained include pore size and pore volume distribution, surface area, porosity, particle size distribution and type of pores. The overall results clearly indicate better characteristics and performance for electrodes with additives as against electrodes without them, such as lower porosity, lower thermal expansion coefficients and greater mechanical strength. These data are analyzed with respect to the process step and electrode type.

  11. Engineering the Composition and Structure of Bimetallic Au-Cu Alloy Nanoparticles in Carbon Nanofibers: Self-Supported Electrode Materials for Electrocatalytic Water Splitting.

    Science.gov (United States)

    Wang, Juan; Zhu, Han; Yu, Danni; Chen, JiaWei; Chen, JiaDong; Zhang, Ming; Wang, LiNa; Du, MingLiang

    2017-06-14

    The bimetallic Au-Cu alloy nanoparticles have been constructed in electrospun carbon nanofibers (Au-Cu/CNFs), employing as high efficient hydrogen evolution reaction (HER) electrode. The morphology, structure, and composition of bimetallic Au-Cu alloy can be controlled by adjusting the precursor nanofibers through a facile approach. With the increased Cu content, the Au-Cu alloy have a transition from the homogeneous AuCu3 alloy phase to the Au3Cu phase with Cu shell. The self-supported bimetallic Au-Cu/CNFs hybrid can be directly employed as electrode materials for water splitting, and it showed excellent electrochemical activity, including long-term stability, high exchange current density, and low overpotential. The outstanding HER performance could be mainly attributed to the synergistic interactions and interfacial effects of Au-Cu alloy with high densities of uncoordinated surface atoms. In addition, the fast charge transport and the fast kinetic for the desorption of the gas were originated from the self-supported three-dimensional architectures consist of integrated Au-Cu/CNFs networks. The Au-Cu/CNFs with mass ratio of 1:2 (Au3Cu-Cu "core-shell" alloy) obtain the lowest overpotential of 83 mV (at j = 10 mA cm(-2)), lowest Tafel slope of 70 mV dec(-1), and highest exchange current density of 0.790 mA cm(-2). The present investigations offer a new strategy for the design and synthesis of unique nanocrystals in energy conversion related application.

  12. Improved electrode material for deep brain stimulation.

    Science.gov (United States)

    Petrossians, A; Whalen, J J; Weiland, J D

    2016-08-01

    Deep brain stimulation (DBS) devices have been implanted for treatment of basic tremor, Parkinson's disease and dystonia. These devices use electrodes in contact with tissue to deliver electrical pulses to targeted cells, to elicit specific therapeutic responses. In general, the neuromodulation industry has been evolving towards smaller, less invasive electrodes. However, current electrode materials do not support small sizes without severely restricting the stimulus output. Hence, an improved electrode material will benefit present and future DBS systems. In this study, five DBS leads were modified using a cost-effective and materials-efficient process for applying an ultra-low impedance platinum-iridium alloy coating. One DBS lead was used for insertion test and four DBS leads were chronically pulsed for 12 weeks. The platinum-iridium alloy significantly improved the electrical properties of the DBS electrodes and was robust to insertion into brain and to 12 weeks of chronic pulsing.

  13. Characteristics of Arcs Between Porous Carbon Electrodes

    OpenAIRE

    Carvou, Erwann; Le Garrec, Jean-Luc; Mitchell, Brian

    2013-01-01

    International audience; Arcs between carbon electrodes present some specific differences compared with metallic arcs. The arc voltage is higher, but does not attain a stable value displaying large fluctuations. Indeed, the arcs are produced by the direct sublimation of the electrodes, without passing through a molten phase. The arc production is also facilitated by both circuit breaking and electric field breakdown. In this paper, arcing has been examined under various conditions (voltage, cu...

  14. Nucleation and electrolytic deposition of lead on model carbon electrodes

    Science.gov (United States)

    Cericola, D.; Spahr, M.

    2016-08-01

    There is a general consensus in the lead acid battery industry for the use of carbon additives as a functional component in the negative paste to boost the battery performance with regards to charge acceptance and cycle life especially for upcoming automotive and energy storage applications. Several mechanisms are discussed in the scientific literature and the affinity of the carbon surfaces to lead species seems to play a key role. With a set of experiments on model carbon electrodes we gave evidence to the fact that some carbon materials promote spontaneous nucleation of lead crystals. We propose a mechanism such that the carbon, as soon as in a lead containing environment, immobilizes some lead on its surface. Such immobilized lead acts as nucleation seed for the deposition of lead when a current is passed through the material. It is therefore possible to differentiate and select the carbon materials based on their ability to form nucleation seeds.

  15. W-doped TiO2 mesoporous electron transport layer for efficient hole transport material free perovskite solar cells employing carbon counter electrodes

    Science.gov (United States)

    Xiao, Yuqing; Cheng, Nian; Kondamareddy, Kiran Kumar; Wang, Changlei; Liu, Pei; Guo, Shishang; Zhao, Xing-Zhong

    2017-02-01

    Doping of TiO2 by metal elements for the scaffold layer of the perovskite solar cells has been proved to be one of the effective methods to improve the power conversion efficiency. In the present work, we report the impact of doping of TiO2 nanoparticles with different amounts of tungsten (W) on the photovoltaic properties of hole transport material free perovskite solar cells (PSCs) that employ carbon counter electrode. Light doping with W (less than 1000 ppm) improves the power conversion efficiencies (PCEs) of solar cells by promoting the electron conductivity in the TiO2 layer which facilitates electron transfer and collection. With the incorporation of W, average efficiency of PSCs is increased from 9.1% for the un-doped samples to 10.53% for the 1000 ppm W-doped samples, mainly originates from the increase of short circuit current density and fill factor. Our champion cell exhibits an impressive PCE of 12.06% when using the 1000 ppm W-doped TiO2 films.

  16. Advanced Materials for Neural Surface Electrodes.

    Science.gov (United States)

    Schendel, Amelia A; Eliceiri, Kevin W; Williams, Justin C

    2014-12-01

    Designing electrodes for neural interfacing applications requires deep consideration of a multitude of materials factors. These factors include, but are not limited to, the stiffness, biocompatibility, biostability, dielectric, and conductivity properties of the materials involved. The combination of materials properties chosen not only determines the ability of the device to perform its intended function, but also the extent to which the body reacts to the presence of the device after implantation. Advances in the field of materials science continue to yield new and improved materials with properties well-suited for neural applications. Although many of these materials have been well-established for non-biological applications, their use in medical devices is still relatively novel. The intention of this review is to outline new material advances for neural electrode arrays, in particular those that interface with the surface of the nervous tissue, as well as to propose future directions for neural surface electrode development.

  17. Novel Carbons as Electrodes for Electrical Energy Storage

    Science.gov (United States)

    Ruoff, Rodney S.

    2014-03-01

    In this talk I will speculate about directions for carbon materials as the electrode(s) in EES systems such as ultracapacitors and Li ion batteries. Perhaps the penultimate electrode material for ultracapacitors (based on charge storage by electrical double layer capacitance, EDLC) would be a ``negative curvature carbon'' (NCC, akin to the Schwartzite structures) with atom thick walls, and possibly substitutionally doped with, e.g., N atoms in case the all-carbon structure were limited by quantum (i.e., intrinsic) capacitance. Such an NCC would have a distribution of pore sizes that would likely (for optimal performance) span ``mesoscale'' and ``microscale'' pores, which in the parlance of porous materials means pores ``above 2-3 nanometers'' and pores ``below about 2 nanometers,'' respectively. Making such materials offers exciting challenges for materials chemists/synthetic chemists, and to date only the ``basic'' Schwarzite structures (ideal crystals studied by DFT with periodic boundary conditions and relatively simple unit cells) have been modeled in terms of properties such as their electronic states and in some cases, potential as all carbon ferromagnets. I identified the NCCs as candidates for EES for ultracapacitors, in a paper published in Science in 2011 with coauthors. We made an aperiodic carbon that had atom thick walls and surface areas as high as 3200 m2/g, along with ``good'' powder electrical conductivity, high carbon content, and apparently close to 100% trivalently bonded carbon in the walls of this very porous carbon. We have learned in one set of experiments, as published in Energy and Environmental Science, that doping with N atoms can increase the EDLC, which we suggest could be a consequence of limiting quantum capacitance in the all-carbon analogue.

  18. Fabrication of catalytic electrodes for molten carbonate fuel cells

    Science.gov (United States)

    Smith, James L.

    1988-01-01

    A porous layer of catalyst material suitable for use as an electrode in a molten carbonate fuel cell includes elongated pores substantially extending across the layer thickness. The catalyst layer is prepared by depositing particulate catalyst material into polymeric flocking on a substrate surface by a procedure such as tape casting. The loaded substrate is heated in a series of steps with rising temperatures to set the tape, thermally decompose the substrate with flocking and sinter bond the catalyst particles into a porous catalytic layer with elongated pores across its thickness. Employed as an electrode, the elongated pores provide distribution of reactant gas into contact with catalyst particles wetted by molten electrolyte.

  19. ELECTROCHEMICAL PROPERTIES OF NANOPOROUS CARBON ELECTRODES

    Directory of Open Access Journals (Sweden)

    P.Nigu

    2002-01-01

    Full Text Available Electrical double layer and electrochemical characteristics at the nanoporous carbon | (C2H54NBF4 + acetonitrile interface have been studied by the cyclic voltammetry and impedance spectroscopy methods. The value of zero charge potential (0.23 V vs. SCE in H2O, the region of ideal polarizability and other characteristics have been established. Analysis of complex plane plots shows that the nanoporous carbon | x M (C2H54NBF4 + acetonitrile interface can be simulated by the equivalent circuit, in which the two parallel conduction parts in the solid and liquid phases are interconnected by the double layer capacitance in parallel with the complex admittance of hindered reaction of the charge transfer process. The values of the characteristic frequency depend on the electrolyte concentration and on the electrode potential, i.e. on the nature of ions adsorbed at the surface of nanoporous carbon electrode.

  20. Using mesoporous carbon electrodes for brackish water desalination.

    Science.gov (United States)

    Zou, Linda; Li, Lixia; Song, Huaihe; Morris, Gayle

    2008-04-01

    Electrosorptive deionisation is an alternative process to remove salt ions from the brackish water. The porous carbon materials are used as electrodes. When charged in low voltage electric fields, they possess a highly charged surface that induces adsorption of salt ions on the surface. This process is reversible, so the adsorbed salt ions can be desorbed and the electrode can be reused. In the study, an ordered mesoporous carbon (OMC) electrode was developed for electrosorptive desalination. The effects of pore arrangement pattern (ordered and random) and pore size distribution (mesopores and micropores) on the desalination performance was investigated by comparing OMC and activated carbon (AC). It were revealed from X-ray diffraction and N(2) sorption measurements that AC has both micropores and mesopores, whereas ordered mesopores are dominant in OMC. Their performance as potential electrodes to remove salt was evaluated by cyclic voltammetry (CV) and galvanostatic charge/discharge tests at a range of electrolyte concentrations and sweep rates. It is deduced that under the same electrochemical condition the specific capacitance values of OMC electrode (i.e. 133 F/g obtained from CV at a sweep rate of 1 mV/s in 0.1M NaCl solution) are larger than those of AC electrode (107 F/g), suggesting that the former has a higher desalting capacity than the latter. Furthermore, the OMC electrode shows a better rate capacity than the AC electrode. In addition, the desalination capacities were quantified by the batch-mode experiment at low voltage of 1.2V in 25 ppm NaCl solution (50 micros/cm conductivity). It was found that the adsorbed ion amounts of OMC and AC electrodes were 11.6 and 4.3 micromol/g, respectively. The excellent electrosorptive desalination performance of OMC electrode might be not only due to the suitable pore size (average of 3.3 nm) for the propagation of the salt ions, but also due to the ordered mesoporous structure that facilitates desorption of the

  1. Carbon nanotube composite materials

    Energy Technology Data Exchange (ETDEWEB)

    O' Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2015-03-24

    A material consisting essentially of a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes dissolved in a solvent. Un-functionalized carbon nanotube concentrations up to 30 wt % and hydroxylated carbon nanotube concentrations up to 40 wt % can be used with even small concentrations of each (less than 2 wt %) useful in producing enhanced conductivity properties of formed thin films.

  2. Carbon nanotube composite materials

    Science.gov (United States)

    O'Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2015-03-24

    A material consisting essentially of a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes dissolved in a solvent. Un-functionalized carbon nanotube concentrations up to 30 wt % and hydroxylated carbon nanotube concentrations up to 40 wt % can be used with even small concentrations of each (less than 2 wt %) useful in producing enhanced conductivity properties of formed thin films.

  3. Catalase-Modified Carbon Electrodes: Persuading Oxygen To Accept Four Electrons Rather Than Two.

    Science.gov (United States)

    Sepunaru, Lior; Laborda, Eduardo; Compton, Richard G

    2016-04-18

    We successfully exploited the natural highly efficient activity of an enzyme (catalase) together with carbon electrodes to produce a hybrid electrode for oxygen reduction, very appropriate for energy transformation. Carbon electrodes, in principle, are cheap but poor oxygen reduction materials, because only two-electron reduction of oxygen occurs at low potentials, whereas four-electron reduction is key for energy-transformation technology. With the immobilization of catalase on the surface, the hydrogen peroxide produced electrochemically is decomposed back to oxygen by the enzyme; the enzyme natural activity on the surface regenerates oxygen, which is further reduced by the carbon electrode with no direct electron transfer between the enzyme and the electrode. Near full four-electron reduction of oxygen is realised on a carbon electrode, which is modified with ease by a commercially available enzyme. The value of such enzyme-modified electrode for energy-transformation devices is evident.

  4. Characterization of Transition-Metal Oxide Deposition on Carbon Electrodes of a Supercapacitor

    Directory of Open Access Journals (Sweden)

    Ying-Chung Chen

    2016-12-01

    Full Text Available In order to fabricate the composite electrodes of a supercapacitor, transition-metal oxide materials NiO and WO3 were deposited on carbon electrodes by electron beam evaporation. The influences of various transition-metal oxides, scan rates of cyclic voltammograms (CVs, and galvanostatic charge/discharge tests on the characteristics of supercapacitor were studied. The charge/discharge efficiency and the lifetime of the composite electrodes were also investigated. It was found that the composite electrodes exhibited more favorable capacitance properties than those of the carbon electrodes at high scan rates. The results revealed the promotion of the capacitance property of the supercapacitor with composite electrode and the improving of the decay property in capacitance at high scan rate. In addition, the charge/discharge efficiency is close to 100% after 5000 cycles, and the composite electrode retains strong adhesion between the electrode material and the substrate.

  5. All-solid-state carbonate-selective electrode based on screen-printed carbon paste electrode

    Science.gov (United States)

    Li, Guang; Lyu, Xiaofeng; Wang, Zhan; Rong, Yuanzhen; Hu, Ruifen; Luo, Zhiyuan; Wang, You

    2017-02-01

    A novel disposable all-solid-state carbonate-selective electrode based on a screen-printed carbon paste electrode using poly(3-octylthiophene-2,5-diyl) (POT) as an ion-to-electron transducer has been developed. The POT was dropped onto the reaction area of the carbon paste electrode covered by the poly(vinyl chloride) (PVC) membrane, which contains N,N-Dioctyl-3α,12α-bis(4-trifluoroacetylbenzoyloxy)-5β-cholan-24-amide as a carbonate ionophore. The electrode showed a near-Nernstian slope of  -27.5 mV/decade with a detection limit of 3.6 * 10-5 mol l-1. Generally, the detection time was 30 s. Because these electrodes are fast, convenient and low in cost, they have the potential to be mass produced and used in on-site testing as disposable sensors. Furthermore, the repeatability, reproducibility and stability have been studied to evaluate the properties of the electrodes. Measurement of the carbonate was also conducted in a human blood solution and achieved good performance.

  6. Oxygen electrode reaction in molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Appleby, A.J.; White, R.E.

    1992-07-07

    Molten carbonate fuel cell system is a leading candidate for the utility power generation because of its high efficiency for fuel to AC power conversion, capability for an internal reforming, and a very low environmental impact. However, the performance of the molten carbonate fuel cell is limited by the oxygen reduction reaction and the cell life time is limited by the stability of the cathode material. An elucidation of oxygen reduction reaction in molten alkali carbonate is essential because overpotential losses in the molten carbonate fuel cell are considerably greater at the oxygen cathode than at the fuel anode. Oxygen reduction on a fully-immersed gold electrode in a lithium carbonate melt was investigated by electrochemical impedance spectroscopy and cyclic voltammetry to determine electrode kinetic and mass transfer parameters. The dependences of electrode kinetic and mass transfer parameters on gas composition and temperature were examined to determine the reaction orders and the activation energies. The results showed that oxygen reduction in a pure lithium carbonate melt occurs via the peroxide mechanism. A mass transfer parameter, D{sub O}{sup 1/2}C{sub O}, estimated by the cyclic voltammetry concurred with that calculated by the EIS technique. The temperature dependence of the exchange current density and the product D{sub O}{sup 1/2}C{sub O} were examined and the apparent activation energies were determined to be about 122 and 175 kJ/ mol, respectively.

  7. Air Brush Fabricated Carbon Nanotube Supercapacitor Electrodes

    Science.gov (United States)

    2010-09-01

    dispersant is not contributing to the capacitance. The electrochemical, cyclic voltametry , measurements were made using a Keithley 4200 Semiconductor...reference electrode. The cyclic voltamogram (CV) was performed in potential ranges of anywhere between –0.9–0.5 V at scan rates ranging from 1–100 mV...Symbols, Acronyms, and Abbreviations AL aluminum CNT carbon nanotube Cu copper CV cyclic voltamogram ESEM environmental scanning electron microscope

  8. Vertically aligned carbon nanotube electrodes for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Welna, Daniel T.; Taylor, Barney E. [Materials and Manufacturing Directorate, Air Force Research Laboratory, AFRL/RX, Wright-Patterson AFB, OH 45433 (United States); UTC, Inc., Beavercreek, OH 45431 (United States); Qu, Liangti [Department of Chemistry, Beijing Institute of Technology, 100081 Beijing (China); Dai, Liming [Department of Chemical Engineering, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH (United States); Durstock, Michael F. [Materials and Manufacturing Directorate, Air Force Research Laboratory, AFRL/RX, Wright-Patterson AFB, OH 45433 (United States)

    2011-02-01

    As portable electronics become more advanced and alternative energy demands become more prevalent, the development of advanced energy storage technologies is becoming ever more critical in today's society. In order to develop higher power and energy density batteries, innovative electrode materials that provide increased storage capacity, greater rate capabilities, and good cyclability must be developed. Nanostructured materials are gaining increased attention because of their potential to mitigate current electrode limitations. Here we report on the use of vertically aligned multi-walled carbon nanotubes (VA-MWNTs) as the active electrode material in lithium-ion batteries. At low specific currents, these VA-MWNTs have shown high reversible specific capacities (up to 782 mAh g{sup -1} at 57 mA g{sup -1}). This value is twice that of the theoretical maximum for graphite and ten times more than their non-aligned equivalent. Interestingly, at very high discharge rates, the VA-MWNT electrodes retain a moderate specific capacity due to their aligned nature (166 mAh g{sup -1} at 26 A g{sup -1}). These results suggest that VA-MWNTs are good candidates for lithium-ion battery electrodes which require high rate capability and capacity. (author)

  9. Activated Carbon Fiber Monoliths as Supercapacitor Electrodes

    Directory of Open Access Journals (Sweden)

    Gelines Moreno-Fernandez

    2017-01-01

    Full Text Available Activated carbon fibers (ACF are interesting candidates for electrodes in electrochemical energy storage devices; however, one major drawback for practical application is their low density. In the present work, monoliths were synthesized from two different ACFs, reaching 3 times higher densities than the original ACFs’ apparent densities. The porosity of the monoliths was only slightly decreased with respect to the pristine ACFs, the employed PVDC binder developing additional porosity upon carbonization. The ACF monoliths are essentially microporous and reach BET surface areas of up to 1838 m2 g−1. SEM analysis reveals that the ACFs are well embedded into the monolith structure and that their length was significantly reduced due to the monolith preparation process. The carbonized monoliths were studied as supercapacitor electrodes in two- and three-electrode cells having 2 M H2SO4 as electrolyte. Maximum capacitances of around 200 F g−1 were reached. The results confirm that the capacitance of the bisulfate anions essentially originates from the double layer, while hydronium cations contribute with a mixture of both, double layer capacitance and pseudocapacitance.

  10. High capacitance of coarse-grained carbide derived carbon electrodes

    Science.gov (United States)

    Dyatkin, Boris; Gogotsi, Oleksiy; Malinovskiy, Bohdan; Zozulya, Yuliya; Simon, Patrice; Gogotsi, Yury

    2016-02-01

    We report exceptional electrochemical properties of supercapacitor electrodes composed of large, granular carbide-derived carbon (CDC) particles. Using a titanium carbide (TiC) precursor, we synthesized 70-250 μm sized particles with high surface area and a narrow pore size distribution. Electrochemical cycling of these coarse-grained powders defied conventional wisdom that a small particle size is strictly required for supercapacitor electrodes and allowed high charge storage densities, rapid transport, and good rate handling ability. The material showcased capacitance above 100 F g-1 at sweep rates as high as 250 mV s-1 in organic electrolyte. 250-1000 micron thick dense CDC films with up to 80 mg cm-2 loading showed superior areal capacitances. The material significantly outperformed its activated carbon counterpart in organic electrolytes and ionic liquids. Furthermore, large internal/external surface ratio of coarse-grained carbons allowed the resulting electrodes to maintain high electrochemical stability up to 3.1 V in ionic liquid electrolyte. In addition to presenting novel insights into the electrosorption process, these coarse-grained carbons offer a pathway to low-cost, high-performance implementation of supercapacitors in automotive and grid-storage applications.

  11. Carbon nanotube macrofilm-based nanocomposite electrodes for energy applications

    Science.gov (United States)

    Cao, Zeyuan

    Finding new electrode materials for energy conversion and storage devices have been the focus of recent research in the fields of science and engineering. Suffering from poor electronic conductivity, chemical and mechanical stability, active electrode materials are usually coupled with different carbon nanostructured materials to form nanocomposite electrodes, showing promising electrochemical performance. Among the carbon nanostructured materials, carbon nanotube (CNT) macrofilms draw great attention owing to their extraordinary properties, such as a large specific surface area, exceptionally high conductivity, porous structure, flexibility, mechanical robustness, and adhesion. They could effectively enhance the electrochemical performance of the incorporated active materials in the nanocomposites. In this dissertation, CNT macrofilm-based nanocomposites are investigated for rechargeable lithium-ion batteries, supercapacitors, and electrocatalysts of fuel cells. The progressive research developed various nanocomposites from cathode materials to anode materials followed by a general nanocomposite solution due to the unique adhesive property of the fragmented CNT macrofilms. The in-situ synthesis strategy are explored to in-situ deposit unlithiated cathode materials V2O5 and lithiated cathode materials LiMn2O4 nanocrystals in the matrix of the CNT macrofilms as nanocomposites to be paired with metallic lithium in half cells. The presence of oxygen-containing functional groups on the surface of the CNT macrofilms after purification can enhance the association with the active materials to enable the facilitated transport of solvated ions to the electrolyte/electrode interfaces and increase the diffusion kinetics, consequently enhancing the battery performance in terms of high specific capacity, rate capability, and cycling stability. It is also significant to demonstrate a reliable, low-cost, and effective route to synthesize the family of metal oxides (MxOy (M=Fe, Co

  12. Gallium Nitride Crystals: Novel Supercapacitor Electrode Materials.

    Science.gov (United States)

    Wang, Shouzhi; Zhang, Lei; Sun, Changlong; Shao, Yongliang; Wu, Yongzhong; Lv, Jiaxin; Hao, Xiaopeng

    2016-05-01

    A type of single-crystal gallium nitride mesoporous membrane is fabricated and its supercapacitor properties are demonstrated for the first time. The supercapacitors exhibit high-rate capability, stable cycling life at high rates, and ultrahigh power density. This study may expand the range of crystals as high-performance electrode materials in the field of energy storage.

  13. Carbon materials for supercapacitors

    Science.gov (United States)

    Gao, Yang

    As an important energy storage device, electrochemical supercapacitors or ultracapacitors fill the gap between conventional dielectric capacitors and batteries in terms of specific energy and power. Although supercapacitors have been used in electric vehicles, digital communication instruments, and pulsed lasers, further improvement of supercapacitor performance is highly needed to enhance the energy density without significantly losing the power density. Additionally, the conventional supercapacitors use rigid packages and liquid electrolytes, which limit applications in transparent and flexible electronics. To address these challenges, the research efforts in this dissertation mainly focused on: 1) improvement of the energy density of carbon nanoonions by chemical activation; 2) laser-assisted activation of carbon nanotubes for improved energy density; 3) fabrication of flexible solid-state supercapacitors based on nanocarbon and manganese dioxide (MnO2) hybrid electrodes; and 4) investigation of the electrochemical performance of graphene as transparent and flexible supercapacitor electrodes.

  14. Metallic carbon materials

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, M.L.; Crespi, V.H.; Louie, S.G.S.; Zettl, A.K.

    1999-11-30

    Novel metallic forms of planar carbon are described, as well as methods of designing and making them. Nonhexagonal arrangements of carbon are introduced into a graphite carbon network essentially without destroying the planar structure. Specifically a form of carbon comprising primarily pentagons and heptagons, and having a large density of states at the Fermi level is described. Other arrangements of pentagons and heptagons that include some hexagons, and structures incorporating squares and octagons are additionally disclosed. Reducing the bond angle symmetry associated with a hexagonal arrangement of carbons increases the likelihood that the carbon material will have a metallic electron structure.

  15. Sol-gel derived electrode materials for supercapacitor applications

    Science.gov (United States)

    Lin, Chuan

    1998-12-01

    Electrochemical capacitors have been receiving increasing interest in recent years for use in energy storage systems because of their high energy and power density and long cycle lifes. Possible applications of electrochemical capacitors include high power pulsed lasers, hybrid power system for electric vehicles, etc. In this dissertation, the preparation of electrode materials for use as electrochemical capacitors has been studied using the sol-gel process. The high surface area electrode materials explored in this work include a synthetic carbon xerogel for use in a double-layer capacitor, a cobalt oxide xerogel for use in a pseudocapacitor, and a carbon-ruthenium xerogel composite, which utilizes both double-layer and faradaic capacitances. The preparation conditions of these materials were investigated in detail to maximize the surface area and optimize the pore size so that more energy could be stored while minimizing mass transfer limitations. The microstructures of the materials were also correlated with their performance as electrochemical capacitors to improve their energy and power densities. Finally, an idealistic mathematical model, including both double-layer and faradaic processes, was developed and solved numerically. This model can be used to perform the parametric studies of an electrochemical capacitor so as to gain a better understanding of how the capacitor works and also how to improve cell operations and electrode materials design.

  16. Carbon Materials Research

    Science.gov (United States)

    2006-08-01

    electrodes, high temperature molds, rocket nozzles and exit cones, tires , ink, nuclear reactors and fuel particles, filters, prosthetics, batteries and...carbon would be highly oriented pyrolytic graphite (HOPG), which is formed by depositing one atom at a time on a surface utilizing the pyrolysis of a...Moreover, it is well known that during pyrolysis , mesophase converts into a matrix that is very anisotropic. The formation of onion-like “sheaths

  17. Electrochemistry of ABTS at Glassy Carbon Electrodes

    Institute of Scientific and Technical Information of China (English)

    Han Zeng; Zhi-qiang Tang; Ling-wen Liao; Jing Kang; Yan-xia Chen

    2011-01-01

    The electrochemical and the mass transport behavior of ABTS2-/ABTS- (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate)) redox couple at glassy carbon electrode (GCE) in phosphate buffer solution (PBS,pH=4.4) is studied in detail by cyclic voltammetry combined with rotating disk electrode system.From the i-E curves recorded at different electrode rotating rate,rate constant,and transfer coefficient for ABTS 2-(≒)ABTS-+e reaction at GCE electrode and the diffusion coefficient of ABTS2- in PBS are estimated to be 4.6× 10-3 cm/s,0.28,and 4.4× 10-6 cm2/s,respectively.The transfer coefficient with a value of ca.0.28 differs largely from the value of 0.5 that is always assumed in the literature.The origins for the difference of the rate constant determined and the challenges for estimating the standard rate constant are discussed.The performance for such ABTS2- mediated bio-cathode toward oxygen reduction reaction is discussed according to the over-potential drop as well as current output limit associated with the charge transfer kinetics of ABTS2- (≒)ABTS- +e redox reaction and/or the mass transport effect.

  18. Desalination with carbon aerogel electrodes. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J.C.; Richardson, J.H.; Fix, D.V. [Lawrence Livermore National Lab., CA (United States); Thomson, S.L.; May, S.C. [Bechtel National, Inc., San Francisco, CA (United States)

    1996-12-04

    Electrically regenerated electrosorption process (carbon aerogel CDI) was developed by LLNL for continuously removing ionic impurities from aqueous streams. A salt solution flows in a channel formed by numerous pairs of parallel carbon aerogel electrodes. Each electrode has a very high BET surface area (2-5.4x10{sup 6}ft{sup 2}lb{sup -1} or 400-1100 m{sup 2}g{sup -1}) and very low electrical resistivity ({le}40 m{Omega}). Ions are removed from the electrolyte by the electric field and electrosorbed onto the carbon aerogel. It is concluded that carbon aerogel CDI may be an energy-efficient alternative to electrodialysis and reverse osmosis for desalination of brackish water ({le}5000 ppM). The intrinsic energy required by this process is about QV/2, where Q is the stored electrical charge and V is the voltage between the electrodes, plus losses. Estimated requirement for desalination of a 2000 ppM feed is -0.53-2.5 Wh/gal{sup -1} (0.5-2.4 kJ L{sup -1}), depending on voltage, flow rate, cell dimensions, aerogel density, recovery ratio, etc. This assumes that 50-70% of the stored electrical energy is reclaimed during regeneration (electrical discharge). Though the energy requirement for desalination of sea water is also low, this application will be much more difficult. Additional work will be required for desalination of streams that contain more than 5000 ppM total dissolved solids (2000 ppM will require electrochemical cells with extremely tight, demanding tolerances). At this present time, the process is best suited for streams with dilute impurities, as recently demonstrated during a field test at LLNL Treatment Facility C.

  19. Synthesis, characterization and application of electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    He, Lin [Iowa State Univ., Ames, IA (United States)

    1995-07-07

    It has been known that significant advances in electrochemistry really depend on improvements in the sensitivity, selectivity, convenience, and/or economy of working electrodes, especially through the development of new working electrode materials. The advancement of solid state chemistry and materials science makes it possible to provide the materials which may be required as satisfactory electrode materials. The combination of solid state techniques with electrochemistry expands the applications of solid state materials and leads to the improvement of electrocatalysis. The study of Ru-Ti4O7 and Pt-Ti4O7 microelectrode arrays as introduced in paper 1 and paper 4, respectively, focuses on their synthesis and characterization. The synthesis is described by high temperature techniques for Ru or Pt microelectrode arrays within a conductive Ti4O7ceramic matrix. The characterization is based on the data obtained by x-ray diffractometry, scanning electron microscopy, voltammetry and amperometry. These microelectrode arrays show significant enhancement in current densities in comparison to solid Ru and Pt electrodes. Electrocatalysis at pyrochlore oxide Bi2Ru2O7.3 and Bi2Ir2O7 electrodes are described in paper 2 and paper 3, respectively. Details are reported for the synthesis and characterization of composite Bi2Ru2O7.3 electrodes. Voltammetric data are examined for evidence that oxidation can occur with transfer of oxygen to the oxidation products in the potential region corresponding to anodic discharge of H2O with simultaneous evolution of O2. Paper 3 includes electrocatalytic activities of composite Bi2Ir2O7 disk electrodes for the oxidation of I- and the reduction of IO3-.

  20. ac impedance of the carbon monofluoride electrode

    Science.gov (United States)

    Suchanski, M. R.

    1985-09-01

    The ac impedance of carbon monofluoride (CF) half-cells and Li/CF batteries that contain 1M LiBF4/4-butyrolactone electrolyte was measured as a function of state of charge. The nonfaradaic components of the CF half-cell impedance were resolved with the aid of a one-dimensional macroscopic treatment of a porous electrode. The values of the nonfaradaic components and their variation with charge withdrawn provide information concerning the nature of cathode discharge products, the degree of tortuosity in the cathode and separator matrices, and the cathode failure mechanism. The CF electrode capacitance, as measured by the low frequency quadrature impedance, can serve as a semiquantitative measure of battery state of charge under certain conditions.

  1. Carbon felt and carbon fiber - A techno-economic assessment of felt electrodes for redox flow battery applications

    Science.gov (United States)

    Minke, Christine; Kunz, Ulrich; Turek, Thomas

    2017-02-01

    Carbon felt electrodes belong to the key components of redox flow batteries. The purpose of this techno-economic assessment is to uncover the production costs of PAN- and rayon-based carbon felt electrodes. Raw material costs, energy demand and the impact of processability of fiber and felt are considered. This innovative, interdisciplinary approach combines deep insights into technical, ecologic and economic aspects of carbon felt and carbon fiber production. Main results of the calculation model are mass balances, cumulative energy demands (CED) and the production costs of conventional and biogenic carbon felts supplemented by market assessments considering textile and carbon fibers.

  2. Field emission properties of the graphenated carbon nanotube electrode

    Science.gov (United States)

    Zanin, H.; Ceragioli, H. J.; Peterlevitz, A. C.; Baranauskas, Vitor; Marciano, F. R.; Lobo, A. O.

    2015-01-01

    Reduced graphene oxide-coated carbon nanotubes (RGO-CNT) electrodes have been prepared by hot filament chemical vapour deposition system in one-step growth process. We studied RGO-CNT electrodes behaviour as cold cathode in field emission test. Our results show that RGO-CNT retain the low threshold voltage typical of CNTs, but with greatly improved emission current stability. The field emission enhancement value is significantly higher than that expected being caused by geometric effect (height divided by the radius of nanotube). This suggested that the field emission of this hybrid structure is not only from a single tip, but eventually it is from several tips with contribution of graphene nanosheets at CNT's walls. This phenomenon explains why the graphenated carbon nanotubes do not burn out as quickly as CNT does until emission ceases completely. These preliminaries results make nanocarbon materials good candidates for applications as electron sources for several devices.

  3. Drop detachment and motion on fuel cell electrode materials.

    Science.gov (United States)

    Gauthier, Eric; Hellstern, Thomas; Kevrekidis, Ioannis G; Benziger, Jay

    2012-02-01

    Liquid water is pushed through flow channels of fuel cells, where one surface is a porous carbon electrode made up of carbon fibers. Water drops grow on the fibrous carbon surface in the gas flow channel. The drops adhere to the superficial fiber surfaces but exhibit little penetration into the voids between the fibers. The fibrous surfaces are hydrophobic, but there is a substantial threshold force necessary to initiate water drop motion. Once the water drops begin to move, however, the adhesive force decreases and drops move with minimal friction, similar to motion on superhydrophobic materials. We report here studies of water wetting and water drop motion on typical porous carbon materials (carbon paper and carbon cloth) employed in fuel cells. The static coefficient of friction on these textured surfaces is comparable to that for smooth Teflon. But the dynamic coefficient of friction is several orders of magnitude smaller on the textured surfaces than on smooth Teflon. Carbon cloth displays a much smaller static contact angle hysteresis than carbon paper due to its two-scale roughness. The dynamic contact angle hysteresis for carbon paper is greatly reduced compared to the static contact angle hysteresis. Enhanced dynamic hydrophobicity is suggested to result from the extent to which a dynamic contact line can track topological heterogeneities of the liquid/solid interface.

  4. Nanostructured Lead Compounds in Electrode Materials of a Lead-Acid Battery

    Directory of Open Access Journals (Sweden)

    A.P. Kuzmenko

    2016-11-01

    Full Text Available The nanostructure and phase composition of the electrode material of lead-acid batteries, formed by chemical transformations with involvement of sulfuric acid solutions of various concentrations, water and carbon dioxide have been studied.

  5. Hybrid Electrodes of Carbon Nanotube and Reduced Graphene Oxide for Energy Storage Applications.

    Science.gov (United States)

    Choi, Eunmi; Chae, Su Jin; Kim, Areum; Kang, Keun Won; Oh, Min Seok; Kwon, Soon Hyeong; Yoon, Sung Pil; Pyo, Sung Gyu

    2015-11-01

    The choice of electrode materials in lithium ion batteries and supercapacitors is important for the stability, capacity, and cycle life of the device. Despite its low capacity, graphite has often been used as an electrode material due to its inherent stability. Due to an increasing demand for large-capacity energy storage systems, there is also a demand for the development of large-capacity Li ion batteries and supercapacitors. Therefore, carbonaceous materials like graphene and carbon nanotubes (CNTs), which have high stability as well as excellent electrical conductivity and mechanical strength, are receiving attention as new electrode materials. Recently, starting from simply applying graphene and CNTs as electrode materials and progressing to the development of hybrid materials, there have been increasing research efforts in enhancing the performance of Li ion batteries and supercapacitors through the use of carbonaceous materials. This paper will discuss new composite materials and electrode structures that use graphene and CNTs for applications in Li ion batteries and supercapacitors.

  6. Self-Templated Synthesis of Mesoporous Carbon from Carbon Tetrachloride Precursor for Supercapacitor Electrodes.

    Science.gov (United States)

    Tang, Duihai; Hu, Shi; Dai, Fang; Yi, Ran; Gordin, Mikhail L; Chen, Shuru; Song, Jiangxuan; Wang, Donghai

    2016-03-23

    A high-surface-area mesoporous carbon material has been synthesized using a self-templating approach via reduction of carbon tetrachloride by sodium potassium alloy. The advantage is the reduction-generated salt templates can be easily removed with just water. The produced mesoporous carbon has a high surface area and a narrow pore size distribution. When used as a supercapacitor electrode, this material exhibits a high specific capacitance (259 F g(-1)) and excellent cycling performance (>92% capacitance retention for 6000 cycles).

  7. Electrostatic atomization: Effect of electrode materials on electrostatic atomizer performance

    Science.gov (United States)

    Sankaran, Abhilash; Staszel, Christopher; Kashir, Babak; Perri, Anthony; Mashayek, Farzad; Yarin, Alexander

    2016-11-01

    Electrostatic atomization was studied experimentally with a pointed electrode in a converging nozzle. Experiments were carried out on poorly conductive canola oil where it was observed that electrode material may affect charge transfer. This points at the possible faradaic reactions that can occur at the surfaces of the electrodes. The supply voltage is applied to the sharp electrode and the grounded nozzle body constitutes the counter-electrode. The charge transfer is controlled by the electrochemical reactions on both the electrodes. The electrical performance study of the atomizer issuing a charged oil jet was conducted using three different nozzle body materials - brass, copper and stainless steel. Also, two sharp electrode materials - brass and stainless steel - were tested. The experimental results revealed that both the nozzle body material, as well as the sharp electrode material affected the spray and leak currents. Moreover, the effect of the sharp electrode material is quite significant. This research is supported by NSF Grant 1505276.

  8. Vanadium based materials as electrode materials for high performance supercapacitors

    Science.gov (United States)

    Yan, Yan; Li, Bing; Guo, Wei; Pang, Huan; Xue, Huaiguo

    2016-10-01

    As a kind of supercapacitors, pseudocapacitors have attracted wide attention in recent years. The capacitance of the electrochemical capacitors based on pseudocapacitance arises mainly from redox reactions between electrolytes and active materials. These materials usually have several oxidation states for oxidation and reduction. Many research teams have focused on the development of an alternative material for electrochemical capacitors. Many transition metal oxides have been shown to be suitable as electrode materials of electrochemical capacitors. Among them, vanadium based materials are being developed for this purpose. Vanadium based materials are known as one of the best active materials for high power/energy density electrochemical capacitors due to its outstanding specific capacitance and long cycle life, high conductivity and good electrochemical reversibility. There are different kinds of synthetic methods such as sol-gel hydrothermal/solvothermal method, template method, electrospinning method, atomic layer deposition, and electrodeposition method that have been successfully applied to prepare vanadium based electrode materials. In our review, we give an overall summary and evaluation of the recent progress in the research of vanadium based materials for electrochemical capacitors that include synthesis methods, the electrochemical performances of the electrode materials and the devices.

  9. On the molecular origin of supercapacitance in nanoporous carbon electrodes.

    Science.gov (United States)

    Merlet, Céline; Rotenberg, Benjamin; Madden, Paul A; Taberna, Pierre-Louis; Simon, Patrice; Gogotsi, Yury; Salanne, Mathieu

    2012-03-04

    Lightweight, low-cost supercapacitors with the capability of rapidly storing a large amount of electrical energy can contribute to meeting continuous energy demands and effectively levelling the cyclic nature of renewable energy sources. The excellent electrochemical performance of supercapacitors is due to a reversible ion adsorption in porous carbon electrodes. Recently, it was demonstrated that ions from the electrolyte could enter sub nanometre pores, greatly increasing the capacitance. However, the molecular mechanism of this enhancement remains poorly understood. Here we provide the first quantitative picture of the structure of an ionic liquid adsorbed inside realistically modelled microporous carbon electrodes. We show how the separation of the positive and negative ions occurs inside the porous disordered carbons, yielding much higher capacitance values (125 F g(-1)) than with simpler electrode geometries. The proposed mechanism opens the door for the design of materials with improved energy storage capabilities. It also sheds new light on situations where ion adsorption in porous structures or membranes plays a role.

  10. High power density electrodes for Carbon supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Portet, C.; Taberna, P.L.; Simon, P.; Flahaut, E.; Laberty-Robert, C. [CIRIMAT, UMR CNRS 5085, 118 Route de Narbonne 31062 Toulouse Cedex (France)

    2005-07-25

    This paper presents results obtained with 4 cm{sup 2} Carbon/Carbon supercapacitors cells in organic electrolyte. In the first approach, a surface treatment for Al current collector foil via the sol-gel route has been used in order to decrease the Al/active material interface resistance. Performances obtained with this original process are: a low equivalent series resistance (ESR) of 0.5 {omega} cm{sup 2} and a specific capacitance of 95 F g{sup -1} of activated carbon. Then, supercapacitors assembled with treated Al foil and active material containing activated carbon/carbon nanotubes (CNTs) with different compositions have been studied. Galvanostatic cycling measurements show that when CNTs content increases, both ESR and specific capacitance are decreased. Fifteen percent appears to be a good compromise between stored energy and delivered power with an ESR of 0.4 {omega} cm{sup 2} and a specific capacitance of 93 F g{sup -1} of carbonaceous active material. Finally, cells frequency behaviour has been characterized by Electrochemical Impedance Spectroscopy. The relaxation time constant of cells decreases when the CNTs content increases. For 15% of CNTs, the time constant is about 30% lower as compared to a cell using pure activated carbon-based electrodes leading to a higher delivered power. (author)

  11. MOLECULAR DESCRIPTION OF ELECTROLYTE SOLUTION IN A CARBON AEROGEL ELECTRODE

    Directory of Open Access Journals (Sweden)

    A.Kovalenko

    2003-01-01

    Full Text Available We develop a molecular theory of aqueous electrolyte solution sorbed in a nanoporous carbon aerogel electrode, based on the replica reference interaction site model (replica RISM for realistic molecular quenched-annealed systems. We also briefly review applications of carbon aerogels for supercapacitor and electrochemical separation devices, as well as theoretical and computer modelling of disordered porous materials. The replica RISM integral equation theory yields the microscopic properties of the electrochemical double layer formed at the surface of carbon aerogel nanopores, with due account of chemical specificities of both sorbed electrolyte and carbon aerogel material. The theory allows for spatial disorder of aerogel pores in the range from micro- to macroscopic size scale. We considered ambient aqueous solution of 1 M sodium chloride sorbed in two model nanoporous carbon aerogels with carbon nanoparticles either arranged into branched chains or randomly distributed. The long-range correlations of the carbon aerogel nanostructure substantially affect the properties of the electrochemical double layer formed by the solution sorbed in nanopores.

  12. Biomass-derived functional porous carbons as novel electrode material for the practical detection of biomolecules in human serum and snail hemolymph.

    Science.gov (United States)

    Veeramani, Vediyappan; Madhu, Rajesh; Chen, Shen-Ming; Lou, Bih-Show; Palanisamy, Jayabal; Vasantha, Vairathevar Sivasamy

    2015-05-22

    The biomass-derived activated carbons (ACs) have been prepared with high surface areas up to 793 m(2) g(-1) is by ZnCl2 activation at three different temperatures, viz. AC700, AC800, and AC900. The AC samples were characterized by a variety of analytical and spectroscopy techniques. The as-synthesized ACs were adopted for the simultaneous electrochemical detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). For comparison, reduced graphene oxide (RGO) was employed for the proposed sensor. The high surface area, modulated pore size and the presence of oxygen surface functional groups like heteroatoms (83.427% C, 1.085% N, 0.383% S, and 0.861% H) in the biomass-derived AC is found to be responsible for the excellent catalytic activities of biomolecules. Fascinatingly, the facile sensor further used to detect biomolecules levels in the snail hemolymph and human blood serum. Notably, the obtained analytical parameters for the biomolecules detection over the AC modified GCE, outperforming several carbon-based modified electrodes in literatures.

  13. Biomass-derived functional porous carbons as novel electrode material for the practical detection of biomolecules in human serum and snail hemolymph

    Science.gov (United States)

    Veeramani, Vediyappan; Madhu, Rajesh; Chen, Shen-Ming; Lou, Bih-Show; Palanisamy, Jayabal; Vasantha, Vairathevar Sivasamy

    2015-01-01

    The biomass-derived activated carbons (ACs) have been prepared with high surface areas up to 793 m2 g−1 is by ZnCl2 activation at three different temperatures, viz. AC700, AC800, and AC900. The AC samples were characterized by a variety of analytical and spectroscopy techniques. The as-synthesized ACs were adopted for the simultaneous electrochemical detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). For comparison, reduced graphene oxide (RGO) was employed for the proposed sensor. The high surface area, modulated pore size and the presence of oxygen surface functional groups like heteroatoms (83.427% C, 1.085% N, 0.383% S, and 0.861% H) in the biomass-derived AC is found to be responsible for the excellent catalytic activities of biomolecules. Fascinatingly, the facile sensor further used to detect biomolecules levels in the snail hemolymph and human blood serum. Notably, the obtained analytical parameters for the biomolecules detection over the AC modified GCE, outperforming several carbon-based modified electrodes in literatures. PMID:25998156

  14. Carbon-Nanotube-Based Electrodes for Biomedical Applications

    Science.gov (United States)

    Li, Jun; Meyyappan, M.

    2008-01-01

    A nanotube array based on vertically aligned nanotubes or carbon nanofibers has been invented for use in localized electrical stimulation and recording of electrical responses in selected regions of an animal body, especially including the brain. There are numerous established, emerging, and potential applications for localized electrical stimulation and/or recording, including treatment of Parkinson s disease, Tourette s syndrome, and chronic pain, and research on electrochemical effects involved in neurotransmission. Carbon-nanotube-based electrodes offer potential advantages over metal macroelectrodes (having diameters of the order of a millimeter) and microelectrodes (having various diameters ranging down to tens of microns) heretofore used in such applications. These advantages include the following: a) Stimuli and responses could be localized at finer scales of spatial and temporal resolution, which is at subcellular level, with fewer disturbances to, and less interference from, adjacent regions. b) There would be less risk of hemorrhage on implantation because nano-electrode-based probe tips could be configured to be less traumatic. c) Being more biocompatible than are metal electrodes, carbon-nanotube-based electrodes and arrays would be more suitable for long-term or permanent implantation. d) Unlike macro- and microelectrodes, a nano-electrode could penetrate a cell membrane with minimal disruption. Thus, for example, a nanoelectrode could be used to generate an action potential inside a neuron or in proximity of an active neuron zone. Such stimulation may be much more effective than is extra- or intracellular stimulation via a macro- or microelectrode. e) The large surface area of an array at a micron-scale footprint of non-insulated nanoelectrodes coated with a suitable electrochemically active material containing redox ingredients would make it possible to obtain a pseudocapacitance large enough to dissipate a relatively large amount of electric charge

  15. Amperometric determination of rutin on carbon paste electrodes

    Directory of Open Access Journals (Sweden)

    Pavla Macikova

    2010-12-01

    Full Text Available Three different carbon paste electrodes (i.e. unmodified, ironphthalocyanine and ionic liquid modified were tested to determinerutin by amperometry. The widest linear concentration range andlowest detection limit were obtained with unmodified carbon pasteelectrode.

  16. Novel Conductive Carbon Black and Polydimethlysiloxane ECG Electrode: A Comparison with Commercial Electrodes in Fresh, Chlorinated, and Salt Water.

    Science.gov (United States)

    Noh, Yeonsik; Bales, Justin R; Reyes, Bersain A; Molignano, Jennifer; Clement, Amanda L; Pins, George D; Florian, John P; Chon, Ki H

    2016-08-01

    In this study, we evaluated the performance of two novel conductive carbon black (CB) and polydimethlysiloxane (PDMS) bio-potential electrodes, with and without an integrated flexible copper mesh, against commercially available electrodes (Polar(®) textile, Silver-coated textile, and carbon rubber). The electrodes were tested in three types of water (fresh/unfiltered, chlorinated, and salt water). Our testing revealed that our CB/PDMS electrode with integrated copper mesh provided a high-fidelity ECG signal morphologies without any amplitude degradation in all of the types of water tested (N = 10). The non-meshed CB/PDMS electrodes were also subjected to a long-term durability test by the US Navy SCUBA divers during which the electrodes maintained ECG signal quality for a 6 h period of continuous use. The results of a material degradation analysis revealed the CB/PDMS composite material does not exhibit significant changes in physical integrity after prolonged exposure to the test conditions. The newly developed meshed CB/PDMS electrodes have the potential to be used in a wide variety of both dry and wet environments including the challenge of obtaining ECG signals in salt water environments.

  17. Density controlled carbon nanotube array electrodes

    Science.gov (United States)

    Ren, Zhifeng F [Newton, MA; Tu, Yi [Belmont, MA

    2008-12-16

    CNT materials comprising aligned carbon nanotubes (CNTs) with pre-determined site densities, catalyst substrate materials for obtaining them and methods for forming aligned CNTs with controllable densities on such catalyst substrate materials are described. The fabrication of films comprising site-density controlled vertically aligned CNT arrays of the invention with variable field emission characteristics, whereby the field emission properties of the films are controlled by independently varying the length of CNTs in the aligned array within the film or by independently varying inter-tubule spacing of the CNTs within the array (site density) are disclosed. The fabrication of microelectrode arrays (MEAs) formed utilizing the carbon nanotube material of the invention is also described.

  18. Fabrication techniques of electrode arrays for carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Vorob' eva, Alla I [Belarusian State University of Informatics and Radioelectronics, Minsk (Belarus)

    2009-03-31

    Techniques for fabricating electrode arrays for carbon nanotubes used as structural elements of various nanoelectronic devices are reviewed. Ways of reducing electrode resistivity and contact resistance in metal-carbon nanotube structures are examined. Advances in and prospects for using nanotubes as interlevel contact junctions in IC multilevel metallization systems are discussed. (from the current literature)

  19. Silver-functionalized carbon nanofiber composite electrodes for ibuprofen detection

    NARCIS (Netherlands)

    Manea, F.; Motoc, S.; Pop, A.; Remes, A.; Schoonman, J.

    2012-01-01

    The aim of this study is to prepare and characterize two types of silver-functionalized carbon nanofiber (CNF) composite electrodes, i.e., silver-decorated CNF-epoxy and silver-modified natural zeolite-CNF-epoxy composite electrodes suitable for ibuprofen detection in aqueous solution. Ag carbon nan

  20. Functional Carbon Materials for Electrochemical Energy Storage

    Science.gov (United States)

    Zhou, Huihui

    The ability to harvest and convert solar energy has been associated with the evolution of human civilization. The increasing consumption of fossil fuels since the industrial revolution, however, has brought to concerns in ecological deterioration and depletion of the fossil fuels. Facing these challenges, humankind is forced to seek for clean, sustainable and renewable energy resources, such as biofuels, hydraulic power, wind power, geothermal energy and other kinds of alternative energies. However, most alternative energy sources, generally in the form of electrical energy, could not be made available on a continuous basis. It is, therefore, essential to store such energy into chemical energy, which are portable and various applications. In this context, electrochemical energy-storage devices hold great promises towards this goal. The most common electrochemical energy-storage devices are electrochemical capacitors (ECs, also called supercapacitors) and batteries. In comparison to batteries, ECs posses high power density, high efficiency, long cycling life and low cost. ECs commonly utilize carbon as both (symmetric) or one of the electrodes (asymmetric), of which their performance is generally limited by the capacitance of the carbon electrodes. Therefore, developing better carbon materials with high energy density has been emerging as one the most essential challenges in the field. The primary objective of this dissertation is to design and synthesize functional carbon materials with high energy density at both aqueous and organic electrolyte systems. The energy density (E) of ECs are governed by E = CV 2/2, where C is the total capacitance and V is the voltage of the devices. Carbon electrodes with high capacitance and high working voltage should lead to high energy density. In the first part of this thesis, a new class of nanoporous carbons were synthesized for symmetric supercapacitors using aqueous Li2SO4 as the electrolyte. A unique precursor was adopted to

  1. Electrochemical Reduction of Oxygen on Multi-walled Carbon Nanotubes Electrode in Alkaline Solution

    Institute of Scientific and Technical Information of China (English)

    You Qun CHU; Chun An MA; Feng Ming ZHAO; Hui HUANG

    2004-01-01

    The multi-walled carbon nanotubes (MWNTs) electrode was constructed using poly- tetrafluoroethylene as binder, and the electrochemical reductive behavior of oxygen in alkaline solution was first examined on this electrode. Compared with other carbon materials, MWNTs show higher electrocatalytic activity, and the reversibility of O2 reduction reaction is greatly improved. The experiments reveal that the electrochemical reduction of O2 to HO2- is controlled by adsorption. The preliminary results illustrate the potential application of MWNTs in fuel cells.

  2. Improving Electrode Durability of PEF Chamber by selecting suitable material

    Science.gov (United States)

    Corrosion resistance of four materials - titanium, platinized titanium, stainless steel, and boron carbide - as electrodes in a Pulsed Electric Field (PEF) system was studied to reduce electrode material migration into the food by electrode corrosion. The PEF process conditions were 28 kV/cm field s...

  3. A viable electrode material for use in microbial fuel cells for tropical regions

    DEFF Research Database (Denmark)

    Offei, Felix; Thygesen, Anders; Mensah, Moses

    2016-01-01

    was 0.66 V and 1.74 W/m3, respectively. The power generated by AC was as high as 86% of the value obtained with the extensively used carbon paper. Scanning electron microscopy and Denaturing Gradient Gel Electrophoresis (DGGE) analysis of AC anode biofilms confirmed that electrogenic bacteria were......Electrode materials are critical for microbial fuel cells (MFC) since they influence the construction and operational costs. This study introduces a simple and efficient electrode material in the form of palm kernel shell activated carbon (AC) obtained in tropical regions. The novel introduction...... of this material is also targeted at introducing an inexpensive and durable electrode material, which can be produced in rural communities to improve the viability of MFCs. The maximum voltage and power density obtained (under 1000 Ω load) using an H-shaped MFC with AC as both anode and cathode electrode material...

  4. NUCLEATION STUDIES OF GOLD ON CARBON ELECTRODES

    Directory of Open Access Journals (Sweden)

    S. SOBRI

    2008-04-01

    Full Text Available Interest has grown in developing non-toxic electrolytes for gold electrodeposition to replace the conventional cyanide-based bath for long term sustainability of gold electroplating. A solution containing thiosulphate and sulphite has been developed specially for microelectronics applications. However, at the end of the electrodeposition process, the spent electrolyte can contain a significant amount of gold in solution. This study has been initiated to investigate the feasibility of gold recovery from a spent thiosulphate-sulphite electrolyte. We have used flat-plate glassy carbon and graphite electrodes to study the mechanism of nucleation and crystal growth of gold deposition from the spent electrolyte. It was found that at the early stages of reduction process, the deposition of gold on glassy carbon exhibits an instantaneous nucleation of non-overlapping particles. At longer times, the particles begin to overlap and the deposition follows a classic progressive nucleation phenomenon. On the other hand, deposition of gold on graphite does not follow the classical nucleation phenomena.

  5. Carbon nanotube based multi electrode arrays for neuronal interfacing: progress and prospects

    OpenAIRE

    Yael eHanein; Lilach eBareket-Keren

    2013-01-01

    Carbon nanotube coatings have been demonstrated over the past several years as a promising material for neuronal interfacing applications. In particular, in the realm of neuronal implants, carbon nanotubes have major advantages owing to their unique mechanical and electrical properties. Here we review recent investigations utilizing carbon nanotubes in neuro-interfacing applications. Cell adhesion, neuronal engineering and multi electrode recordings with carbon nanotubes are described. We als...

  6. Flexible, transparent electrodes using carbon nanotubes

    Science.gov (United States)

    2012-01-01

    We prepare thin single-walled carbon nanotube networks on a transparent and flexible substrate with different densities, using a very simple spray method. We measure the electric impedance at different frequencies Z(f) in the frequency range of 40 Hz to 20 GHz using two different methods: a two-probe method in the range up to 110 MHz and a coaxial (Corbino) method in the range of 10 MHz to 20 GHz. We measure the optical absorption and electrical conductivity in order to optimize the conditions for obtaining optimum performance films with both high electrical conductivity and transparency. We observe a square resistance of 1 to 8.5 kΩ for samples showing 65% to 85% optical transmittance, respectively. For some applications, we need flexibility and not transparency: for this purpose, we deposit a thick film of single-walled carbon nanotubes on a flexible silicone substrate by spray method from an aqueous suspension of carbon nanotubes in a surfactant (sodium dodecyl sulphate), thereby obtaining a flexible conducting electrode showing an electrical resistance as low as 200 Ω/sq. When stretching up to 10% and 20%, the electrical resistance increases slightly, recovering the initial value for small elongations up to 10%. We analyze the stretched and unstretched samples by Raman spectroscopy and observe that the breathing mode on the Raman spectra is highly sensitive to stretching. The high-energy Raman modes do not change, which indicates that no defects are introduced when stretching. Using this method, flexible conducting films that may be transparent are obtained just by employing a very simple spray method and can be deposited on any type or shape of surface. PMID:23074999

  7. Field emission properties of the graphenated carbon nanotube electrode

    Energy Technology Data Exchange (ETDEWEB)

    Zanin, H., E-mail: hudson.zanin@bristol.ac.uk [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Faculdade de Engenharia Elétrica e Computação, Departamento de Semicondutores, Instrumentos e Fotônica, Universidade Estadual de Campinas, UNICAMP, Av. Albert Einstein N. 400, CEP 13 083-852 Campinas, São Paulo (Brazil); Ceragioli, H.J.; Peterlevitz, A.C.; Baranauskas, Vitor [Faculdade de Engenharia Elétrica e Computação, Departamento de Semicondutores, Instrumentos e Fotônica, Universidade Estadual de Campinas, UNICAMP, Av. Albert Einstein N. 400, CEP 13 083-852 Campinas, São Paulo (Brazil); Marciano, F.R.; Lobo, A.O. [Laboratory of Biomedical Nanotechnology/Institute of Research and Development at UNIVAP, Av. Shishima Hifumi, 2911, CEP 12244-000 Sao Jose dos Campos, SP (Brazil)

    2015-01-01

    Graphical abstract: - Highlights: • Facile method to prepare graphenated carbon nanotubes (g-CNTs). • The electric field emission behaviour of g-CNTs was studied. • g-CNTs show better emission current stability than non-graphenated CNTs. - Abstract: Reduced graphene oxide-coated carbon nanotubes (RGO-CNT) electrodes have been prepared by hot filament chemical vapour deposition system in one-step growth process. We studied RGO-CNT electrodes behaviour as cold cathode in field emission test. Our results show that RGO-CNT retain the low threshold voltage typical of CNTs, but with greatly improved emission current stability. The field emission enhancement value is significantly higher than that expected being caused by geometric effect (height divided by the radius of nanotube). This suggested that the field emission of this hybrid structure is not only from a single tip, but eventually it is from several tips with contribution of graphene nanosheets at CNT's walls. This phenomenon explains why the graphenated carbon nanotubes do not burn out as quickly as CNT does until emission ceases completely. These preliminaries results make nanocarbon materials good candidates for applications as electron sources for several devices.

  8. Carbon Nanotubes Counter Electrode for Dye-Sensitized Solar Cells Application

    Directory of Open Access Journals (Sweden)

    Drygała A.

    2016-06-01

    Full Text Available The influence of the carbon nanotubes counter electrode deposited on the FTO glass substrates on the structure and optoelectrical properties of dye-sensitized solar cells counter electrode (CE was analysed. Carbon materials have been applied in DSSC s in order to produce low-cost solar cells with reasonable efficiency. Platinum is a preferred material for the counter electrode because of its high conductivity and catalytic activity. However, the costs of manufacturing of the platinum counter electrode limit its use to large-scale applications in solar cells. This paper presents the results of examining the structure and properties of the studied layers, defining optical properties of conductive layers and electrical properties of dye-sensitized solar cells manufactured with the use of carbon nanotubes.

  9. Characterization of Carbon Nanotube/Graphene on Carbon Cloth as an Electrode for Air-Cathode Microbial Fuel Cells

    Directory of Open Access Journals (Sweden)

    Hung-Yin Tsai

    2015-01-01

    Full Text Available Microbial fuel cells (MFCs, which can generate low-pollution power through microbial decomposition, have become a potentially important technology with applications in environmental protection and energy recovery. The electrode materials used in MFCs are crucial determinants of their capacity to generate electricity. In this study, we investigate the performance of using carbon nanotube (CNT and graphene-modified carbon-cloth electrodes in a single-chamber MFC. We develop a process for fabricating carbon-based modified electrodes and Escherichia coli HB101 in an air-cathode MFC. The results show that the power density of MFCs can be improved by applying a coat of either graphene or CNT to a carbon-cloth electrode, and the graphene-modified electrode exhibits superior performance. In addition, the enhanced performance of anodic modification by CNT or graphene was greater than that of cathodic modification. The internal resistance decreased from 377 kΩ for normal electrodes to 5.6 kΩ for both electrodes modified by graphene with a cathodic catalyst. Using the modified electrodes in air-cathode MFCs can enhance the performance of power generation and reduce the associated costs.

  10. Hierarchical porous carbon aerogel derived from bagasse for high performance supercapacitor electrode.

    Science.gov (United States)

    Hao, Pin; Zhao, Zhenhuan; Tian, Jian; Li, Haidong; Sang, Yuanhua; Yu, Guangwei; Cai, Huaqiang; Liu, Hong; Wong, C P; Umar, Ahmad

    2014-10-21

    Renewable, cost-effective and eco-friendly electrode materials have attracted much attention in the energy conversion and storage fields. Bagasse, the waste product from sugarcane that mainly contains cellulose derivatives, can be a promising candidate to manufacture supercapacitor electrode materials. This study demonstrates the fabrication and characterization of highly porous carbon aerogels by using bagasse as a raw material. Macro and mesoporous carbon was first prepared by carbonizing the freeze-dried bagasse aerogel; consequently, microporous structure was created on the walls of the mesoporous carbon by chemical activation. Interestingly, it was observed that the specific surface area, the pore size and distribution of the hierarchical porous carbon were affected by the activation temperature. In order to evaluate the ability of the hierarchical porous carbon towards the supercapacitor electrode performance, solid state symmetric supercapacitors were assembled, and a comparable high specific capacitance of 142.1 F g(-1) at a discharge current density of 0.5 A g(-1) was demonstrated. The fabricated solid state supercapacitor displayed excellent capacitance retention of 93.9% over 5000 cycles. The high energy storage ability of the hierarchical porous carbon was attributed to the specially designed pore structures, i.e., co-existence of the micropores and mesopores. This research has demonstrated that utilization of sustainable biopolymers as the raw materials for high performance supercapacitor electrode materials is an effective way to fabricate low-cost energy storage devices.

  11. Fabrication and electrical properties of single wall carbon nanotube channel and graphene electrode based transistors arrays

    Energy Technology Data Exchange (ETDEWEB)

    Seo, M.; Kim, H.; Kim, Y. H.; Yun, H.; McAllister, K.; Lee, S. W., E-mail: leesw@konkuk.ac.kr [Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); Na, J.; Kim, G. T. [School of Electrical Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Lee, B. J.; Kim, J. J.; Jeong, G. H. [Department of Nano Applied Engineering, Kangwon National University, Kangwon-do 200-701 (Korea, Republic of); Lee, I.; Kim, K. S. [Department of Physics and Graphene Research Institute, Sejong University, Seoul 143-747 (Korea, Republic of)

    2015-07-20

    A transistor structure composed of an individual single-walled carbon nanotube (SWNT) channel with a graphene electrode was demonstrated. The integrated arrays of transistor devices were prepared by transferring patterned graphene electrode patterns on top of the aligned SWNT along one direction. Both single and multi layer graphene were used for the electrode materials; typical p-type transistor and Schottky diode behavior were observed, respectively. Based on our fabrication method and device performances, several issues are suggested and discussed to improve the device reliability and finally to realize all carbon based future electronic systems.

  12. Development of advanced carbon based composite electrodes for the detection and the degradation of organic pollutants in water via electrochemical/photoelectrochemical processes

    OpenAIRE

    2014-01-01

    Ph.D. (Chemistry) In this study, carbon based electrode materials such as glassy carbon, graphene, diamond and exfoliated graphite were explored as suitable electrode materials for electrochemical detection, electrochemical and photoelectrochemical degradation of organic water pollutants. Graphene modified glassy carbon electrode sensor was developed for bisphenol A. Cyclic voltammetry was used to study the electrochemical properties of the prepared graphene- modified glassy carbon electro...

  13. Study of the Electrocatalytic Activity of Cerium Oxide and Gold-Studded Cerium Oxide Nanoparticles Using a Sonogel-Carbon Material as Supporting Electrode: Electroanalytical Study in Apple Juice for Babies

    Directory of Open Access Journals (Sweden)

    José Mª Palacios-Santander

    2013-04-01

    Full Text Available The present work reports a study of the electrocatalytic activity of CeO2 nanoparticles and gold sononanoparticles (AuSNPs/CeO2 nanocomposite, deposited on the surface of a Sonogel-Carbon (SNGC matrix used as supporting electrode and the application of the sensing devices built with them to the determination of ascorbic acid (AA used as a benchmark analyte. Cyclic voltammetry (CV and differential pulse voltammetry (DPV were used to investigate the electrocatalytic behavior of CeO2- and AuSNPs/CeO2-modified SNGC electrodes, utilizing different concentrations of CeO2 nanoparticles and different AuSNPs:CeO2 w/w ratios. The best detection and quantification limits, obtained for CeO2 (10.0 mg·mL−1- and AuSNPs/CeO2 (3.25% w/w-modified SNGC electrodes, were 1.59 × 10−6 and 5.32 × 10−6 M, and 2.93 × 10−6 and 9.77 × 10−6 M, respectively, with reproducibility values of 5.78% and 6.24%, respectively, for a linear concentration range from 1.5 µM to 4.0 mM of AA. The electrochemical devices were tested for the determination of AA in commercial apple juice for babies. The results were compared with those obtained by applying high performance liquid chromatography (HPLC as a reference method. Recovery errors below 5% were obtained in most cases, with standard deviations lower than 3% for all the modified SNGC electrodes. Bare, CeO2- and AuSNPs/CeO2-modified SNGC electrodes were structurally characterized using scanning electron microscopy (SEM and energy dispersive X-ray spectroscopy (EDS. AuSNPs and AuSNPs/CeO2 nanocomposite were characterized by UV–vis spectroscopy and X-ray diffraction (XRD, and information about their size distribution and shape was obtained by transmission electron microscopy (TEM. The advantages of employing CeO2 nanoparticles and AuSNPs/CeO2 nanocomposite in SNGC supporting material are also described. This research suggests that the modified electrode can be a very promising voltammetric sensor for the determination

  14. Study of the electrocatalytic activity of cerium oxide and gold-studded cerium oxide nanoparticles using a Sonogel-Carbon material as supporting electrode: electroanalytical study in apple juice for babies.

    Science.gov (United States)

    Abdelrahim, M Yahia M; Benjamin, Stephen R; Cubillana-Aguilera, Laura Ma; Naranjo-Rodríguez, Ignacio; de Cisneros, José L Hidalgo-Hidalgo; Delgado, Juan José; Palacios-Santander, José Ma

    2013-04-12

    The present work reports a study of the electrocatalytic activity of CeO2 nanoparticles and gold sononanoparticles (AuSNPs)/CeO2 nanocomposite, deposited on the surface of a Sonogel-Carbon (SNGC) matrix used as supporting electrode and the application of the sensing devices built with them to the determination of ascorbic acid (AA) used as a benchmark analyte. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the electrocatalytic behavior of CeO2- and AuSNPs/CeO2-modified SNGC electrodes, utilizing different concentrations of CeO2 nanoparticles and different AuSNPs:CeO2 w/w ratios. The best detection and quantification limits, obtained for CeO2 (10.0 mg·mL(-1))- and AuSNPs/CeO2 (3.25% w/w)-modified SNGC electrodes, were 1.59 × 10(-6) and 5.32 × 10(-6) M, and 2.93 × 10(-6) and 9.77 × 10(-6) M, respectively, with reproducibility values of 5.78% and 6.24%, respectively, for a linear concentration range from 1.5 µM to 4.0 mM of AA. The electrochemical devices were tested for the determination of AA in commercial apple juice for babies. The results were compared with those obtained by applying high performance liquid chromatography (HPLC) as a reference method. Recovery errors below 5% were obtained in most cases, with standard deviations lower than 3% for all the modified SNGC electrodes. Bare, CeO2- and AuSNPs/CeO2-modified SNGC electrodes were structurally characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). AuSNPs and AuSNPs/CeO2 nanocomposite were characterized by UV-vis spectroscopy and X-ray diffraction (XRD), and information about their size distribution and shape was obtained by transmission electron microscopy (TEM). The advantages of employing CeO2 nanoparticles and AuSNPs/CeO2 nanocomposite in SNGC supporting material are also described. This research suggests that the modified electrode can be a very promising voltammetric sensor for the determination of

  15. Study of the Electrocatalytic Activity of Cerium Oxide and Gold-Studded Cerium Oxide Nanoparticles Using a Sonogel-Carbon Material as Supporting Electrode: Electroanalytical Study in Apple Juice for Babies

    Science.gov (United States)

    Abdelrahim, M. Yahia M.; Benjamin, Stephen R.; Cubillana-Aguilera, Laura Ma; Naranjo-Rodríguez, Ignacio; Hidalgo-Hidalgo de Cisneros, Josè L.; Delgado, Juan Josè; Palacios-Santander, Josè Ma

    2013-01-01

    The present work reports a study of the electrocatalytic activity of CeO2 nanoparticles and gold sononanoparticles (AuSNPs)/CeO2 nanocomposite, deposited on the surface of a Sonogel-Carbon (SNGC) matrix used as supporting electrode and the application of the sensing devices built with them to the determination of ascorbic acid (AA) used as a benchmark analyte. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the electrocatalytic behavior of CeO2- and AuSNPs/CeO2-modified SNGC electrodes, utilizing different concentrations of CeO2 nanoparticles and different AuSNPs:CeO2 w/w ratios. The best detection and quantification limits, obtained for CeO2 (10.0 mg·mL−1)- and AuSNPs/CeO2 (3.25% w/w)-modified SNGC electrodes, were 1.59 × 10−6 and 5.32 × 10−6 M, and 2.93 × 10−6 and 9.77 × 10−6 M, respectively, with reproducibility values of 5.78% and 6.24%, respectively, for a linear concentration range from 1.5 μM to 4.0 mM of AA. The electrochemical devices were tested for the determination of AA in commercial apple juice for babies. The results were compared with those obtained by applying high performance liquid chromatography (HPLC) as a reference method. Recovery errors below 5% were obtained in most cases, with standard deviations lower than 3% for all the modified SNGC electrodes. Bare, CeO2- and AuSNPs/CeO2-modified SNGC electrodes were structurally characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). AuSNPs and AuSNPs/CeO2 nanocomposite were characterized by UV-vis spectroscopy and X-ray diffraction (XRD), and information about their size distribution and shape was obtained by transmission electron microscopy (TEM;. The advantages of employing CeO2 nanoparticles and AuSNPs/CeO2 nanocomposite in SNGC supporting material are also described. This research suggests that the modified electrode can be a very promising voltammetric sensor for the determination of

  16. A top-down approach for fabricating free-standing bio-carbon supercapacitor electrodes with a hierarchical structure

    OpenAIRE

    Yingzhi Li; Qinghua Zhang; Junxian Zhang; Lei Jin; Xin Zhao; Ting Xu

    2015-01-01

    Biomass has delicate hierarchical structures, which inspired us to develop a cost-effective route to prepare electrode materials with rational nanostructures for use in high-performance storage devices. Here, we demonstrate a novel top-down approach for fabricating bio-carbon materials with stable structures and excellent diffusion pathways; this approach is based on carbonization with controlled chemical activation. The developed free-standing bio-carbon electrode exhibits a high specific ca...

  17. Carbon nanotube detectors for microchip CE: comparative study of single-wall and multiwall carbon nanotube, and graphite powder films on glassy carbon, gold, and platinum electrode surfaces.

    Science.gov (United States)

    Pumera, Martin; Merkoçi, Arben; Alegret, Salvador

    2007-04-01

    The performance of microchip electrophoresis/electrochemistry system with carbon nanotube (CNT) film electrodes was studied. Electrocatalytic activities of different carbon materials (single-wall CNT (SWCNT), multiwall CNT (MWCNT), carbon powder) cast on different electrode substrates (glassy carbon (GC), gold, and platinum) were compared in a microfluidic setup and their performance as microchip electrochemical detectors was assessed. An MWCNT film on a GC electrode shows electrocatalytic effect toward oxidation of dopamine (E(1/2) shift of 0.09 V) and catechol (E(1/2) shift of 0.19 V) when compared to a bare GC electrode, while other CNT/carbon powder films on the GC electrode display negligible effects. Modification of a gold electrode by graphite powder results in a strong electrocatalytic effect toward oxidation of dopamine and catechol (E(1/2) shift of 0.14 and 0.11 V, respectively). A significant shift of the half-wave potentials to lower values also provide the MWCNT film (E(1/2) shift of 0.08 and 0.08 V for dopamine and catechol, respectively) and the SWCNT film (E(1/2) shift of 0.10 V for catechol) when compared to a bare gold electrode. A microfluidic device with a CNT film-modified detection electrode displays greatly improved separation resolution (R(s)) by a factor of two compared to a bare electrode, reflecting the electrocatalytic activity of CNT.

  18. Particulate inverse opal carbon electrodes for lithium-ion batteries.

    Science.gov (United States)

    Kang, Da-Young; Kim, Sang-Ok; Chae, Yu Jin; Lee, Joong Kee; Moon, Jun Hyuk

    2013-01-29

    Inverse opal carbon materials were used as anodes for lithium ion batteries. We applied particulate inverse opal structures and their dispersion in the formation of anode electrodes via solution casting. We prepared aminophenyl-grafted inverse opal carbons (a-IOC), inverse opal carbons with mesopores (mIOC), and bare inverse opal carbons (IOC) and investigated the electrochemical behavior of these samples as anode materials. Surface modification by aminophenyl groups was confirmed by XPS measurements. TEM images showed mesopores, and the specific area of mIOC was compared with that of IOC using BET analysis. A half-cell test was performed to compare a-IOC with IOC and mIOC with IOC. In the case of the a-IOC structure, the cell test revealed no improvement in the reversible specific capacity or the cycle performance. The mIOC cell showed a reversible specific capacity of 432 mAh/g, and the capacity was maintained at 88%-approximately 380 mAh/g-over 20 cycles.

  19. ;Green; carbon with hierarchical three dimensional porous structure derived from - Pongamia pinnata seed oil extract cake and NiCo2O4-Ni(OH)2/Multiwall carbon nanotubes nanocomposite as electrode materials for high performance asymmetric supercapacitor

    Science.gov (United States)

    Chaitra, K.; Narendra, Reddy; Venkatesh, Krishna; Nagaraju, N.; Kathyayini, Nagaraju

    2017-07-01

    Herein, we report for the first time synthesis and electrochemical supercapacitance performance of 3-D hierarchical porous ;Green; carbon derived from Pongamia pinnata seed oil extract cake and its activation using different amounts of KOH. Also, nanocomposites of multiwalled carbon nanotubes (MWCNT) with various weight percentages of Ni and Co were prepared by hydrothermal method. Physico-chemical properties of ;Green; carbon and nanocomposites were analyzed by Powder X-ray Diffraction, Brunner Emmett Teller surface area, Scanning Electron Microscopy-Elemental Dispersive Spectrum, Transmission Electron Microscopy and Raman techniques. KOH activated carbon was found associated with combination of micropores & mesopores while the nanocomposite with mixture of spinel NiCo2O4 and Ni(OH)2. Porous carbon activated with 2:1::KOH:C (KC2) and the nanocomposite with 1:1 Ni & Co (NC1) exhibited excellent electrochemical performance in three electrode system. Further, fabricated asymmetric supercapacitor (AS) device Ni-Co-MWCNT (NC1)//KC2 exhibited specific capacitance (Cs) of 177 F/g as determined by cyclic voltammetry at 10 mV/s and retained 90% even at 3000th cycle in life cycle test conducted at high current density of 50 A/g. In order to evaluate its practical performance, the AS device was charged to 1.8 V at 5 A/g and used successfully to power a calculator for more than 1 h.

  20. Mutagens in urine of carbon electrode workers

    Energy Technology Data Exchange (ETDEWEB)

    Pasquini, R.; Monarca, S.; Sforzolini, G.S.; Conti, R.; Fagioli, F.

    1982-01-01

    Following previous work carried out in an Italian factory producing carbon electrodes and evaluating the occupational mutagenic-carcinogenic hazards, the authors studied the presence of mutagen metabolites in the urine of workers in the same factory who were exposed to petroleum coke and pitch and in the urine of a control group of unexposed workers. The urine samples were concentrated by absorption on XAD-2 columns and were tested using the Salmonella/microsome assay (strain TA98, TA100, TA1535, TA1538) with and without the addition of beta-glucuronidase and metabolizing system. The collection of urine samples was carried out twice, with an interval of 2 months; 'before working time', 'after working time', and also during Sunday. The results showed that urine samples collected 'before' occupational exposure (upon waking) or on Sunday revealed no mutagenic activity in either worker groups and that the urine samples collected after or during occupational exposure revealed high mutagenic activity in the exposed workers, with a statistically significant difference between the mean of the revertants/plate values for exposed and unexposed workers. On the basis of the previous and the present research, the authors suggest that application of the Salmonella/microsome test to work environments could offer useful and suitable tool for evaluating the health hazards due to mutagenic/carcinogenic substances from occupational exposure.

  1. Effect of carbon microfiber materials on sensitivity of adenosine and hydroxyadenine at carbon microfiber sensors

    Directory of Open Access Journals (Sweden)

    K.M.M. Abou El-Nour

    2015-07-01

    Full Text Available The relationship between the sensitivity measurements and microfiber electrodes made from different carbon microfiber materials, such as polyacrylonitrile (PAN T650 and PAN HCB and Pitch P25 was established in this work. The different microfiber electrodes were nanostructured by an electrochemical pretreatment method. Sensitivity of adenosine (ADO and 2,8-dihydroxyadenine (2,8-DHA was measured at different carbon microfiber sensors made from different carbon microfiber materials. Sensitivity of PAN microfiber electrodes for ADO and 2,8-DHA determinations measured at 500 V s−1 vs. SCE is higher than that measured at Pitch P25 microfiber electrodes due to more defects in PAN microfiber electrodes. Adsorption of ADO and 2,8-DHA is greater at PAN HCB electrodes. High conductivity of PAN fibers correlates with sensitivity determinations of the investigated analytes.

  2. Changes in Carbon Electrode Morphology Affect Microbial Fuel Cell Performance with Shewanella oneidensis MR-1

    Directory of Open Access Journals (Sweden)

    David V. P. Sanchez

    2015-03-01

    Full Text Available The formation of biofilm-electrodes is crucial for microbial fuel cell current production because optimal performance is often associated with thick biofilms. However, the influence of the electrode structure and morphology on biofilm formation is only beginning to be investigated. This study provides insight on how changing the electrode morphology affects current production of a pure culture of anode-respiring bacteria. Specifically, an analysis of the effects of carbon fiber electrodes with drastically different morphologies on biofilm formation and anode respiration by a pure culture (Shewanella oneidensis MR-1 were examined. Results showed that carbon nanofiber mats had ~10 fold higher current than plain carbon microfiber paper and that the increase was not due to an increase in electrode surface area, conductivity, or the size of the constituent material. Cyclic voltammograms reveal that electron transfer from the carbon nanofiber mats was biofilm-based suggesting that decreasing the diameter of the constituent carbon material from a few microns to a few hundred nanometers is beneficial for electricity production solely because the electrode surface creates a more relevant mesh for biofilm formation by Shewanella oneidensis MR-1.

  3. Carbon nanofibers grafted on activated carbon as an electrode in high-power supercapacitors.

    Science.gov (United States)

    Gryglewicz, Grażyna; Śliwak, Agata; Béguin, François

    2013-08-01

    A hybrid electrode material for high-power supercapacitors was fabricated by grafting carbon nanofibers (CNFs) onto the surface of powdered activated carbon (AC) through catalytic chemical vapor deposition (CCVD). A uniform thin layer of disentangled CNFs with a herringbone structure was deposited on the carbon surface through the decomposition of propane at 450 °C over an AC-supported nickel catalyst. CNF coating was controlled by the reaction time and the nickel content. The superior CNF/AC composite displays excellent electrochemical performance in a 0.5 mol L(-1) solution of K2 SO4 due to its unique structure. At a high scan rate (100 mV s(-1) ) and current loading (20 A g(-1) ), the capacitance values were three- and fourfold higher than those for classical AC/carbon black composites. Owing to this feature, a high energy of 10 Wh kg(-1) was obtained over a wide power range in neutral medium at a voltage of 0.8 V. The significant enhancement of charge propagation is attributed to the presence of herringbone CNFs, which facilitate the diffusion of ions in the electrode and play the role of electronic bridges between AC particles. An in situ coating of AC with short CNFs (below 200 nm) is a very attractive method for producing the next generation of carbon composite materials with a high power performance in supercapacitors working in neutral medium.

  4. Attractive forces in microporous carbon electrodes for capacitive deionization

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Porada, S.; Levi, M.; Bazant, M.Z.

    2014-01-01

    The recently developed modified Donnan (mD) model provides a simple and useful description of the electrical double layer in microporous carbon electrodes, suitable for incorporation in porous electrode theory. By postulating an attractive excess chemical potential for each ion in the micropores

  5. Wireless desalination using inductively powered porous carbon electrodes

    NARCIS (Netherlands)

    Kuipers, J.; Porada, S.

    2013-01-01

    Water desalination by capacitive deionization (CDI) uses electrochemical cell pairs formed of porous carbon electrodes, which are brought in contact with the water that must be desalinated. Upon applying a cell voltage or current between the electrodes, ions are electrosorbed and water is produced

  6. Wireless desalination using inductively powered porous carbon electrodes

    NARCIS (Netherlands)

    Kuipers, J.; Porada, S.

    2013-01-01

    Water desalination by capacitive deionization (CDI) uses electrochemical cell pairs formed of porous carbon electrodes, which are brought in contact with the water that must be desalinated. Upon applying a cell voltage or current between the electrodes, ions are electrosorbed and water is produced o

  7. Alternate electrode materials for the SP100 reactor. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Randich, E.

    1992-05-01

    This work was performed in response to a request by the Astro-Space Division of the General Electric Co. to develop alternate electrodes materials for the electrodes of the PD2 modules to be used in the SP100 thermoelectric power conversion system. Initially, the project consisted of four tasks: (1) development of a ZrB{sub 2} (C) CVD coating on SiMo substrates, (2) development of a ZrB{sub 2} (C) CVD coating on SiGe substrates, (3) development of CVI W for porous graphite electrodes, and (4) technology transfer of pertinent developed processes. The project evolved initially into developing only ZrB{sub 2} coatings on SiGe and graphite substrates, and later into developing ZrB{sub 2} coatings only on graphite substrates. Several sizes of graphite and pyrolytic carbon-coated graphite substrates were coated with ZrB{sub 2} during the project. For budgetary reasons, the project was terminated after half the allotted time had passed. Apart from the production of coated specimens for evaluation, the major accomplishment of the project was the development of the CVD processing to produce the desired coatings.

  8. Unconventional supercapacitors from nanocarbon-based electrode materials to device configurations.

    Science.gov (United States)

    Liu, Lili; Niu, Zhiqiang; Chen, Jun

    2016-07-25

    As energy storage devices, supercapacitors that are also called electrochemical capacitors possess high power density, excellent reversibility and long cycle life. The recent boom in electronic devices with different functions in transparent LED displays, stretchable electronic systems and artificial skin has increased the demand for supercapacitors to move towards light, thin, integrated macro- and micro-devices with transparent, flexible, stretchable, compressible and/or wearable abilities. The successful fabrication of such supercapacitors depends mainly on the preparation of innovative electrode materials and the design of unconventional supercapacitor configurations. Tremendous research efforts have been recently made to design and construct innovative nanocarbon-based electrode materials and supercapacitors with unconventional configurations. We review here recent developments in supercapacitors from nanocarbon-based electrode materials to device configurations. The advances in nanocarbon-based electrode materials mainly include the assembly technologies of macroscopic nanostructured electrodes with different dimensions of carbon nanotubes/nanofibers, graphene, mesoporous carbon, activated carbon, and their composites. The electrodes with macroscopic nanostructured carbon-based materials overcome the issues of low conductivity, poor mechanical properties, and limited dimensions that are faced by conventional methods. The configurational design of advanced supercapacitor devices is presented with six types of unconventional supercapacitor devices: flexible, micro-, stretchable, compressible, transparent and fiber supercapacitors. Such supercapacitors display unique configurations and excellent electrochemical performance at different states such as bending, stretching, compressing and/or folding. For example, all-solid-state simplified supercapacitors that are based on nanostructured graphene composite paper are able to maintain 95% of the original capacity at

  9. Conducting polymer/carbon nanocoil composite electrodes for efficient supercapacitors

    KAUST Repository

    Baby, Rakhi Raghavan

    2012-01-01

    Herein, we report for the first time, conducting polymer (polyaniline (PANI) and polypyrrole (PPY)) coated carbon nanocoils (CNCs) as efficient binder-free electrode materials for supercapacitors. CNCs act as a perfect backbone for the uniform distribution of the conducting polymers in the composites. In two electrode configuration, the samples exhibited high specific capacitance with the values reaching up to 360 and 202 F g -1 for PANI/CNCs and PPY/CNCs respectively. The values obtained for specific capacitance and maximum storage energy per unit mass of the composites were found to be comparable to one of the best reported values for polymer coated multi-walled carbon nanotubes. In addition, the fabricated PANI/CNC based supercapacitors exhibited a high value of 44.61 Wh kg -1 for maximum storage energy per unit mass. Although the devices exhibit an initial capacitance loss due to the instability of the polymer, the specific capacitance stabilizes at a fixed value after 500 charge-discharge cycles. © 2012 The Royal Society of Chemistry.

  10. Converting biowaste corncob residue into high value added porous carbon for supercapacitor electrodes.

    Science.gov (United States)

    Qu, Wen-Hui; Xu, Yuan-Yuan; Lu, An-Hui; Zhang, Xiang-Qian; Li, Wen-Cui

    2015-08-01

    In this report, corncob residue, the main by-product in the furfural industry, is used as a precursor to prepare porous carbon by a simple and direct thermal treatment: one-step activation without pre-carbonization. As a consequence, the corncob residue derived porous carbon achieves a high surface area of 1210 m(2) g(-1) after ash-removal. The carbon material has the advantages of low cost and low environmental impact, with a superior electrochemical performance compared to those polymer-based synthetic carbons as electrode material for a supercapacitor. The carbon electrode exhibits a high capacitance of 314 F g(-1) in 6M KOH electrolyte. The corresponding sample also shows a superb cycling stability. Almost no capacitance decay was observed after 100,000 cycles. The excellent electrochemical performance is due to the combination of a high specific surface area with a fraction of mesopores and highly stable structure.

  11. Lead-carbon electrode designed for renewable energy storage with superior performance in partial state of charge operation

    Science.gov (United States)

    Zhang, Wen-Li; Yin, Jian; Lin, Zhe-Qi; Shi, Jun; Wang, Can; Liu, De-Bo; Wang, Yue; Bao, Jin-Peng; Lin, Hai-Bo

    2017-02-01

    Renewable energy storage is a key issue in our modern electricity-powered society. Lead acid batteries (LABs) are operated at partial state of charge in renewable energy storage system, which causes the sulfation and capacity fading of Pb electrode. Lead-carbon composite electrode is a good solution to the sulfation problem of LAB. In this paper, a rice-husk-derived hierarchically porous carbon with micrometer-sized large pores (denoted as RHC) has been used as the component of lead-carbon composite electrode. Scanning electron microscopy was used to characterize the morphology of lead-carbon composite electrode. Electrochemical impedance spectroscopy was used to determine the charge transfer capability of lead-carbon composite electrode. Both full charge-discharge method and charge-discharge method operating at harsh partial state of charge condition have been used to prove the superior energy storage capability of lead-carbon composite electrode. Experiment results prove that the micrometer-sized pores of RHC are beneficial to the construction and stability of lead-carbon composite electrode. Microporous carbon material with high surface area is not suitable for the construction of lead-carbon electrode due to the ruin of lead-carbon structure caused by severe electrochemical hydrogen evolution.

  12. Capacitive, deionization with carbon aerogel electrodes: Carbonate, sulfate, and phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J.C.; Fix, D.V.; Mack, G.V.; Pekala, R.W.; Poco, J.F.

    1995-07-24

    A process for the capacitive deionization (CDI) of water with a stack of carbon aerogel electrodes has been developed by Lawrence Livermore National Laboratory. Unlike ion exchange, one of the more conventional deionization processes, no chemicals are required for regeneration of the system. Electricity is used instead. Water with various anions and cations is pumped through the electrochemical cell. After polarization, ions are electrostatically removed from the water and held in the electric double layers formed at the surfaces of electrodes. The water leaving the cell is purified, as desired. The effects of cell voltage on the electrosorption capacities for Na{sub 2}SO{sub 4}, Na{sub 3}PO{sub 4}, and Na{sub 2}CO{sub 3} have been investigated and are reported here. Results for NaCl and NaNO{sub 3} have been reported previously. Possible applications for CDI are as a replacement for ion exchange processes which remove heavy metals and radioisotopes from process and waste water in various industries, as well as to remove inorganic ions from feedwater for fossil and nuclear power plants.

  13. Electroadsorption Desalination with Carbon Nanotube/PAN-Based Carbon Fiber Felt Composites as Electrodes

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2014-01-01

    Full Text Available The chemical vapor deposition method is used to prepare CNT (carbon nanotube/PCF (PAN-based carbon fiber felt composite electrodes in this paper, with the surface morphology of CNT/PCF composites and electroadsorption desalination performance being studied. Results show such electrode materials with three-dimensional network nanostructures having a larger specific surface area and narrower micropore distribution, with a huge number of reactive groups covering the surface. Compared with PCF electrodes, CNT/PCF can allow for a higher adsorption and desorption rate but lower energy consumption; meanwhile, under the condition of the same voltage change, the CNT/PCF electrodes are provided with a better desalination effect. The study also found that the higher the original concentration of the solution, the greater the adsorption capacity and the lower the adsorption rate. At the same time, the higher the solution’s pH, the better the desalting; the smaller the ions’ radius, the greater the amount of adsorption.

  14. Understanding the influence of the electrode material on microbial fuel cell performance

    Science.gov (United States)

    Sanchez, David V. P.

    In this thesis, I deploy sets of electrodes into microbial fuel cells (MFC), characterize their performance, and evaluate the influence of both platinum catalysts and carbon-based electrodes on current production. The platinum work centers on improving current production by optimizing the use of the catalyst using nano-fabrication techniques. The carbon-electrode work seeks to determine the influence of the bare electrode on biofilm-anode current production. The development of electrodes for MFCs has boomed over the past decade, however, experiments aimed at identifying how catalyst deposition methods and electrode properties influence current production have been limited. The research conducted here is an attempt to expand this knowledge base for platinum catalysts and carbon electrodes. In the initial chapters (4 and 5), I discuss our attempt to decrease catalyst loadings while increasing current production through the use of platinum nanoparticles. The results demonstrate that incorporating platinum nanoparticles throughout the anode and cathode is an efficient means of increasing MFC current production relative to surface deposition because it increases catalyst surface area. The later chapters (chapters 6 and 7) develop an understanding of the importance of electrode properties (i.e. surface area, activation resistance, conductivity, surface morphology) by electrochemically evaluating well-studied anode-respiring pure cultures on different carbon electrode architectures. Two different architectures are produced by using tubular and platelet shaped constituent materials (i.e. carbon fibers and graphene nanoplatelets) and the morphologies of the electrodes are varied by altering the size of the constituent material. The electrodes are characterized and evaluated in MFCs using either Shewanella oneidensis MR-1 or Geobacter sulfurreducens as the innoculant because their bioelectrochemical physiologies are the most documented in the literature. Using the

  15. Aqueous processing of composite lithium ion electrode material

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jianlin; Armstrong, Beth L.; Daniel, Claus; Wood, III, David L.

    2017-06-20

    A method of making a battery electrode includes the steps of dispersing an active electrode material and a conductive additive in water with at least one dispersant to create a mixed dispersion; treating a surface of a current collector to raise the surface energy of the surface to at least the surface tension of the mixed dispersion; depositing the dispersed active electrode material and conductive additive on a current collector; and heating the coated surface to remove water from the coating.

  16. Transduction mechanism of carbon nanotubes in solid-contact ion-selective electrodes.

    Science.gov (United States)

    Crespo, Gastón A; Macho, Santiago; Bobacka, Johan; Rius, F Xavier

    2009-01-15

    Porous carbon materials and carbon nanotubes were recently used as solid contacts in ion-selective electrodes (ISE), and the signal transduction mechanism of these carbon-based materials is therefore of great interest. In this work the ion-to-electron transduction mechanism of carbon nanotubes is studied by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Single-walled carbon nanotubes (SWCNT) are deposited on glassy carbon (GC) disk electrodes by repetitive spraying, resulting in SWCNT layers with thicknesses of 10, 35, and 50 mum. The impedance spectra of these GC/SWCNT electrodes in contact with aqueous electrolyte solution show a very small resistance and a large bulk capacitance that is related to a large effective double layer at the SWCNT/electrolyte interface. Interestingly, the impedance response of GC/SWCNT is very similar to that of poly(3,4-ethylenedioxythiophene) (PEDOT) film electrodes studied earlier under the same experimental conditions. The same equivalent circuit is valid for both types of materials. The reason is that both materials can be described schematically as an asymmetric capacitor where one side is formed by electronic charge (electrons/holes) in the SWCNT wall or along the conjugated polymer chain of PEDOT and the other side is formed by ions (anions/cations) in the solution (or in the ion-selective membrane when used as a solid contact in ISE).

  17. Fabrication, Characterization and Electrocatalysis of an Ordered Carbon Nanotube Electrode

    Institute of Scientific and Technical Information of China (English)

    陈静; 包建春; 蔡称心

    2003-01-01

    A method for fabrication of ordered carbon nanotube (CNT) film,which was template-synthesized within the highly ordered pores of a commercially available alumina template membrane,modified glassy carbon(CNT/GC) electrode was established.The CNT/GC electrode showed excellent electrocatalytic activity toward dopamine electrochemical reaction without introducing any electrochemically active group into CNT film or activating any electrochemically active group into CNT film or activating the electrode electrochemically.DA undergoes ideal reversible electrochemical reaction on CNT/GC electrode at low scan rate(≤20mV/s) with an excellent reproducibility and stability.The CNT/GC electrode might be used in biosensors because the highly ordered CNT may present a steric effect on more efficient redox reactions of biomolecules.

  18. Materials analyses and electrochemical impedance of implantable metal electrodes.

    Science.gov (United States)

    Howlader, Matiar M R; Ul Alam, Arif; Sharma, Rahul P; Deen, M Jamal

    2015-04-21

    Implantable electrodes with high flexibility, high mechanical fixation and low electrochemical impedance are desirable for neuromuscular activation because they provide safe, effective and stable stimulation. In this paper, we report on detailed materials and electrical analyses of three metal implantable electrodes - gold (Au), platinum (Pt) and titanium (Ti) - using X-ray photoelectron spectroscopy (XPS), scanning acoustic microscopy, drop shape analysis and electrochemical impedance spectroscopy. We investigated the cause of changes in electrochemical impedance of long-term immersed Au, Pt and Ti electrodes on liquid crystal polymers (LCPs) in phosphate buffered saline (PBS). We analyzed the surface wettability, surface and interface defects and the elemental depth profile of the electrode-adhesion layers on the LCP. The impedance of the electrodes decreased at lower frequencies, but increased at higher frequencies compared with that of the short-term immersion. The increase of impedances was influenced by the oxidation of the electrode/adhesion-layers that affected the double layer capacitance behavior of the electrode/PBS. The oxidation of the adhesion layer for all the electrodes was confirmed by XPS. Alkali ions (sodium) were adsorbed on the Au and Pt surfaces, but diffused into the Ti electrode and LCPs. The Pt electrode showed a higher sensitivity to surface and interface defects than that of Ti and Au electrodes. These findings may be useful when designing electrodes for long-term implantable devices.

  19. Compliant Electrode and Composite Material for Piezoelectric Wind and Mechanical Energy Conversions

    Science.gov (United States)

    Chen, Bin (Inventor)

    2015-01-01

    A thin film device for harvesting energy from wind. The thin film device includes one or more layers of a compliant piezoelectric material formed from a composite of a polymer and an inorganic material, such as a ceramic. Electrodes are disposed on a first side and a second side of the piezoelectric material. The electrodes are formed from a compliant material, such as carbon nanotubes or graphene. The thin film device exhibits improved resistance to structural fatigue upon application of large strains and repeated cyclic loadings.

  20. Stability of carbon electrodes for aqueous lithium-air secondary batteries

    Science.gov (United States)

    Ohkuma, Hirokazu; Uechi, Ichiro; Matsui, Masaki; Takeda, Yasuo; Yamamoto, Osamu; Imanishi, Nobuyuki

    2014-01-01

    The air electrode performance of various carbon materials, such as Ketjen black (KB), acetylene black (AB and AB-S), Vulcan XC-72R (VX), and vapor grown carbon fiber (VGCF) with and without La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) catalyst were examined in an aqueous solution of saturated LiOH with 10 M LiCl in the current density range 0.2-2.0 mA cm-2. The best performance for oxygen reduction and evolution reactions was observed for the KB electrode, which has the highest surface area among the carbon materials examined. A steady over-potential of 0.2 V was obtained for the oxygen reduction reaction using the KB electrode without the catalyst, while the over-potential was 0.15 V for KB with the LSCF catalyst at 2.0 mA cm-2. The over-potentials for the oxygen evolution reaction were slightly higher than those for the oxygen reduction reaction, and gradually increased with the polarization period. Analysis of the gas in the cell after polarization above 0.4 V revealed the evolution of a small amount of CO during the oxygen evolution reaction by the decomposition of carbon in the electrode. The amount of CO evolved was significantly decreased by the addition of LSCF to the carbon electrode.

  1. High-performance supercapacitor electrode from cellulose-derived, inter-bonded carbon nanofibers

    Science.gov (United States)

    Cai, Jie; Niu, Haitao; Wang, Hongxia; Shao, Hao; Fang, Jian; He, Jingren; Xiong, Hanguo; Ma, Chengjie; Lin, Tong

    2016-08-01

    Carbon nanofibers with inter-bonded fibrous structure show high supercapacitor performance when being used as electrode materials. Their preparation is highly desirable from cellulose through a pyrolysis technique, because cellulose is an abundant, low cost natural material and its carbonization does not emit toxic substance. However, interconnected carbon nanofibers prepared from electrospun cellulose nanofibers and their capacitive behaviors have not been reported in the research literature. Here we report a facile one-step strategy to prepare inter-bonded carbon nanofibers from partially hydrolyzed cellulose acetate nanofibers, for making high-performance supercapacitors as electrode materials. The inter-fiber connection shows considerable improvement in electrode electrochemical performances. The supercapacitor electrode has a specific capacitance of ∼241.4 F g-1 at 1 A g-1 current density. It maintains high cycling stability (negligible 0.1% capacitance reduction after 10,000 cycles) with a maximum power density of ∼84.1 kW kg-1. They may find applications in the development of efficient supercapacitor electrodes for energy storage applications.

  2. Oxygen reduction on teflon-bonded carbon electrode

    Institute of Scientific and Technical Information of China (English)

    周德璧; 黄可龙; 张世民

    2004-01-01

    Oxygen reduction on Teflon-bonded carbon gas diffusion electrode without catalyst in 6 mol/L KOH solution was investigated with acimpedance spectroscopy and other electrochemical techniques. The kinetic parameters were measured with an exchange current density of J0= 3.44 × 10-9 and a Tafel slope of 46 mV/dec in low overpotential range (-0.05 --0.14 V vs SCE), which are comparable with those reported on carbon supported platinum electrode. The reaction mechanism of OR and the active effect of carbon black were examined.

  3. Carbon nanotube based multi electrode arrays for neuronal interfacing: progress and prospects

    Directory of Open Access Journals (Sweden)

    Yael eHanein

    2013-01-01

    Full Text Available Carbon nanotube coatings have been demonstrated over the past several years as a promising material for neuronal interfacing applications. In particular, in the realm of neuronal implants, carbon nanotubes have major advantages owing to their unique mechanical and electrical properties. Here we review recent investigations utilizing carbon nanotubes in neuro-interfacing applications. Cell adhesion, neuronal engineering and multi electrode recordings with carbon nanotubes are described. We also highlight prospective advances in this field, in particular, progress towards flexible, bio-compatible carbon nanotubes technology.

  4. Facile preparation of nickel/carbonized wood nanocomposite for environmentally friendly supercapacitor electrodes

    Science.gov (United States)

    Yaddanapudi, Haritha Sree; Tian, Kun; Teng, Shiang; Tiwari, Ashutosh

    2016-09-01

    We are reporting a facile way to prepare nickel/carbon nanocomposites from wood as a novel electrode material for supercapacitors. The surface morphology and the structure of the as-prepared electrodes were studied by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results indicate that after high-temperature carbonization process, the wood is converted into graphitic carbon with nickel nanoparticles uniformly distributed within the three dimensional structure of the wood. Electrochemical characterization such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge measurements were conducted. These results showed that the introduction of nickel into the carbonized wood improves the specific capacitance and the cyclic stability of the nanocomposite electrode over that of the pure carbonized wood electrode. The composite electrode displayed an enhanced capacitive performance of 3616 F/g at 8 A/g, and showed an excellent capacitance retention after 6000 charge-discharge cycles. These results endow the nickel nanoparticles impregnated carbonized wood with a great potential for future application in supercapacitors.

  5. New class of carbon-nanotube aerogel electrodes for electrochemical power sources

    Energy Technology Data Exchange (ETDEWEB)

    Bordjiba, T.; Mohamedi, M.; Dao, L.H. [Institut National de Recherche Scientifique (INRS) - Energie, Materiaux et Telecommunications, University of Quebec, 1650 Blvd. Lionel Boulet, Varennes, QC, J3X 1S2 (Canada)

    2008-02-18

    Novel binderless carbon nanotube aerogel (CNAG) electrodes are developed. The materials exhibit a remarkable specific surface area of 1059 m{sup 2} g{sup -1} with a special textural porosity with almost equal amounts of mesopores and micropores. These nanostructured CNAG electrodes have a wide range of potential applications in electrochemical power sources. The CNAGs great potential as electrodes for supercapacitor applications is demonstrated by a specific capacitance as high as 524 F g{sup -1}. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  6. Operation of a Segmented Hall Thruster with Low-sputtering Carbon-velvet Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Raitses, Y.; Staack, D.; Dunaevsky, A.; Fisch, N.J.

    2005-12-01

    Carbon fiber velvet material provides exceptional sputtering resistance properties exceeding those for graphite and carbon composite materials. A 2 kW Hall thruster with segmented electrodes made of this material was operated in the discharge voltage range of 200–700 V. The arcing between the floating velvet electrodes and the plasma was visually observed, especially, during the initial conditioning time, which lasted for about 1 h. The comparison of voltage versus current and plume characteristics of the Hall thruster with and without segmented electrodes indicates that the magnetic insulation of the segmented thruster improves with the discharge voltage at a fixed magnetic field. The observations reported here also extend the regimes wherein the segmented Hall thruster can have a narrower plume than that of the conventional nonsegmented thruster.

  7. Improved Positive Electrode Materials for Lithium-ion Batteries

    Science.gov (United States)

    Conry, Thomas Edward

    pyrolysis is a simple, inexpensive, and scalable method used to produce highly uniform and phase-pure particle materials. The materials are synthesized here as porous, carbon-coated spherical particles with micron-sized diameters and nanoscale primary particles. The LiMPO4 ( M=Fe,Co) olivine electrodes display exceptional electrochemical properties, in terms of high discharge capacities, rate capability, and cycling stability. The excellent performance is due to the particle morphologies that include a hierarchical pore structure and conductive carbon network throughout the particles. This allows liquid electrolyte penetration into the particle interiors, thus limiting the necessary solid-state diffusion distances, as well as efficient charge transfer and collection.

  8. Surface modifications of electrode materials for lithium ion batteries

    Science.gov (United States)

    Fu, L. J.; Liu, H.; Li, C.; Wu, Y. P.; Rahm, E.; Holze, R.; Wu, H. Q.

    2006-02-01

    Since the birth of the lithium ion battery in the early 1990s, its development has been very rapid and it has been widely applied as power source for a lot of light and high value electronics due to its significant advantages over traditional rechargeable battery systems. Recent research demonstrates the importance of surface structural features of electrode materials for their electrochemical performance, and in this paper the latest progress on this aspect is reviewed. Electrode materials are either anodic or cathodic ones. The former mainly include graphitic carbons, whose surfaces can be modified by mild oxidation, deposition of metals and metal oxides, coating with polymers and other kinds of carbons. Through these modifications, the surface structures of the graphitic carbon anodes are improved, and these improvements include: (1) smoothing the active edge surfaces by removing some reactive sites and/or defects on the graphite surface, (2) forming a dense oxide layer on the graphite surface, and (3) covering active edge structures on the graphite surface. Meanwhile, other accompanying changes occur: (1) production of nanochannels/micropores, (2) an increase in the electronic conductivity, (3) an inhibition of structural changes during cycling, (4) a reduction of the thickness of the SEI (solid-electrolyte-interface) layer, and (5) an increase in the number of host sites for lithium storage. As a result, the direct contact of graphite with the electrolyte solution is prevented, its surface reactivity with electrolytes, the decomposition of electrolytes, the co-intercalation of the solvated lithium ions and the charge-transfer resistance are decreased, and the movement of graphene sheets is inhibited. When the surfaces of cathode materials, mainly including LiCoO 2, LiNiO 2 and LiMn 2O 4, are coated with oxides such as MgO, Al 2O 3, ZnO, SnO 2, ZrO 2, Li 2Oṡ2B 2O 3 glass and other electroactive oxides, the coating can prevent their direct contact with the

  9. Status of Biomass Derived Carbon Materials for Supercapacitor Application

    Directory of Open Access Journals (Sweden)

    Talam Kibona Enock

    2017-01-01

    Full Text Available Environmental concerns and energy security uncertainties associated with fossil fuels have driven the world to shift to renewable energy sources. However, most renewable energy sources with exception of hydropower are intermittent in nature and thus need storage systems. Amongst various storage systems, supercapacitors are the promising candidates for energy storage not only in renewable energies but also in hybrid vehicles and portable devices due to their high power density. Supercapacitor electrodes are almost invariably made of carbon derived from biomass. Several reviews had been focused on general carbon materials for supercapacitor electrode. This review is focused on understanding the extent to which different types of biomasses have been used as porous carbon materials for supercapacitor electrodes. It also details hydrothermal microwave assisted, ionothermal, and molten salts carbonization as techniques of synthesizing activated carbon from biomasses as well as their characteristics and their impacts on electrochemical performance.

  10. Low-dimensional carbon and MXene-based electrochemical capacitor electrodes

    Science.gov (United States)

    Yoon, Yeoheung; Lee, Keunsik; Lee, Hyoyoung

    2016-04-01

    Due to their unique structure and outstanding intrinsic physical properties such as extraordinarily high electrical conductivity, large surface area, and various chemical functionalities, low-dimension-based materials exhibit great potential for application in electrochemical capacitors (ECs). The electrical properties of electrochemical capacitors are determined by the electrode materials. Because energy charge storage is a surface process, the surface properties of the electrode materials greatly influence the electrochemical performance of the cell. Recently, graphene, a single layer of sp2-bonded carbon atoms arrayed into two-dimensional carbon nanomaterial, has attracted wide interest as an electrode material for electrochemical capacitor applications due to its unique properties, including a high electrical conductivity and large surface area. Several low-dimensional materials with large surface areas and high conductivity such as onion-like carbons (OLCs), carbide-derived carbons (CDCs), carbon nanotubes (CNTs), graphene, metal hydroxide, transition metal dichalcogenides (TMDs), and most recently MXene, have been developed for electrochemical capacitors. Therefore, it is useful to understand the current issues of low-dimensional materials and their device applications.

  11. Electroanalysis of NADH Using Conducting and Redox Active Polymer/Carbon Nanotubes Modified Electrodes-A Review

    Directory of Open Access Journals (Sweden)

    Shen-Ming Chen

    2008-01-01

    Full Text Available Past few decades, conducting and redox active polymers play a critical role in the development of transducers for biosensing. It has been evidenced by increasing numerous reports on conducting and redox active polymers incorporated electrodes for assay of biomolcules. This review highlights the potential uses of electrogenerated polymer modified electrodes and polymer/carbon nanotubes composite modified electrodes for electroanalysis of reduced form of nicotinamide adenine dinuceltoide (NADH. In addition, carbon electrodes modified with organic and inorganic materials as modifier have been discussed in detail for the quantification of NADH based on mediator or mediator-less methods.

  12. Oxygen electrode in molten carbonate fuel cells

    Science.gov (United States)

    Dave, B. B.; White, R. E.; Srinivasan, S.; Appleby, A. J.

    1990-12-01

    During this quarter, impedance data were analyzed for an oxygen reduction process in molten carbonate electrolyte and a manuscript, Impedance Analysis for Oxygen Reduction in a Lithium Carbonate Melt: Effects of Partial Pressure of Carbon Dioxide and Temperature, was prepared to be submitted to Journal of the Electrochemical Society for publication.

  13. Carbon nanotube electrodes for hot-wire electrochemistry.

    Science.gov (United States)

    Gründler, Peter; Frank, Otakar; Kavan, Ladislav; Dunsch, Lothar

    2009-02-23

    The use and preparation of single-walled carbon nanotubes (SWCNTs) at thin metallic wire electrodes for hot-wire electrochemical studies is described. The nanotubes were deposited on metal substrates such as gold by electrophoresis from a dispersion containing sodium dodecyl sulphate as an anionic surfactant. The formation of a layer of pure SWCNTs is achieved by thermal treatment at 350 degrees C. When heated in situ by a strong ac current, the electrodes can be used for electrochemical studies of nanotubes at increased temperatures. The state and functionality of the electrodes were characterized by Raman spectroscopy, scanning electron microscopy, and cyclic voltammetry with both anionic and cationic redox systems (dopamine, ferrocene carboxylic acid). First time experiments at the heated SWCNT electrodes demonstrated an excellent suitability of these as-prepared electrodes for thermoelectrochemical studies.

  14. Evaluation of electrode materials for all-copper hybrid flow batteries

    Science.gov (United States)

    Leung, Puiki; Palma, Jesus; Garcia-Quismondo, Enrique; Sanz, Laura; Mohamed, M. R.; Anderson, Marc

    2016-04-01

    This work evaluates a number of two- and three-dimensional electrodes for the reactions of an all-copper hybrid flow battery. Half- and full-cell experiments are conducted by minimizing the crossover effect of the copper(II) species. The battery incorporates a Nafion® cation exchange membrane and the negative electrolyte is maintained at the monovalent (colourless) state by the incorporating copper turnings in the electrolyte reservoir. Under such conditions, the half-cell coulombic efficiencies of the negative electrode reactions are all higher than 90% regardless of electrode materials and the state-of-charge (SOC). With charge-discharge cycling the half-cell from a 0% SOC, the coulombic efficiencies of the positive electrode reactions are lower than 76% with the planar carbon electrode, which further decrease in shorter charge-discharge cycles. Polarization and half-cell charge-discharge experiments suggest that the high-surface-area electrodes effectively reduce the overpotentials and improve the coulombic efficiencies of both electrode reactions. When copper fibres and carbon felt are used as the negative and positive electrodes, the average coulombic and voltage efficiencies of an all-copper flow battery are as high as c.a. 99% and c.a. 60% at 50 mA cm-2 for 35 cycles.

  15. Mesoporous carbon materials

    Science.gov (United States)

    Dai, Sheng; Fulvio, Pasquale Fernando; Mayes, Richard T.; Wang, Xiqing; Sun, Xiao-Guang; Guo, Bingkun

    2014-09-09

    A conductive mesoporous carbon composite comprising conductive carbon nanoparticles contained within a mesoporous carbon matrix, wherein the conductive mesoporous carbon composite possesses at least a portion of mesopores having a pore size of at least 10 nm and up to 50 nm, and wherein the mesopores are either within the mesoporous carbon matrix, or are spacings delineated by surfaces of said conductive carbon nanoparticles when said conductive carbon nanoparticles are fused with each other, or both. Methods for producing the above-described composite, devices incorporating them (e.g., lithium batteries), and methods of using them, are also described.

  16. A self-template strategy for the synthesis of mesoporous carbon nanofibers as advanced supercapacitor electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wei; Zhang, Fan; Dou, Yuqian; Wu, Zhangxiong; Liu, Haijing; Qian, Xufang; Gu, Dong; Xia, Yongyao; Tu, Bo; Zhao, Dongyuan [Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials and Laboratory of Advanced Materials, Fudan University, Shanghai 200433 (China)

    2011-05-15

    Self-construction: A facile self-templating strategy is presented for the synthesis of mesoporous carbon nanofibers by using zinc glycolate fibers as the built-in template. The spectacular architectures show excellent performances as recommended electrode material for electrochemical capacitors. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Carbon: The Ultimate Electrode Choice for Widely Distributed Polymer Solar Cells

    DEFF Research Database (Denmark)

    Benatto, Gisele Alves dos Reis; Roth, Bérenger; Madsen, Morten Vesterager

    2014-01-01

    As mass-produced, low-cost organic electronics enter our everyday lives, so does the waste from them. The challenges associated with end-of-life management must be addressed by careful design and carbon-based electrodes are central to these developments. Here, the reproducible production of vacuum......-, indium tin oxide (ITO)-, and silver-free solar cells in a fully packaged form using only roll-to-roll processing is reported. Replacing silver with carbon as electrode material signifi cantly lowers the manufacturing cost and makes the organic photovoltaic (OPV) modules environmentally safe while...

  18. Carbon electrode for desalination purpose in capacitive deionization

    Science.gov (United States)

    Endarko, Fadilah, Nurul; Anggoro, Diky

    2016-03-01

    Carbon electrodes for desalination purpose have been successfully synthesized using activated carbon powder (BET surface area=700 - 1400 m2/g), carbon black and polyvinyl alcohol (PVA) binder by cross-linking method with glutaric acid (GA) at 120 °C. The electrochemical properties of the carbon electrodes were analyzed using electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) whilst the physical properties were observed with scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX). In order to assess the desalting performance, salt removal experiments were performed by constructing a capacitive deionization unit cell with five pairs of carbon electrodes. For each pair consisted of two parallel carbon electrodes separated by a spacer. Desalination and regeneration processes were also observed in the salt-removal experiments. The salt-removal experiments were carried out in single-pass mode using a solution with 0.1 M NaCl at a flow rate of 10 mL/min. A voltage of 3 V was applied to the cell for 60 minutes for both processes in desalination and regeneration. The result showed that the percentage value of the salt-removal was achieved at 20%.

  19. Hierarchical porous carbon aerogel derived from bagasse for high performance supercapacitor electrode

    Science.gov (United States)

    Hao, Pin; Zhao, Zhenhuan; Tian, Jian; Li, Haidong; Sang, Yuanhua; Yu, Guangwei; Cai, Huaqiang; Liu, Hong; Wong, C. P.; Umar, Ahmad

    2014-09-01

    Renewable, cost-effective and eco-friendly electrode materials have attracted much attention in the energy conversion and storage fields. Bagasse, the waste product from sugarcane that mainly contains cellulose derivatives, can be a promising candidate to manufacture supercapacitor electrode materials. This study demonstrates the fabrication and characterization of highly porous carbon aerogels by using bagasse as a raw material. Macro and mesoporous carbon was first prepared by carbonizing the freeze-dried bagasse aerogel; consequently, microporous structure was created on the walls of the mesoporous carbon by chemical activation. Interestingly, it was observed that the specific surface area, the pore size and distribution of the hierarchical porous carbon were affected by the activation temperature. In order to evaluate the ability of the hierarchical porous carbon towards the supercapacitor electrode performance, solid state symmetric supercapacitors were assembled, and a comparable high specific capacitance of 142.1 F g-1 at a discharge current density of 0.5 A g-1 was demonstrated. The fabricated solid state supercapacitor displayed excellent capacitance retention of 93.9% over 5000 cycles. The high energy storage ability of the hierarchical porous carbon was attributed to the specially designed pore structures, i.e., co-existence of the micropores and mesopores. This research has demonstrated that utilization of sustainable biopolymers as the raw materials for high performance supercapacitor electrode materials is an effective way to fabricate low-cost energy storage devices.Renewable, cost-effective and eco-friendly electrode materials have attracted much attention in the energy conversion and storage fields. Bagasse, the waste product from sugarcane that mainly contains cellulose derivatives, can be a promising candidate to manufacture supercapacitor electrode materials. This study demonstrates the fabrication and characterization of highly porous carbon

  20. Gold nanoparticle decorated multi-walled carbon nanotubes as counter electrode for dye sensitized solar cells.

    Science.gov (United States)

    Kaniyoor, Adarsh; Ramaprabhu, Sundara

    2012-11-01

    A novel counter electrode material for dye sensitized solar cells (DSSCs) composed of nanostructured Au particles decorated on functionalized multi-walled carbon nanotubes (f-MWNTs) is demonstrated for the first time. MWNTs synthesized by catalytic chemical vapor deposition technique are purified and functionalized by treating with concentrated acids. Au nanoparticles are decorated on f-MWNTs by a rapid and facile microwave assisted polyol reduction method. The materials are characterized by X-ray diffractometry, Fourier transform infra red spectroscopy and electron microscopy. The DSSC fabricated with Au/f-MWNTs based counter electrode shows enhanced power conversion efficiency (eta) of 4.9% under AM 1.5G simulated solar radiation. In comparison, the reference DSSCs fabricated with f-MWNTs and Pt counter electrodes show eta of 2.1% and 4.5%. This high performance of Au/f-MWNTs counter electrode is investigated using electrochemical impedance spectroscopy and cyclic voltammetry studies.

  1. Nickel Oxide as an Electrode Material for Supercapacitors

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The preparation of Ni oxide films and their capacitive mechanism are discussed in this paper. Nickel oxide film electrodes perform pseudocapacitance in aqueous KOH and NaOH but perform double layer capacitance in LiCIO4/PC (propylence carbonate). The effect of increasing the specific capacitance was observed when Ni oxide film electrodes are doped with Co. A specific capacitance of around 70 F/g was achieved when using Ni oxide films doped with Co as electrodes and 1 mol/L aqueous KOH or NaOH as an electrolyte.

  2. Mn based olivine electrode material with high power and energy.

    Science.gov (United States)

    Kim, Jongsoon; Seo, Dong-Hwa; Kim, Sung-Wook; Park, Young-Uk; Kang, Kisuk

    2010-02-28

    We report the Mn based olivine electrode material with high power and energy. Easier and more frequent nucleation by Fe and Co in Mn-based olivines significantly enhanced the rate capability as evidenced by the electrochemical results.

  3. A Viable Electrode Material for Use in Microbial Fuel Cells for Tropical Regions

    Directory of Open Access Journals (Sweden)

    Felix Offei

    2016-01-01

    Full Text Available Electrode materials are critical for microbial fuel cells (MFC since they influence the construction and operational costs. This study introduces a simple and efficient electrode material in the form of palm kernel shell activated carbon (AC obtained in tropical regions. The novel introduction of this material is also targeted at introducing an inexpensive and durable electrode material, which can be produced in rural communities to improve the viability of MFCs. The maximum voltage and power density obtained (under 1000 Ω load using an H-shaped MFC with AC as both anode and cathode electrode material was 0.66 V and 1.74 W/m3, respectively. The power generated by AC was as high as 86% of the value obtained with the extensively used carbon paper. Scanning electron microscopy and Denaturing Gradient Gel Electrophoresis (DGGE analysis of AC anode biofilms confirmed that electrogenic bacteria were present on the electrode surface for substrate oxidation and the formation of nanowires.

  4. Inkjet printed multiwall carbon nanotube electrodes for dielectric elastomer actuators

    Science.gov (United States)

    Baechler, Curdin; Gardin, Samuele; Abuhimd, Hatem; Kovacs, Gabor

    2016-05-01

    Dielectric elastomers (DE’s) offer promising applications as soft and light-weight electromechanical actuators. It is known that beside the dielectric material, the electrode properties are of particular importance regarding the DE performance. Therefore, in recent years various studies have focused on the optimization of the electrode in terms of conductivity, stretchability and reliability. However, less attention was given to efficient electrode processing and deposition methods. In the present study, digital inkjet printing was used to deposit highly conductive and stretchable electrodes on silicone. Inkjet printing is a versatile and cost effective deposition method, which allows depositing complex-shaped electrode patterns with high precision. The electrodes were printed using an ink based on industrial low-cost MWCNT. Experiments have shown that the strain-conductivity properties of the printed electrode are strongly depended on the deposition parameters like drop-spacing and substrate temperature. After the optimization of the printing parameters, thin film electrodes could be deposited showing conductivities of up to 30 S cm-1 without the need of any post-treatment. In addition, electromechanical tests with fabricated DE actuators have revealed that the inkjet printed MWCNT electrodes are capable to self-clear in case of a dielectric breakdown.

  5. Self-supported carbon electrodes obtained by tape casting

    Directory of Open Access Journals (Sweden)

    Rubio-Marcos, F.

    2006-06-01

    Full Text Available This paper describes the preparation and electrochemical response of self-supported carbon electrodes prepared by tape casting. The dc electrical conductivity, σ, of the electrodes was determined by four-wire resistance measurements and a relation between the graphite/organic additives ratio and the electrical conductivity was established. The application of these self-supported carbon electrodes as working electrodes in analytical techniques was also evaluated using norepinephrine as electroactive substance in cyclic voltammetry and chronoamperometry. The results were compared with the traditional electrodes, carbon paste electrodes (CPEs, showing that the new self-supported carbon electrodes had both lower background noise and higher analytical response.

    Este artículo describe la preparación y respuesta electroquímica de electrodos de carbono autosoportados preparados mediante colado en cinta. La conductividad eléctrica en corriente continua de este nuevo tipo de electrodos de carbono se ha determinado usando el método de cuatro puntas y se ha establecido una relación ente la relación grafito/aditivos orgánicos y la conductividad eléctrica. La aplicación de estos electrodos autosoportados como electrodos de trabajo en diversas técnicas electroanalíticas también se ha evaluado, empleando norepinefrina como analito en voltametría cíclica y en cronoamperometría. Los resultados se compararon con los obtenidos empleando los electrodos de pasta de carbono tradicionales como electrodos de trabajo, viéndose que la señal de los nuevos electrodos autosoportados poseía menor ruido de fondo y mayor respuesta analítica.

  6. All-Carbon Electrode Consisting of Carbon Nanotubes on Graphite Foil for Flexible Electrochemical Applications

    Directory of Open Access Journals (Sweden)

    Je-Hwang Ryu

    2014-03-01

    Full Text Available We demonstrate the fabrication of an all-carbon electrode by plasma-enhanced chemical vapor deposition for use in flexible electrochemical applications. The electrode is composed of vertically aligned carbon nanotubes that are grown directly on a flexible graphite foil. Being all-carbon, the simple fabrication process and the excellent electrochemical characteristics present an approach through which high-performance, highly-stable and cost-effective electrochemical applications can be achieved.

  7. Enhancing the electrochemical response of myoglobin with carbon nanotube electrodes.

    Science.gov (United States)

    Esplandiu, M J; Pacios, M; Cyganek, L; Bartroli, J; del Valle, M

    2009-09-02

    In this paper, the electrochemical behavior of different myoglobin-modified carbon electrodes is evaluated. In particular, the performance of voltammetric biosensors made of forest-like carbon nanotubes, carbon nanotube composites and graphite composites is compared by monitoring mainly the electrocatalytic reduction of H(2)O(2) by myoglobin and their corresponding electroanalytical characteristics. Graphite composites showed the worst electroanalytical performance, exhibiting a small linear range, a limit of detection (LOD) of 9 x 10(-5) M and low sensitivity. However, it was found that the electrochemical response was enhanced with the use of carbon nanotube-based electrodes with LOD up to 5 x 10(-8) M, higher sensitivities and wider linear range response. On the one hand, in the case of the CNT epoxy composite, the improvement in the response can be mainly attributed to its more porous surface which allows the immobilization of higher amounts of the electroactive protein. On the other hand, in the case of the forest-like CNT electrodes, the enhancement is due to an increase in the electron transfer kinetics. These findings encourage the use of myoglobin-modified carbon nanotube electrodes as potential (bio)sensors of H(2)O(2) or O(2) in biology, microbiology and environmental fields.

  8. An overview of carbon materials for flexible electrochemical capacitors.

    Science.gov (United States)

    He, Yongmin; Chen, Wanjun; Gao, Caitian; Zhou, Jinyuan; Li, Xiaodong; Xie, Erqing

    2013-10-07

    Under the background of the quick development of lightweight, flexible, and wearable electronic devices in our society, a flexible and highly efficient energy management strategy is needed for their counterpart energy-storage systems. Among them, flexible electrochemical capacitors (ECs) have been considered as one of the most promising candidates because of their significant advantages in power and energy densities, and unique properties of being flexible, lightweight, low-cost, and environmentally friendly compared with current energy storage devices. In a common EC, carbon materials play an irreplaceable and principal role in its energy-storage performance. Up till now, most progress towards flexible ECs technologies has mostly benefited from the continuous development of carbon materials. As a result, in view of the dual remarkable highlights of ECs and carbon materials, a summary of recent research progress on carbon-based flexible EC electrode materials is presented in this review, including carbon fiber (CF, consisting of carbon microfiber-CMF and carbon nanofiber-CNF) networks, carbon nanotube (CNT) and graphene coatings, CNT and/or graphene papers (or films), and freestanding three-dimensional (3D) flexible carbon-based macroscopic architectures. Furthermore, some promising carbon materials for great potential applications in flexible ECs are introduced. Finally, the trends and challenges in the development of carbon-based electrode materials for flexible ECs and their smart applications are analyzed.

  9. Electrochemical impedance spectroscopy on nanostructured carbon electrodes grown by supersonic cluster beam deposition

    Energy Technology Data Exchange (ETDEWEB)

    Bettini, Luca Giacomo; Bardizza, Giorgio; Podesta, Alessandro; Milani, Paolo; Piseri, Paolo, E-mail: piseri@mi.infn.it [Universita degli Studi di Milano, Dipartimento di Fisica and CIMaINa (Italy)

    2013-02-15

    Nanostructured porous films of carbon with density of about 0.5 g/cm{sup 3} and 200 nm thickness were deposited at room temperature by supersonic cluster beam deposition (SCBD) from carbon clusters formed in the gas phase. Carbon film surface topography, determined by atomic force microscopy, reveals a surface roughness of 16 nm and a granular morphology arising from the low kinetic energy ballistic deposition regime. The material is characterized by a highly disordered carbon structure with predominant sp2 hybridization as evidenced by Raman spectroscopy. The interface properties of nanostructured carbon electrodes were investigated by cyclic voltammetry and electrochemical impedance spectroscopy employing KOH 1 M solution as aqueous electrolyte. An increase of the double layer capacitance is observed when the electrodes are heat treated in air or when a nanostructured nickel layer deposited by SCBD on top of a sputter deposited film of the same metal is employed as a current collector instead of a plain metallic film. This enhancement is consistent with an improved charge injection in the active material and is ascribed to the modification of the electrical contact at the interface between the carbon and the metal current collector. Specific capacitance values up to 120 F/g have been measured for the electrodes with nanostructured metal/carbon interface.

  10. Arsenic species interactions with a porous carbon electrode as determined with an electrochemical quartz crystal microbalance

    Science.gov (United States)

    Morallón, Emilia; Arias-Pardilla, Joaquín; Calo, J.M.; Cazorla-Amorós, D.

    2009-01-01

    The interactions of arsenic species with platinum and porous carbon electrodes were investigated with an electrochemical quartz crystal microbalance (EQCM) and cyclic voltammetry in alkaline solutions. It is shown that the redox reactions in arsenic-containing solutions, due to arsenic reduction/deposition, oxidation/desorption, and electrocatalyzed oxidation by Pt can be readily distinguished with the EQCM. This approach was used to show that the arsenic redox reactions on the carbon electrode are mechanistically similar to that on the bare Pt electrode. This could not be concluded with just classical cyclic voltammetry alone due to the obfuscation of the faradaic features by the large capacitative effects of the carbon double layer. For the porous carbon electrode, a continual mass loss was always observed during potential cycling, with or without arsenic in the solution. This was attributed to electrogasification of the carbon. The apparent mass loss per cycle was observed to decrease with increasing arsenic concentration due to a net mass increase in adsorbed arsenic per cycle that increased with arsenic concentration, offsetting the carbon mass loss. Additional carbon adsorption sites involved in arsenic species interactions are created during electrogasification, thereby augmenting the net uptake of arsenic per cycle. It is demonstrated that EQCM, and in particular the information given by the behavior of the time derivative of the mass vs. potential, or massogram, is very useful for distinguishing arsenic species interactions with carbon electrodes. It may also prove to be effective for investigating redox/adsorption/desorption behavior of other species in solution with carbon materials as well. PMID:20161369

  11. Arsenic species interactions with a porous carbon electrode as determined with an electrochemical quartz crystal microbalance.

    Science.gov (United States)

    Morallón, Emilia; Arias-Pardilla, Joaquín; Calo, J M; Cazorla-Amorós, D

    2009-06-30

    The interactions of arsenic species with platinum and porous carbon electrodes were investigated with an electrochemical quartz crystal microbalance (EQCM) and cyclic voltammetry in alkaline solutions. It is shown that the redox reactions in arsenic-containing solutions, due to arsenic reduction/deposition, oxidation/desorption, and electrocatalyzed oxidation by Pt can be readily distinguished with the EQCM. This approach was used to show that the arsenic redox reactions on the carbon electrode are mechanistically similar to that on the bare Pt electrode. This could not be concluded with just classical cyclic voltammetry alone due to the obfuscation of the faradaic features by the large capacitative effects of the carbon double layer.For the porous carbon electrode, a continual mass loss was always observed during potential cycling, with or without arsenic in the solution. This was attributed to electrogasification of the carbon. The apparent mass loss per cycle was observed to decrease with increasing arsenic concentration due to a net mass increase in adsorbed arsenic per cycle that increased with arsenic concentration, offsetting the carbon mass loss. Additional carbon adsorption sites involved in arsenic species interactions are created during electrogasification, thereby augmenting the net uptake of arsenic per cycle.It is demonstrated that EQCM, and in particular the information given by the behavior of the time derivative of the mass vs. potential, or massogram, is very useful for distinguishing arsenic species interactions with carbon electrodes. It may also prove to be effective for investigating redox/adsorption/desorption behavior of other species in solution with carbon materials as well.

  12. Performance and cycle life of carbon- and conductive-based air electrodes for rechargeable Zn-air battery applications

    Science.gov (United States)

    Chellapandi Velraj, Samgopiraj

    The development of high-performance, cyclically stable bifunctional air electrodes are critical to the commercial deployment of rechargeable Zn-air batteries. The carbon material predominantly used as support material in the air electrodes due to its higher surface area and good electrical conductivity suffers from corrosion at high oxygen evolution overpotentials. This study addresses the carbon corrosion issues and suggests alternate materials to replace the carbon as support in the air electrode. In this study, Sm0.5Sr0.5CoO3-delta with good electrochemical performance and cyclic lifetime was identified as an alternative catalyst material to the commonly used La0.4Ca 0.6CoO3 catalyst for the carbon-based bifunctional electrodes. Also, a comprehensive study on the effects of catalyst morphology, testing conditions on the cycle life as well as the relevant degradation mechanism for the carbon-based electrode was conducted in this dissertation. The cyclic life of the carbon-based electrodes was strongly dependent on the carbon support material, while the degradation mechanisms were entirely controlled by the catalyst particle size/morphology. Some testing conditions like resting time and electrolyte concentration did not change the cyclic life or degradation mechanism of the carbon-based electrode. The current density used for cyclic testing was found to dictate the degradation mechanism leading to the electrode failure. An alternate way to circumvent the carbon corrosion is to replace the carbon support with a suitable electrically-conductive ceramic material. In this dissertation, LaNi0.9Mn0.1O3, LaNi 0.8Co0.2O3, and NiCo2O4 were synthesized and evaluated as prospective support materials due to their good electrical conductivity and their ability to act as the catalyst needed for the bifunctional electrode. The carbon-free electrodes had remarkably higher catalytic activity for oxygen evolution reaction (OER) when compared to the carbon-based electrode. However

  13. The Impact of Surface Chemistry on Bio-derived Carbon Performance as Supercapacitor Electrodes

    Science.gov (United States)

    Alshareef, Niman H.; Whitehair, Daniel; Xia, Chuan

    2017-03-01

    In this study, we demonstrate that highly functionalized and porous carbons can be derived from palm-leaf waste using the template-free facile synthesis process. The derived carbons have high content of nitrogen dopant, high surface area, and various defects. Moreover, these carbons exhibit a high electrical conductivity (107 S m-1). Thanks to the high content of edge N (64.3%) and highly microporous nature (82% of microspores), these biomass-derived carbons show promising performance when used as supercapacitor electrodes. To be specific, these carbonaceous materials show a specific capacitance as high as 197 and 135 F g-1 at 2 and 20 A g-1 in three-electrode configuration, respectively. Furthermore, the symmetrical cells using palm-leaf-derived carbon show an energy density of 8.4 Wh Kg-1 at a power density of 0.64 kW Kg-1, with high cycling life stability (˜8% loss after 10,000 continuous charge-discharge cycles at 20 A g-1). Interestingly, as the power density increases from 4.4 kW kg-1 to 36.8 kW kg-1, the energy density drops slowly from 8.4 Wh kg-1 to 3.4 Wh kg-1. Getting such extremely high power density without significant loss of energy density indicates that these palm-leaf-derived carbons have excellent electrode performance as supercapacitor electrodes.

  14. The Impact of Surface Chemistry on Bio-derived Carbon Performance as Supercapacitor Electrodes

    Science.gov (United States)

    Alshareef, Niman H.; Whitehair, Daniel; Xia, Chuan

    2016-12-01

    In this study, we demonstrate that highly functionalized and porous carbons can be derived from palm-leaf waste using the template-free facile synthesis process. The derived carbons have high content of nitrogen dopant, high surface area, and various defects. Moreover, these carbons exhibit a high electrical conductivity (107 S m-1). Thanks to the high content of edge N (64.3%) and highly microporous nature (82% of microspores), these biomass-derived carbons show promising performance when used as supercapacitor electrodes. To be specific, these carbonaceous materials show a specific capacitance as high as 197 and 135 F g-1 at 2 and 20 A g-1 in three-electrode configuration, respectively. Furthermore, the symmetrical cells using palm-leaf-derived carbon show an energy density of 8.4 Wh Kg-1 at a power density of 0.64 kW Kg-1, with high cycling life stability (˜8% loss after 10,000 continuous charge-discharge cycles at 20 A g-1). Interestingly, as the power density increases from 4.4 kW kg-1 to 36.8 kW kg-1, the energy density drops slowly from 8.4 Wh kg-1 to 3.4 Wh kg-1. Getting such extremely high power density without significant loss of energy density indicates that these palm-leaf-derived carbons have excellent electrode performance as supercapacitor electrodes.

  15. The Impact of Surface Chemistry on Bio-derived Carbon Performance as Supercapacitor Electrodes

    KAUST Repository

    Alshareef, Husam N.

    2016-12-23

    In this study, we demonstrate that highly functionalized and porous carbons can be derived from palm-leaf waste using the template-free facile synthesis process. The derived carbons have high content of nitrogen dopant, high surface area, and various defects. Moreover, these carbons exhibit a high electrical conductivity (107 S m−1). Thanks to the high content of edge N (64.3%) and highly microporous nature (82% of microspores), these biomass-derived carbons show promising performance when used as supercapacitor electrodes. To be specific, these carbonaceous materials show a specific capacitance as high as 197 and 135 F g−1 at 2 and 20 A g−1 in three-electrode configuration, respectively. Furthermore, the symmetrical cells using palm-leaf-derived carbon show an energy density of 8.4 Wh Kg−1 at a power density of 0.64 kW Kg−1, with high cycling life stability (∼8% loss after 10,000 continuous charge–discharge cycles at 20 A g−1). Interestingly, as the power density increases from 4.4 kW kg−1 to 36.8 kW kg−1, the energy density drops slowly from 8.4 Wh kg−1 to 3.4 Wh kg−1. Getting such extremely high power density without significant loss of energy density indicates that these palm-leaf-derived carbons have excellent electrode performance as supercapacitor electrodes.

  16. 碳基双电层电容器电极材料的研究进展%Research Progress of Carbon-Based Electrode Materials for Electric Double-Layer Capacitors

    Institute of Scientific and Technical Information of China (English)

    刘小军; 徐新华; 黄壮昌

    2011-01-01

    Electric double-layer capacitors (EDLCs) as new energy storage devices between conventional capacitors and storage batteries, have much advantageous properties, such as higher energy density and higher power density,quick charge capability,long cycle life and environment friendly. Due to these excellent properties, they are used widely in national defense, military engineering and many civil fields such as hybrid electrical vehicles,digital telecommunication and computer,etc. This article depicts briefly the working principles of electric double-layer capacitors, and reviews the recent research progress of carbon-based electrode materials for e-lectric double-layer capacitors.%双电层电容器是一种介于电池与传统电容器之间的新型储能元件,具有较高的能量密度和功率密度,且充电速度快、循环寿命长、对环境无污染,广泛应用于国防、军工以及电动汽车、数字通讯、计算机等众多民用领域.简述了双电层电容器的基本工作原理,综述了碳基双电层电容器电极材料的研究进展.

  17. Carbon Tolerant Fuel Electrodes for Reversible Sofc Operating on Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Papazisi Kalliopi Maria

    2017-01-01

    Full Text Available A challenging barrier for the broad, successful implementation of Reversible Solid Oxide Fuel Cell (RSOFC technology for Mars application utilizing CO2 from the Martian atmosphere as primary reactant, remains the long term stability by the effective control and minimization of degradation resulting from carbon built up. The perovskitic type oxide material La0.75Sr0.25Cr0.9Fe0.1O3-δ (LSCF has been developed and studied for its performance and tolerance to carbon deposition, employed as bi-functional fuel electrode in a Reversible SOFC operating on the CO2 cycle (Solid Oxide Electrolysis Cell/SOEC: CO2 electrolysis, Solid Oxide Fuel Cell/SOFC: power generation through the electrochemical reaction of CO and oxygen. A commercial state-of-the-art NiO-YSZ (8% mol Y2O3 stabilized ZrO2 cermet was used as reference material. CO2 electrolysis and fuel cell operation in 70% CO/CO2 were studied in the temperature range of 900-1000°C. YSZ was used as electrolyte while LSM-YSZ/LSM (La0.2Sr0.8MnO3 as oxygen electrode. Results showed that LSCF had high and stable performance under RSOFC operation.

  18. Fuel cell electrode interconnect contact material encapsulation and method

    Science.gov (United States)

    Derose, Anthony J.; Haltiner, Jr., Karl J.; Gudyka, Russell A.; Bonadies, Joseph V.; Silvis, Thomas W.

    2016-05-31

    A fuel cell stack includes a plurality of fuel cell cassettes each including a fuel cell with an anode and a cathode. Each fuel cell cassette also includes an electrode interconnect adjacent to the anode or the cathode for providing electrical communication between an adjacent fuel cell cassette and the anode or the cathode. The interconnect includes a plurality of electrode interconnect protrusions defining a flow passage along the anode or the cathode for communicating oxidant or fuel to the anode or the cathode. An electrically conductive material is disposed between at least one of the electrode interconnect protrusions and the anode or the cathode in order to provide a stable electrical contact between the electrode interconnect and the anode or cathode. An encapsulating arrangement segregates the electrically conductive material from the flow passage thereby, preventing volatilization of the electrically conductive material in use of the fuel cell stack.

  19. Highly porous activated carbons from resource-recovered Leucaena leucocephala wood as capacitive deionization electrodes.

    Science.gov (United States)

    Hou, Chia-Hung; Liu, Nei-Ling; Hsi, Hsing-Cheng

    2015-12-01

    Highly porous activated carbons were resource-recovered from Leucaena leucocephala (Lam.) de Wit. wood through combined chemical and physical activation (i.e., KOH etching followed by CO2 activation). This invasive species, which has severely damaged the ecological economics of Taiwan, was used as the precursor for producing high-quality carbonaceous electrodes for capacitive deionization (CDI). Carbonization and activation conditions strongly influenced the structure of chars and activated carbons. The total surface area and pore volume of activated carbons increased with increasing KOH/char ratio and activation time. Overgasification induced a substantial amount of mesopores in the activated carbons. In addition, the electrochemical properties and CDI electrosorptive performance of the activated carbons were evaluated; cyclic voltammetry and galvanostatic charge/discharge measurements revealed a typical capacitive behavior and electrical double layer formation, confirming ion electrosorption in the porous structure. The activated-carbon electrode, which possessed high surface area and both mesopores and micropores, exhibited improved capacitor characteristics and high electrosorptive performance. Highly porous activated carbons derived from waste L. leucocephala were demonstrated to be suitable CDI electrode materials.

  20. mwnts composite film modified glassy carbon electrode

    African Journals Online (AJOL)

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    electrochemical behaviours of hydroquinone (HQ) and catechol (CC) were investigated using cyclic ... Key words/phrases: Catechol, hydroquinone, multiwall carbon nanotubes, poly(para-amino ... zymes and synthesize different new organic/-.

  1. Toward Uniformly Dispersed Battery Electrode Composite Materials: Characteristics and Performance.

    Science.gov (United States)

    Kwon, Yo Han; Huie, Matthew M; Choi, Dalsu; Chang, Mincheol; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S; Reichmanis, Elsa

    2016-02-10

    Battery electrodes are complex mesoscale systems comprised of electroactive components, conductive additives, and binders. In this report, methods for processing electrodes with dispersion of the components are described. To investigate the degree of material dispersion, a spin-coating technique was adopted to provide a thin, uniform layer that enabled observation of the morphology. Distinct differences in the distribution profile of the electrode components arising from individual materials physical affinities were readily identified. Hansen solubility parameter (HSP) analysis revealed pertinent surface interactions associated with materials dispersivity. Further studies demonstrated that HSPs can provide an effective strategy to identify surface modification approaches for improved dispersions of battery electrode materials. Specifically, introduction of surfactantlike functionality such as oleic acid (OA) capping and P3HT-conjugated polymer wrapping on the surface of nanomaterials significantly enhanced material dispersity over the composite electrode. The approach to the surface treatment on the basis of HSP study can facilitate design of composite electrodes with uniformly dispersed morphology and may contribute to enhancing their electrical and electrochemical behaviors. The conductivity of the composites and their electrochemical performance was also characterized. The study illustrates the importance of considering electronic conductivity, electron transfer, and ion transport in the design of environments incorporating active nanomaterials.

  2. DNA Nano-netting Intertexture on Carbon Electrodes

    Institute of Scientific and Technical Information of China (English)

    Xiang Qin LIN; Xiao Hua JIANG; Li Ping LU

    2004-01-01

    Native calf thymus double stranded DNA (ct-dsDNA) is successfully immobilized from solution onto carbon substrates by covalent linkages under an optimized deposition potential of 1.8±0.3 V vs.50 mmol/L NaCl-Ag/AgCl.The long chain DNA fabricates a layer of well conductive nano-netting intertexture, which is stable in pH 14 alkaline solution and in boiling water.The ct-dsDNA modified carbon fiber disk electrode shows two to three orders of magnitude enlarged electrode effective surface area and similarly enlarged voltammetric responses to Co(phen)33+ and dopamine.Thermal dissociated single stranded ct-DNA can also lead to similar result.This modified electrode will find wide applications in the fields of DNA-based electrochemical biosensors.

  3. Carbon nanotube yarns as strong flexible conductive capacitive electrodes

    NARCIS (Netherlands)

    Liu, F.; Wagterveld, R.M.; Gebben, B.; Otto, M.J.; Biesheuvel, P.M.; Hamelers, H.V.M.

    2015-01-01

    Carbon nanotube (CNT) yarn, consisting of 23 µm diameter CNT filaments, can be used as capacitive electrodes that are long, flexible, conductive and strong, for applications in energy and electrochemical water treatment. We measure the charge storage capacity as function of salt concentration, and u

  4. Functional Single-walled Carbon Nanotube Electrodes for Solar Energy Conversion

    Science.gov (United States)

    Blackburn, Jeffrey

    2010-03-01

    In this presentation, we discuss our progress in producing high surface area electrodes from single-walled carbon nanotubes (SWNTs) and the utilization of these electrodes in solar energy conversion devices. SWNTs have several fundamental properties that make them attractive for functional electrodes, including high electron and hole mobilities, a tunable work function with an energy range relevant to many photovoltaic devices, and optical transitions in the visible and near infrared that may be useful for solar driven photochemical reactions. Additionally, they possess numerous properties amenable to practical, scalable, and economic electrode deposition including abundant source material, a natural disposition for solution processing, and high surface area and flexibility. All of these features make them extremely attractive for replacing conventional electrodes, such as tin-doped indium oxide (ITO), which suffer from questionable world supply, high temperature/low pressure deposition requirements, and brittleness. We will present our development of a versatile and scalable ultrasonic spray process for producing SWNT electrodes with high transparency, high conductivity, and very low surface roughness. This method can be adapted for aqueous and organic solvents, allowing SWNT electrodes to be sprayed on a variety of different substrates, including directly on photovoltaic devices. The performance of PV devices incorporating our electrodes is nearly equivalent to devices incorporating traditional transparent conducting oxides. Finally, we demonstrate that this method can be extended to the production of a variety of different functional SWNT electrodes, including bio-hybrid electrodes for the production of hydrogen fuel. These electrodes achieve electrolytic current densities close to that of platinum at a fraction of the cost. We will discuss devices incorporating bulk SWNTs as well as SWNTs enriched in specific electronic structures.

  5. Electroanalysis using modified hierarchical nanoporous carbon materials.

    Science.gov (United States)

    Rodriguez, Rusbel Coneo; Moncada, Angelica Baena; Acevedo, Diego F; Planes, Gabriel A; Miras, Maria C; Barbero, Cesar A

    2013-01-01

    The role of the electrode nanoporosity in electroanalytical processes is discussed and specific phenomena (slow double layer charging, local pH effects) which can be present in porous electrode are described. Hierarchical porous carbon (HPC) materials are synthesized using a hard template method. The three dimensional carbon porosity is examined using scanning electron microscopy on flat surfaces cut using a focused ion beam (FIB-SEM). The electrochemical properties of the HPC are measured using cyclic voltammetry, AC impedance, chronoamperometry and Probe Beam Deflection (PBD) techniques. Chronoamperometry measurements of HPC seems to fit a transmission line model. PBD data show evidence of local pH changes inside the pores, during double layer charging. The HPC are modified by in situ (chemical or electrochemical) formation of metal (Pt/Ru) or metal oxide (CoOx, Fe3O4) nanoparticles. Additionally, HPC loaded with Pt decorated magnetite (Fe3O4) nanoparticles is produced by galvanic displacement. The modified HPC materials are used for the electroanalysis of different substances (CO, O2, AsO3(-3)). The role of the nanoporous carbon substrate in the electroanalytical data is evaluated.

  6. Carbon Cryogel Silicon Composite Anode Materials for Lithium Ion Batteries

    Science.gov (United States)

    Woodworth James; Baldwin, Richard; Bennett, William

    2010-01-01

    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 10 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-4,9 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  7. Nanoporous carbon derived from agro-waste pineapple leaves for supercapacitor electrode

    Science.gov (United States)

    Sodtipinta, Jedsada; Amornsakchai, Taweechai; Pakawatpanurut, Pasit

    2017-09-01

    By using KOH as the chemical activating agent in the synthesis, the activated carbon derived from pineapple leaf fiber (PALF) was prepared. The structure, morphology, and the surface functional groups of the as-prepared activated carbon were investigated using x-ray diffraction, field emission scanning electron microscope equipped with energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. The electrochemical behavior and performance of the as-synthesized activated carbon electrode were measured using the cyclic voltammetry and the electrochemical impedance spectroscopy in 1 M Na2SO4 electrolyte solution in three-electrode setup. The activated carbon electrode exhibited the specific capacitance of 131.3 F g-1 at a scan rate of 5 mV s-1 with excellent cycling stability. The capacitance retention after 1000 cycles was about 97% of the initial capacitance at a scan rate of 30 mV s-1. Given these good electrochemical properties along with the high abundance of PALF, this activated carbon electrode has the potential to be one of the materials for future large-scale production of the electrochemical capacitors. Invited talk at 5th Thailand International Nanotechnology Conference (Nano Thailand-2016), 27-29 November 2016, Nakhon Ratchasima, Thailand.

  8. Enhanced performance of electrospun carbon fibers modified with carbon nanotubes: promising electrodes for enzymatic biofuel cells.

    Science.gov (United States)

    Engel, A Both; Cherifi, A; Tingry, S; Cornu, D; Peigney, A; Laurent, Ch

    2013-06-21

    New nanostructured electrodes, promising for the production of clean and renewable energy in biofuel cells, were developed with success. For this purpose, carbon nanofibers were produced by the electrospinning of polyacrylonitrile solution followed by convenient thermal treatments (stabilization followed by carbonization at 1000, 1200 and 1400° C), and carbon nanotubes were adsorbed on the surfaces of the fibers by a dipping method. The morphology of the developed electrodes was characterized by several techniques (SEM, Raman spectroscopy, electrical conductivity measurement). The electrochemical properties were evaluated through cyclic voltammetry, where the influence of the carbonization temperature of the fibers and the beneficial contribution of the carbon nanotubes were observed through the reversibility and size of the redox peaks of K3Fe(CN)6 versus Ag/AgCl. Subsequently, redox enzymes were immobilized on the electrodes and the electroreduction of oxygen to water was realized as a test of their efficiency as biocathodes. Due to the fibrous and porous structure of these new electrodes, and to the fact that carbon nanotubes may have the ability to promote electron transfer reactions of redox biomolecules, the new electrodes developed were capable of producing higher current densities than an electrode composed only of electrospun carbon fibers.

  9. Preparation and electrochemical characterization of C/PANI composite electrode materials

    Institute of Scientific and Technical Information of China (English)

    LAI Yan-qing; LI Jing; LI Jie; LU Hai; ZHANG Zhi-an; LIU Ye-xiang

    2006-01-01

    Taking the nano-sized carbon black and aniline monomer as precursor and (NH4)2 S2 O6 as oxidant, the well coated C/polyaniline(C/PANI) composite materials were prepared by in situ polymerization of the aniline on the surface of well-dispersed nano-sized carbon black for supercapacitor. The micro-structure of the C/PANI composite electrode materials were analyzed by SEM. The electrochemical properties of C/ PANI and PANI composite electrode were characterized by means of the galvanostatic charge-discharge experiment, cyclic voltammetric measurement and impedance spectroscopy analysis. The results show that by adding the nano-sized carbon black in the process of chemical polymerization of the aniline, the polyaniline can be in situ polymerized and well-coated onto the carbon black particles, which may effectively improve the aggregation of particles and the electrolyte penetration.with PANI electrode, C/PANI electrode shows more desired capacitance characteristics, smaller internal resistance and better cycle performance.

  10. High temperature SU-8 pyrolysis for fabrication of carbon electrodes

    DEFF Research Database (Denmark)

    Hassan, Yasmin Mohamed; Caviglia, Claudia; Hemanth, Suhith

    2017-01-01

    In this work, we present the investigation of the pyrolysis parameters at high temperature (1100 °C) for the fabrication of two-dimensional pyrolytic carbon electrodes. The electrodes were fabricated by pyrolysis of lithographically patterned negative epoxy based photoresist SU-8. A central...... composite experimental design was used to identify the influence of dwell time at the highest pyrolysis temperature and heating rate on electrical, electrochemical and structural properties of the pyrolytic carbon: Van der Pauw sheet resistance measurements, cyclic voltammetry, electrochemical impedance...... spectroscopy and Raman spectroscopy were used to characterize the pyrolytic carbon. The results show that the temperature increase from 900 °C to 1100 °C improves the electrical and electrochemical properties. At 1100 °C, longer dwell time leads to lower resistivity, while the variation of the pyrolysis...

  11. Fabrication optimisation of carbon fiber electrode with Taguchi method.

    Science.gov (United States)

    Cheng, Ching-Ching; Young, Ming-Shing; Chuang, Chang-Lin; Chang, Ching-Chang

    2003-07-01

    In this study, we describe an optimised procedure for fabricating carbon fiber electrodes using Taguchi quality engineering method (TQEM). The preliminary results show a S/N ratio improvement from 22 to 30 db (decibel). The optimised parameter was tested by using a glass micropipette (0.3 mm outer/2.5 mm inner length of carbon fiber) dipped into PBS solution under 2.9 V triangle-wave electrochemical processing for 15 s, followed by coating treatment of micropipette on 2.6 V DC for 45 s in 5% Nafion solution. It is thus shown that Taguchi process optimisation can improve cost, manufacture time and quality of carbon fiber electrodes.

  12. Nanostructured Electrode Materials for Fuel Cells and Supercapacitors

    Institute of Scientific and Technical Information of China (English)

    W.Sugimoto; T.Saida; Y.Takasu

    2007-01-01

    1 Results Owing to its electrochemical stability, catalytic activity and high electrical conductivity, ruthenium-based oxides have been realized in electrochemistry as excellent electrode materials with applications ranging from electrocatalysts for industrial electrolysis to high power energy storage. Recent studies have suggested that RuOx may have an active role in electrocatalysts for fuel cells.We have been engaged in the fundamental and practical study of nanostructured RuO2-based electrodes[1-5]....

  13. Graphene oxide - Polyvinyl alcohol nanocomposite based electrode material for supercapacitors

    Science.gov (United States)

    Pawar, Pranav Bhagwan; Shukla, Shobha; Saxena, Sumit

    2016-07-01

    Supercapacitors are high capacitive energy storage devices and find applications where rapid bursts of power are required. Thus materials offering high specific capacitance are of fundamental interest in development of these electrochemical devices. Graphene oxide based nanocomposites are mechanically robust and have interesting electronic properties. These form potential electrode materials efficient for charge storage in supercapacitors. In this perspective, we investigate low cost graphene oxide based nanocomposites as electrode material for supercapacitor. Nanocomposites of graphene oxide and polyvinyl alcohol were synthesized in solution phase by integrating graphene oxide as filler in polyvinyl alcohol matrix. Structural and optical characterizations suggest the formation of graphene oxide and polyvinyl alcohol nanocomposites. These nanocomposites were found to have high specific capacitance, were cyclable, ecofriendly and economical. Our studies suggest that nanocomposites prepared by adding 0.5% wt/wt of graphene oxide in polyvinyl alcohol can be used an efficient electrode material for supercapacitors.

  14. Preparation, applications, and digital simulation of carbon interdigitated array electrodes.

    Science.gov (United States)

    Liu, Fei; Kolesov, Grigory; Parkinson, B A

    2014-08-05

    Carbon interdigitated array (IDA) electrodes with features sizes down to 1.2 μm were fabricated by controlled pyrolysis of patterned photoresist. Cyclic voltammetry of reversible redox species produced the expected steady-state currents. The collection efficiency depends on the IDA electrode spacing, which ranged from around 2.7 to 16.5 μm, with the smaller dimensions achieving higher collection efficiencies of up to 98%. The signal amplification because of redox cycling makes it possible to detect species at relatively low concentrations (10(-5) molar) and the small spacing allows detection of transient electrogenerated species with much shorter lifetimes (submillisecond). Digital simulation software that accounts for both the width and height of electrode elements as well as the electrode spacing was developed to model the IDA electrode response. The simulations are in quantitative agreement with experimental data for both a simple fast one electron redox reaction and an electron transfer with a following chemical reaction at the IDAs with larger gaps whereas currents measured for the smallest IDA electrodes, that were larger than the simulated currents, are attributed to convection from induced charge electrokinetic flow.

  15. Preparation, Applications, and Digital Simulation of Carbon Interdigitated Array Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fei; Kolesov, Grigory; Parkinson, Bruce A.

    2014-12-16

    Carbon interdigitated array (IDA) electrodes with features sizes down to 1.2 μm were fabricated by controlled pyrolysis of patterned photoresist. Cyclic voltam-metry of reversible redox species produced the expected steady-state currents. The collection efficiency depends on the IDA electrode spacing, which ranged from around 2.7 to 16.5 μm, with the smaller dimensions achieving higher collection efficiencies of up to 98%. The signal amplification because of redox cycling makes it possible to detect species at relatively low concentrations (10–5 molar) and the small spacing allows detection of transient electrogenerated species with much shorter lifetimes (submillisecond). Digital simulation software that accounts for both the width and height of electrode elements as well as the electrode spacing was developed to model the IDA electrode response. The simulations are in quantitative agreement with experimental data for both a simple fast one electron redox reaction and an electron transfer with a following chemical reaction at the IDAs with larger gaps whereas currents measured for the smallest IDA electrodes, that were larger than the simulated currents, are attributed to convection from induced charge electrokinetic flow. This work was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the Department of Energy, Office of Science Office of Basic Energy Sciences.

  16. Development of carbon paste electrodes modified by molecularly imprinted polymer as potentiometry sensor of uric acid

    Science.gov (United States)

    Khasanah, Miratul; Darmokoesoemo, Handoko; Widayanti, Nesti; Kadmi, Yassine; Elmsellem, Hicham; Kusuma, Heri Septya

    The development of carbon paste electrodes modified by molecularly imprinted polymer (MIP) for the potentiometric analysis of uric acid was carried out in this study. The aim of the study was to determine the optimum composition of the electrode constituent material, the optimum pH of the uric acid solution, and the performance of the electrode, which was measured by its response time, measurement range, Nernst factor, detection limits, selectivity coefficient, precision, accuracy, and life time. MIP was made from methyl methacrylate as the monomer, ethylene glycol dimethacrylate as the cross-linker, and uric acid as the template. Electrodes that give optimum performance were produced from carbon, MIP, and paraffin with a ratio of 40:25:35 (% w/w). The obtained results show that the measurement of uric acid solution gives optimum results at pH 5, Nernst factor of 30.19 mV/decade, and a measurement range of 10-6-10-3 M. The minimum detection limit of this method was 3.03.10-6 M, and the precision and accuracy toward uric acid with concentration of 10-6-10-3 M ranged between 1.36-2.03% and 63.9-166%. The selectivity coefficient value was less than 1, which indicated that the electrode was selective against uric acid and not interfered with by urea. This electrode has a response time of less than 2 min; its life time is 8 weeks with 104 usage times.

  17. Lithium-ion capacitors with 2D Nb2CTx (MXene) - carbon nanotube electrodes

    Science.gov (United States)

    Byeon, Ayeong; Glushenkov, Alexey M.; Anasori, Babak; Urbankowski, Patrick; Li, Jingwen; Byles, Bryan W.; Blake, Brian; Van Aken, Katherine L.; Kota, Sankalp; Pomerantseva, Ekaterina; Lee, Jae W.; Chen, Ying; Gogotsi, Yury

    2016-09-01

    There is a growing interest to hybrid energy storage devices, such as lithium-ion capacitors, in which battery-type electrodes are combined with capacitor-type ones. It is anticipated that the energy density (either gravimetric or volumetric) of lithium-ion capacitors is improved if pseudocapacitive or fast insertion materials are used instead of conventional activated carbon (AC) in the capacitor-type electrode. MXenes, a new family of two-dimensional transition metal carbides, demonstrate metallic conductivity and fast charge-discharge behavior that make them suitable for this application. In this study, we move beyond single electrodes, half-cell studies and demonstrate three types of hybrid cells using Nb2CTx-carbon nanotube (CNT) films. It is shown that lithiated graphite/Nb2CTx-CNT, Nb2CTx-CNT/LiFePO4 and lithiated Nb2CTx-CNT/Nb2CTx-CNT cells are all able to operate within 3 V voltage windows and deliver capacities of 43, 24 and 36 mAh/g (per total weight of two electrodes), respectively. Moreover, the polarity of the electrodes can be reversed in the symmetric Nb2CTx-CNT cells from providing a positive potential between 0 and 3 V to a negative one from -3 to 0 V. It is shown that the volumetric energy density (50-70 Wh/L) of our first-generation devices with MXene electrodes exceeds that of a lithium titanate/AC capacitor.

  18. Citric acid cycle biomimic on a carbon electrode.

    Science.gov (United States)

    Sokic-Lazic, Daria; Minteer, Shelley D

    2008-12-01

    The citric acid cycle is one of the main metabolic pathways living cells utilize to completely oxidize biofuels to carbon dioxide and water. The overall goal of this research is to mimic the citric acid cycle at the carbon surface of an electrode in order to achieve complete oxidation of ethanol at a bioanode to increase biofuel cell energy density. In order to mimic this process, dehydrogenase enzymes (known to be the electron or energy producing enzymes of the citric acid cycle) are immobilized in cascades at an electrode surface along with non-energy producing enzymes necessary for the cycle to progress. Six enzymatic schemes were investigated each containing an additional dehydrogenase enzyme involved in the complete oxidation of ethanol. An increase in current density is observed along with an increase in power density with each additional dehydrogenase immobilized on an electrode, reflecting increased electron production at the bioanode with deeper oxidation of the ethanol biofuel. By mimicking the complete citric acid cycle on a carbon electrode, power density was increased 8.71-fold compared to a single enzyme (alcohol dehydrogenase)-based ethanol/air biofuel cell.

  19. Material Flows and Carbon Cycles

    Science.gov (United States)

    Worrell, E.

    2003-12-01

    The industrial sector emits almost 43 percent of the global anthropogenic carbon dioxide emissions to produce materials and products. Furthermore, energy is used to move materials and products and process the waste. Hence, a large amount of energy is consumed and CO2 is emitted to sustain our materials system. Until recently, studies investigating mitigation options focused on changes in the energy system. For industrial processes most studies evaluate how the current materials system can be maintained producing fewer greenhouse gas emissions. Three elements of a strategy to improve the long-term materials productivity are the reduction of dissipative uses of non-biodegradable materials, secondly, the re-design of products to use less material or design for re-use or recycling, and thirdly, develop more efficient technologies for material conversion and recycling. This will reduce or eliminate the need to extract virgin materials from the environment, and reduce CO2 emissions from the energy-intensive production processes. To assess measures to reduce materials consumption, fossil fuels consumption and CO2 emissions, detailed understanding of the material system is needed. The lifecycle of materials has to be investigated including all branches of industry with all the inputs and outputs. We start with a discussion of materials and the carbon cycle focusing on the contribution of materials to anthropogenic carbon flows. We discuss CO2 emissions from energy use in materials extraction and production, fossil (e.g. plastics) and biomass carbon (e.g. lumber, paper) used as feedstock of materials, and mineral sources (e.g. cement). We discuss opportunities to reduce CO2 emissions by improving the efficiency with which society uses materials through product design, material substitution, product reuse and material recycling.

  20. Microwave synthesis of electrode materials for lithium batteries

    Indian Academy of Sciences (India)

    M Harish Bhat; B P Chakravarthy; P A Ramakrishnan; A Levasseur; K J RAO

    2000-12-01

    A novel microwave method is described for the preparation of electrode materials required for lithium batteries. The method is simple, fast and carried out in most cases with the same starting material as in conventional methods. Good crystallinity has been noted and lower temperatures of reaction has been inferred in cases where low temperature products have been identified.

  1. Bulk Mechanical Properties of Single Walled Carbon Nanotube Electrodes

    Science.gov (United States)

    Giarra, Matthew; Landi, Brian; Cress, Cory; Raffaelle, Ryne

    2007-03-01

    The unique properties of single walled carbon nanotubes (SWNTs) make them especially well suited for use as electrodes in power devices such as lithium ion batteries, hydrogen fuel cells, solar cells, and supercapacitors. The performances of such devices are expected to be influenced, at least in part, by the mechanical properties of the SWNTs used in composites or in stand alone ``papers.'' Therefore, the elastic moduli and ultimate tensile strengths of SWNT papers were measured as functions of temperature, SWNT purity, SWNT length, and SWNT bundling. The SWNTs used to produce the papers were synthesized in an alexandrite laser vaporization reactor at 1100^oC and purified using conventional acid-reflux conditions. Characterization of the SWNTs was performed using SEM, BET, TGA, and optical and Raman spectroscopy. The purified material was filtered and dried to yield papers of bundled SWNTs which were analyzed using dynamic mechanical analysis (DMA). It was observed that the mechanical properties of acid-refluxed SWNT papers were significantly improved by controlled thermal oxidation and strain-hardening. Elastic moduli of SWNT papers were measured between 3 and 6 GPa. Ultimate (breaking) tensile stresses were measured between 45 and 90 MPa at 1-3% strain. These results and their implications in regard to potential applications in power devices will be discussed.

  2. Metallic nanoparticles deposited on carbon microspheres: novel materials for combinatorial electrochemistry and electroanalysis.

    Science.gov (United States)

    Baron, Ronan; Wildgoose, Gregory G; Compton, Richard G

    2009-04-01

    This review deals with the preparation of metallic nanoparticles on glassy carbon microspheres and the use of these new hybrid materials for combinatorial electrochemistry and electroanalysis. First, the preparation of gold, silver and palladium nanoparticles on glassy carbon microspheres by a simple electroless procedure is described. Then, different types of electrodes modified with glassy carbon microspheres are described. These are: (i) glassy carbon electrodes modified by a composite film of glassy carbon microspheres and multi-walled carbon nanotubes, (ii) basal plane pyrolylic graphite electrodes modified by the abrasive attachment of glassy carbon microspheres and (iii) carbon-epoxy composite electrodes loaded with glassy carbon microspheres. The three types of electrode architectures described consist of metallic nanoparticles embedded in a carbon matrix and each of the electrode macrodisc surfaces actually correspond to a random metallic nanoelectrode array. Carbon-epoxy composite electrodes have good characteristics for their use as practical sensors. Furthermore, the use of several kinds of metallic nanoparticles allows the construction of a multi-analyte electrode and the screening of electroactive materials by following a combinatorial approach.

  3. Ceramic carbon electrode-based anodes for use in the copper-chlorine thermochemical cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, S.; Easton, E.B. [Univ. of Ontario Inst. of Technology, Oshawa, ON (Canada). Faculty of Science

    2009-07-01

    A thermochemical cycle is a process by which water is decomposed into hydrogen and oxygen through a series of chemical reactions. The chemicals that are used in these reactions are regenerated and recycled during the process. Sol-gel chemistry is becoming more common for the synthesis of electrode materials. The sol-gel reaction can be conducted in the presence of a carbon black to form a ceramic carbon electrode (CCE). The resultant CCE structure contains electronically conductive carbon particle pathways that are bound together through the ceramic binder, which can also promote ion transport. The CCE structure also has a high active surface area and is chemically and thermally robust. This paper presented an investigation of CCE materials prepared using 3-aminopropyl trimethoxysilane. Several electrochemical experiments including cyclic voltammetry and electrochemical impedance spectroscopy were performed to characterize their suitability as anode electrode materials for use in the electrochemical step of the copper-chlorine thermochemical cycle. Subsequent experiments included the manipulation of the relative ratio of organosilane carbon precursors to gauge its impact on electrode properties and performance. An overview of the materials characterization and electrochemical measurements were also presented. Specifically, the paper presented the experiment with particular reference to the CCE preparation; electrochemical experiments; thermal analysis; and scanning electron microscopy. Results were also provided. These included TGA analysis; scanning electron microscopy analysis; electrochemical characterization; and anodic polarization. Characterization of these CCE material demonstrated that they had good thermal stability, could be used at high temperatures, and were therefore, very promising anode materials. 15 refs., 7 figs.

  4. Fast redox of composite electrode of nitroxide radical polymer and carbon with polyacrylate binder

    Science.gov (United States)

    Komaba, Shinichi; Tanaka, Tatsuya; Ozeki, Tomoaki; Taki, Takayuki; Watanabe, Hiroaki; Tachikawa, Hiroyuki

    For organic radical batteries, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA) has been reported as a promising positive electrode material. The PTMA/C composite electrode prepared with polyacrylate binder demonstrated the fast redox performance for the application to aprotic secondary batteries. When the variation in discharge capacities of the PTMA/C composite electrode was tested galvanostatically at 20 C rates, the electrode retained 96% of the initial capacity after 1000 cycles. This is attributed to the fact that the redox of PTMA is a simple reaction to form the oxoammonium salt doped with ClO 4 - anions in the electrolyte. When the PTMA/C composite electrode was discharged at different C rates, the electrode retained 81% of the theoretical capacity even at 50 C rates. This remarkably high rate capability originates from the fast electron-transfer kinetic of the 2,2,6,6-tetramethylpiperidine- N-oxyl (so-called TEMPO) radical, partially jelled polyacrylate binder, and the improved conductivity throughout the electrode by thoroughly mixing with carbon.

  5. Pristine multi-walled carbon nanotubes/SDS modified carbon paste electrode as an amperometric sensor for epinephrine.

    Science.gov (United States)

    Thomas, Tony; Mascarenhas, Ronald J; D' Souza, Ozma J; Detriche, Simon; Mekhalif, Zineb; Martis, Praveen

    2014-07-01

    An amperometric sensor for the determination of epinephrine (EP) was fabricated by modifying the carbon paste electrode (CPE) with pristine multi-walled carbon nanotubes (pMWCNTs) using bulk modification followed by drop casting of sodium dodecyl sulfate (SDS) onto the surface for its optimal potential application. The modified electrode showed an excellent electrocatalytic activity towards EP by decreasing the overpotential and greatly enhancing the current sensitivity. FE-SEM images confirmed the dispersion of pMWCNTs in the CPE matrix. EDX analysis ensured the surface coverage of SDS. A comparative study of pMWCNTs with those of oxidized MWCNTs (MWCNTsOX) modified electrodes reveals that the former is the best base material for the construction of the sensor with advantages of lower oxidation overpotential and the least background current. The performance of the modified electrode was impressive in terms of the least charge transfer resistance (Rct), highest values for diffusion coefficient (DEP) and standard heterogeneous electron transfer rate constant (k°). Analytical characterization of the modified electrode exhibited two linear dynamic ranges from 1.0×10(-7) to 1.0×10(-6)M and 1.0×10(-6) to 1.0×10(-4)M with a detection limit of (4.5±0.18)×10(-8)M. A 100-fold excess of serotonin, acetaminophen, folic acid, uric acid, tryptophan, tyrosine and cysteine, 10-fold excess of ascorbic acid and twofold excess of dopamine do not interfere in the quantification of EP at this electrode. The analytical applications of the modified electrode were demonstrated by determining EP in spiked blood serum and adrenaline tartrate injection. The modified electrode involves a simple fabrication procedure, minimum usage of the modifier, quick response, excellent stability, reproducibility and anti-fouling effects.

  6. Transparent Electrodes: A Review of the Use of Carbon-Based Nanomaterials

    Directory of Open Access Journals (Sweden)

    Edgar J. López-Naranjo

    2016-01-01

    Full Text Available Transparent conducting electrodes (TCE are extensively applied in a great range of optoelectronic and photovoltaic equipment (e.g., solar cells, touch panels, and flexible devices. Carbon-based nanomaterials are considered as suitable replacements to substitute traditional materials to manufacture TCE due to their remarkable characteristics, for example, high optical transmittance and outstanding electrical properties. In comparison with traditional indium tin oxide electrodes, carbon-based electrodes show good mechanical properties, chemical stability, and low cost. Nevertheless, major issues related to the development of good quality manufacture methods to produce carbon-based nanomaterials have to be overcome to meet massive market requirements. Hence, the development of alternative TCE materials as well as appropriate large production techniques that meet the requirements of a proper sheet resistance along with a high optical transparency is a priority. Therefore, in this work, we summarize and discuss novel production and synthesis methods, chemical treatments, and hybrid materials developed to satisfy the worldwide request for carbon-based nanomaterials.

  7. Thermo-Electrochemical Cells Based on Carbon Nanotube Electrodes by Electrophoretic Deposition

    Institute of Scientific and Technical Information of China (English)

    Weijin Qian; Mingxuan Cao; Fei Xie; Changkun Dong

    2016-01-01

    Drawbacks of low efficiency and high cost of the electrode materials have restricted the wide applications of the thermo-electrochemical cells (TECs). Due to high specific areas and electrical conductivities, the low cost multi-walled carbon nanotubes (MWNTs) are promising alternative electrode materials. In this work, the MWNT films of up to 16 cm2 were synthesized on stainless steel substrates by the electrophoretic deposition (EPD) to make the thermo-electrochemical electrodes. MWNT electrodes based on TECs were characterized by cyclic voltammetry and the long-term stability tests with the potassium ferri/ferrocyanide electrolyte. The TECs reached the current density of 45.2 A m-2 and the maximum power density of 0.82 W m-2. The relative power conversion efficiency of the MWNT electrode is 50%higher than that for the Pt electrode. Meanwhile, the TECs was operated continuously for 300 h without performance degradation. With the priorities of low cost and simple fabrication, EPD-based MWNT TECs may become commercially viable.

  8. Oxygen electrode reaction in molten carbonate fuel cells. Final report, September 15, 1987--September 14, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Dave, Bhasker B. [Texas A & M Univ., College Station, TX (United States)

    1992-07-07

    Molten carbonate fuel cell system is a leading candidate for the utility power generation because of its high efficiency for fuel to AC power conversion, capability for an internal reforming, and a very low environmental impact. However, the performance of the molten carbonate fuel cell is limited by the oxygen reduction reaction and the cell life time is limited by the stability of the cathode material. An elucidation of oxygen reduction reaction in molten alkali carbonate is essential because overpotential losses in the molten carbonate fuel cell are considerably greater at the oxygen cathode than at the fuel anode. Oxygen reduction on a fully-immersed gold electrode in a lithium carbonate melt was investigated by electrochemical impedance spectroscopy and cyclic voltammetry to determine electrode kinetic and mass transfer parameters. The dependences of electrode kinetic and mass transfer parameters on gas composition and temperature were examined to determine the reaction orders and the activation energies. The results showed that oxygen reduction in a pure lithium carbonate melt occurs via the peroxide mechanism. A mass transfer parameter, DO1/2CO, estimated by the cyclic voltammetry concurred with that calculated by the EIS technique. The temperature dependence of the exchange current density and the product DO1/2CO were examined and the apparent activation energies were determined to be about 122 and 175 kJ/ mol, respectively.

  9. Effects of binders on the performance of electric double-layer capacitors of carbon nanotube electrodes

    Institute of Scientific and Technical Information of China (English)

    LI Chensha; WANG Dazhi; ZHANG Baoyou; WANG Xiaofeng; CAO Maosheng; LIANG Ji

    2005-01-01

    Polarizable electrodes of electric double layer capacitor (EDLCs) were made from carhon nanotubes. Effects of different binders, which are phenolic resin (PF) and polytetrafluoroethylene (PTFE), on the properties of polarizable electrodes are studied. Results indicate that the microstructure, pore size distribution and specific capacitance of the electrodes with PTFE binder are superior to those electrodes with PF binder after carbonization. The suitable binder (PTFE) for carbon nanotubes electrodes is proposed.

  10. Direct proteins electrochemistry based on ionic liquid mediated carbon nanotube modified glassy carbon electrode.

    Science.gov (United States)

    Zhao, Qiang; Zhan, Dongping; Ma, Hongyang; Zhang, Meiqin; Zhao, Yifang; Jing, Ping; Zhu, Zhiwei; Wan, Xinhua; Shao, Yuanhua; Zhuang, Qiankun

    2005-01-01

    A novel glassy carbon electrode modified by a gel containing multi-walled carbon nanotubes (MWNTs) and ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF6) is reported. The gel is formed by grinding of MWNTs and BMIPF6. Such gel is then coated on the surface of a glassy carbon electrode. We have employed scanning electron microscopy, Fourier transform infrared spectrometry (FTIR) and cyclic voltammetry to characterize the modified electrode. The direct electron transfers of hemoglobin and catalase on the modified electrode have been observed and studied in detail electrochemically. Hemoglobin is verified to be adsorbed on the modified electrode with the retention of conformation, which has been proved by microscopic FTIR. The electrochemical response of the adsorbed hemoglobin on the modified electrode is very stable, and shows repeated changes in the different pH solutions. It also has shown electrocatalysis to the reduction of oxygen and trichloroacetic acid. Catalase adsorbed on the gel modified electrode still keep activity to hydrogen peroxide. This work provides a simple and easy approach to construct biosensors based on the carbon nanotubes and ionic liquids.

  11. Enhanced Growth and Redox Characteristics of Some Conducting Polymers on Carbon Nanotube Modified Electrodes

    Institute of Scientific and Technical Information of China (English)

    R.Saraswathi

    2007-01-01

    1 Results Recent studies on the electrochemistry of a number of active compounds at carbon nanotube electrodes have proved beyond doubt their excellent electrocatalytic properties.Particularly,the advancements accomplished towards the functionalization of carbon nanotubes resulting in their enhanced solubilization in aqueous solutions have helped in the preparation of stable carbon nanotube electrodes.Glassy carbon has been invariably the preferred substrate for casting carbon nanotube electrodes.Such c...

  12. Sustainable Materials for Sustainable Energy Storage: Organic Na Electrodes.

    Science.gov (United States)

    Oltean, Viorica-Alina; Renault, Stéven; Valvo, Mario; Brandell, Daniel

    2016-03-01

    In this review, we summarize research efforts to realize Na-based organic materials for novel battery chemistries. Na is a more abundant element than Li, thereby contributing to less costly materials with limited to no geopolitical constraints while organic electrode materials harvested from biomass resources provide the possibility of achieving renewable battery components with low environmental impact during processing and recycling. Together, this can form the basis for truly sustainable electrochemical energy storage. We explore the efforts made on electrode materials of organic salts, primarily carbonyl compounds but also Schiff bases, unsaturated compounds, nitroxides and polymers. Moreover, sodiated carbonaceous materials derived from biomasses and waste products are surveyed. As a conclusion to the review, some shortcomings of the currently investigated materials are highlighted together with the major limitations for future development in this field. Finally, routes to move forward in this direction are suggested.

  13. Sustainable Materials for Sustainable Energy Storage: Organic Na Electrodes

    Directory of Open Access Journals (Sweden)

    Viorica-Alina Oltean

    2016-03-01

    Full Text Available In this review, we summarize research efforts to realize Na-based organic materials for novel battery chemistries. Na is a more abundant element than Li, thereby contributing to less costly materials with limited to no geopolitical constraints while organic electrode materials harvested from biomass resources provide the possibility of achieving renewable battery components with low environmental impact during processing and recycling. Together, this can form the basis for truly sustainable electrochemical energy storage. We explore the efforts made on electrode materials of organic salts, primarily carbonyl compounds but also Schiff bases, unsaturated compounds, nitroxides and polymers. Moreover, sodiated carbonaceous materials derived from biomasses and waste products are surveyed. As a conclusion to the review, some shortcomings of the currently investigated materials are highlighted together with the major limitations for future development in this field. Finally, routes to move forward in this direction are suggested.

  14. The rise of organic electrode materials for energy storage.

    Science.gov (United States)

    Schon, Tyler B; McAllister, Bryony T; Li, Peng-Fei; Seferos, Dwight S

    2016-11-07

    Organic electrode materials are very attractive for electrochemical energy storage devices because they can be flexible, lightweight, low cost, benign to the environment, and used in a variety of device architectures. They are not mere alternatives to more traditional energy storage materials, rather, they have the potential to lead to disruptive technologies. Although organic electrode materials for energy storage have progressed in recent years, there are still significant challenges to overcome before reaching large-scale commercialization. This review provides an overview of energy storage systems as a whole, the metrics that are used to quantify the performance of electrodes, recent strategies that have been investigated to overcome the challenges associated with organic electrode materials, and the use of computational chemistry to design and study new materials and their properties. Design strategies are examined to overcome issues with capacity/capacitance, device voltage, rate capability, and cycling stability in order to guide future work in the area. The use of low cost materials is highlighted as a direction towards commercial realization.

  15. Polyanion‐Type Electrode Materials for Sodium‐Ion Batteries

    Science.gov (United States)

    Ni, Qiao; Wu, Feng

    2017-01-01

    Sodium‐ion batteries, representative members of the post‐lithium‐battery club, are very attractive and promising for large‐scale energy storage applications. The increasing technological improvements in sodium‐ion batteries (Na‐ion batteries) are being driven by the demand for Na‐based electrode materials that are resource‐abundant, cost‐effective, and long lasting. Polyanion‐type compounds are among the most promising electrode materials for Na‐ion batteries due to their stability, safety, and suitable operating voltages. The most representative polyanion‐type electrode materials are Na3V2(PO4)3 and NaTi2(PO4)3 for Na‐based cathode and anode materials, respectively. Both show superior electrochemical properties and attractive prospects in terms of their development and application in Na‐ion batteries. Carbonophosphate Na3MnCO3PO4 and amorphous FePO4 have also recently emerged and are contributing to further developing the research scope of polyanion‐type Na‐ion batteries. However, the typical low conductivity and relatively low capacity performance of such materials still restrict their development. This paper presents a brief review of the research progress of polyanion‐type electrode materials for Na‐ion batteries, summarizing recent accomplishments, highlighting emerging strategies, and discussing the remaining challenges of such systems. PMID:28331782

  16. Electrosynthesis and catalytic activity of polymer-nickel particles composite electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    Melki, Tahar; Zouaoui, Ahmed; Bendemagh, Barkahoum [Universite Ferhat Abbas, Setif (Algeria). Faculte des Sciences de l' Ingenieur. Dept. du Tronc Commun; Oliveira, Ione M.F. de; Oliveira, Gilver F. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Lepretre, Jean-Claude [UMR-5631 CNRS-INPG-UJF, St. Martin d' Heres Cedex (France). Lab. d' Electrochimie et de Physicochimie des Materiaux et Interfaces; Bucher, Christophe; Mou tet, Jean-Claude [Universite Joseph Fourier Grenoble 1 (France). Dept. de Chimie Moleculaire], e-mail: Jean-Claude.Moutet@ujf-grenoble.fr

    2009-07-01

    Nickel-polymer composite electrode materials have been synthesized using various strategies, all comprising the electrochemical reduction of nickel(II) cations or complexes, incorporated by either ion-exchange or complexation into various poly(pyrrole-carboxylate) thin films coated by oxidative electropolymerization onto carbon electrodes. The electrocatalytic activity and the stability of the different composites have been then evaluated in the course of the electrocatalytic hydrogenation of ketones and enones in aqueous electrolytes. The best results were obtained using nickel-polymer composites synthesized by electroreduction of nickel(II) ions complexed into polycarboxylate films, which are characterized by a high catalytic activity and a good operational stability. (author)

  17. Nanostructured Ion Storage Electrode Materials for Lithium Batteries and Supercapacitors

    Institute of Scientific and Technical Information of China (English)

    S.R.S.Prabaharan

    2007-01-01

    1 Results Performance of lithium-ion batteries, electrochemical capacitors, and other electric-energy storage devices is not only determined simply by macroscopic chemical composition of their electrode, but also strongly affected by shape and size of the active materials. Nanostructured materials are distinguished from conventional polycrystalline materials by the nanometer size of the structural units that compose them, and they often exhibit properties that are drastically different from the conventi...

  18. Electrochemical impedance-based DNA sensor using a modified single walled carbon nanotube electrode

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Jessica E. [Department of Mechanical Engineering, University of South Florida, Tampa, FL (United States); Nanomaterials and Nanomanufacturing Research Center, University of South Florida, Tampa, FL (United States); Pillai, Shreekumar [Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL (United States); Ram, Manoj Kumar, E-mail: mkram@usf.edu [Department of Mechanical Engineering, University of South Florida, Tampa, FL (United States); Nanomaterials and Nanomanufacturing Research Center, University of South Florida, Tampa, FL (United States); Kumar, Ashok [Department of Mechanical Engineering, University of South Florida, Tampa, FL (United States); Nanomaterials and Nanomanufacturing Research Center, University of South Florida, Tampa, FL (United States); Singh, Shree R. [Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL (United States)

    2011-07-20

    Carbon nanotubes have become promising functional materials for the development of advanced electrochemical biosensors with novel features which could promote electron-transfer with various redox active biomolecules. This paper presents the detection of Salmonella enterica serovar Typhimurium using chemically modified single walled carbon nanotubes (SWNTs) with single stranded DNA (ssDNA) on a polished glassy carbon electrode. Hybridization with the corresponding complementary ssDNA has shown a shift in the impedance studies due to a higher charge transfer in ssDNA. The developed biosensor has revealed an excellent specificity for the appropriate targeted DNA strand. The methodologies to prepare and functionalize the electrode could be adopted in the development of DNA hybridization biosensor.

  19. Microbial community structure of different electrode materials in constructed wetland incorporating microbial fuel cell.

    Science.gov (United States)

    Wang, Junfeng; Song, Xinshan; Wang, Yuhui; Abayneh, Befkadu; Ding, Yi; Yan, Denghua; Bai, Junhong

    2016-12-01

    The microbial fuel cell coupled with constructed wetland (CW-MFC) microcosms were operated under fed-batch mode for evaluating the effect of electrode materials on bioelectricity generation and microbial community composition. Experimental results indicated that the bioenergy output in CW-MFC increased with the substrate concentration; maximum average voltage (177mV) was observed in CW-MFC with carbon fiber felt (CFF). In addition, the four different materials resulted in the formation of significantly different microbial community distribution around the anode electrode. The relative abundance of Proteobacteria in CFF and foamed nickel (FN) was significantly higher than that in stainless steel mesh (SSM) and graphite rod (GR) samples. Notably, the findings indicate that CW-MFC utilizing FN anode electrode could apparently improve relative abundance of Dechloromonas, which has been regarded as a denitrifying and phosphate accumulating microorganism.

  20. Modelling of cycling of lithium battery with microporous carbon electrode

    Directory of Open Access Journals (Sweden)

    D. Portnyagin

    2008-12-01

    Full Text Available Charge/discharge cycles of lithium cell with microporous carbon electrode under potentiodynamic control have been modelled. Predictions of the models with variable and constant diffusion coefficient neglecting the electric field inside the particle (CPM, DFM are compared to the predictions of the models with variable and constant diffusion coefficient in which electrostatic interaction inside the particles of carbon electrode (CPME, DFME is taken into account. There is observed a considerable difference between both. Electrostatic interactions of lithium ions with each other and the charge distributed inside the particle promote intercalation during the discharge of the cell and deintercalation during the charge. The dependance of the effect of hysteresis during the cycling of the cell on the rate of change of the applied voltage is studied. The larger is the speed of change of the applied voltage the more effective is hysteresis. We have also obtained concentration profiles at different stages of charge/discharge process.

  1. Silicon Composite Anode Materials for Lithium Ion Batteries Based on Carbon Cryogels and Carbon Paper

    Science.gov (United States)

    Woodworth, James; Baldwin, Richard; Bennett, William

    2010-01-01

    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nanofoams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  2. Carbon Cryogel and Carbon Paper-Based Silicon Composite Anode Materials for Lithium-Ion Batteries

    Science.gov (United States)

    Woodworth, James; Baldwin, Richard; Bennett, William

    2010-01-01

    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 6 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-5 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  3. High-performance Supercapacitor cells with Activated Carbon/MWNT nanocomposite electrodes

    Science.gov (United States)

    Markoulidis, F.; Lei, C.; Lekakou, C.; Figgemeier, E.; Duff, D.; Khalil, S.; Martorana, B.; Cannavaro, I.

    2012-09-01

    The purpose of this work was to investigate and improve the performance of supercapacitor cells with carbon-based nanocomposite electrodes. The electrode structure comprised activated carbon (AC), four types of multi-wall nanotubes (MWNTs) and two alternative polymer binders, Polyvinyl alcohol (PVA) or Polyvinylidene fluoride (PVDF). Electrode fabrication involved various stages of mixing and dispersion of the AC powder and carbon nanotubes, rolling and coating of the AC/MWNT/binder paste on an aluminium substrate which also served as current collector. The organic electrolyte utilised was 1M tetraethylammonium tetrafluoroborate (TEABF4) fully dissolved in propylene carbonate (PC). All devices were of the electrochemical double layer capacitor (EDLC) type, incorporating four layers of tissue paper as separator material. The surface topography of the so fabricated electrodes was investigated with scanning electrode microscopy (SEM). Overall cell performance was evaluated with a multi-channel potentiostat/galvanostat/impedance analyser. Each supercapacitor cell was subjected to Cyclic Voltammetry (CV) at various scan rates from 0.01 V/s to 1 V/s, Charge-Discharge at a fixed current steps (2 mA) and Electrochemical Impedance Spectroscopy (EIS) with frequency range from 10 mHz to 1 MHz. It was established that an AC-based supercapacitor with 0.15%w/w MWNT content and 30 μm roll-coated, nanocomposite electrodes provided superior energy and power and energy densities while the cells was immersed in the electrolyte; well above those generated by the AC-based EDLC cells.

  4. Voltammetric behaviour of oligonucleotide lipoplexes adsorbed onto glassy carbon electrodes

    OpenAIRE

    Piedade, J. A. P.; M. Mano; Lima, M. C. Pedroso de; Oretskaya, T S; Oliveira-Brett, A. M.

    2004-01-01

    The voltammetric behaviour of oligonucleotide lipoplexes (ODN-lipoplexes) prepared from short oligodeoxynucleotides (ODN), with different base compositions, and liposomes of the cationic lipid DOTAP, was studied by differential pulse voltammetry with a glassy carbon mini-electrode. It was found that the ODN base composition influences the ODN-lipoplex voltammetric response. Differential pulse voltammograms for ODN-lipoplexes of the ODN adenosine nucleotides present two different features when...

  5. Voltammetric determination of Arbutin on carbon paste electrode

    OpenAIRE

    Libánský, Milan; Zima, Jiří; Barek, Jiří; Dejmková, Hana

    2011-01-01

    Arbutin (hydroquinone- -D-glukopyranoside) belongs among the most frequent active substances in skin-whitening cosmetics. In this matrix, its content does not require sensitive, but rather simple, quick and cheap methods of determination, which can be supplied by electrochemical methods. Method for determination of Arbutin was developed using differential pulse voltammetry at a carbon paste electrode in Britton-Robinson buffer (pH 2). The concentration dependence proved a linear respons...

  6. Surface and interface engineering of electrode materials for lithium-ion batteries.

    Science.gov (United States)

    Wang, Kai-Xue; Li, Xin-Hao; Chen, Jie-Sheng

    2015-01-21

    Lithium-ion batteries are regarded as promising energy storage devices for next-generation electric and hybrid electric vehicles. In order to meet the demands of electric vehicles, considerable efforts have been devoted to the development of advanced electrode materials for lithium-ion batteries with high energy and power densities. Although significant progress has been recently made in the development of novel electrode materials, some critical issues comprising low electronic conductivity, low ionic diffusion efficiency, and large structural variation have to be addressed before the practical application of these materials. Surface and interface engineering is essential to improve the electrochemical performance of electrode materials for lithium-ion batteries. This article reviews the recent progress in surface and interface engineering of electrode materials including the increase in contact interface by decreasing the particle size or introducing porous or hierarchical structures and surface modification or functionalization by metal nanoparticles, metal oxides, carbon materials, polymers, and other ionic and electronic conductive species. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. ELECTROANALYTICAL APPLICATIONS OF CARBOXYL-MODIFIED CARBON NANOTUBE FILM ELECTRODES

    Institute of Scientific and Technical Information of China (English)

    C.G. Hu; W.L. Wang; K.J. Liao; W. Zhu

    2003-01-01

    The electrochemical behavior of a carboxyl-modified carbon nanotube films was investigated to explore its possibility in electroanalytical applicaton. Cyclic voltammetry of quinone was conducted in 1mol/L Na2SO4, which showed a stable, quasi-reversible voltammetric response for quinone / hydroquinone, and the anodic and the cathodic peak potentials were 0.657V and -0.029V (vs. SCE) at a scan rate of 0.1V.s-1, respectively. Both anodic and cathodic peak currents depended linearly on the square root of the scan rate over the range of 0.01-0. 5 V.s-1, which suggested that the process of the electrode reactions was diffusion-controlled. Carboxyl-modified carbon nanotube electrodes made it possible to determine low level of dopamine selectively in the presence of a large excess of ascorbic acid in acidic media using derivative voltammetry.The results obtained were discussed in details. This work demonstrates the potential of carboxyl-modified carbon nanotube electrodes for electroanalytical applications.

  8. Materials for carbon dioxide separation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qingqing

    2014-10-01

    The CO{sub 2} adsorption capacities at room temperature have been investigated by comparing carbon nanotubes, fullerene, graphenes, graphite and granular activated carbons. It turned out that the amount of the micropore surface area was dominating the CO{sub 2} adsorption ability. Another promising class of materials for CO{sub 2} capture and separation are CaO derived from the eggshells. Two aspects were studied in present work: a new hybrid materials synthesized by doping the CaTiO{sub 3} and the relationship between physisorption and chemisorption properties of CaO-based materials.

  9. Enhanced hydrogen production of PbTe-PbS/TNAs electrodes modified with ordered mesoporous carbon.

    Science.gov (United States)

    Gao, Shiyuan; Wang, Bin; Liu, Zhongqing

    2017-10-15

    PbTe-PbS/TiO2 nanotube arrays (PbTe-PbS/TNAs) were synthesized by the successive ionic layer adsorption and reaction (SILAR) followed by linear sweep voltammetry (LSV). Using Nafion as a binder, ordered mesoporous carbon was cast on these materials to generate the modified electrodes OMC/PbTe-PbS/TNAs. It was demonstrated that the electrode modification with OMC could enhance the charge transfer between the electrode surface and the electrolyte solution, improve the energy band bending of the electrode/electrolyte interface, increase the active electrochemical surface area of the electrode, and reduce the overpotential of the electrode reactions. Under ambient conditions, the short circuit current density (37.84mAcm(-)(2)) and the active electrochemical surface area (29mFcm(-)(2)) of the OMC/PbTe-PbS/TNAs electrode were 27.49% and 36.79% higher than that of PbTe-PbS/TNAs (29.68mAcm(-)(2) and 21.2mFcm(-)(2)), respectively. A particularly important feature of the OMC modification is that the hot electron extraction capability of the PbTe-PbS/TNAs electrode remained in the new system to provide rapid enhancement of short circuit current density upon increasing temperature. The OMC/PbTe-PbS/TNAs electrode registered a hydrogen generation rate of 11mLcm(2)h(-)(1), with an energy efficiency of 98.79% and a heat efficiency of 43.03% under cell voltage of 1.0V at 55°C. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. New Materials for Oxygen Reduction Electrodes

    DEFF Research Database (Denmark)

    Johansson, Tobias Peter

    This thesis is concerned with the discovery, characterisation and testing of new catalysts for the oxygen reduction reaction (ORR). A theroretical screening study was performed, in close collaboration with the theory group at the Center for Atomicscale Materials Design (CAMD), searching for catal......This thesis is concerned with the discovery, characterisation and testing of new catalysts for the oxygen reduction reaction (ORR). A theroretical screening study was performed, in close collaboration with the theory group at the Center for Atomicscale Materials Design (CAMD), searching...... as the sputter cleaned Pt3Sc. The deposition of Y on a Pt(111) crystal was then investigated. It was found that when annealing the crystal above 800 K a Pt overlayer was formed on top of a PtxY structure. Low energy electron diffraction (LEED) was used to probe the ordering of the surface and the LEED patterns...

  11. Carbon nanotube/felt composite electrodes without polymer binders

    Energy Technology Data Exchange (ETDEWEB)

    Rosolen, J. Mauricio; Matsubara, E.Y.; Marchesin, Marcel S.; Lala, Stella M.; Montoro, L.A.; Tronto, S. [Departamento de Quimica-FFCLRP, Universidade de Sao Paulo, Ribeirao Preto 14040-930, SP (Brazil)

    2006-11-08

    In this work we have investigated the suitability of composite electrodes consisting of cup-stacked and bamboo-like carbon nanotubes (CNT) synthesized directly onto a carbon felt for both lithium storage and double-layer capacitance applications. The CNT/felt composite electrode was prepared using catalytic chemical vapor decomposition on the carbon felt. The microstructure of the electrodes was characterized by scanning electron microscopy. Electrochemical characterization of the CNT/felt, either submitted or not to acid treatment for extraction of the catalytic particles used during the CNT growth, was carried out using 1molL{sup -1} LiPF{sub 6} in mixtures of ethylene carbonate, dimethyl carbonate, diethyl carbonate, and propylene carbonate. The carbon nanotubes loading and the type of CNT, whether open or closed, on the felt were the most significant factors regarding the electrochemical properties of the composite. With respect to the application of the composite to lithium storage, an anomalous behavior in the reversible specific capacity as a function of the current was detected. The capacity was found to be large at higher current values. The best reversible specific capacity was found for the open-CNT/felt (275mAhg{sup -1} at 0.16Ag{sup -1}, and 200mAhg{sup -1} at 0.82Ag{sup -1}), on an area of 0.634mm{sup 2}. The double-layer capacitance of the CNT decreased with increasing current. In the case of the open-CNT with a CNT loading of 13.93mg, the composite provided 40.3{mu}Fcm{sup 2} or about 12Fg{sup -1} at 10mA of polarization current using 1molL{sup -1} LiPF{sub 6} in mixtures of ethylene carbonate and dimethyl carbonate. For the closed-CNT with a CNT loading of 9.3mg, the double-layer capacitance was 30Fg{sup -1} at 20mA in 1M H{sub 2}SO{sub 4}. (author)

  12. Disposable planar reference electrode based on carbon nanotubes and polyacrylate membrane.

    Science.gov (United States)

    Rius-Ruiz, F Xavier; Bejarano-Nosas, Diego; Blondeau, Pascal; Riu, Jordi; Rius, F Xavier

    2011-07-15

    In this technical note, we report a new all-solid-state planar reference electrode based on single-walled carbon nanotubes and photocured poly(n-butylacrylate) (poly(nBA)) membrane containing the Ag/AgCl/Cl(-) ion system. Single-walled carbon nanotubes functionalized with octadecylamide (SWCNT-ODA) and deposited by drop-casting onto a disposable screen-printed electrode are an excellent all-solid-state transducer. The novel potentiometric planar reference electrode shows low potential variability (calibration slopes inferior to 2 mV/dec) for a wide range of chemical species (i.e., ions, small molecules, proteins) in a wide calibration range, redox pairs, changes in pH, and changes in ambient light. Potentiometric medium-term signal stability (-0.9 ± 0.2 mV/h) and electrochemical impedance characterization confirm the correct solid contact between the SWCNT-ODA layer and photocured poly(nBA) membrane. Overall, the materials used and the simple fabrication by screen-printing and drop-casting enable a high throughput and highly parallel and cost-effective mass manufacture of the new disposable reference electrode. Moreover, the reference electrode has a long shelf life, a characteristic that can be of special interest in decentralized and multiplexing potentiometric analysis.

  13. Fiber and fabric solar cells by directly weaving carbon nanotube yarns with CdSe nanowire-based electrodes.

    Science.gov (United States)

    Zhang, Luhui; Shi, Enzheng; Ji, Chunyan; Li, Zhen; Li, Peixu; Shang, Yuanyuan; Li, Yibin; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai; Cao, Anyuan

    2012-08-21

    Electrode materials are key components for fiber solar cells, and when combined with active layers (for light absorption and charge generation) in appropriate ways, they enable design and fabrication of efficient and innovative device structures. Here, we apply carbon nanotube yarns as counter electrodes in combination with CdSe nanowire-grafted primary electrodes (Ti wire) for making fiber and fabric-shaped photoelectrochemical cells with power conversion efficiencies in the range 1% to 2.9%. The spun-twist long nanotube yarns possess both good electrical conductivity and mechanical flexibility compared to conventional metal wires or carbon fibers, which facilitate fabrication of solar cells with versatile configurations. A unique feature of our process is that instead of making individual fiber cells, we directly weave single or multiple nanotube yarns with primary electrodes into a functional fabric. Our results demonstrate promising applications of semiconducting nanowires and carbon nanotubes in woven photovoltaics.

  14. Electroanalysis of trimethoprim on metalloporphyrin incorporated glassy carbon electrode.

    Science.gov (United States)

    Rajith, Leena; Kumar, Krishnapillai Girish

    2010-09-01

    Trimethoprim (TMP) is a bacteriostatic antibiotic mainly used in the prophylaxis and treatment of urinary tract infections. It belongs to the class of chemotherapeutic agents known as dihydrofolate reductase inhibitors. Its use is associated with idiosyncratic reactions, including liver toxicity and agranulocytosis. In order to determine TMP electrochemically, a metalloporphyrin modified glassy carbon electrode was prepared by coating [5,10,15,20- tetrakis(4-methoxyphenyl) porphyrinato]Mn (III)chloride (TMOPPMn(III)Cl) solution on the surface of the electrode. The electrochemical behaviour of TMP in Phosphate buffer solution (PBS) on TMOPPMn(III)Cl modified glassy carbon electrode (TMOPPMn(III)Cl/GCE) was explored using differential pulse voltammetry (DPV). The voltammograms showed enhanced oxidation response at the TMOPPMn (III)Cl/GCE with respect to the bare GCE for TMP, attributable to the electrocatalytic activity of TMOPPMn(III)Cl. Electrochemical parameters of the oxidation of TMP on the modified electrode were analyzed. The electro-oxidation of TMP was found to be irreversible, pH dependent and adsorption controlled on the modified electrode. It is found that the oxidation peak current is proportional to the concentration of TMP over the range 6 × 10⁻⁸ - 1 × 10⁻⁶ M with a very low detection limit of 3 × 10⁻⁹ M at 2 min open circuit accumulation. The repeatability expressed as relative standard deviation (RSD) for n = 9 was 3.2% and the operational stability was found to be 20 days. Another striking feature is that equimolar concentration of sulfamethoxazole did not interfere in the determination of TMP. Applicability to assay the drug in urine and tablet samples has also been studied.

  15. Electric and electrochemical properties of catalytically active oxygen electrode materials

    NARCIS (Netherlands)

    Burggraaf, A.J.; Dijk, van M.P.; Vries, de K.J.

    1986-01-01

    The electrical conductivity has been investigated of some oxygen ion and mixed conducting materials. Electrodes are prepared from thin sputtered layers of these oxides combined with a small Au or Pt strip. The kinetics of the oxygen reaction has been studied for temperatures of 820–1020 K and PO2 va

  16. Measurements of Electrode Skin Impedances using Carbon Rubber Electrodes - First Results

    Science.gov (United States)

    Kaufmann, Steffen; Ardelt, Gunther; Ryschka, Martin

    2013-04-01

    Non-invasive bioimpedance measurement as a tool in biomedical engineering and life sciences allows conclusions about condition and composition of living tissue. For interfacing the electronic conduction of the instrumentation and the ionic conduction of the tissue, electrodes are needed. A crucial point is the uncertainty arising from the unknown, time-varying and current density depend Electrode Skin Impedance (ESI). This work presents ESI measurements using carbon rubber electrodes on different human test subjects. The measurements for this work are carried out by employing a high accuracy Bioimpedance Measurement System (BMS) developed by the authors group, which is based on a Field Programmable Gate Array (FPGA) System on Chip (SoC). The system is able to measure magnitude and phase of complex impedances using a two- or four-electrode setup, with excitation currents from 60 μA to 5 mA in a frequency range from about 10 kHz to 300 kHz. Achieved overall measurement uncertainties are below 1%.

  17. Nitrogen-doped porous carbon monoliths from polyacrylonitrile (PAN) and carbon nanotubes as electrodes for supercapacitors

    Science.gov (United States)

    Wang, Yanqing; Fugetsu, Bunshi; Wang, Zhipeng; Gong, Wei; Sakata, Ichiro; Morimoto, Shingo; Hashimoto, Yoshio; Endo, Morinobu; Dresselhaus, Mildred; Terrones, Mauricio

    2017-01-01

    Nitrogen-doped porous activated carbon monoliths (NDP-ACMs) have long been the most desirable materials for supercapacitors. Unique to the conventional template based Lewis acid/base activation methods, herein, we report on a simple yet practicable novel approach to production of the three-dimensional NDP-ACMs (3D-NDP-ACMs). Polyacrylonitrile (PAN) contained carbon nanotubes (CNTs), being pre-dispersed into a tubular level of dispersions, were used as the starting material and the 3D-NDP-ACMs were obtained via a template-free process. First, a continuous mesoporous PAN/CNT based 3D monolith was established by using a template-free temperature-induced phase separation (TTPS). Second, a nitrogen-doped 3D-ACM with a surface area of 613.8 m2/g and a pore volume 0.366 cm3/g was obtained. A typical supercapacitor with our 3D-NDP-ACMs as the functioning electrodes gave a specific capacitance stabilized at 216 F/g even after 3000 cycles, demonstrating the advantageous performance of the PAN/CNT based 3D-NDP-ACMs.

  18. Nitrogen-doped porous carbon monoliths from polyacrylonitrile (PAN) and carbon nanotubes as electrodes for supercapacitors

    Science.gov (United States)

    Wang, Yanqing; Fugetsu, Bunshi; Wang, Zhipeng; Gong, Wei; Sakata, Ichiro; Morimoto, Shingo; Hashimoto, Yoshio; Endo, Morinobu; Dresselhaus, Mildred; Terrones, Mauricio

    2017-01-01

    Nitrogen-doped porous activated carbon monoliths (NDP-ACMs) have long been the most desirable materials for supercapacitors. Unique to the conventional template based Lewis acid/base activation methods, herein, we report on a simple yet practicable novel approach to production of the three-dimensional NDP-ACMs (3D-NDP-ACMs). Polyacrylonitrile (PAN) contained carbon nanotubes (CNTs), being pre-dispersed into a tubular level of dispersions, were used as the starting material and the 3D-NDP-ACMs were obtained via a template-free process. First, a continuous mesoporous PAN/CNT based 3D monolith was established by using a template-free temperature-induced phase separation (TTPS). Second, a nitrogen-doped 3D-ACM with a surface area of 613.8 m2/g and a pore volume 0.366 cm3/g was obtained. A typical supercapacitor with our 3D-NDP-ACMs as the functioning electrodes gave a specific capacitance stabilized at 216 F/g even after 3000 cycles, demonstrating the advantageous performance of the PAN/CNT based 3D-NDP-ACMs. PMID:28074847

  19. Electrode Materials for Lithium/Sodium-Ion Batteries

    DEFF Research Database (Denmark)

    Shen, Yanbin

    2014-01-01

    Shen systematically investigated the controlled synthesis of electrode materials for lithium/sodium ion batteries. She also investigated their formation mechanisms and structural evolution during the operation of batteries using in situ/operando X-ray diffraction techniques. The research findings...... provide insights into formation mechanisms of Li4Ti5O12 anode material from both hydrothermal and solid-state reaction. The results also contribute to a thorough understanding of the intercalation and decay mechanisms of O3/P2 layered sodium cathode materials in sodium ion batteries.......The synthesis of electrode materials for lithium/sodium ion batteries and their structural stability during lithium/sodium insertion/extraction are the two essential issues that have limited battery application in the fields requiring long cycle life and high safety. During her PhD studies, Yanbin...

  20. Electrode Materials for Lithium/Sodium-Ion Batteries

    DEFF Research Database (Denmark)

    Shen, Yanbin

    2014-01-01

    The synthesis of electrode materials for lithium/sodium ion batteries and their structural stability during lithium/sodium insertion/extraction are the two essential issues that have limited battery application in the fields requiring long cycle life and high safety. During her PhD studies, Yanbin...... Shen systematically investigated the controlled synthesis of electrode materials for lithium/sodium ion batteries. She also investigated their formation mechanisms and structural evolution during the operation of batteries using in situ/operando X-ray diffraction techniques. The research findings...... provide insights into formation mechanisms of Li4Ti5O12 anode material from both hydrothermal and solid-state reaction. The results also contribute to a thorough understanding of the intercalation and decay mechanisms of O3/P2 layered sodium cathode materials in sodium ion batteries....

  1. Gold nanoparticles directly modified glassy carbon electrode for non-enzymatic detection of glucose

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Gang; Shu, Honghui; Ji, Kai [Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Faculty of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China); Oyama, Munetaka [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8520 (Japan); Liu, Xiong [Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Faculty of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China); He, Yunbin, E-mail: ybhe@hubu.edu.cn [Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Faculty of Materials Science and Engineering, Hubei University, No. 368 Youyi Avenue, Wuchang, Wuhan 430062 (China)

    2014-01-01

    This work describes controllable preparation of gold nanoparticles on glassy carbon electrodes by using the seed mediated growth method, which contains two steps, namely, nanoseeds attachment and nanocrystals growth. The size and the dispersion of gold nanoparticles grown on glassy carbon electrodes could be easily tuned through the growth time based on results of field-emission scanning electron microscopy. Excellent electrochemical catalytic characteristics for glucose oxidation were observed for the gold nanoparticles modified glassy carbon electrodes (AuNPs/GC), resulting from the extended active surface area provided by the dense gold nanoparticles attached. It exhibited a wide linear range from 0.1 mM to 25 mM with the sensitivity of 87.5 μA cm{sup −2} mM{sup −1} and low detection limit down to 0.05 mM for the sensing of glucose. The common interfering species such as chloride ion, ascorbic acid, uric acid and 4-acetamidophenol were verified having no interference effect on the detection of glucose. It is demonstrated that the seed mediated method is one of the facile approaches for fabricating Au nanoparticles modified substrates, which could work as one kind of promising electrode materials for the glucose nonenzymatic sensing.

  2. Carbon and Nickel Oxide/Carbon Composites as Electrodes for Supercapacitors

    Institute of Scientific and Technical Information of China (English)

    Liutauras Marcinauskas; Zydrunas Kavaliauskas; Vitas Valincius

    2012-01-01

    The carbon and nickel oxide/carbon composite electrodes were prepared by plasma jet and magnetron sput-tering techniques. The investigations were performed to evaluate the influence of the Ar/C2H2 ratio on the specific capacitance values of carbon and NiO/carbon electrodes. The obtained electrodes were investigated by scanning electron microscopy, Raman scattering spectroscopy (RS), and X-ray diffraction techniques. The surface of the carbon electrodes became less porous and more homogenous with increasing Ar/C2H2. The RS results indicated that the fraction of the sp2 carbon sites increased with increasing Ar/C2H2 ratio. The increase of the Ar/C2H2 ratio increased the capacitance values from 0.73 up to 3.8 F/g. Meanwhile, after the deposition of the nickel oxide on the carbon, the capacitance increased ten and more times and varied in the range of 7.6-86.1 F/g.

  3. Natural materials for carbon capture.

    Energy Technology Data Exchange (ETDEWEB)

    Myshakin, Evgeniy M. (National Energy Technology Laboratory, Pittsburgh, PA); Romanov, Vyacheslav N. (National Energy Technology Laboratory, Pittsburgh, PA); Cygan, Randall Timothy

    2010-11-01

    Naturally occurring clay minerals provide a distinctive material for carbon capture and carbon dioxide sequestration. Swelling clay minerals, such as the smectite variety, possess an aluminosilicate structure that is controlled by low-charge layers that readily expand to accommodate water molecules and, potentially, carbon dioxide. Recent experimental studies have demonstrated the efficacy of intercalating carbon dioxide in the interlayer of layered clays but little is known about the molecular mechanisms of the process and the extent of carbon capture as a function of clay charge and structure. A series of molecular dynamics simulations and vibrational analyses have been completed to assess the molecular interactions associated with incorporation of CO2 in the interlayer of montmorillonite clay and to help validate the models with experimental observation.

  4. Size dependent electrochemical detection of trace heavy metal ions based on nano-patterned carbon sphere electrodes

    Science.gov (United States)

    Zhang, Lu-Hua; Li, Wen-Cui; Yan, Dong; Wang, Hua; Lu, An-Hui

    2016-07-01

    The challenge in efficient electrochemical detection of trace heavy metal ions (HMI) for early warning is to construct an electrode with a nano-patterned architecture. In this study, a range of carbon electrodes with ordered structures were fabricated using colloidal hollow carbon nanospheres (HCSs) as sensing materials for trace HMI (represented by Pb(ii)) detection by square wave anodic stripping voltammetry. The regular geometrical characteristics of the carbon electrode allow it to act as a model system for the estimation of electron transfer pathways by calculating contact points between HCSs and a glassy carbon electrode. A clear correlation between the contact points and the electron transfer resistance has been established, which fits well with the quadratic function model and is dependent on the size of HCSs. To our knowledge, this is the first clear function that expresses the structure-sensing activity relationship of carbon-based electrodes. The prepared carbon electrode is capable of sensing Pb(ii) with a sensitivity of 0.160 μA nM-1, which is much higher than those of other electrodes reported in the literature. Its detection limit of 0.6 nM is far below the guideline value (72 nM) given by the US Environmental Protection Agency. In addition, the carbon electrode could be a robust alternative to various heavy metal sensors.The challenge in efficient electrochemical detection of trace heavy metal ions (HMI) for early warning is to construct an electrode with a nano-patterned architecture. In this study, a range of carbon electrodes with ordered structures were fabricated using colloidal hollow carbon nanospheres (HCSs) as sensing materials for trace HMI (represented by Pb(ii)) detection by square wave anodic stripping voltammetry. The regular geometrical characteristics of the carbon electrode allow it to act as a model system for the estimation of electron transfer pathways by calculating contact points between HCSs and a glassy carbon electrode. A

  5. Fiber and fabric solar cells by directly weaving carbon nanotube yarns with CdSe nanowire-based electrodes

    Science.gov (United States)

    Zhang, Luhui; Shi, Enzheng; Ji, Chunyan; Li, Zhen; Li, Peixu; Shang, Yuanyuan; Li, Yibin; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai; Cao, Anyuan

    2012-07-01

    Electrode materials are key components for fiber solar cells, and when combined with active layers (for light absorption and charge generation) in appropriate ways, they enable design and fabrication of efficient and innovative device structures. Here, we apply carbon nanotube yarns as counter electrodes in combination with CdSe nanowire-grafted primary electrodes (Ti wire) for making fiber and fabric-shaped photoelectrochemical cells with power conversion efficiencies in the range 1% to 2.9%. The spun-twist long nanotube yarns possess both good electrical conductivity and mechanical flexibility compared to conventional metal wires or carbon fibers, which facilitate fabrication of solar cells with versatile configurations. A unique feature of our process is that instead of making individual fiber cells, we directly weave single or multiple nanotube yarns with primary electrodes into a functional fabric. Our results demonstrate promising applications of semiconducting nanowires and carbon nanotubes in woven photovoltaics.Electrode materials are key components for fiber solar cells, and when combined with active layers (for light absorption and charge generation) in appropriate ways, they enable design and fabrication of efficient and innovative device structures. Here, we apply carbon nanotube yarns as counter electrodes in combination with CdSe nanowire-grafted primary electrodes (Ti wire) for making fiber and fabric-shaped photoelectrochemical cells with power conversion efficiencies in the range 1% to 2.9%. The spun-twist long nanotube yarns possess both good electrical conductivity and mechanical flexibility compared to conventional metal wires or carbon fibers, which facilitate fabrication of solar cells with versatile configurations. A unique feature of our process is that instead of making individual fiber cells, we directly weave single or multiple nanotube yarns with primary electrodes into a functional fabric. Our results demonstrate promising applications

  6. Development of graphite-polymer composites as electrode materials

    Directory of Open Access Journals (Sweden)

    Carolina Maria Fioramonti Calixto

    2007-06-01

    Full Text Available Graphite powder was mixed to polyurethane, silicon rubber and Araldite® (epoxy in order to prepare composite materials to be used in the preparation of electrodes. Results showed that voltammetric response could be obtained when at least 50% of graphite (w.w-1 is present in the material. SEM and thermogravimetry were also used in the characterization of the composites.

  7. Sensor development exploiting graphite-epoxy composite as electrode material

    Science.gov (United States)

    Azevedo, André L. M.; Oliveira, Renato S.; Ponzio, Eduardo A.; Semaan, Felipe S.

    2015-11-01

    This study presents some results regarding the development and characterization of graphite-epoxy composites for use as working electrodes in electroanalysis. Such composites were preliminary assessed by TGA-DTA, AFM, XDR and cyclic voltammetry (CV), standing for a suitable stable and low cost material for electroanalytical purposes. The described material was used, in its best proportion (65% graphite m/m), to build a cell electrochemistry.

  8. Modified glassy carbon electrodes based on carbon nanostructures for ultrasensitive electrochemical determination of furazolidone

    Energy Technology Data Exchange (ETDEWEB)

    Shahrokhian, Saeed, E-mail: shahrokhian@sharif.edu [Department of Chemistry, Sharif University of Technology, Tehran 11155-9516 (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Naderi, Leila [Department of Chemistry, Sharif University of Technology, Tehran 11155-9516 (Iran, Islamic Republic of); Ghalkhani, Masoumeh [Department of Chemistry, Faculty of Science, Shahid Rajaee Teacher Training University, Lavizan, Tehran (Iran, Islamic Republic of); Institute for advanced technology, Shahid Rajaee Teacher Training University, Lavizan, Tehran, 16788 (Iran, Islamic Republic of)

    2016-04-01

    The electrochemical behavior of Furazolidone (Fu) was investigated on the surface of the glassy carbon electrode modified with different carbon nanomaterials, including carbon nanotubes (CNTs), carbon nanoparticles (CNPs), nanodiamond-graphite (NDG), graphene oxide (GO), reduced graphene oxide (RGO) and RGO-CNT hybrids (various ratios) using linear sweep voltammetry (LSV). The results of voltammetric studies exhibited a considerable increase in the cathodic peak current of Fu at the RGO modified GCE, compared to other modified electrodes and also bare GCE. The surface morphology and nature of the RGO film was thoroughly characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. The modified electrode showed two linear dynamic ranges of 0.001–2.0 μM and 2.0–10.0 μM with a detection limit of 0.3 nM for the voltammetric determination of Fu. This sensor was used successfully for Fu determination in pharmaceutical and clinical preparations. - Highlights: • The electrochemical behavior of Furazolidone (Fu) was investigated on the surface of the modified electrode with different carbon nanomaterials by Linear sweep voltammetry. • Two linear dynamic ranges and a low detection limit were obtained. • The modified electrode was applied for the detection of Fu in pharmaceutical and clinical preparations.

  9. Carbon nanopipette electrodes for dopamine detection in Drosophila.

    Science.gov (United States)

    Rees, Hillary R; Anderson, Sean E; Privman, Eve; Bau, Haim H; Venton, B Jill

    2015-04-01

    Small, robust, sensitive electrodes are desired for in vivo neurotransmitter measurements. Carbon nanopipettes have been previously manufactured and used for single-cell drug delivery and electrophysiological measurements. Here, a modified fabrication procedure was developed to produce batches of solid carbon nanopipette electrodes (CNPEs) with ∼250 nm diameter tips, and controllable lengths of exposed carbon, ranging from 5 to 175 μm. The electrochemical properties of CNPEs were characterized with fast-scan cyclic voltammetry (FSCV) for the first time. CNPEs were used to detect the electroactive neurotransmitters dopamine, serotonin, and octopamine. CNPEs were significantly more sensitive for serotonin detection than traditional carbon-fiber microelectrodes (CFMEs). Similar to CFMEs, CNPEs have a linear response for dopamine concentrations ranging from 0.1 to 10 μM and a limit of detection of 25 ± 5 nM. Recordings with CNPEs were stable for over 3 h when the applied triangle waveform was scanned between -0.4 and +1.3 V vs Ag/AgCl/Cl(-) at 400 V/s. CNPEs were used to detect endogenous dopamine release in Drosophila larvae using optogenetics, which verified the utility of CNPEs for in vivo neuroscience studies. CNPEs are advantageous because they are 1 order of magnitude smaller in diameter than typical CFMEs and have a sharp, tunable geometry that facilitates penetration and implantation for localized measurements in distinct regions of small organisms, such as the Drosophila brain.

  10. Asymmetric Electrodes Constructed with PAN-Based Activated Carbon Fiber in Capacitive Deionization

    Directory of Open Access Journals (Sweden)

    Mingzhe Li

    2014-01-01

    Full Text Available Capacitive deionization (CDI method has drawn much attention for its low energy consumption, low pollution, and convenient manipulation. Activated carbon fibers (ACFs possess high adsorption ability and can be used as CDI electrode material. Herein, two kinds of PAN-based ACFs with different specific surface area (SSA were used for the CDI electrodes. The CDI performance was investigated; especially asymmetric electrodes’ effect was evaluated. The results demonstrated that PAN-based ACFs showed a high electrosorption rate (complete electrosorption in less than half an hour and moderate electrosorption capacity (up to 0.2 mmol/g. CDI experiments with asymmetric electrodes displayed a variation in electrosorption capacity between forward voltage and reverse voltage. It can be attributed to the electrical double layer (EDL overlap effect and inner pore potential; thus the ions with smaller hydrated ionic radius can be adsorbed more easily.

  11. Electrochemical behavior of adrenaline at the carbon atom wire modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Xue Kuanhong [Chemistry Department, Nanjing Normal University, Jiangsu Engineering Research Center for Bio-medical Function Materials, 122 NingHai Road, Nanjing, JiangSu 210097 (China)], E-mail: khxue@njnu.edu.cn; Liu Jiamei [Chemistry Department, Nanjing Normal University, Jiangsu Engineering Research Center for Bio-medical Function Materials, 122 NingHai Road, Nanjing, JiangSu 210097 (China); Wei Ribing [Chemistry Department, Nanjing Normal University, Jiangsu Engineering Research Center for Bio-medical Function Materials, 122 NingHai Road, Nanjing, JiangSu 210097 (China); Chen Shaopeng [Chemistry Department, Nanjing Normal University, Jiangsu Engineering Research Center for Bio-medical Function Materials, 122 NingHai Road, Nanjing, JiangSu 210097 (China)

    2006-09-11

    Electrochemical behavior of adrenaline at an electrode modified by carbon atom wires (CAWs), a new material, was investigated by cyclic voltammetry combined with UV-vis spectrometry, and forced convection method. As to the electrochemical response of redox of adrenaline/adrenalinequinone couple in 0.50 M H{sub 2}SO{sub 4}, at a nitric acid treated CAW modified electrode, the anodic and cathodic peak potentials E {sub pa} and E {sub pc} shifted by 87 mV negatively and 139 mV in the positive direction, respectively, and standard heterogeneous rate constant k {sup 0} increased by 16 times compared to the corresponding bare electrode, indicating the extraordinary activity of CAWs in electrocatalysis for the process.

  12. Graphitic carbon nitride nanosheet electrode-based high-performance ionic actuator

    Science.gov (United States)

    Wu, Guan; Hu, Ying; Liu, Yang; Zhao, Jingjing; Chen, Xueli; Whoehling, Vincent; Plesse, Cédric; Nguyen, Giao T. M.; Vidal, Frédéric; Chen, Wei

    2015-01-01

    Ionic actuators have attracted attention due to their remarkably large strain under low-voltage stimulation. Because actuation performance is mainly dominated by the electrochemical and electromechanical processes of the electrode layer, the electrode material and structure are crucial. Here, we report a graphitic carbon nitride nanosheet electrode-based ionic actuator that displays high electrochemical activity and electromechanical conversion abilities, including large specific capacitance (259.4 F g−1) with ionic liquid as the electrolyte, fast actuation response (0.5±0.03% in 300 ms), large electromechanical strain (0.93±0.03%) and high actuation stability (100,000 cycles) under 3 V. The key to the high performance lies in the hierarchical pore structure with dominant size actuation performance. PMID:26028354

  13. Batteries: Recent Advances in Carbon Materials

    Directory of Open Access Journals (Sweden)

    I. Francis Cheng

    2017-01-01

    Full Text Available We welcome readers to this Special Issue of C. From the standpoint of economics of energy storage, carbon electrodes offer the practicality of large-scale applications with the promise of improved performance.[...

  14. Activation of glassy carbon electrodes by photocatalytic pretreatment

    Energy Technology Data Exchange (ETDEWEB)

    Dumanli, Onur [Department of Chemistry, Faculty of Science and Art, Ondokuz Mayis University, Kurupelit, 55139 Samsun (Turkey); Onar, A. Nur [Department of Chemistry, Faculty of Science and Art, Ondokuz Mayis University, Kurupelit, 55139 Samsun (Turkey)], E-mail: nonar@omu.edu.tr

    2009-11-01

    This paper describes a simple and rapid photocatalytic pretreatment procedure that removes contaminants from glassy carbon (GC) surfaces. The effectiveness of TiO{sub 2} mediated photocatalytic pretreatment procedure was compared to commonly used alumina polishing procedure. Cyclic voltammetric and chronocoulometric measurements were carried out to assess the changes in electrode reactivity by using four redox systems. Electrochemical measurements obtained on photocatalytically treated GC electrodes showed a more active surface relative to polished GC. In cyclic voltammograms of epinephrine, Fe(CN){sub 6}{sup 3-/4-} and ferrocene redox systems, higher oxidation and reduction currents were observed. The heterogeneous electron transfer rate constants (k{sup o}) were calculated for Fe(CN){sub 6}{sup 3-/4-} and ferrocene which were greater for photocatalytic pretreatment. Chronocoulometry was performed in order to find the amount of adsorbed methylene blue onto the electrode and was calculated as 0.34 pmol cm{sup -2} for photocatalytically pretreated GC. The proposed photocatalytic GC electrode cleansing and activating pretreatment procedure was more effective than classical alumina polishing.

  15. Electrochemical reduction of imazamethabenz methyl on mercury and carbon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Montoya, Mercedes, E-mail: mmontoya@uhu.e [Departamento de Ingenieria Quimica, Quimica Fisica y Quimica Organica, Universidad de Huelva, Campus El Carmen, Facultad de Ciencias Experimentales, E-21071 Huelva (Spain); Pintado, Sara; Rodriguez Mellado, Jose Miguel [Departamento de Quimica Fisica y Termodinamica Aplicada, Universidad de Cordoba, Campus Universitario de Rabanales, edificio ' Marie Curie' , E-14014 Cordoba (Spain)

    2010-03-30

    This paper presents polarographic and voltammetric studies of the reduction of the herbicide imazamethabenz methyl (2/3-methyl-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-p-toluate), on mercury and carbon electrodes. The electrochemical studies were performed in strongly acidic media (0.1-2.7 M H{sub 2}SO{sub 4}) as well as in the pH range of 1-12. The overall reduction process involves the uptake of two electrons. The results obtained in polarography show that there is the reduction of two species, related via an acid-base equilibrium, and having very close reduction potentials. The voltammetric results obtained with a glassy carbon electrode were very similar to those observed on mercury electrodes. The reducible group in the molecule is the imidazolinone ring. In strongly acidic media (pH < pK{sub a}), the reaction mechanism proposed is the reduction of the protonated herbicide by an electrochemical-chemical-electrochemical (ECE) process, being the r.d.s. the second electron transfer. At pH > pK{sub a} the neutral form of the herbicide is reduced and the second electron transfer becomes reversible or quasi-reversible. In basic media, the species reduced is the deprotonated imazamethabenz methyl and the r.d.s. is the second electron transfer.

  16. Effects of Carbon Structure and Mixing Sequence in an Expander on the Capacity of Negative Electrodes in a Traction Battery

    Science.gov (United States)

    Meenakorn, Somsak; Termsuksawad, Preecha; Phiboonkulsumrit, Sorraya

    2015-01-01

    Expanders were prepared by mixing barium sulfate, sodium lignosulfonate, and carbon materials by a high speed mixer. Effects of type of carbon materials and mixing sequence on electrochemical property of electrode were studied. Three different carbon materials: medium structure carbon black, high structure carbon black, and multi-wall carbon nanotube, were employed. The amount of charge and charge transfer resistance of electrode using different expanders were investigated by cyclic voltammetry and electrochemical impedance spectroscopy, respectively. Prepared expanders were characterized by a transmission electron microscope and a field emission scanning electron microscope. The capacity of the battery was tested by the high discharge rate test. Negative active materials were characterized by a field emission scanning electron microscope. The results showed that the type of carbon material and mixing sequence influenced the structure of carbon network in an expander and resulted in the change of the amount of charge and charge transfer resistance. All prepared expanders exhibited higher amount of charge and lower charge transfer resistance than those of a commercial expander. The highest amount of charge was obtained when the expander was prepared by mixing medium structure carbon black for 90 s before adding high structure carbon black. The high discharge test shows that the capacity of a battery using NAM prepared by this expander is approximately 10% higher than that using a commercial expander. The higher capacity is due to an increase of the surface area of NAM.

  17. Improved Electrodes for High Temperature Proton Exchange Membrane Fuel Cells using Carbon Nanospheres.

    Science.gov (United States)

    Zamora, Héctor; Plaza, Jorge; Cañizares, Pablo; Lobato, Justo; Rodrigo, Manuel A

    2016-05-23

    This work evaluates the use of carbon nanospheres (CNS) in microporous layers (MPL) of high temperature proton exchange membrane fuel cell (HT-PEMFC) electrodes and compares the characteristics and performance with those obtained using conventional MPL based on carbon black. XRD, hydrophobicity, Brunauer-Emmett-Teller theory, and gas permeability of MPL prepared with CNS were the parameters evaluated. In addition, a short life test in a fuel cell was carried out to evaluate performance under accelerated stress conditions. The results demonstrate that CNS is a promising alternative to traditional carbonaceous materials because of its high electrochemical stability and good electrical conductivity, suitable to be used in this technology.

  18. Electrode material comprising graphene-composite materials in a graphite network

    Energy Technology Data Exchange (ETDEWEB)

    Kung, Harold H.; Lee, Jung K.

    2017-08-08

    A durable electrode material suitable for use in Li ion batteries is provided. The material is comprised of a continuous network of graphite regions integrated with, and in good electrical contact with a composite comprising graphene sheets and an electrically active material, such as silicon, wherein the electrically active material is dispersed between, and supported by, the graphene sheets.

  19. Electrode material comprising graphene-composite materials in a graphite network

    Energy Technology Data Exchange (ETDEWEB)

    Kung, Harold H.; Lee, Jung K.

    2014-07-15

    A durable electrode material suitable for use in Li ion batteries is provided. The material is comprised of a continuous network of graphite regions integrated with, and in good electrical contact with a composite comprising graphene sheets and an electrically active material, such as silicon, wherein the electrically active material is dispersed between, and supported by, the graphene sheets.

  20. Composite electrodes of activated carbon derived from cassava peel and carbon nanotubes for supercapacitor applications

    Science.gov (United States)

    Taer, E.; Iwantono, Yulita, M.; Taslim, R.; Subagio, A.; Salomo, Deraman, M.

    2013-09-01

    In this paper, a composite electrode was prepared from a mixture of activated carbon derived from precarbonization of cassava peel (CP) and carbon nanotubes (CNTs). The activated carbon was produced by pyrolysis process using ZnCl2 as an activation agent. A N2 adsorption-desorption analysis for the sample indicated that the BET surface area of the activated carbon was 1336 m2 g-1. Difference percentage of CNTs of 0, 5, 10, 15 and 20% with 5% of PVDF binder were added into CP based activated carbon in order to fabricate the composite electrodes. The morphology and structure of the composite electrodes were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The SEM image observed that the distribution of CNTs was homogeneous between carbon particles and the XRD pattern shown the amorphous structure of the sample. The electrodes were fabricated for supercapacitor cells with 316L stainless steel as current collector and 1 M sulfuric acid as electrolyte. An electrochemical characterization was performed by using an electrochemical impedance spectroscopy (EIS) method using a Solatron 1286 instrument and the addition of CNTs revealed to improve the resistant and capacitive properties of supercapacitor cell.

  1. Understanding electrode materials of rechargeable lithium batteries via DFT calculations

    Institute of Scientific and Technical Information of China (English)

    Tianran Zhang; Daixin Li; Zhanliang Tao; Jun Chenn

    2013-01-01

    Rechargeable lithium batteries have achieved a rapid advancement and commercialization in the past decade owing to their high capacity and high power density. Different functional materials have been put forward progressively, and each possesses distinguishing structural features and electrochemical properties. In virtue of density functional theory (DFT) calculations, we can start from a specific structure to get a deep comprehension and accurate prediction of material properties and reaction mechanisms. In this paper, we review the main progresses obtained by DFT calculations in the electrode materials of rechargeable lithium batteries, aiming at a better understanding of the common electrode materials and gaining insights into the battery performance. The applications of DFT calculations involve in the following points of crystal structure modeling and stability investigations of delithiated and lithiated phases, average lithium intercalation voltage, prediction of charge distributions and band structures, and kinetic studies of lithium ion diffusion processes, which can provide atomic understanding of the capacity, reaction mechanism, rate capacity, and cycling ability. The results obtained from DFT are valuable to reveal the relationship between the structure and the properties, promoting the design of new electrode materials.

  2. Investigation of activated carbon adsorbent electrode for electrosorption-based uranium extraction from seawater

    Energy Technology Data Exchange (ETDEWEB)

    Yim, Man Sung; Ismail, Aznan Fazli [Dept. of Nuclear and Quantum Engineering (NQe), 291 Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2015-08-15

    To support the use of nuclear power as a sustainable electric energy generating technology, long-term supply of uranium is very important. The objective of this research is to investigate the use of new adsorbent material for cost effective uranium extraction from seawater. An activated carbon-based adsorbent material is developed and tested through an electrosorption technique in this research. Adsorption of uranium from seawater by activated carbon electrodes was investigated through electrosorption experiments up to 300 minutes by changing positive potentials from +0.2V to +0.8V (vs. Ag/AgCl). Uranium adsorption by the activated carbon electrode developed in this research reached up to 3.4 g-U/kg-adsorbent material, which is comparable with the performance of amidoxime-based adsorbent materials. Electrosorption of uranium ions from seawater was found to be most favorable at +0.4V (vs. Ag/AgCl). The cost of chemicals and materials in the present research was compared with that of the amidoxime-based approach as part of the engineering feasibility examination.

  3. Attractive forces in microporous carbon electrodes for capacitive deionization

    CERN Document Server

    Biesheuvel, P M; Levi, M; Bazant, M Z

    2013-01-01

    The recently developed modified Donnan (mD) model provides a simple and useful description of the electrical double layer in microporous carbon electrodes, suitable for incorporation in porous electrode theory. By postulating an attractive excess chemical potential for each ion in the micropores that is inversely proportional to the total ion concentration, we show that experimental data for capacitive deionization (CDI) can be accurately predicted over a wide range of applied voltages and salt concentrations. Since the ion spacing and Bjerrum length are each comparable to the micropore size (few nm), we postulate that the attraction results from fluctuating bare Coulomb interactions between individual ions and the metallic pore surfaces (image forces) that are not captured by meanfield theories, such as the Poisson-Boltzmann-Stern model or its mathematical limit for overlapping double layers, the Donnan model. Using reasonable estimates of the micropore permittivity and mean size (and no other fitting parame...

  4. Performance of a combined capacitor based on ultrafine nickel oxide/carbon nanotubes composite electrodes

    Institute of Scientific and Technical Information of China (English)

    Xiaofeng Wang; Yanqiu Cao; Yiqiang Lu; Qiqian Sha; Ji Liang

    2004-01-01

    A new sol-gel process for the preparation of ultrafine nickel hydroxide electrode materials was developed. The composite electrodes consisting of carbon nanotubes and Ni(OH)2 were developed by mixing the hydroxide and carbon nanotubes together in different mass ratios. In order to enhance energy density, a combined type pseudocapacitor/electric double layer capacitor was considered and its electrochemical properties were characterized by cyclic voltammetry and dc charge/discharge test. The combined capacitor shows excellent capacitor behavior with an operating voltage up to 1.6 V in KOH aqueous electrolyte. Stable charge/discharge behaviors were observed with much higher specific capacitance values of 24 F/g compared with that of EDLC (12F/g) by introducing 60% Ni(OH)2 in the anode material. By using the modified anode of a Ni(OH)2/carbon nanotubes composite electrode, the specific capacitance of the cell was less sensitive to discharge current density compared with that of the capacitor employing pure nickel hydroxide as anode. The combined capacitor in this study exhibits high energy density and stable power characteristics.

  5. Hierarchical mesoporous nickel cobaltite nanoneedle/carbon cloth arrays as superior flexible electrodes for supercapacitors

    Science.gov (United States)

    Zhang, Deyang; Yan, Hailong; Lu, Yang; Qiu, Kangwen; Wang, Chunlei; Tang, Chengchun; Zhang, Yihe; Cheng, Chuanwei; Luo, Yongsong

    2014-03-01

    Hierarchical mesoporous NiCo2O4 nanoneedle arrays on carbon cloth have been fabricated by a simple hydrothermal approach combined with a post-annealing treatment. Such unique array nanoarchitectures exhibit remarkable electrochemical performance with high capacitance and desirable cycle life at high rates. When evaluated as an electrode material for supercapacitors, the NiCo2O4 nanoneedle arrays supported on carbon cloth was able to deliver high specific capacitance of 660 F g-1 at current densities of 2 A g-1 in 2 M KOH aqueous solution. In addition, the composite electrode shows excellent mechanical behavior and long-term cyclic stability (91.8% capacitance retention after 3,000 cycles). The fabrication method presented here is facile, cost-effective, and scalable, which may open a new pathway for real device applications.

  6. High performance lithium insertion negative electrode materials for electrochemical devices

    Energy Technology Data Exchange (ETDEWEB)

    Channu, V.S. Reddy, E-mail: chinares02@gmail.com [SMC Corporation, College Station, TX 77845 (United States); Rambabu, B. [Solid State Ionics and Surface Sciences Lab, Department of Physics, Southern University and A& M College, Baton Rouge, LA 70813 (United States); Kumari, Kusum [Department of Physics, National Institute of Technology, Warangal (India); Kalluru, Rajmohan R. [The University of Southern Mississippi, College of Science and Technology, 730 E Beach Blvd, Long Beach, MS 39560 (United States); Holze, Rudolf [Institut für Chemie, AG Elektrochemie, Technische Universität Chemnitz, D-09107 Chemnitz (Germany)

    2016-11-30

    Highlights: • LiCrTiO{sub 4} nanostructures were synthesized for electrochemical applications by soft chemical synthesis followed by annealing. • The presence of Cr and Ti elements are confirmed from the EDS spectrum. • Oxalic acid assisted LiCrTiO{sub 4} electrode shows higher specific capacity (mAh/g). - Abstract: Spinel LiCrTiO{sub 4} oxides to be used as electrode materials for a lithium ion battery and an asymmetric supercapacitor were synthesized using a soft-chemical method with and without chelating agents followed by calcination at 700 °C for 10 h. Structural and morphological properties were studied with powder X-ray diffraction, scanning electron and transmission electron microscopy. Particles of 50–10 nm in size are observed in the microscopic images. The presence of Cr and Ti is confirmed from the EDS spectrum. Electrochemical properties of LiCrTiO{sub 4} electrode were examined in a lithium ion battery. The electrode prepared with oxalic acid-assisted LiCrTiO{sub 4} shows higher specific capacity.This LiCrTiO{sub 4} is also used as anode material for an asymmetric hybrid supercapacitor. The cell exhibits a specific capacity of 65 mAh/g at 1 mA/cm{sup 2}. The specific capacity decreases with increasing current densities.

  7. Deposition of boron doped diamond and carbon nanomaterials on graphite foam electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Marton, Marian, E-mail: marian.marton@stuba.sk; Vojs, Marian; Kotlár, Mário; Michniak, Pavol; Vančo, Ľubomír; Veselý, Marian; Redhammer, Robert

    2014-09-01

    Highlights: • The possibility of boron doped diamond deposition on porous carbon foam by HFCVD method was demonstrated. • Various carbon forms were synthesized including BDD, thin films of graphite nanosheets, carbon nanowalls, graphite nanotips and its composites. • Carbon nanowalls were overgrown by BDD nanocrystals, thus creating a new type of carbon nanomaterial not published yet, a CNW/BDD composite with a unique Raman spectrum. - Abstract: Boron doped diamond (BDD) has remarkable physical and chemical properties, that makes it an attractive material for electrochemical applications. In this study, deposition process of BDD on porous carbon foam electrodes was performed by HFCVD method. After depositions, the substrates were not homogenously covered by the BDD thin film only. Depending on the deposition temperature, foam porosity and distance from heated filaments, different carbon nanomaterials were synthesized. The boron doped diamond, graphite nanosheets, carbon nanowalls and its composites occurred on the foams outer and inner surfaces. Two new observed types of carbon structures, the carbon nanowalls – boron doped diamond composite and graphite nanotips are analyzed and described. Analyses were made by SEM and Raman spectroscopy. The influence of deposition conditions on the growth process is discussed.

  8. Direct Electrochemistry of Catalase on Single Wall Carbon Nanotubes Modified Glassy Carbon Electrode

    Institute of Scientific and Technical Information of China (English)

    Qiang ZHAO; Lun Hui GUAN; Zhen Nan GU; Qian Kun ZHUANG

    2005-01-01

    Direct electrochemistry of catalase (Ct) has been studied on single wall carbon nanotubes (SWNTs) modified glassy carbon (GC) electrode. A pair of well-defined nearly reversible redox peaks is given at --0.48 V (vs. SCE) in 0.1 mol/L phosphate solution (pH 7.0).The peak current in cyclic voltammogram is proportional to the scan rate. The peak potential of catalase is shifted to more negative value when the pH increases. Catalase can adsorb on the SWNTs modified electrode.

  9. Ion-selective carbon-paste electrodes for halides and silver(I) ions

    NARCIS (Netherlands)

    Mesaric, S.; Dahmen, E.A.M.F.

    1973-01-01

    The behaviour of a simple type of ion-selective electrode for halogens and silver has been studied. The electrode consists of a plastic body filled with carbon paste, the surface of which can be easily renewed. The paste composition is based on carbon-nujol (5:1, w/v) or carbon-paraffin wax (3:1,w/w

  10. Enhancing the capacitances of electric double layer capacitors based on carbon nanotube electrodes by carbon dioxide activation and acid oxidization

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Polarizable electrodes of electric double layer capacitors(EDLCs) were made from carbon nanotubes(CNTs).Effect of carbon dioxide activation together with acid oxidation for the electrodes on the characteristics and performances of electrodes and EDLCs was studied.Carbon dioxide activation changed the microstructure of the electrodes,increased the effective surface area of CNTs and optimized the distribution of apertures of the electrodes.Acid oxidization modified the surface characteristics of CNTs.Based on the polarizable electrodes treated by carbon dioxide activation and acid oxidization,the performances of EDLCs were greatly enhanced.The specific capacitance of the electrodes with organic electrolyte was increased from 21.8 F/g to 60.4 F/g.

  11. Novel Nanostructured Electrodes Obtained by Pyrolysis of Composite Polymeric Materials

    DEFF Research Database (Denmark)

    Amato, Letizia; Schulte, Lars; Heiskanen, Arto

    2015-01-01

    In this work, we compare pyrolyzed carbon derived from the photoresist SU‐8 alone or in combination with polystyrene and poly(styrene)‐block‐poly(dimethylsiloxane) copolymer (PS‐b‐PDMS), to be used as novel materials for micro‐ and nanoelectrodes. The pyrolyzed carbon films are evaluated with sca...

  12. Vertically Aligned Carbon Nanotube Electrodes for Lithium-Ion Batteries

    Science.gov (United States)

    2011-01-01

    37] Z. Yang, H. Wu, Mater. Chem. Phys. 71 (2001) 7. [38] D. Linden , T.B. Reddy, Handbook of Batteries , 3rd ed., McGraw-Hill Co., Inc., New York, 2005. ...Lithium-ion Energy storage Battery a b s t r a c t As portable electronics becomemore advanced and alternative energy demands becomemore prevalent, the...aligned carbon nanotube electrodes for lithium-ion batteries 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d. PROJECT

  13. The Use of Carbon Aerogel Electrodes for Environmental Cleanup.

    Science.gov (United States)

    1996-01-01

    electrodes, deionization of water, heavy metal removal from water, SERDP 16. PRICE CODE N/A 17. SECURITY CLASSIFICATION 18. SECURITY 19. SECURITY...electrophoresis, respectively. The carbon aeorgel cell has been used for the separation of copper, zinc, cadmium, and lead from 0.1 M KNO3 solutions, as...from a fixed, 500 ml volume of a 0.1 M KNO3 solution (Fig. 2). The electrolyte was circulated through the electrochemical cell at a rate of 50 ml/min

  14. Carbon conductor- and binder-free organic electrode for flexible organic rechargeable batteries with high energy density

    Science.gov (United States)

    Kim, Tae Sin; Lim, Ji-Eun; Oh, Min-Suk; Kim, Jae-Kwang

    2017-09-01

    For the first time, we report a poly (2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA)-based organic electrode with 100 wt% active material loading. The electrochemical performance of the PTMA electrode for organic batteries was improved by replacing the aluminum current collector by graphite ones. The use of graphite current collector reduces the cell weight and increases its mechanical flexibility. The resulting battery with the new carbon conductor- and binder-free organic electrode with polyimide-based gel polymer electrolyte (GPE) displayed significantly higher increased energy density (470 Wh kg-1vs. cell weight), which is essential for making organic batteries competitive with conventional Li ion batteries.

  15. Carbon material for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Bourlinos, Athanasios; Steriotis, Theodore; Stubos, Athanasios; Miller, Michael A

    2016-09-13

    The present invention relates to carbon based materials that are employed for hydrogen storage applications. The material may be described as the pyrolysis product of a molecular precursor such as a cyclic quinone compound. The pyrolysis product may then be combined with selected transition metal atoms which may be in nanoparticulate form, where the metals may be dispersed on the material surface. Such product may then provide for the reversible storage of hydrogen. The metallic nanoparticles may also be combined with a second metal as an alloy to further improve hydrogen storage performance.

  16. NiO nanosheet assembles for supercapacitor electrode materials

    Institute of Scientific and Technical Information of China (English)

    Huanhao Xiao; Shunyu Yao; Hongda Liu; Fengyu Qu; Xu Zhang n; Xiang Wu n

    2016-01-01

    In this paper, large scale hierarchically assembled NiO nanosheets have been favorably fabricated through a facile hydrothermal route. The as-prepared NiO nanosheet assembles were characterized in detail by various analytical techniques. The results showed these nanosheets present the thickness of about 30 nm and the surface area is 116.9 m2 g ? 1. These NiO nanosheet assembles were used as the working electrode materials in electrochemical tests, which demonstrated a specific capacitance value of 81.67 F g ? 1 at the current density of 0.5 A g ? 1 and excellent long cycle-life stability with 78.5% of its discharge specific capacitance retention after 3000 cycles at the current density of 0.5 A g?1, revealing the as-synthesized NiO nanosheet assembles might be a promising electrode material for supercapacitor applications.

  17. Graphene incorporated, N doped activated carbon as catalytic electrode in redox active electrolyte mediated supercapacitor

    Science.gov (United States)

    Gao, Zhiyong; Liu, Xiao; Chang, Jiuli; Wu, Dapeng; Xu, Fang; Zhang, Lingcui; Du, Weimin; Jiang, Kai

    2017-01-01

    Graphene incorporated, N doped activated carbons (GNACs) are synthesized by alkali activation of graphene-polypyrrole composite (G-PPy) at different temperatures for application as electrode materials of supercapacitors. Under optimal activation temperature of 700 °C, the resultant samples, labeled as GNAC700, owns hierarchically porous texture with high specific surface area and efficient ions diffusion channels, N, O functionalized surface with apparent pseudocapacitance contribution and high wettability, thus can deliver a moderate capacitance, a high rate capability and a good cycleability when used as supercapacitor electrode. Additionally, the GNAC700 electrode demonstrates high catalytic activity for the redox reaction of pyrocatechol/o-quinone pair in H2SO4 electrolyte, thus enables a high pseudocapacitance from electrolyte. Under optimal pyrocatechol concentration in H2SO4 electrolyte, the electrode capacitance of GNAC700 increases by over 4 folds to 512 F g-1 at 1 A g-1, an excellent cycleability is also achieved simultaneously. Pyridinic- N is deemed to be responsible for the high catalytic activity. This work provides a promising strategy to ameliorate the capacitive performances of supercapacitors via the synergistic interaction between redox-active electrolyte and catalytic electrodes.

  18. Electrospun FeS2@Carbon Fiber Electrode as a High Energy Density Cathode for Rechargeable Lithium Batteries.

    Science.gov (United States)

    Zhu, Yujie; Fan, Xiulin; Suo, Liumin; Luo, Chao; Gao, Tao; Wang, Chunsheng

    2016-01-26

    In this study, an FeS2@carbon fiber electrode is developed with FeS2 nanoparticles either embedded in or attached to carbon fibers by using an electrospinning method. By applying this binder-free, metal-current-collector-free FeS2@carbon fiber electrode, both the redox reaction and capacity decay mechanisms for the Li-FeS2 system are revealed by changing the electrolyte (conventional carbonate electrolyte and a "solvent-in-salt"-type Li-S battery electrolyte) and working voltage ranges (1.0-3.0 V and 1.5-3.0 V vs Li/Li(+)). The FeS2@carbon fiber electrode shows stable cycling performance in both the conventional carbonate electrolyte and the solvent-in-salt-type Li-S battery electrolyte in the voltage range of 1.5-3.0 V. Electrochemical tests in the solvent-in-salt-type Li-S battery electrolyte indicate that the Li-FeS2 system becomes a hybrid of the Li-S cell and Li-iron sulfide cell after the initial cycle. Based on the understanding on the capacity decay mechanisms, the cycling stability of the Li-FeS2 system in the voltage range of 1.0-3.0 V is then significantly enhanced by coating the FeS2@carbon fiber electrode with a thin layer of Al2O3. The Al2O3-coated electrode demonstrates excellent cycling performance with high discharge energy densities at both the material level (∼1300 Wh/kg-FeS2) and the electrode level (∼1000 Wh/kg-FeS2 electrode).

  19. Copper indium disulfide nanocrystals supported on carbonized chicken eggshell membranes as efficient counter electrodes for dye-sensitized solar cells

    Science.gov (United States)

    Wang, Lidan; He, Jianxin; Zhou, Mengjuan; Zhao, Shuyuan; Wang, Qian; Ding, Bin

    2016-05-01

    A domestic waste, chicken eggshell membrane (ESM), is used as a raw material to fabricate carbonized ESM loaded with chalcopyrite CuInS2 nanocrystals (denoted CESM-CuInS2) by a simple liquid impregnation and carbonization method. The CESM-CuInS2 composite possesses a natural three-dimensional macroporous network structure in which numerous CuInS2 nanocrystals with a size of about 25 nm are inlaid in carbon submicron fibers that form a microporous network. The CESM-CuInS2 composite is used as the counter electrode in a dye-sensitized solar cell (DSSC) and its photoelectric performance is tested. The DSSC with a CESM-CuInS2 counter electrode exhibits a short-circuit current density of 12.48 mA cm-2, open-circuit voltage of 0.78 V and power conversion efficiency of 5.8%; better than the corresponding values for a DSSC with a CESM counter electrode, and comparable to that of a reference DSSC with a platinum counter electrode. The favorable photoelectric performance of the CESM-CuInS2 counter electrode is attributed to its hierarchical structure, which provides a large specific surface area and numerous catalytically active sites to facilitate the oxidation of the electrolyte. This new composite material has many advantages, such as low cost and simple preparation, compared with Pt and pure CuInS2 counter electrodes.

  20. Multi-walled carbon nanotubes and metal-organic framework nanocomposites as novel hybrid electrode materials for the determination of nano-molar levels of lead in a lab-on-valve format.

    Science.gov (United States)

    Wang, Yang; Wu, Yichun; Xie, Jing; Ge, Huali; Hu, Xiaoya

    2013-09-07

    Metal-organic frameworks have been the subject of intense research because of their unique physicochemical properties. The presented study investigates the application of multi-wall carbon nanotubes and metal-organic frameworks (MWCNTs@Cu3(BTC)2) nanoparticles-modified electrode for the determination of trace levels of lead. The nanocomposites were prepared by solvothermal synthesis and characterized in detail. The experimental procedure was carried out by accumulating lead on the electrode surface and subsequently measuring with differential pulse anodic stripping voltammetry in a lab-on-valve format. The main parameters affecting the analytical performance, including the amount of MWCNTs@Cu3(BTC)2 suspension, supporting electrolyte and its pH, stripping mode, and flow rate, have been investigated in detail. Under the optimum conditions, the oxidation peak current displayed a calibration response for lead over a concentration range from 1.0 × 10(-9) to 5.0 × 10(-8) mol L(-1) with a excellent detection limit of 7.9 × 10(-10) mol L(-1). The relative standard deviation of 7 successive scans was 3.10% for 1.0 × 10(-8) mol L(-1) lead. The established method showed a great improvement in sensitivity and sample throughput for lead analysis.

  1. High-performance flexible electrode based on electrodeposition of polypyrrole/MnO2 on carbon cloth for supercapacitors

    Science.gov (United States)

    Fan, Xingye; Wang, Xiaolei; Li, Ge; Yu, Aiping; Chen, Zhongwei

    2016-09-01

    A highly flexible electrodes based on electrodeposited MnO2 and polypyrrole composite on carbon cloth is designed and developed by a facile in-situ electrodeposition technique. Such flexible composite electrodes with multiply layered structure possess a high specific capacitance of 325 F g-1 at a current density of 0.2 A g-1, and an excellent rate capability with a capacitance retention of 70% at a high current density of 5.0 A g-1. The superior electrochemical performance is mainly due to the unique electrode with improved ion- and electron-transportation pathways as well as the efficient utilization of active materials and electrode robustness. The excellent electrochemical performance and the low cost property endow this flexible nanocomposite electrode with great promise in applications of flexible supercapacitors.

  2. Material for electrodes of low temperature plasma generators

    Science.gov (United States)

    Caplan, Malcolm; Vinogradov, Sergel Evge'evich; Ribin, Valeri Vasil'evich; Shekalov, Valentin Ivanovich; Rutberg, Philip Grigor'evich; Safronov, Alexi Anatol'evich

    2008-12-09

    Material for electrodes of low temperature plasma generators. The material contains a porous metal matrix impregnated with a material emitting electrons. The material uses a mixture of copper and iron powders as a porous metal matrix and a Group IIIB metal component such as Y.sub.2O.sub.3 is used as a material emitting electrons at, for example, the proportion of the components, mass %: iron: 3-30; Y.sub.2O.sub.3:0.05-1; copper: the remainder. Copper provides a high level of heat conduction and electric conductance, iron decreases intensity of copper evaporation in the process of plasma creation providing increased strength and lifetime, Y.sub.2O.sub.3 provides decreasing of electronic work function and stability of arc burning. The material can be used for producing the electrodes of low temperature AC plasma generators used for destruction of liquid organic wastes, medical wastes, and municipal wastes as well as for decontamination of low level radioactive waste, the destruction of chemical weapons, warfare toxic agents, etc.

  3. Potentiometric application of boron- and phosphorus-doped glassy carbon electrodes

    Directory of Open Access Journals (Sweden)

    ZORAN V. LAUSEVIC

    2001-03-01

    Full Text Available Acomparative study was carried out of the potentiometric application of boronand phosphorus-doped and undoped glassy carbon samples prepared at the same heat treatment temperature (HTT 1000°C. The electrochemical activities of the obtained electrode materials were investigated on the example of argentometric titrations. It was found that the electrochemical behaviour of the doped glassy carbon samples are very similar to a Sigri (undoped glassy carbon sample (HTT 2400°C. The experiments showed that the potentiometric response depends on the polarization mode, the nature of the sample, the pretreatment of the electrode surface, and the nature of the supporting electrolyte. The amounts of iodide, bromide, and of chloridewere determined to be 1.27 mg, 0.80 mg and 0.54 mg, respectively, with a maximum relative standard deviation of less than 1.1%. The obtained results are in good agreement with the results of comparative potentiometric titrations using a silver indicator electrode. The titrationmethod was applied to the indirect determination of pyridoxine hydrochloride, i.e., vitamin B6.

  4. Synergistic effect of carbon nanofiber/nanotube composite catalyst on carbon felt electrode for high-performance all-vanadium redox flow battery.

    Science.gov (United States)

    Park, Minjoon; Jung, Yang-jae; Kim, Jungyun; Lee, Ho il; Cho, Jeaphil

    2013-10-01

    Carbon nanofiber/nanotube (CNF/CNT) composite catalysts grown on carbon felt (CF), prepared from a simple way involving the thermal decomposition of acetylene gas over Ni catalysts, are studied as electrode materials in a vanadium redox flow battery. The electrode with the composite catalyst prepared at 700 °C (denoted as CNF/CNT-700) demonstrates the best electrocatalytic properties toward the V(2+)/V(3+) and VO(2+)/VO2(+) redox couples among the samples prepared at 500, 600, 700, and 800 °C. Moreover, this composite electrode in the full cell exhibits substantially improved discharge capacity and energy efficiency by ~64% and by ~25% at 40 mA·cm(-2) and 100 mA·cm(-2), respectively, compared to untreated CF electrode. This outstanding performance is due to the enhanced surface defect sites of exposed edge plane in CNF and a fast electron transfer rate of in-plane side wall of the CNT.

  5. An effective nanostructured assembly for ion-selective electrodes. An ionophore covalently linked to carbon nanotubes for Pb2+ determination.

    Science.gov (United States)

    Parra, Enrique J; Blondeau, Pascal; Crespo, Gastón A; Rius, F Xavier

    2011-02-28

    We report on the synthesis of a new hybrid material, i.e. benzo-18-crown-6 covalently linked to multi-wall carbon nanotubes, and its use in solid-state ion-selective electrodes both as a receptor and an ion-to-electron transducer. This new concept leads to potentiometric sensors with extremely high selectivity.

  6. Application of a multiwalled carbon nanotube-chitosan composite as an electrode in the electrosorption process for water purification.

    Science.gov (United States)

    Ma, Chih-Yu; Huang, Shih-Ching; Chou, Pei-Hsin; Den, Walter; Hou, Chia-Hung

    2016-03-01

    In this study, a multiwalled carbon nanotubes-chitosan (CNTs-CS) composite electrode was fabricated to enable water purification by electrosorption. The CNTs-CS composite electrode was shown to possess excellent capacitive behaviors and good pore accessibility by electrochemical impedance spectroscopy, galvanostatic charge-discharge, and cyclic voltammetry measurements in 1 M H2SO4 electrolyte. Moreover, the CNTs-CS composite electrode showed promising performance for capacitive water desalination. At an electric potential of 1.2 V, the electrosorption capacity and electrosorption rate of NaCl ions on the CNTs-CS composite electrode were determined to be 10.7 mg g(-1) and 0.051 min(-1), respectively, which were considerably higher than those of conventional activated electrodes. The improved electrosorption performance could be ascribed to the existence of mesopores. Additionally, the feasibility of electrosorptive removal of aniline from an aqueous solution has been demonstrated. Upon polarization at 0.6 V, the CNTs-CS composite electrode had a larger electrosorption capacity of 26.4 mg g(-1) and a higher electrosorption rate of 0.006 min(-1) for aniline compared with the open circuit condition. The enhanced adsorption resulted from the improved affinity between aniline and the electrode under electrochemical assistance involving a nonfaradic process. Consequently, the CNT-CS composite electrode, exhibiting typical double-layer capacitor behavior and a sufficient potential range, can be a potential electrode material for application in the electrosorption process.

  7. Atomic layer deposition encapsulated activated carbon electrodes for high voltage stable supercapacitors.

    Science.gov (United States)

    Hong, Kijoo; Cho, Moonkyu; Kim, Sang Ouk

    2015-01-28

    Operating voltage enhancement is an effective route for high energy density supercapacitors. Unfortunately, widely used activated carbon electrode generally suffers from poor electrochemical stability over 2.5 V. Here we present atomic layer deposition (ALD) encapsulation of activated carbons for high voltage stable supercapacitors. Two-nanometer-thick Al2O3 dielectric layers are conformally coated at activated carbon surface by ALD, well-maintaining microporous morphology. Resultant electrodes exhibit excellent stability at 3 V operation with 39% energy density enhancement from 2.5 V operation. Because of the protection of surface functional groups and reduction of electrolyte degradation, 74% of initial voltage was maintained 50 h after full charge, and 88% of capacitance was retained after 5000 cycles at 70 °C accelerated test, which correspond to 31 and 17% improvements from bare activated carbon, respectively. This ALD-based surface modification offers a general method to enhance electrochemical stability of carbon materials for diverse energy and environmental applications.

  8. Pt nanoparticle modified single walled carbon nanotube network electrodes for electrocatalysis: control of the specific surface area over three orders of magnitude

    NARCIS (Netherlands)

    Miller, T.S.; Sansuk, S.; Lai, S.C.S.; Macpherson, J.V.; Unwin, P.R.

    2015-01-01

    The electrodeposition of Pt nanoparticles (NPs) on two-dimensional single walled carbon nanotube (SWNT) network electrodes is investigated as a means of tailoring electrode surfaces with a well-defined amount of electrocatalytic material. Both Pt NP deposition and electrocatalytic studies are undert

  9. Electrografting of 3-Aminopropyltriethoxysilane on a Glassy Carbon Electrode for the Improved Adhesion of Vertically Oriented Mesoporous Silica Thin Films.

    Science.gov (United States)

    Nasir, Tauqir; Zhang, Lin; Vilà, Neus; Herzog, Grégoire; Walcarius, Alain

    2016-05-03

    Vertically oriented mesoporous silica has proven to be of interest for applications in a variety of fields (e.g., electroanalysis, energy, and nanotechnology). Although glassy carbon is widely used as an electrode material, the adherence of silica deposits is rather poor, causing mechanical instability. A solution to improve the adhesion of mesoporous silica films onto glassy carbon electrodes without compromising the vertical orientation and the order of the mesopores will greatly contribute to the use of this kind of modified carbon electrode. We propose here the electrografting of 3-aminopropyltriethoxysilane on glassy carbon as a molecular glue to improve the mechanical stability of the silica film on the electrode surface without disturbing the vertical orientation and the order of the mesoporous silica obtained by electrochemically assisted self-assembly. These findings are supported by a series of surface chemistry techniques such as X-ray photoelectron spectroscopy, scanning and transmission electron microscopy, and cyclic voltammetry. Finally, methylviologen was used as a model redox probe to investigate the cathodic potential region of both glassy carbon and indium tin oxide electrodes modified with mesoporous silica in order to demonstrate further the interest in the approach developed here.

  10. Glucose biosensor based on a glassy carbon electrode modified with polythionine and multiwalled carbon nanotubes.

    Directory of Open Access Journals (Sweden)

    Wenwei Tang

    Full Text Available A novel glucose biosensor was fabricated. The first layer of the biosensor was polythionine, which was formed by the electrochemical polymerisation of the thionine monomer on a glassy carbon electrode. The remaining layers were coated with chitosan-MWCNTs, GOx, and the chitosan-PTFE film in sequence. The MWCNTs embedded in FAD were like "conductive wires" connecting FAD with electrode, reduced the distance between them and were propitious to fast direct electron transfer. Combining with good electrical conductivity of PTH and MWCNTs, the current response was enlarged. The sensor was a parallel multi-component reaction system (PMRS and excellent electrocatalytic performance for glucose could be obtained without a mediator. The glucose sensor had a working voltage of -0.42 V, an optimum working temperature of 25°C, an optimum working pH of 7.0, and the best percentage of polytetrafluoroethylene emulsion (PTFE in the outer composite film was 2%. Under the optimised conditions, the biosensor displayed a high sensitivity of 2.80 µA mM(-1 cm(-2 and a low detection limit of 5 µM (S/N = 3, with a response time of less than 15 s and a linear range of 0.04 mM to 2.5 mM. Furthermore, the fabricated biosensor had a good selectivity, reproducibility, and long-term stability, indicating that the novel CTS+PTFE/GOx/MWCNTs/PTH composite is a promising material for immobilization of biomolecules and fabrication of third generation biosensors.

  11. Graphene-Based Carbon Materials for Electrochemical Energy Storage

    Directory of Open Access Journals (Sweden)

    Fei Liu

    2013-01-01

    Full Text Available Because of their unique 2D structure and numerous fascinating properties, graphene-based materials have attracted particular attention for their potential applications in energy storage devices. In this review paper, we focus on the latest work regarding the development of electrode materials for batteries and supercapacitors from graphene and graphene-based carbon materials. To begin, the advantages of graphene as an electrode material and the existing problems facing its use in this application will be discussed. The next several sections deal with three different methods for improving the energy storage performance of graphene: the restacking of the nanosheets, the doping of graphene with other elements, and the creation of defects on graphene planes. State-of-the-art work is reviewed. Finally, the prospects and further developments in the field of graphene-based materials for electrochemical energy storage are discussed.

  12. High performance lithium insertion negative electrode materials for electrochemical devices

    Science.gov (United States)

    Channu, V. S. Reddy; Rambabu, B.; Kumari, Kusum; Kalluru, Rajmohan R.; Holze, Rudolf

    2016-11-01

    Spinel LiCrTiO4 oxides to be used as electrode materials for a lithium ion battery and an asymmetric supercapacitor were synthesized using a soft-chemical method with and without chelating agents followed by calcination at 700 °C for 10 h. Structural and morphological properties were studied with powder X-ray diffraction, scanning electron and transmission electron microscopy. Particles of 50-10 nm in size are observed in the microscopic images. The presence of Cr and Ti is confirmed from the EDS spectrum. Electrochemical properties of LiCrTiO4 electrode were examined in a lithium ion battery. The electrode prepared with oxalic acid-assisted LiCrTiO4 shows higher specific capacity.This LiCrTiO4 is also used as anode material for an asymmetric hybrid supercapacitor. The cell exhibits a specific capacity of 65 mAh/g at 1 mA/cm2. The specific capacity decreases with increasing current densities.

  13. Electrochemical Techniques for Intercalation Electrode Materials in Rechargeable Batteries.

    Science.gov (United States)

    Zhu, Yujie; Gao, Tao; Fan, Xiulin; Han, Fudong; Wang, Chunsheng

    2017-03-16

    Understanding of the thermodynamic and kinetic properties of electrode materials is of great importance to develop new materials for high performance rechargeable batteries. Compared with computational understanding of physical and chemical properties of electrode materials, experimental methods provide direct and convenient evaluation of these properties. Often, the information gained from experimental work can not only offer feedback for the computational methods but also provide useful insights for improving the performance of materials. However, accurate experimental quantification of some properties can still be challenging. Among them, chemical diffusion coefficient is one representative example. It is one of the most crucial parameters determining the kinetics of intercalation compounds, which are by far the dominant electrode type used in rechargeable batteries. Therefore, it is of significance to quantitatively evaluate this parameter. For this purpose, various electrochemical techniques have been invented, for example, galvanostatic intermittent titration technique (GITT), potentiostatic intermittent titration technique (PITT), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). One salient advantage of these electrochemical techniques over other characterization techniques is that some implicit thermodynamic and kinetic quantities can be linked with the readily measurable electrical signals, current, and voltage, with very high precision. Nevertheless, proper application of these techniques requires not just an understanding of the structure and chemistry of the studied materials but sufficient knowledge of the physical model for ion transport within solid host materials and the analysis method to solve for chemical diffusion coefficient. Our group has been focusing on using various electrochemical techniques to investigate battery materials, as well as developing models for studying some emerging materials. In this Account, the

  14. Sustainable carbon materials from hydrothermal processes

    CERN Document Server

    Titirici, Maria-Magdalena

    2013-01-01

    The production of low cost and environmentally friendly high performing carbon materials is crucial for a sustainable future. Sustainable Carbon Materials from Hydrothermal Processes describes a sustainable and alternative technique to produce carbon from biomass in water at low temperatures, a process known as Hydrothermal Carbonization (HTC). Sustainable Carbon Materials from Hydrothermal Processes presents an overview of this new and rapidly developing field, discussing various synthetic approaches, characterization of the final products, and modern fields of application fo

  15. Niobium doped lanthanum calcium ferrite perovskite as a novel electrode material for symmetrical solid oxide fuel cells

    Science.gov (United States)

    Kong, Xiaowei; Zhou, Xiaoliang; Tian, Yu; Wu, Xiaoyan; Zhang, Jun; Zuo, Wei

    2016-09-01

    Development of cost-effective and efficient electrochemical catalysts for the fuel cells electrode is of prime importance to emerging renewable energy technologies. Here, we report for the first time the novel La0.9Ca0.1Fe0.9Nb0.1O3-δ (LCFNb) perovskite with good potentiality for the electrode material of the symmetrical solid oxide fuel cells (SSOFC). The Sc0.2Zr0.8O2-δ (SSZ) electrolyte supported symmetrical cells with impregnated LCFNb and LCFNb/SDC (Ce0.8Sm0.2O2-δ) electrodes achieve relatively high power outputs with maximum power densities (MPDs) reaching up to 392 and 528.6 mW cm-2 at 850 °C in dry H2, respectively, indicating the excellent electro-catalytic activity of LCFNb towards both hydrogen oxidation and oxygen reduction. Besides, the MPDs of the symmetrical cells with LCFNb/SDC composite electrodes in CO and syngas (CO: H2 = 1:1) are almost identical to those in H2, implying that LCFNb material has similar catalytic activities to carbon monoxide compared with hydrogen. High durability in both H2, CO and syngas during the short term stability tests for 50 h are also obtained, showing desirable structure stability, and carbon deposition resistance of LCFNb based electrodes. The present results indicate that the LCFNb perovskite with remarkable cell performance is a promising electrode material for symmetrical SOFCs.

  16. Polymyxin-coated Au and carbon nanotube electrodes for stable [NiFe]-hydrogenase film voltammetry.

    NARCIS (Netherlands)

    Hoeben, F.J.M.; Heller, I.; Albracht, S.P.J.; Dekker, C.; Lemay, S.G.; Heering, H.A.

    2008-01-01

    We report on the use of polymyxin (PM), a cyclic cationic lipodecapeptide, as an electrode modifier for studying protein film voltammetry (PFV) on Au and single-walled carbon nanotube (SWNT) electrodes. Pretreating the electrodes with PM allows for the subsequent immobilization of an active

  17. Polymyxin-coated Au and carbon nanotube electrodes for stable [NiFe]-hydrogenase film voltammetry.

    NARCIS (Netherlands)

    Hoeben, F.J.M.; Heller, I.; Albracht, S.P.J.; Dekker, C.; Lemay, S.G.; Heering, H.A.

    2008-01-01

    We report on the use of polymyxin (PM), a cyclic cationic lipodecapeptide, as an electrode modifier for studying protein film voltammetry (PFV) on Au and single-walled carbon nanotube (SWNT) electrodes. Pretreating the electrodes with PM allows for the subsequent immobilization of an active submonol

  18. Carbon Fiber-gold/mercury Dual-electrode Detection for Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A carbon fiber-gold/mercury dual-electrode for capillary electrophoresis is constructed. Cysteine, glutathione, ascorbic acid and uric acid can be detected simultaneously and selectively at the dual-electrode, respectively. The capillary electrophoresis / dual-electrode detection system has been used to determine these compounds in human blood samples.

  19. Nitrite electrochemical sensor based on prussian blue/single-walled carbon nanotubes modified pyrolytic graphite electrode

    CSIR Research Space (South Africa)

    Adekunle, AS

    2011-09-01

    Full Text Available that single-walled carbon nanotubes-Prussian blue hybrid (SWCNT-PB) modified electrode demonstrated greater sensitivity and catalysis towards nitrite compared to PB or a SWCNT modified electrode. The current response of the electrode was reduced...

  20. Hierarchical Porous Carbon Counter Electrode for Dye-Sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    WANG Gui-Qiang; HUANG Cong-Gong; XING Wei; ZHUO Shu-Ping

    2011-01-01

    Hierarchical porous carbon is prepared by a combination of self-organization and chemical activation and explored as counter electrode for dye-sensitized solar cells.Pore structure analysis shows that micropores generated within the mesopore wall and the pristine mesopore structure of mesoporous carbon are preserved during KOH activation. Electrochemical impedance spectroscopy studies demonstrate a relatively high electrocatalytic activity of hierarchical porous carbon electrode for triiodide reduction, as compared with a pristine mesoporous carbon electrode. This enhanced electrocatalytic activity is beneficial for improving the photovoltaic performance of dyesensitized solar cells. The overall conversion efficiency of dye-sensitized solar cells with the hierarchical porous carbon electrode increased by 11.5% compared with that of the cell with a pristine mesoporous carbon electrode.

  1. Influence of carbonisation on selected engineering properties of carbon resin electrodes for electrochemical treatment of wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Oke, I.A. [Obafemi Awolowo Univ., Ile-Ife (Nigeria). Dept. of Civil Engineering

    2009-10-15

    Carbon resin electrodes (CRE) developed using a non-heat treatment process were investigated in an effort to determine the influence of several properties on electrode performance. These included density; electrical resistance; microstructure; hydroscopy; stability moisture content; and compressive and flexural strength. The influences of carbonization temperature, carbon particle size, and compaction pressure were also analyzed. Results of the study showed that the electrical resistance and density of the CRE decreased with increases in carbonization temperatures. Particle size, compacting pressure, and the percentage of resin used in the electrodes also influenced electrical resistance. The carbonization of the CREs from 30 to 220 degrees C reduced specific electrical resistance and density. The carbonization temperature did not have a significant effect on wetness, compressive and flexural strength, or on the stability and moisture content of the electrodes. It was concluded that the cost of producing the CREs is significantly cheaper than the cost of heat-treated electrodes. 78 refs., 9 tabs., 8 figs.

  2. Polymer-Assisted Direct Deposition of Uniform Carbon Nanotube Bundle Networks for High Performance Transparent Electrodes

    KAUST Repository

    Hellstrom, Sondra L.

    2009-06-23

    Flexible transparent electrodes are crucial for touch screen, flat panel display, and solar cell technologies. While carbon nanotube network electrodes show promise, characteristically poor dispersion properties have limited their practicality. We report that addition of small amounts of conjugated polymer to nanotube dispersions enables straightforward fabrication of uniform network electrodes by spin-coating and simultaneous tuning of parameters such as bundle size and density. After treatment in thionyl chloride, electrodes have sheet resistances competitive with other reported carbon nanotube based transparent electrodes to date. © 2009 American Chemical Society.

  3. Composite supercapacitor electrodes made of activated carbon/PEDOT:PSS and activated carbon/doped PEDOT

    Indian Academy of Sciences (India)

    T S Sonia; P A Mini; R Nandhini; Kalluri Sujith; Balakrishnan Avinash; S V Nair; K R V Subramanian

    2013-08-01

    In this paper, we report on the high electrical storage capacity of composite electrodes made from nanoscale activated carbon combined with either poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) or PEDOT doped with multiple dopants such as ammonium persulfate (APS) and dimethyl sulfoxide (DMSO). The composites were fabricated by electropolymerization of the conducting polymers (PEDOT:PSS, doped PEDOT) onto the nanoscale activated carbon backbone, wherein the nanoscale activated carbon was produced by ball-milling followed by chemical and thermal treatments. Activated carbon/PEDOT:PSS yielded capacitance values of 640 F g-1 and 26mF cm-2, while activated carbon/doped PEDOT yielded capacitances of 1183 F g-1 and 42 mF cm-2 at 10 mV s-1. This is more than five times the storage capacity previously reported for activated carbon–PEDOT composites. Further, use of multiple dopants in PEDOT improved the storage performance of the composite electrode well over that of PEDOT:PSS. The composite electrodes were characterized for their electrochemical behaviour, structural and morphological details and electronic conductivity and showed promise as high-performance energy storage systems.

  4. Single electrode heat effects. I. Peltier entropies of gas electrodes in carbonate paste electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, T. (Technical Univ. of Denmark, Lyngby); Broers, G.H.J.

    1977-02-01

    Standard Peltier entropies for the reactions /sup 1///sub 2/O/sub 2/ + CO/sub 2/ + 2e/sup -/ ..-->.. CO/sub 3//sup - -/ and 2CO/sub 2/ + 2e/sup -/ ..-->.. CO + CO/sub 3//sup - -/ in molten carbonate paste elctrolytes at 1000/sup 0/K have been determined from thermogalvanic measurements. The results are -217 and -118 J/mole/sup 0/K, respectively. No dependence on electrolyte composition is observed. The reversible part of the Peltier entropy for the oxygen electrode reaction is estimated from thermodynamic data and reasonable agreement with the experimental results is found. It is concluded that the main contribution to the Peltier entropy arises from the transition from gaseous to liquid state, whereas the transfer entropies of the ionic species are of minor importance.

  5. Imprinted zeolite modified carbon paste electrode as a potentiometric sensor for uric acid

    Science.gov (United States)

    Khasanah, Miratul; Widati, Alfa Akustia; Fitri, Sarita Aulia

    2016-03-01

    Imprinted zeolite modified carbon paste electrode (carbon paste-IZ) has been developed and applied to determine uric acid by potentiometry. The imprinted zeolite (IZ) was synthesized by the mole ratio of uric acid/Si of 0.0306. The modified electrode was manufactured by mass ratio of carbon, IZ and solid paraffin was 40:25:35. The modified electrode had shown the measurement range of 10-5 M to 10-2 M with Nernst factor of 28.6 mV/decade, the detection limit of 5.86 × 10-6 M and the accuracy of 95.3 - 105.0%. Response time of the electrode for uric acid 10-5 M - 10-2 M was 25 - 44 s. The developed electrode showed the high selectivity toward uric acid in the urea matrix. Life time of the carbon paste-IZ electrode was 10 weeks.

  6. Development of carbon electrodes for electrochemistry, solid-state electronics and multimodal atomic force microscopy imaging

    Science.gov (United States)

    Morton, Kirstin Claire

    Carbon is one of the most remarkable elements due to its wide abundance on Earth and its many allotropes, which include diamond and graphite. Many carbon allotropes are conductive and in recent decades scientists have discovered and synthesized many new forms of carbon, including graphene and carbon nanotubes. The work in this thesis specifically focuses on the fabrication and characterization of pyrolyzed parylene C (PPC), a conductive pyrocarbon, as an electrode material for diodes, as a conductive coating for atomic force microscopy (AFM) probes and as an ultramicroelectrode (UME) for the electrochemical interrogation of cellular systems in vitro. Herein, planar and three-dimensional (3D) PPC electrodes were microscopically, spectroscopically and electrochemically characterized. First, planar PPC films and PPC-coated nanopipettes were utilized to detect a model redox species, Ru(NH3) 6Cl3. Then, free-standing PPC thin films were chemically doped, with hydrazine and concentrated nitric acid, to yield p- and n-type carbon films. Doped PPC thin films were positioned in conjunction with doped silicon to create Schottky and p-n junction diodes for use in an alternating current half-wave rectifier circuit. Pyrolyzed parylene C has found particular merit as a 3D electrode coating of AFM probes. Current sensing-atomic force microscopy imaging in air of nanoscale metallic features was undertaken to demonstrate the electronic imaging applicability of PPC AFM probes. Upon further insulation with parylene C and modification with a focused ion beam, a PPC UME was microfabricated near the AFM probe apex and utilized for electrochemical imaging. Subsequently, scanning electrochemical microscopy-atomic force microscopy imaging was undertaken to electrochemically quantify and image the spatial location of dopamine exocytotic release, elicited mechanically via the AFM probe itself, from differentiated pheochromocytoma 12 cells in vitro.

  7. Fabrication and electrochemical behavior of single-walled carbon nanotube/graphite-based electrode

    Energy Technology Data Exchange (ETDEWEB)

    Moghaddam, Abdolmajid Bayandori [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran P.O. Box 14155-6455, Tehran (Iran, Islamic Republic of); Medical Nanotechnology Research Centre, Medical Sciences/University of Tehran, P.O. Box 14155-6451, Tehran (Iran, Islamic Republic of); Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran P.O. Box 14155-6455, Tehran (Iran, Islamic Republic of)], E-mail: Ganjali@khayam.ut.ac.ir; Dinarvand, Rassoul [Medical Nanotechnology Research Centre, Medical Sciences/University of Tehran, P.O. Box 14155-6451, Tehran (Iran, Islamic Republic of); Razavi, Taherehsadat [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran P.O. Box 14155-6455, Tehran (Iran, Islamic Republic of); Riahi, Siavash [Institute of Petroleum Engineering, Faculty of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Rezaei-Zarchi, Saeed [Department of Biology, Payam-e-Noor University, Yazd (Iran, Islamic Republic of); Norouzi, Parviz [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran P.O. Box 14155-6455, Tehran (Iran, Islamic Republic of)

    2009-01-01

    An electrochemical method for determining the dihydroxybenzene derivatives on glassy carbon (GC) has been developed. In this method, the performance of a single-walled carbon nanotube (SWCNT)/graphite-based electrode, prepared by mixing SWCNTs and graphite powder, was described. The resulting electrode shows an excellent behavior for redox of 3,4-dihydroxybenzoic acid (DBA). SWCNT/graphite-based electrode presents a significant decrease in the overvoltage for DBA oxidation as well as a dramatic improvement in the reversibility of DBA redox behavior in comparison with graphite-based and glassy carbon (GC) electrodes. In addition, scanning electron microscopy (SEM) and atomic force microscopy (AFM) procedures performed for used SWCNTs.

  8. Nanoscale Electrochemistry of sp(2) Carbon Materials: From Graphite and Graphene to Carbon Nanotubes.

    Science.gov (United States)

    Unwin, Patrick R; Güell, Aleix G; Zhang, Guohui

    2016-09-20

    Carbon materials have a long history of use as electrodes in electrochemistry, from (bio)electroanalysis to applications in energy technologies, such as batteries and fuel cells. With the advent of new forms of nanocarbon, particularly, carbon nanotubes and graphene, carbon electrode materials have taken on even greater significance for electrochemical studies, both in their own right and as components and supports in an array of functional composites. With the increasing prominence of carbon nanomaterials in electrochemistry comes a need to critically evaluate the experimental framework from which a microscopic understanding of electrochemical processes is best developed. This Account advocates the use of emerging electrochemical imaging techniques and confined electrochemical cell formats that have considerable potential to reveal major new perspectives on the intrinsic electrochemical activity of carbon materials, with unprecedented detail and spatial resolution. These techniques allow particular features on a surface to be targeted and models of structure-activity to be developed and tested on a wide range of length scales and time scales. When high resolution electrochemical imaging data are combined with information from other microscopy and spectroscopy techniques applied to the same area of an electrode surface, in a correlative-electrochemical microscopy approach, highly resolved and unambiguous pictures of electrode activity are revealed that provide new views of the electrochemical properties of carbon materials. With a focus on major sp(2) carbon materials, graphite, graphene, and single walled carbon nanotubes (SWNTs), this Account summarizes recent advances that have changed understanding of interfacial electrochemistry at carbon electrodes including: (i) Unequivocal evidence for the high activity of the basal surface of highly oriented pyrolytic graphite (HOPG), which is at least as active as noble metal electrodes (e.g., platinum) for outer

  9. Flexible carbon nanotube--Cu2O hybrid electrodes for li-ion batteries.

    Science.gov (United States)

    Goyal, Anubha; Reddy, Arava L M; Ajayan, Pulickel M

    2011-06-20

    This study demonstrates the formation of a flexible and free-standing carbon nanotube-copper oxide-poly(vinylidene fluoride) (CNT-Cu(2) O-PVDF) nanocomposite and its application as an electrode-separator material for Li-ion batteries. Binder-free hybrid electrodes are obtained by conformally coating CNTs with Cu(2) O via electrodeposition and then embedding the resulting architecture into a porous poly(vinylidene fluoride-hexafluoropropylene) PVDF-HFP-SiO(2) polymer electrolyte membrane. The synergistic presence of high-capacity transition metal oxides and conductive CNTs results in twice the reversible areal capacity of 2.3 mAh cm(-2) as compared to 1.2 mAh cm(-2) for pure CNTs.

  10. Carbon nanotubes/holey graphene hybrid film as binder-free electrode for flexible supercapacitors.

    Science.gov (United States)

    Deng, Lingjuan; Gu, Yuanzi; Gao, Yihong; Ma, Zhanying; Fan, Guang

    2017-05-15

    The practical application of graphene (GR) has still been hindered because of its unsatisfied physical and chemical properties resulting from the irreversible agglomerates. Preparation of GR-based materials with designed porosities is essential for its practical application. In this work, a facile and scalable method is developed to synthesize carbon nanotubes/holey graphene (CNT/HGR) flexible film using functional CNT and HGR as precursors. Owing to the existence of the small amount CNT, the CNT-5/HGR flexible film with a 3D conductive interpenetrated architecture exhibit significantly improved ion diffusion rate compared to that of the HGR. Moreover, CNT-5/HGR flexible film can be used as binder-free supercapacitor electrodes with ultrahigh specific capacitances of 268Fg(-1), excellent rate capabilities, and superior cycling stabilities. CNT-5/HGR flexible film could be used to fabricate high-performance flexible supercapacitors electrodes. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. High-efficiency electrochemical thermal energy harvester using carbon nanotube aerogel sheet electrodes

    Science.gov (United States)

    Im, Hyeongwook; Kim, Taewoo; Song, Hyelynn; Choi, Jongho; Park, Jae Sung; Ovalle-Robles, Raquel; Yang, Hee Doo; Kihm, Kenneth D.; Baughman, Ray H.; Lee, Hong H.; Kang, Tae June; Kim, Yong Hyup

    2016-02-01

    Conversion of low-grade waste heat into electricity is an important energy harvesting strategy. However, abundant heat from these low-grade thermal streams cannot be harvested readily because of the absence of efficient, inexpensive devices that can convert the waste heat into electricity. Here we fabricate carbon nanotube aerogel-based thermo-electrochemical cells, which are potentially low-cost and relatively high-efficiency materials for this application. When normalized to the cell cross-sectional area, a maximum power output of 6.6 W m-2 is obtained for a 51 °C inter-electrode temperature difference, with a Carnot-relative efficiency of 3.95%. The importance of electrode purity, engineered porosity and catalytic surfaces in enhancing the thermocell performance is demonstrated.

  12. High-efficiency electrochemical thermal energy harvester using carbon nanotube aerogel sheet electrodes.

    Science.gov (United States)

    Im, Hyeongwook; Kim, Taewoo; Song, Hyelynn; Choi, Jongho; Park, Jae Sung; Ovalle-Robles, Raquel; Yang, Hee Doo; Kihm, Kenneth D; Baughman, Ray H; Lee, Hong H; Kang, Tae June; Kim, Yong Hyup

    2016-02-03

    Conversion of low-grade waste heat into electricity is an important energy harvesting strategy. However, abundant heat from these low-grade thermal streams cannot be harvested readily because of the absence of efficient, inexpensive devices that can convert the waste heat into electricity. Here we fabricate carbon nanotube aerogel-based thermo-electrochemical cells, which are potentially low-cost and relatively high-efficiency materials for this application. When normalized to the cell cross-sectional area, a maximum power output of 6.6 W m(-2) is obtained for a 51 °C inter-electrode temperature difference, with a Carnot-relative efficiency of 3.95%. The importance of electrode purity, engineered porosity and catalytic surfaces in enhancing the thermocell performance is demonstrated.

  13. Magnetic entrapment for fast, simple and reversible electrode modification with carbon nanotubes: application to dopamine detection.

    Science.gov (United States)

    Baldrich, Eva; Gómez, Rodrigo; Gabriel, Gemma; Muñoz, Francesc Xavier

    2011-01-15

    Carbon nanotubes (CNT) have been exploited for an important number of electroanalytical and sensing purposes. Specifically, CNT incorporation to an electrode surface coating increases its roughness and area, provides electrocatalytic activity towards a variety of molecules, and improves electron transfer. This modification is generally based on the irreversible deposition of CNT on surface. Nevertheless, CNT are highly porous materials that might promote molecule non-specific adsorption and/or electrodeposition, which could induce sample-to-sample cross-contamination and affect measurement specificity and reproducibility. This drawback has been often circumvented by combining CNT with charged polymers able to repel molecules of opposed charge. We demonstrate that single-walled CNT (SWCNT) have a strong tendency to non-specifically adsorb onto the surface of protein-coated magnetic particles (MP). Magnetic capture of those MP generates CNT coentrapment and allows extremely fast, simple and reversible production of SWCNT electrodes. We have exploited this phenomenon for the production of modified screen-printed electrodes (MP/CNT-SPE), which have been characterized by Scanning Electron Microscopy. The surface has been additionally optimized by evaluating the electrochemical performance of SPE modified with different amounts and proportions of MP and CNT. The modified devices have then been used for dopamine detection. MP/CNT-SPE generated improved assay sensitivity, lower limit of detection, and up to 500% higher current signals than bare electrodes. Magnetic entrapment is proposed as a promising strategy for the fast, simple and reversible generation of nanostructured electrodes of enhanced performance within a few minutes and electrode re-utilisation by simple magnet removal and surface washing.

  14. Nanostructured Mo-based electrode materials for electrochemical energy storage.

    Science.gov (United States)

    Hu, Xianluo; Zhang, Wei; Liu, Xiaoxiao; Mei, Yueni; Huang, Yunhui

    2015-04-21

    The development of advanced energy storage devices is at the forefront of research geared towards a sustainable future. Nanostructured materials are advantageous in offering huge surface to volume ratios, favorable transport features, and attractive physicochemical properties. They have been extensively explored in various fields of energy storage and conversion. This review is focused largely on the recent progress in nanostructured Mo-based electrode materials including molybdenum oxides (MoO(x), 2 ≤ x ≤ 3), dichalconides (MoX2, X = S, Se), and oxysalts for rechargeable lithium/sodium-ion batteries, Mg batteries, and supercapacitors. Mo-based compounds including MoO2, MoO3, MoO(3-y) (0 energy storage systems because of their unique physicochemical properties, such as conductivity, mechanical and thermal stability, and cyclability. In this review, we aim to provide a systematic summary of the synthesis, modification, and electrochemical performance of nanostructured Mo-based compounds, as well as their energy storage applications in lithium/sodium-ion batteries, Mg batteries, and pseudocapacitors. The relationship between nanoarchitectures and electrochemical performances as well as the related charge-storage mechanism is discussed. Moreover, remarks on the challenges and perspectives of Mo-containing compounds for further development in electrochemical energy storage applications are proposed. This review sheds light on the sustainable development of advanced rechargeable batteries and supercapacitors with nanostructured Mo-based electrode materials.

  15. Electrochemical reduction of dilute chromate solutions on carbon felt electrodes

    NARCIS (Netherlands)

    Frenzel, Ines; Holdik, Hans; Barmashenko, Vladimir; Stamatialis, Dimitrios F.; Wessling, Matthias

    2006-01-01

    Carbon felt is a potential material for electrochemical reduction of chromates. Very dilute solutions may be efficiently treated due to its large specific surface area and high porosity. In this work, the up-scaling of this technology is investigated using a new type of separated cell and once-throu

  16. Manganese Detection with a Metal Catalyst Free Carbon Nanotube Electrode: Anodic versus Cathodic Stripping Voltammetry

    Science.gov (United States)

    Yue, Wei; Bange, Adam; Riehl, Bill L.; Riehl, Bonnie D.; Johnson, Jay M.; Papautsky, Ian; Heineman, William R.

    2013-01-01

    Anodic stripping voltammetry (ASV) and cathodic stripping voltammetry (CSV) were used to determine Mn concentration using metal catalyst free carbon nanotube (MCFCNT) electrodes and square wave stripping voltammetry (SWSV). The MCFCNTs are synthesized using a Carbo Thermal Carbide Conversion method which results in a material that does not contain residual transition metals. Detection limits of 120 nM and 93 nM were achieved for ASV and CSV, respectively, with a deposition time of 60 s. CSV was found to be better than ASV in Mn detection in many aspects, such as limit of detection and sensitivity. The CSV method was used in pond water matrix addition measurements. PMID:24235806

  17. Manganese Detection with a Metal Catalyst Free Carbon Nanotube Electrode: Anodic versus Cathodic Stripping Voltammetry.

    Science.gov (United States)

    Yue, Wei; Bange, Adam; Riehl, Bill L; Riehl, Bonnie D; Johnson, Jay M; Papautsky, Ian; Heineman, William R

    2012-10-01

    Anodic stripping voltammetry (ASV) and cathodic stripping voltammetry (CSV) were used to determine Mn concentration using metal catalyst free carbon nanotube (MCFCNT) electrodes and square wave stripping voltammetry (SWSV). The MCFCNTs are synthesized using a Carbo Thermal Carbide Conversion method which results in a material that does not contain residual transition metals. Detection limits of 120 nM and 93 nM were achieved for ASV and CSV, respectively, with a deposition time of 60 s. CSV was found to be better than ASV in Mn detection in many aspects, such as limit of detection and sensitivity. The CSV method was used in pond water matrix addition measurements.

  18. Core-double-shell, carbon nanotube@polypyrrole@MnO₂ sponge as freestanding, compressible supercapacitor electrode.

    Science.gov (United States)

    Li, Peixu; Yang, Yanbing; Shi, Enzheng; Shen, Qicang; Shang, Yuanyuan; Wu, Shiting; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Yuan, Quan; Cao, Anyuan; Wu, Dehai

    2014-04-09

    Design and fabrication of structurally optimized electrode materials are important for many energy applications such as supercapacitors and batteries. Here, we report a three-component, hierarchical, bulk electrode with tailored microstructure and electrochemical properties. Our supercapacitor electrode consists of a three-dimensional carbon nanotube (CNT) network (also called sponge) as a flexible and conductive skeleton, an intermediate polymer layer (polypyrrole, PPy) with good interface, and a metal oxide layer outside providing more surface area. These three components form a well-defined core-double-shell configuration that is distinct from simple core-shell or hybrid structures, and the synergistic effect leads to enhanced supercapacitor performance including high specific capacitance (even under severe compression) and excellent cycling stability. The mechanism study reveals that the shell sequence is a key factor; in our system, the CNT-PPy-MnO2 structure shows higher capacitance than the CNT-MnO2-PPy sequence. Our porous core-double-shell sponges can serve as freestanding, compressible electrodes for various energy devices.

  19. Carbon nanotube-coated macroporous sponge for microbial fuel cell electrodes

    KAUST Repository

    Xie, Xing

    2012-01-01

    The materials that are used to make electrodes and their internal structures significantly affect microbial fuel cell (MFC) performance. In this study, we describe a carbon nanotube (CNT)-sponge composite prepared by coating a sponge with CNTs. Compared to the CNT-coated textile electrodes evaluated in prior studies, CNT-sponge electrodes had lower internal resistance, greater stability, more tunable and uniform macroporous structure (pores up to 1 mm in diameter), and improved mechanical properties. The CNT-sponge composite also provided a three-dimensional scaffold that was favorable for microbial colonization and catalytic decoration. Using a batch-fed H-shaped MFC outfitted with CNT-sponge electrodes, an areal power density of 1.24 W m -2 was achieved when treating domestic wastewater. The maximum volumetric power density of a continuously fed plate-shaped MFC was 182 W m -3. To our knowledge, these are the highest values obtained to date for MFCs fed domestic wastewater: 2.5 times the previously reported maximum areal power density and 12 times the previously reported maximum volumetric power density. © 2011 The Royal Society of Chemistry.

  20. Production method of raw material dispersion liquid for reaction layer of gas diffusion electrode

    Energy Technology Data Exchange (ETDEWEB)

    Furuya, Choichi; Motoo, Satoshi

    1987-10-13

    Heretofore, in order to make a raw material dispersion liquid of a reaction layer of a gas diffusion electrode, water repellent carbon, polytetrafluoroethylene, water and a surface active agent are mixed, then a cake is made by filtering this mixed liquid and afterwards the cake is heated and dried before being crushed. Since this crushing is done mechanically, homogeneous fine raw material powders cannot be obtained. Accordingly, even when a reaction layer is made by sintering a mixture of this powder, hydrophilic carbon black or hydrophilic carbon black carrying catalyst, and polytetrafluoroethylene, the hydrophilic part and the water repellent part are not distributed homogeneously and the catalytic performance of the reaction layer declines. In order to solve this, this invention proposes a production method that water repellent carbon black, polyterafluoroethylene, water and a surface active agent are mixed, then this mixture is frozen so that the surface active agent may not become active and homogeneous condensed cores of water repellent carbon black and polytetrafluoroethylene powders may be formed, and afterwards a homogeneous fine raw material dispersion liquid is made from thawing the condensed cores without change by thawing the above frozen mixture.

  1. Electron Cyclotron Resonance-Sputtered Nanocarbon Film Electrode Compared with Diamond-Like Carbon and Glassy Carbon Electrodes as Regards Electrochemical Properties and Biomolecule Adsorption

    Science.gov (United States)

    Xue, Qiang; Kato, Dai; Kamata, Tomoyuki; Umemura, Shigeru; Hirono, Shigeru; Niwa, Osamu

    2012-09-01

    The electrochemical properties and biocompatible characteristics at an electron cyclotron resonance (ECR)-sputtered nanocarbon film electrode, a diamond-like carbon (DLC) electrode and a glassy carbon (GC) electrode have been studied. The three carbon electrodes show significant current reductions with increased peak separations as a result of protein fouling before oxygen plasma treatment, but the current reductions of the ECR-sputtered nanocarbon and DLC film electrodes are smaller than that of the GC electrode due to their superior surface flatness. The oxygen plasma pretreated ECR-sputtered nanocarbon film electrode exhibits a significant improvement in anti-fouling performance with an improved electron transfer. This is because the pretreated ECR-sputtered nanocarbon film enabled the surface to introduce surface oxygen functionalities that not only improve the interaction between the analytes and the electrode surface but also make the film surface more hydrophilic, which is important for the suppression of biomolecule adsorption. At the same time, the pretreated ECR-sputtered nanocarbon film also retained an ultraflat surface even after pretreatment as a result of the low background current. This excellent performance can only be achieved with our ECR-sputtered nanocarbon film, indicating that our film is promising for application to electrochemical detectors for various biomolecular analytes.

  2. Vanadium nitride quantum dot/nitrogen-doped microporous carbon nanofibers electrode for high-performance supercapacitors

    Science.gov (United States)

    Wu, Yage; Ran, Fen

    2017-03-01

    In this article, vanadium nitride quantum dot/nitrogen-doped microporous carbon nanofibers (VNQD/CNF) is developed by a method of combination of electrostatic spinning and high-temperature calcination under the atmosphere of NH3: N2 = 3: 2 for high performance supercapacitors. VNQD dispersing into CNF, enrichment of N atom doped in carbon bulk, and abundant porous structure not only prevent the growth and aggregation of VN nanoparticles, improve electrical conductivity, wettability, and stability of the electrode materials, but also enhance fast migration of electrolyte ions during the electrochemical process. Thus, VNQD/CNF exhibits a high specific capacitance of 406.5 F g-1 at 0.5 A g-1 and a good rate capability with a capacitance retention of 75.1% at 5.0 A g-1. Additionally, VNQD/CNF as a negative electrode are combined with Ni(OH)2 as a positive electrode to fabricate the hybrid supercapacitor of VNQD/CNF//Ni(OH)2. Remarkably, at a power density of 774.6 W kg-1, the supercapacitor device delivers an ultrahigh energy density of 31.2 Wh kg-1.

  3. Electrochemical Determination of Chlorpyrifos on a Nano-TiO₂Cellulose Acetate Composite Modified Glassy Carbon Electrode.

    Science.gov (United States)

    Kumaravel, Ammasai; Chandrasekaran, Maruthai

    2015-07-15

    A rapid and simple method of determination of chlorpyrifos is important in environmental monitoring and quality control. Electrochemical methods for the determination of pesticides are fast, sensitive, reproducible, and cost-effective. The key factor in electrochemical methods is the choice of suitable electrode materials. The electrode materials should have good stability, reproducibility, more sensitivity, and easy method of preparation. Mercury-based electrodes have been widely used for the determination of chlorpyrifos. From an environmental point of view mercury cannot be used. In this study a biocompatible nano-TiO2/cellulose acetate modified glassy carbon electrode was prepared by a simple method and used for the electrochemical sensing of chlorpyrifos in aqueous methanolic solution. Electroanalytical techniques such as cyclic voltammetry, differential pulse voltammetry, and amperometry were used in this work. This electrode showed very good stability, reproducibility, and sensitivity. A well-defined peak was obtained for the reduction of chlorpyrifos in cyclic voltammetry and differential pulse voltammetry. A smooth noise-free current response was obtained in amperometric analysis. The peak current obtained was proportional to the concentration of chlorpyrifos and was used to determine the unknown concentration of chlorpyrifos in the samples. Analytical parameters such as LOD, LOQ, and linear range were estimated. Analysis of real samples was also carried out. The results were validated through HPLC. This composite electrode can be used as an alternative to mercury electrodes reported in the literature.

  4. Metal-Free Counter Electrode for Efficient Dye-Sensitized Solar Cells through High Surface Area and Large Porous Carbon

    Directory of Open Access Journals (Sweden)

    Pavuluri Srinivasu

    2011-01-01

    Full Text Available Highly efficient, large mesoporous carbon is fabricated as a metal-free counter electrode for dye-sensitized solar cells. The mesoporous carbon shows very high energy conversion efficiency of 7.1% compared with activated carbon. The mesoporous carbon is prepared and characterized by nitrogen adsorption, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. The nitrogen adsorption data reveals that the material possesses BET specific surface area ca.1300 m2/g and pore diameter 4.4 nm. Hexagonal rod-like morphology and ordered pore structure of mesoporous carbon are confirmed by electron microscopy data. The better performance of this carbon material is greatly benefited from its ordered interconnected mesoporous structure and high surface area.

  5. Optimization of fuel cell membrane electrode assemblies for transition metal ion-chelating ordered mesoporous carbon cathode catalysts

    OpenAIRE

    Johanna K. Dombrovskis; Cathrin Prestel; Anders E. C. Palmqvist

    2014-01-01

    Transition metal ion-chelating ordered mesoporous carbon (TM-OMC) materials were recently shown to be efficient polymer electrolyte membrane fuel cell (PEMFC) catalysts. The structure and properties of these catalysts are largely different from conventional catalyst materials, thus rendering membrane electrode assembly (MEA) preparation parameters developed for conventional catalysts not useful for applications of TM-OMC catalysts. This necessitates development of a methodology to incorporate...

  6. Effect of Structure on the Storage Characteristics of ManganeseOxide Electrode Materials

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Joon; Doeff, Marca M.

    2006-01-31

    Eleven types of manganese-containing electrode materialswere subjected to long-term storage at 55oC in 1M LiPF6 ethylenecarbonate/dimethyl carbonate (EC/DMC) solutions. The amount of manganesedissolution observed depended upon the sample surface area, the averageMn oxidation state, the structure, and substitution levels of themanganese oxide. In some cases, structural changes such as solvateformation were exacerbated by the high temperature storage, andcontributed to capacity fading upon cycling even in the absence ofsignificant Mn dissolution. The most stable materials appear to beTi-substituted tunnel structures and mixed metal layered oxides with Mnin the +4 oxidation state.

  7. The Effect of Anodic Surface Treatment on the Oxidation of Catechols at Ultrasmall Carbon Ring Electrodes

    Science.gov (United States)

    1991-07-09

    selectivity. A model of the surface formed following anodic oxidation is consistent with previous models involving both surface cleanliness and carbon...involving both surface cleanliness and carbon structure orientation. 2 INTRODUCTION Because of the vast electroanalytical utility of carbon electrodes...of the electron transfer rate following treatment are a function of the surface cleanliness and the orientation of the carbon structure

  8. Anodes - Materials for negative electrodes in electrochemical energy technology

    Science.gov (United States)

    Holze, Rudolf

    2014-06-01

    The basic concepts of electrodes and electrochemical cells (including both galvanic and electrolytic ones) are introduced and illustrated with practical examples. Particular attention is paid to negative electrodes in primary and secondary cells, fuel cell electrodes and electrodes in redox flow batteries. General features and arguments pertaining to selection, optimization and further development are highlighted.

  9. USE OF BATTERY CARBON AS ELECTRODES IN ARC DISCHARGE METHOD FOR FABRICATION OF CARBON-MODIFIED TIO2

    Directory of Open Access Journals (Sweden)

    Isya Fitria Andhika

    2016-09-01

    Full Text Available Fabrication with carbon-modified TiO2 by arc discharge method in liquid medium has been studied. This research was performed in two steps including fabrication and characterization. This fabrication was done by arcdischarge method with graphite electrodes from dry cell batteries and liquid medium suspension of TiO2 in ethanol 30, 50 and 70 %. A strong current was applied to electrode as 10 -50 A (20-40 V. Nanocomposites formed on the liquid medium surface were collected and characterized using X-ray diffraction (XRD,scanning electron microscope (SEM dan energy dispersive spectroscopy (EDS to determine crystallinity, surface morphology and the constituent elements, respectively. XRD data shows that the most effective fabrication TiO2/Karbon by liquid medium in ethanol 50 % indicated from the formation of a new peak with high intensity of TiC on 2Ɵ= 36.02 °. SEM data shows that the morphology of each aggregated TiO2/Karbon compared to the morphology of TiO2. In addition, EDS data shows the presence of the element carbon, titanium and oxygen in the same area indicating that the successful formation of composite material between TiO2 dan carbon.

  10. Hairy carbon electrodes studied by cyclic voltammetry and battery discharge testing

    Science.gov (United States)

    Chung, Deborah D. L.; Shui, Xiaoping; Frysz, Christine A.

    1993-01-01

    Hairy carbon is a new material developed by growing submicron carbon filaments on conventional carbon substrates. Typical substrate materials include carbon black, graphite powder, carbon fibers, and glassy carbon. A catalyst is used to initiate hair growth with carbonaceous gases serving as the carbon source. To study the electrochemical behavior of hairy carbons, cyclic voltammetry (CV) and discharge testing were conducted. In both cases, hairy carbon results surpassed those of the substrate material alone.

  11. Electrochemical behaviorof carbon paste electrode modified with Carbon Nanofibers: Application to detection of Bisphenol A

    Directory of Open Access Journals (Sweden)

    N.Achargui

    2016-12-01

    Full Text Available The electrochemical behavior of carbon paste electrode modified with carbon nanofibers has been studied using cyclic voltammetry (CV, electrochemical impedance spectroscopy (EIS and scaning electron microscopy. The response of modified electrodein ferroferricyanidesolutionshows reversible behavior and significant increment in current value compared to the bare CPE indicating that CNFs act as efficient electron mediator to catalyze reactions at the surface. The modified electrode has been used to study the electrochemical response of bisphenol Ausing different electrochemical techniques such as cyclic voltammetry, linear sweep voltammetry, differential pulse voltammetry and square wave voltammetry. The oxidation peak of BPA was observed at about 0.53 V in phosphate buffer solution at pH 6.7. The oxidation peak current of BPA varied linearly with concentration over a wide range of 5µmol L-1 to 400 µmol L-1 and the detection limit of this method was found to be 0.55 µmol L-1

  12. Electrochemical Determination of Glycoalkaloids Using a Carbon Nanotubes-Phenylboronic Acid Modified Glassy Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Huiying Wang

    2013-11-01

    Full Text Available A versatile strategy for electrochemical determination of glycoalkaloids (GAs was developed by using a carbon nanotubes-phenylboronic acid (CNTs-PBA modified glassy carbon electrode. PBA reacts with α-solanine and α-chaconine to form a cyclic ester, which could be utilized to detect GAs. This method allowed GA detection from 1 μM to 28 μM and the detection limit was 0.3 μM. Affinity interaction of GAs and immobilized PBA caused an essential change of the peak current. The CNT-PBA modified electrodes were sensitive for detection of GAs, and the peak current values were in quite good agreement with those measured by the sensors.

  13. Electrochemical Determination of Glycoalkaloids Using a Carbon Nanotubes-Phenylboronic Acid Modified Glassy Carbon Electrode

    Science.gov (United States)

    Wang, Huiying; Liu, Mingyue; Hu, Xinxi; Li, Mei; Xiong, Xingyao

    2013-01-01

    A versatile strategy for electrochemical determination of glycoalkaloids (GAs) was developed by using a carbon nanotubes-phenylboronic acid (CNTs-PBA) modified glassy carbon electrode. PBA reacts with α-solanine and α-chaconine to form a cyclic ester, which could be utilized to detect GAs. This method allowed GA detection from 1 μM to 28 μM and the detection limit was 0.3 μM. Affinity interaction of GAs and immobilized PBA caused an essential change of the peak current. The CNT-PBA modified electrodes were sensitive for detection of GAs, and the peak current values were in quite good agreement with those measured by the sensors. PMID:24287539

  14. Electrooxidation of DNA at glassy carbon electrodes modified with multiwall carbon nanotubes dispersed in polyethylenimine

    Energy Technology Data Exchange (ETDEWEB)

    Luque, Guillermina L.; Ferreyra, Nancy F. [INFIQC, Departamento de Fisico Quimica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Granero, Adrian [INFIQC, Departamento de Fisico Quimica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Departamento de Quimica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Rio Cuarto (Argentina); Bollo, Soledad [Laboratorio de Bioelectroquimica, Facultad de Ciencias Quimicas y Farmaceuticas, Universidad de Chile, P.O. Box 233, Santiago (Chile); Rivas, Gustavo A., E-mail: grivas@fcq.unc.edu.ar [INFIQC, Departamento de Fisico Quimica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2011-10-30

    This work reports the electrochemical response of the complex between dsDNA and PEI formed in solution and at the surface of glassy carbon electrodes (GCE) modified with a dispersion of multi-walled carbon nanotubes in polyethylenimine (CNT-PEI). Scanning Electron Microscopy and Scanning Electrochemical Microscopy demonstrate that the dispersion covers the whole surface of the electrode although there are areas with higher density of CNT and, consequently, with higher electrochemical reactivity. The adsorption of DNA at GCE/CNT-PEI is fast and it is mainly driven by electrostatic forces. A clear oxidation signal is obtained either for dsDNA or a heterooligonucleotide of 21 bases (oligoY) at potentials smaller than those for the oxidation at bare GCE. The comparison of the behavior of DNA before and after thermal treatment demonstrated that the electrochemical response highly depends on the 3D structure of the nucleic acid.

  15. Towards ultrathick battery electrodes: aligned carbon nanotube-enabled architecture.

    Science.gov (United States)

    Evanoff, Kara; Khan, Javed; Balandin, Alexander A; Magasinski, Alexandre; Ready, W Jud; Fuller, Thomas F; Yushin, Gleb

    2012-01-24

    Vapor deposition techniques were utilized to synthesize very thick (∼1 mm) Li-ion battery anodes consisting of vertically aligned carbon nanotubes coated with silicon and carbon. The produced anode demonstrated ultrahigh thermal (>400 W·m(-1) ·K(-1)) and high electrical (>20 S·m(-1)) conductivities, high cycle stability, and high average capacity (>3000 mAh·g(Si) (-1)). The processes utilized allow for the conformal deposition of other materials, thus making it a promising architecture for the development of Li-ion anodes and cathodes with greatly enhanced electrical and thermal conductivities.

  16. Bioelectrocatalytic carbon ceramic gas electrode for reduction of dioxygen and its application in a zinc-dioxygen cell

    Energy Technology Data Exchange (ETDEWEB)

    Nogala, W.; Celebanska, A.; Opallo, M. [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, PL-01-224 Warszawa (Poland); Wittstock, G. [Faculty of Mathematics and Science, Department of Pure and Applied Chemistry, Carl von Ossietzky University of Oldenburg, Center of Interface Science (CIS), D-26111 Oldenburg (Germany)

    2010-12-15

    An enzyme-modified carbon ceramic electrode was constructed and studied that is capable to reduce dioxygen supplied from the gas phase. The permeation of the electrode material and its hydrophobic silicate component was studied by scanning electrochemical microscopy. The mass-transfer coefficient of dioxygen in methyltrimethoxysilane-based silicate was estimated to be 6.44 x 10{sup -5} cm{sup 2} s{sup -1}. After modification of the electrode with bilirubin oxidase and immersion in deareated aqueous electrolyte, the dioxygen bioelectrocatalytic reduction is observed with onset potential at 0.45 V. The constructed electrode was successfully applied as cathode in a zinc-dioxygen cell. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. The Application of Nafion Metal Catalyst Free Carbon Nanotube Modified Gold Electrode: Voltammetric Zinc Detection in Serum

    Science.gov (United States)

    Yue, Wei; Bange, Adam; Riehl, Bill L.; Johnson, Jay M.; Papautsky, Ian; Heineman, William R.

    2013-01-01

    Metal catalyst free carbon nanotube (MCFCNT) whiskers were first used as an electrode modification material on a gold electrode surface for zinc voltammetric measurements. A composite film of Nafion and MCFCNT whiskers was applied to a gold electrode surface to form a mechanically stable sensor. The sensor was then used for zinc detection in both acetate buffer solution and extracted bovine serum solution. A limit of detection of 53 nM was achieved for a 120 s deposition time. The zinc in bovine serum was extracted via a double extraction procedure using dithizone in chloroform as a zinc chelating ligand. The modified electrode was found to be both reliable and sensitive for zinc measurements in both matrices. PMID:24436574

  18. Electrochemical investigation of NO at single-wall carbon nanotubes modified electrodes

    Indian Academy of Sciences (India)

    Tingliang Xia; Hongmei Bi; Keying Shi

    2010-05-01

    The NO electro-oxidation was investigated at various single-wall carbon nanotubes (SWCNTs) modified electrodes by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Compared with the glassy carbon electrode, the SWCNTs modified electrodes possess higher electro-catalytic activity to NO electro-oxidation. CV results indicate that the peak current density of NO electro-oxidation at the SWCNT-COOH (SWCNTs with carboxyl groups) modified electrode is the highest and the peak potential is the most negative among the four kinds of electrodes. EIS indicates that the charge transfer resistance of NO electro-oxidation at the SWCNT-COOH modified electrode is the least. The determined factors (charge transfer and mass transfer of diffusion) of NO electro-oxidation are different in varied potential region. The mechanism of NO electro-oxidation reaction at the SWCNTs modified electrodes is also discussed.

  19. Direct reduction of carbon dioxide to formate in high-gas-capacity ionic liquids at post-transition-metal electrodes.

    Science.gov (United States)

    Watkins, John D; Bocarsly, Andrew B

    2014-01-01

    As an approach to combat the increasing emissions of carbon dioxide in the last 50 years, the sequestration of carbon dioxide gas in ionic liquids has become an attractive research area. Ionic liquids can be made that possess incredibly high molar absorption and specificity characteristics for carbon dioxide. Their high carbon dioxide solubility and specificity combined with their high inherent electrical conductivity also creates an ideal medium for the electrochemical reduction of carbon dioxide. Herein, a lesser studied ionic liquid, 1-ethyl-3-methylimidazolium trifluoroacetate, was used as both an effective carbon dioxide capture material and subsequently as an electrochemical matrix with water for the direct reduction of carbon dioxide into formate at indium, tin, and lead electrodes in good yield (ca. 3 mg h(-1) cm(-2)).

  20. Characterization of the SEI on a carbon film electrode by combinedEQCM and spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    evans@socrates.berkeley.edu

    2002-01-01

    The electrochemical quartz crystal microbalance (EQCM) andcyclic voltammetry have been applied simultaneously to characterizeelectron-beam deposited carbon film electrodes in LiClO4 orLiPF6-containing mixed electrolytes of ethylene carbonate (EC) anddimethyl carbonate (DMC). The structure of the carbon electrode was foundto be amorphous/disordered using Raman spectroscopy. Cyclic voltammetryin LiClO4 / EC+DMC demonstrated features typical of Liintercalation/deintercalation into/from the disordered carbon electrode,and EQCM showed a corresponding mass increase/decrease. Contrary to thecase of LiClO4 / EC+DMC electrolyte, LiPF6/EC+DMC electrolyte showed noLi deintercalation out of the thin-film carbon electrode. Combined EQCMand spectroscopic ellipsometry data were compared, and the solidelectrolyte interphase density after the first cycle in LiClO4 /EC+DMCwas estimated to be 1.3 g/cm3.

  1. Studies on two classes of positive electrode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wilcox, James Douglas [Univ. of California, Berkeley, CA (United States)

    2008-12-01

    The development of advanced lithium-ion batteries is key to the success of many technologies, and in particular, hybrid electric vehicles. In addition to finding materials with higher energy and power densities, improvements in other factors such as cost, toxicity, lifetime, and safety are also required. Lithium transition metal oxide and LiFePO4/C composite materials offer several distinct advantages in achieving many of these goals and are the focus of this report. Two series of layered lithium transition metal oxides, namely LiNi1/3Co1/3-yMyMn1/3O2 (M=Al, Co, Fe, Ti) and LiNi0.4Co0.2-yMyMn0.4O2 (M = Al, Co, Fe), have been synthesized. The effect of substitution on the crystal structure is related to shifts in transport properties and ultimately to the electrochemical performance. Partial aluminum substitution creates a high-rate positive electrode material capable of delivering twice the discharge capacity of unsubstituted materials. Iron substituted materials suffer from limited electrochemical performance and poor cycling stability due to the degradation of the layered structure. Titanium substitution creates a very high rate positive electrode material due to a decrease in the anti-site defect concentration. LiFePO4 is a very promising electrode material but suffers from poor electronic and ionic conductivity. To overcome this, two new techniques have been developed to synthesize high performance LiFePO4/C composite materials. The use of graphitization catalysts in conjunction with pyromellitic acid leads to a highly graphitic carbon coating on the surface of LiFePO4 particles. Under the proper conditions, the room temperature electronic conductivity can be improved by nearly five orders of magnitude over untreated materials. Using Raman spectroscopy, the improvement in conductivity and rate performance of

  2. Magnetite nanoparticles-chitosan composite containing carbon paste electrode for glucose biosensor application.

    Science.gov (United States)

    Kavitha, A L; Prabu, H Gurumallesh; Babu, S Ananda; Suja, S K

    2013-01-01

    This work was aimed to develop reusable magnetite chitosan composite containing carbon paste electrode for biosensor application. Glucose oxidase (GOx) enzyme was used to prepare GOx-magnetite-chitosan nanocomposite containing carbon paste electrode for sensitive detection of glucose. The immobilized enzyme retained its bioactivity, exhibited a surface confined reversible electron transfer reaction, and had good stability. The surface parameters like surface coverage (tau), Diffusion coefficient (D0), and rate constant (kS) were studied. The carbon paste modified electrode virtually eliminated the interference during the detection of glucose. The excellent performance of the biosensor is attributed to large surface-to-volume ratio, high conductivity and good biocompatibility of chitosan, which enhances the enzyme absorption and promotes electron transfer between redox enzymes and the surface of electrode. The shelf life of the developed electrode system is about 12 weeks under refrigerated conditions. We report for the first time in the fabrication of carbon paste bioelectrode containing magnetite-chitosan-GOx.

  3. Synergetic Hybrid Aerogels of Vanadia and Graphene as Electrode Materials of Supercapacitors

    Directory of Open Access Journals (Sweden)

    Xuewei Fu

    2016-08-01

    Full Text Available The performance of synergetic hybrid aerogel materials of vanadia and graphene as electrode materials in supercapacitors was evaluated. The hybrid materials were synthesized by two methods. In Method I, premade graphene oxide (GO hydrogel was first chemically reduced by L-ascorbic acid and then soaked in vanadium triisopropoxide solution to obtain V2O5 gel in the pores of the reduced graphene oxide (rGO hydrogel. The gel was supercritically dried to obtain the hybrid aerogel. In Method II, vanadium triisopropoxide was hydrolyzed from a solution in water with GO particles uniformly dispersed to obtain the hybrid gel. The hybrid aerogel was obtained by supercritical drying of the gel followed by thermal reduction of GO. The electrode materials were prepared by mixing 80 wt % hybrid aerogel with 10 wt % carbon black and 10 wt % polyvinylidene fluoride. The hybrid materials in Method II showed higher capacitance due to better interactions between vanadia and graphene oxide particles and more uniform vanadia particle distribution.

  4. Advanced Carbon Materials for Environmental and Energy Applications

    KAUST Repository

    Dua, Rubal

    2014-05-01

    Carbon based materials, including porous carbons and carbon layer composites, are finding increased usage in latest environmental and energy related research. Among porous carbon materials, hierarchical porous carbons with multi-modal porosity are proving out to be an effective solution for applications where the traditional activated carbons fail. Thus, there has been a lot of recent interest in developing low-cost, facile, easy to scale-up, synthesis techniques for producing such multi-modal porous carbons. This dissertation offers two novel synthesis techniques: (i) ice templating integrated with hard templating, and (ii) salt templating coupled with hard templating, for producing such hierarchically porous carbons. The techniques offer tight control and tunability of porosity (macro- meso- and microscale) in terms of both size and extent. The synthesized multi-modal porous carbons are shown to be an effective solution for three important environment related applications – (i) Carbon dioxide capture using amine supported hierarchical porous carbons, (ii) Reduction in irreversible fouling of membranes used for wastewater reuse through a deposition of a layer of hierarchical porous carbons on the membrane surface, (iii) Electrode materials for electrosorptive applications. Finally, because of their tunability, the synthesized multi-modal porous carbons serve as excellent model systems for understanding the effect of different types of porosity on the performance of porous carbons for these applications. Also, recently, there has been a lot of interest in developing protective layer coatings for preventing photo-corrosion of semiconductor structures (in particular Cu2O) used for photoelectrochemical water splitting. Most of the developed protective strategies to date involve the use of metals or co-catalyst in the protective layer. Thus there is a big need for developing low-cost, facile and easy to scale protective coating strategies. Based on the expertise

  5. Development of Carbon Based optically Transparent Electrodes from Pyrolyzed Photoresist for the Investigation of Phenomena at Electrified Carbon-Solution Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Donner, Sebastian [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    The work presented herein describes a fundamental investigations of carbon as electrode material by using the pyrolysis of photoresist to create an optically transparent material. The development of these carbon-based optically transparent electrodes (C-OTEs) enables investigations of molecular interactions within the electrical double layer, processes that are central to a wide range of important phenomena, including the impact of changes in the surface charge density on adsorption. The electrochemical importance of carbon cannot be understated, having relevance to separations and detection by providing a wide potential window and low background current in addition to being low cost and light weight. The interactions that govern the processes at the carbon electrode surface has been studied extensively. A variety of publications from the laboratories of McCreery and Kinoshita provide in depth summaries about carbon and its many applications in electrochemistry. These studies reveal that defects, impurities, oxidation, and a variety of functional groups create adsorption sites on carbon surfaces with different characteristics. The interest in C-OTEs was sparked by the desire to study and understand the behavior of individual molecules at electrified interfaces. It draws on the earlier development of Electrochemically Modulated Liquid Chromatography (EMLC), which uses carbon as the stationary phase. EMLC takes advantage of changing the applied potential to the carbon electrode to influence the retention behavior of analytes. However, perspectives gained from, for example, chromatographic measurements reflect the integrated response of a large ensemble of potentially diverse interactions between the adsorbates and the carbon electrode. Considering the chemically and physically heterogeneous surface of electrode materials such as glassy carbon, the integrated response provides little insight into the interactions at a single molecule level. To investigate individual

  6. Design and synthesis of polymer, carbon and composite electrodes for high energy and high power supercapacitors

    Science.gov (United States)

    Arcila Velez, Margarita Rosa

    Supercapacitors (SCs) are promising energy storage devices because they deliver energy faster than Li-ion batteries and store larger amounts of charge compared to dielectric capacitors. SCs are classified in electrical double layer capacitors (EDLCs) and pseudocapacitors, based on their charge storage mechanism. EDLCs store charge electrostatically, i.e. by physical charge separation. This mechanism limits the storable amount of energy to the available surface area of the electrode, typically made of carbon materials, but grants good cycling stability of the SC device. Pseudocapacitor electrodes, commonly made of conducting polymers or metal oxides, store charge faradaically, i.e. through redox reactions throughout the bulk material, which allows them to store significantly larger amounts of energy than EDLCs, but their stability is compromised due to the partial irreversibility of the faradaic processes. To accomplish the commercialization of SCs, devices must show a combination of high charge storage capacities and long-term stability, besides being cost-effective. To tackle the current issues of SCs, this field of study has taken mainly two directions: 1) the development of new architectures and nanostructures of the active materials, which has shown to increase the surface area, enhance stability, and facilitate ion diffusion; and 2) fabrication of composites between non-faradaic (carbon), faradaic materials, and/or redox-active components to achieve a balance between the amount of energy stored and the stability. Following the first approach, a continuous process to grow vertically aligned carbon nanotubes (VACNTs) on cost-effective aluminum foil was developed. The resulting electrodes were analyzed as SC electrodes and in symmetric cells, and the influence of the arrangement of the nanotubes and the synthesis conditions was studied. The performance of the VACNTs produced continuously showed similar performance to the VACNTs produced stationarily and the

  7. In-situ Raman spectroscopy as a characterization tool for carbon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Panitz, J.-C.; Joho, F.B.; Novak, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Lithium intercalation and de-intercalation into/from graphite electrodes in a nonaqueous electrolyte has been studied using in-situ Raman spectroscopy. Our experiments give information on the electrode-electrolyte interface with improved spatial resolution. The spectra taken from the electrode surface change with electrode potential. In this way, information on the nature of the chemical species present during charging and discharging half cycles is gained. For the first time, mapping techniques were applied to investigate if lithium intercalation proceeds homogeneously on the carbon electrode. (author) 3 figs., 1 tab., 4 refs.

  8. Plasma Activation of Integrated Carbon Nanotube Electrodes for Electrochemical Detection of Catechol

    Institute of Scientific and Technical Information of China (English)

    WANG Shenggao; WANG Tao; LI Yanqiong; ZHAO Xiujian; HAN Jianjun; WANG Jianhua

    2007-01-01

    In this study,integrated multi-wall carbon nanotube (MWCNT) electrodes were prepared in the holes of glass directly by microwave plasma chemical vapour deposition (MWPCVD).The electrochemical behaviour of catechol at the integrated MWCNT electrodes was investigated.The oxygen plasma treated CNT electrodes had better electrochemical performance for the analysis of catechol than that of as-synthesized CNT electrodes.Both the as-synthesized CNTs and plasma treated CNTs were characterized by TEM(transmission electron microscopy,XPS(X-ray photoelectron spectroscopy) and Raman spectroscopy.The results revealed that the oxygen plasma activation is an effective method to enhance the electrochemical properties of CNT electrodes.

  9. From condiment to metal-organic framework and its derived 3D architecture nanoporous carbon for supercapacitor electrodes

    Science.gov (United States)

    Wang, Qiang; Lu, Xiaowang; Chen, Zhidong

    2017-02-01

    The crystalline metal-organic-framework (MOF) microrods from monosodium glutamate and zinc acetate dihydrate were spontaneously formed by mixing their solution at room temperature. After carbonization in an inert atmosphere, these MOF microrods are evolved into N and O co-doped nanoporous carbon with 3D-architecture. The model of gas bubbles is elucidated for the formation of these interconnected porous structure. As the electrode material for supercapacitor, the derived nanoporous carbon at the temperature of 800 °C exhibits good capacitance performance in alkali aqueous electrolyte.

  10. Flexible and Robust Thermoelectric Generators Based on All-Carbon Nanotube Yarn without Metal Electrodes.

    Science.gov (United States)

    Choi, Jaeyoo; Jung, Yeonsu; Yang, Seung Jae; Oh, Jun Young; Oh, Jinwoo; Jo, Kiyoung; Son, Jeong Gon; Moon, Seung Eon; Park, Chong Rae; Kim, Heesuk

    2017-08-22

    As practical interest in flexible/or wearable power-conversion devices increases, the demand for high-performance alternatives to thermoelectric (TE) generators based on brittle inorganic materials is growing. Herein, we propose a flexible and ultralight TE generator (TEG) based on carbon nanotube yarn (CNTY) with excellent TE performance. The as-prepared CNTY shows a superior electrical conductivity of 3147 S/cm due to increased longitudinal carrier mobility derived from a highly aligned structure. Our TEG is innovative in that the CNTY acts as multifunctions in the same device. The CNTY is alternatively doped into n- and p-types using polyethylenimine and FeCl3, respectively. The highly conductive CNTY between the doped regions is used as electrodes to minimize the circuit resistance, thereby forming an all-carbon TEG without additional metal deposition. A flexible TEG based on 60 pairs of n- and p-doped CNTY shows the maximum power density of 10.85 and 697 μW/g at temperature differences of 5 and 40 K, respectively, which are the highest values among reported TEGs based on flexible materials. We believe that the strategy proposed here to improve the power density of flexible TEG by introducing highly aligned CNTY and designing a device without metal electrodes shows great potential for the flexible/or wearable power-conversion devices.

  11. Electrochemical Reduction of Carbon Dioxide to Methanol by Direct Injection of Electrons into Immobilized Enzymes on a Modified Electrode.

    Science.gov (United States)

    Schlager, Stefanie; Dumitru, Liviu Mihai; Haberbauer, Marianne; Fuchsbauer, Anita; Neugebauer, Helmut; Hiemetsberger, Daniela; Wagner, Annika; Portenkirchner, Engelbert; Sariciftci, Niyazi Serdar

    2016-03-21

    We present results for direct bio-electrocatalytic reduction of CO2 to C1 products using electrodes with immobilized enzymes. Enzymatic reduction reactions are well known from biological systems where CO2 is selectively reduced to formate, formaldehyde, or methanol at room temperature and ambient pressure. In the past, the use of such enzymatic reductions for CO2 was limited due to the necessity of a sacrificial co-enzyme, such as nicotinamide adenine dinucleotide (NADH), to supply electrons and the hydrogen equivalent. The method reported here in this paper operates without the co-enzyme NADH by directly injecting electrons from electrodes into immobilized enzymes. We demonstrate the immobilization of formate, formaldehyde, and alcohol dehydrogenases on one-and-the-same electrode for direct CO2 reduction. Carbon felt is used as working electrode material. An alginate-silicate hybrid gel matrix is used for the immobilization of the enzymes on the electrode. Generation of methanol is observed for the six-electron reduction with Faradaic efficiencies of around 10%. This method of immobilization of enzymes on electrodes offers the opportunity for electrochemical application of enzymatic electrodes to many reactions in which a substitution of the expensive sacrificial co-enzyme NADH is desired.

  12. Porous carbon-coated graphite electrodes for energy production from salinity gradient using reverse electrodialysis

    Science.gov (United States)

    Lee, Su-Yoon; Jeong, Ye-Jin; Chae, So-Ryong; Yeon, Kyeong-Ho; Lee, Yunkyu; Kim, Chan-Soo; Jeong, Nam-Jo; Park, Jin-Soo

    2016-04-01

    Performance of graphite foil electrodes coated by porous carbon black (i.e., Vulcan) was investigated in comparison with metal electrodes for reverse electrodialysis (RED) application. The electrode slurry that was used for fabrication of the porous carbon-coated graphite foil is composed of 7.2 wt% of carbon black (Vulcan X-72), 0.8 wt% of a polymer binder (polyvinylidene fluoride, PVdF), and 92.0 wt% of a mixing solvent (dimethylacetamide, DMAc). Cyclic voltammograms of both the porous carbon (i.e., Vulcan)-coated graphite foil electrode and the graphite foil electrode without Vulcan showed good reversibility in the hexacyanoferrate(III) (i.e., Fe(CN)63-) and hexacyanoferrate(II) (i.e., Fe(CN)64-) redox couple and 1 M Na2SO4 at room temperature. However, anodic and cathodic current of the Vulcan-coated graphite foil electrode was much higher than those of the graphite foil electrode. Using a bench-scale RED stack, the current-voltage polarization curve of the Vulcan-coated graphite electrode was compared to that of metal electrodes such as iridium (Ir) and platinum (Pt). From the results, it was confirmed that resistance of four different electrodes increased with the following order: the Vulcan-coated graphite foilVulcan-coated graphite foil showed 5-10% higher power density than the metal mesh electrodes. From the polarization curve of the Vulcan-coated graphite foil electrode, it was found that total resistance decreased as thickness and geometric surface area of the electrode increased.

  13. Binder-Free and Carbon-Free Nanoparticle Batteries: A Method for Nanoparticle Electrodes without Polymeric Binders or Carbon Black

    KAUST Repository

    Ha, Don-Hyung

    2012-10-10

    In this work, we have developed a new fabrication method for nanoparticle (NP) assemblies for Li-ion battery electrodes that require no additional support or conductive materials such as polymeric binders or carbon black. By eliminating these additives, we are able to improve the battery capacity/weight ratio. The NP film is formed by using electrophoretic deposition (EPD) of colloidally synthesized, monodisperse cobalt NPs that are transformed through the nanoscale Kirkendall effect into hollow Co 3O 4. EPD forms a network of NPs that are mechanically very robust and electrically connected, enabling them to act as the Li-ion battery anode. The morphology change through cycles indicates stable 5-10 nm NPs form after the first lithiation remained throughout the cycling process. This NP-film battery made without binders and conductive additives shows high gravimetric (>830 mAh/g) and volumetric capacities (>2100 mAh/cm 3) even after 50 cycles. Because similar films made from drop-casting do not perform well under equal conditions, EPD is seen as the critical step to create good contacts between the particles and electrodes resulting in this significant improvement in battery electrode assembly. This is a promising system for colloidal nanoparticles and a template for investigating the mechanism of lithiation and delithiation of NPs. © 2012 American Chemical Society.

  14. production of manual arc welding electrodes with local raw materials

    African Journals Online (AJOL)

    CHUKSSUCCESS 4 LOVE

    effectively with titanium dioxide based electrode (a foreign electrode) with tensile strength of. 606.7N/mm . ... composition and mechanical properties as ... bead from oxidation during welding. ... Manganese (Mn), Slag, Silicon (Si) and Iron. 2. 3.

  15. The performance of supercapacitor electrodes developed from chemically activated carbon produced from waste tea

    Science.gov (United States)

    Inal, I. Isil Gurten; Holmes, Stuart M.; Banford, Anthony; Aktas, Zeki

    2015-12-01

    Highly microporous and mesoporous activated carbons were produced from waste tea for application as supercapacitor electrodes, utilising a chemical activation method involving treatment with either K2CO3 or H3PO4. The area, pore structure characteristics and surface functionality of the activated carbons were evaluated to investigate the influence on electrochemical performance. The performance of the activated carbons as supercapacitor electrodes was tested by cyclic voltammetry (CV), impedance spectroscopy (EIS) and galvanostatic charge-discharge (GCD) measurements, in an aqueous electrolyte. The results showed that the pore structure and type of the activated carbon have significant impact on the supercapacitor performance. Both waste tea-based activated carbon electrodes showed good cyclic stability. However, despite its lower specific surface area the highly microporous activated carbon produced with K2CO3, exhibited much better capacitive performance than that of the mesoporous activated carbon produced with H3PO4.

  16. A Multiwall Carbon Nanotube-chitosan Modified Electrode for Selective Detection of Dopamine in the Presence of Ascorbic Acid

    Institute of Scientific and Technical Information of China (English)

    Ling Yan JIANG; Chuan Yin LIU; Li Ping JIANG; Guang Han LU

    2005-01-01

    A novel multiwall carbon nanotube-chitosan modified electrode has been prepared.The modified electrode resolves the overlapping voltammetric response of dopamine and ascorbic acid into two well-defined peak by 212 mY. The mechanism of discrimination of dopamine from ascorbic acid is discussed. Dopamine can be determined selectively with the carbon nanotube-chitosan modified electrode. The electrode shows good sensitivity, selectivity and stability.keywords: Nanotube-chitosan modified electrode, dopamine, ascorbic acid.

  17. Work function determination of promising electrode materials for thermionic converters

    Science.gov (United States)

    Jacobson, D.

    1977-01-01

    Work performed on this contract was primarily for the evaluation of selected electrode materials for thermionic energy converters. The original objective was to characterize selected nickel based superalloys up to temperatures of 1400 K. It was found that an early selection, Inconel 800 produced a high vapor pressure which interfered with the vacuum emission measurements. The program then shifted to two other areas. The first area was to obtain emission from the superalloys in a cesiated atmosphere. The cesium plasma helps to suppress the vaporization interference. The second area involved characterization of the Lanthanum-Boron series as thermionic emitters. These final two areas resulted in three journal publications which are attached to this report.

  18. Identification and Mitigation of Generated Solid By-Products during Advanced Electrode Materials Processing.

    Science.gov (United States)

    Tsai, Candace S J; Dysart, Arthur D; Beltz, Jay H; Pol, Vilas G

    2016-03-01

    A scalable, solid-state elevated-temperature process was developed to produce high-capacity carbonaceous electrode materials for energy storage devices via decomposition of a starch-based precursor in an inert atmosphere. In a separate study, it is shown that the fabricated carbonaceous architectures are useful as an excellent electrode material for lithium-ion, sodium-ion, and lithium-sulfur batteries. This article focuses on the study and analysis of the formed nanometer-sized by-products during the lab-scale synthesis of the carbon material. The material production process was studied in operando (that is, during the entire duration of heat treatment). The unknown downstream particles in the process exhaust were collected and characterized via aerosol and liquid suspensions, and they were quantified using direct-reading instruments for number and mass concentrations. The airborne emissions were collected using the Tsai diffusion sampler (TDS) for characterization and further analysis. Released by-product aerosols collected in a deionized (DI) water trap were analyzed, and the aerosols emitted from the post-water-suspension were collected and characterized. After long-term sampling, individual particles in the nanometer size range were observed in the exhaust aerosol with layer-structured aggregates formed on the sampling substrate. Upon the characterization of the released aerosol by-products, methods were identified to mitigate possible human and environmental exposures upon industrial implementation.

  19. Electroanalysis of some common pesticides using conducting polymer/multiwalled carbon nanotubes modified glassy carbon electrode.

    Science.gov (United States)

    Manisankar, P; Sundari, Pl Abirama; Sasikumar, R; Palaniappan, Sp

    2008-09-15

    The cyclic voltammetric behaviour of three common pesticides such as isoproturon (ISO), voltage (VOL) and dicofol (DCF) was investigated at glassy carbon electrode (GCE), multiwalled carbon nanotubes modified GCE (MWCNTs/GCE), polyaniline (PANI) and polypyrrole (PPY) deposited MWCNT/GCE. The modified electrode film was characterized by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). The electroactive behaviour of the pesticides was realized from the cyclic voltammetric studies. The differential pulse voltammetric principle was used to analyze the above-mentioned pesticides using MWCNT/GCE, PANI/MWCNT/GCE and PPY/MWCNT/GCE. Effects of accumulation potential, accumulation time, Initial scan potential, amplitude and pulse width were examined for the optimization of stripping conditions. The PANI/MWCNT/GCE performed well among the three electrode systems and the determination range obtained was 0.01-100 mgL(-1) for ISO, VOL and DCF respectively. The limit of detection (LOD) was 0.1 microgL(-1) for ISO, 0.01 microgL(-1) for VOL and 0.05 microgL(-1) for DCF on PANI/MWCNT/GCE modified system. It is significant to note that the PANI/MWCNT/GCE modified system results in the lowest LOD in comparison with the earlier reports. Suitability of this method for the trace determination of pesticide in spiked samples was also realized.

  20. A highly permeable and enhanced surface area carbon-cloth electrode for vanadium redox flow batteries

    Science.gov (United States)

    Zhou, X. L.; Zhao, T. S.; Zeng, Y. K.; An, L.; Wei, L.

    2016-10-01

    In this work, a high-performance porous electrode, made of KOH-activated carbon-cloth, is developed for vanadium redox flow batteries (VRFBs). The macro-scale porous structure in the carbon cloth formed by weaving the carbon fibers in an ordered manner offers a low tortuosity (∼1.1) and a broad pore distribution from 5 μm to 100 μm, rendering the electrode a high hydraulic permeability and high effective ionic conductivity, which are beneficial for the electrolyte flow and ion transport through the porous electrode. The use of KOH activation method to create nano-scale pores on the carbon-fiber surfaces leads to a significant increase in the surface area for redox reactions from 2.39 m2 g-1 to 15.4 m2 g-1. The battery assembled with the present electrode delivers an energy efficiency of 80.1% and an electrolyte utilization of 74.6% at a current density of 400 mA cm-2, as opposed to an electrolyte utilization of 61.1% achieved by using a conventional carbon-paper electrode. Such a high performance is mainly attributed to the combination of the excellent mass/ion transport properties and the high surface area rendered by the present electrode. It is suggested that the KOH-activated carbon-cloth electrode is a promising candidate in redox flow batteries.

  1. Development of electrochemical oxidase biosensors based on carbon nanotube-modified carbon film electrodes for glucose and ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Gouveia-Caridade, Carla; Pauliukaite, Rasa; Brett, Christopher M.A. [Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra (Portugal)

    2008-10-01

    Functionalised multi-walled carbon nanotubes (MWCNTs) were cast on glassy carbon (GC) and carbon film electrodes (CFE), and were characterised electrochemically and applied in a glucose-oxidase-based biosensor. MWCNT-modified carbon film electrodes were then used to develop an alcohol oxidase (AlcOx) biosensor, in which AlcOx-BSA was cross-linked with glutaraldehyde and attached by drop-coating. The experimental conditions, applied potential and pH, for ethanol monitoring were optimised, and ethanol was determined amperometrically at -0.3 V vs. SCE at pH 7.5. Electrocatalytic effects of MWCNT were observed with respect to unmodified carbon film electrodes. The sensitivity obtained was 20 times higher at carbon film/MWCNT-based biosensors than without MWCNT. (author)

  2. Electrochemical behaviors of a wearable woven textile Li-ion battery consisting of a core and wound electrode fibers coated with active materials

    Science.gov (United States)

    Kim, C.; Bang, S.; Zhou, D.; Yun, S.

    2017-04-01

    A new fiber-type Li-ion battery that consists of carbon nanotube fibers deposited with active materials has been developed and tested. The active materials, LiMn2O4 and Li4Ti5O12, were deposited on the surface of carbon nanotube fibers in order to use as electrodes. Tensile strength of the CNT fibers with active material was measured by tensile tests to investigate the mechanical characteristics. Electrochemical property is also measured by a battery tester during charging and discharging. The results show that current discharge capacity is about 25 mAh/g between 3.0 V and 4.2 V. That means the fiber with active materials is good for an anode electrode. Mathematical material models considering the lithium concentration and the length of Li-C bond have been established in order to predict the effective elastic modulus of electrode composite materials.

  3. Facile preparation of poly(methylene blue) modified carbon paste electrode for the detection and quantification of catechin.

    Science.gov (United States)

    Manasa, G; Mascarenhas, Ronald J; Satpati, Ashis K; D'Souza, Ozma J; Dhason, A

    2017-04-01

    Free radicals are formed as byproducts of metabolism, and are highly unstable due to the presence of unpaired electrons. They readily react with other important cellular components such as DNA causing them damage. Antioxidants such as (+)-catechin (CAT), neutralize free radicals in the blood stream. Hence there is a need for detection and quantification of catechin concentration in various food sources and beverages. Electro-oxidative properties of catechin were investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). A carbon paste working electrode modified by electropolymerizing methylene blue (MB) was fabricated. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) techniques were used to study the surface morphology of the electrode. Quasi-reversible electron transfer reaction occurred at +0.260V through a diffusion controlled process. In comparison to the bare carbon paste electrode (CPE), there was a significant 5.3 times increment in anodic current sensitivity at the modified electrode at physiological pH. Our findings indicate that for the electro-oxidation of CAT, CPE is a better base material for electropolymerization of MB compared to glassy carbon electrode (GCE). Nyquist plot followed the theoretical shape, indicating low interfacial charge transfer resistance of 0.095kΩ at the modified electrode. Calibration plots obtained by DPV were linear in two ranges of 1.0×10(-3) to 1.0×10(-6) and 1.0×10(-7) to 0.1×10(-8)M. The limit of detection (LOD) and limit of quantification (LOQ) was 4.9nM and 14nM respectively. Application of the developed electrode was demonstrated by detecting catechin in green tea and spiked fruit juice with satisfactory recoveries. The sensor was stable, sensitive, selective and reproducible. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Ultra low Pt-loading electrode prepared by displacement of electrodeposited Cu particles on a porous carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liao, M.J. [The State Key Laboratory of Power Transmission Equipment and System Security and New Technology, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Wei, Z.D.; Li, L. [The State Key Laboratory of Power Transmission Equipment and System Security and New Technology, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); School of Material Science and Engineering, Chongqing University, Chongqing 400044 (China); Chen, S.G.; Ji, M.B.; Wang, Y.Q. [School of Material Science and Engineering, Chongqing University, Chongqing 400044 (China)

    2010-08-15

    Ultra low Pt-loading and high Pt utilization electrodes were prepared by displacement of electrodeposited Cu on a porous carbon electrode. Copper particles were electrodeposited on a porous carbon electrode (PCE) by four-step deposition (FSD) at first. The size and dispersion of deposited Cu particles were markedly improved with application of the FSD. The Cu deposits were then displaced by platinum as dipping a Cu/PCE in a platinum salt solution. Sequentially, Pt particles supported on the PCE were obtained. The Pt/PCE electrode prepared via the FSD of Cu overcomes the problem of the hydrogen evolution reaction accompanied with direct platinum electrochemical deposition, and has a high Pt dispersion. The single cell consisting of the electrodes Pt/PCE via the FSD of Cu outputs a power of 0.45 W cm{sup -2} with ultra low Pt loadings of 0.196 mg cm{sup -2} MEA (0.098 mg cm{sup -2} per each side of the MEA) at no backpressure of reactant gases. (author)

  5. Lignin-Derived Advanced Carbon Materials.

    Science.gov (United States)

    Chatterjee, Sabornie; Saito, Tomonori

    2015-12-07

    Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. By applying specific pretreatments and manufacturing methods, lignin can be converted into a variety of value-added carbon materials. However, the physical and chemical heterogeneities of lignin complicate its use as a feedstock. Herein lignin manufacturing process, the effects of pretreatments and manufacturing methods on the properties of product lignin, and structure-property relationships in various applications of lignin-derived carbon materials, such as carbon fibers, carbon mats, activated carbons, carbon films, and templated carbon, are discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Nanostructured membranes and electrodes with sulfonic acid functionalized carbon nanotubes

    KAUST Repository

    Tripathi, Bijay Prakash

    2011-02-01

    Herein we report the covalent functionalization of multiwall carbon nanotubes by grafting sulfanilic acid and their dispersion into sulfonated poly(ether ether ketone). The nanocomposites were explored as an option for tuning the proton and electron conductivity, swelling, water and alcohol permeability aiming at nanostructured membranes and electrodes for application in alcohol or hydrogen fuel cells and other electrochemical devices. The nanocomposites were extensively characterized, by studying their physicochemical and electrochemical properties. They were processed as self-supporting films with high mechanical stability, proton conductivity of 4.47 × 10 -2 S cm-1 at 30 °C and 16.8 × 10-2 S cm-1 at 80 °C and 100% humidity level, electron conductivity much higher than for the plain polymer. The methanol permeability could be reduced to 1/20, keeping water permeability at reasonable values. The ratio of bound water also increases with increasing content of sulfonated filler, helping in keeping water in the polymer in conditions of low external humidity level. © 2010 Elsevier B.V.

  7. Resistive random access memory enabled by carbon nanotube crossbar electrodes.

    Science.gov (United States)

    Tsai, Cheng-Lin; Xiong, Feng; Pop, Eric; Shim, Moonsub

    2013-06-25

    We use single-walled carbon nanotube (CNT) crossbar electrodes to probe sub-5 nm memory domains of thin AlOx films. Both metallic and semiconducting CNTs effectively switch AlOx bits between memory states with high and low resistance. The low-resistance state scales linearly with CNT series resistance down to ∼10 MΩ, at which point the ON-state resistance of the AlOx filament becomes the limiting factor. Dependence of switching behavior on the number of cross-points suggests a single channel to dominate the overall characteristics in multi-crossbar devices. We demonstrate ON/OFF ratios up to 5 × 10(5) and programming currents of 1 to 100 nA with few-volt set/reset voltages. Remarkably low reset currents enable a switching power of 10-100 nW and estimated switching energy as low as 0.1-10 fJ per bit. These results are essential for understanding the ultimate scaling limits of resistive random access memory at single-nanometer bit dimensions.

  8. Nanostructured membranes and electrodes with sulfonic acid functionalized carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, Bijay P. [Electro-Membrane Processes Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G.B. Marg, Bhavnagar 364002, Gujarat (India); Department of Membranes for Sustainable Energy, GKSS Research Centre Geesthacht GmbH, Max Planck Str. 1, D-21502 Geesthacht (Germany); Schieda, M. [Department of Membranes for Sustainable Energy, GKSS Research Centre Geesthacht GmbH, Max Planck Str. 1, D-21502 Geesthacht (Germany); Shahi, Vinod K. [Electro-Membrane Processes Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G.B. Marg, Bhavnagar 364002, Gujarat (India); Nunes, Suzana P. [King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia)

    2011-02-01

    Herein we report the covalent functionalization of multiwall carbon nanotubes by grafting sulfanilic acid and their dispersion into sulfonated poly(ether ether ketone). The nanocomposites were explored as an option for tuning the proton and electron conductivity, swelling, water and alcohol permeability aiming at nanostructured membranes and electrodes for application in alcohol or hydrogen fuel cells and other electrochemical devices. The nanocomposites were extensively characterized, by studying their physicochemical and electrochemical properties. They were processed as self-supporting films with high mechanical stability, proton conductivity of 4.47 x 10{sup -2} S cm{sup -1} at 30 C and 16.8 x 10{sup -2} S cm{sup -1} at 80 C and 100% humidity level, electron conductivity much higher than for the plain polymer. The methanol permeability could be reduced to 1/20, keeping water permeability at reasonable values. The ratio of bound water also increases with increasing content of sulfonated filler, helping in keeping water in the polymer in conditions of low external humidity level. (author)

  9. Nanostructured membranes and electrodes with sulfonic acid functionalized carbon nanotubes

    Science.gov (United States)

    Tripathi, Bijay P.; Schieda, M.; Shahi, Vinod K.; Nunes, Suzana P.

    Herein we report the covalent functionalization of multiwall carbon nanotubes by grafting sulfanilic acid and their dispersion into sulfonated poly(ether ether ketone). The nanocomposites were explored as an option for tuning the proton and electron conductivity, swelling, water and alcohol permeability aiming at nanostructured membranes and electrodes for application in alcohol or hydrogen fuel cells and other electrochemical devices. The nanocomposites were extensively characterized, by studying their physicochemical and electrochemical properties. They were processed as self-supporting films with high mechanical stability, proton conductivity of 4.47 × 10 -2 S cm -1 at 30 °C and 16.8 × 10 -2 S cm -1 at 80 °C and 100% humidity level, electron conductivity much higher than for the plain polymer. The methanol permeability could be reduced to 1/20, keeping water permeability at reasonable values. The ratio of bound water also increases with increasing content of sulfonated filler, helping in keeping water in the polymer in conditions of low external humidity level.

  10. Metal-electrode-free Window-like Organic Solar Cells with p-Doped Carbon Nanotube Thin-film Electrodes.

    Science.gov (United States)

    Jeon, Il; Delacou, Clement; Kaskela, Antti; Kauppinen, Esko I; Maruyama, Shigeo; Matsuo, Yutaka

    2016-08-16

    Organic solar cells are flexible and inexpensive, and expected to have a wide range of applications. Many transparent organic solar cells have been reported and their success hinges on full transparency and high power conversion efficiency. Recently, carbon nanotubes and graphene, which meet these criteria, have been used in transparent conductive electrodes. However, their use in top electrodes has been limited by mechanical difficulties in fabrication and doping. Here, expensive metal top electrodes were replaced with high-performance, easy-to-transfer, aerosol-synthesized carbon nanotubes to produce transparent organic solar cells. The carbon nanotubes were p-doped by two new methods: HNO3 doping via 'sandwich transfer', and MoOx thermal doping via 'bridge transfer'. Although both of the doping methods improved the performance of the carbon nanotubes and the photovoltaic performance of devices, sandwich transfer, which gave a 4.1% power conversion efficiency, was slightly more effective than bridge transfer, which produced a power conversion efficiency of 3.4%. Applying a thinner carbon nanotube film with 90% transparency decreased the efficiency to 3.7%, which was still high. Overall, the transparent solar cells had an efficiency of around 50% that of non-transparent metal-based solar cells (7.8%).

  11. Metal-electrode-free Window-like Organic Solar Cells with p-Doped Carbon Nanotube Thin-film Electrodes

    Science.gov (United States)

    Jeon, Il; Delacou, Clement; Kaskela, Antti; Kauppinen, Esko I.; Maruyama, Shigeo; Matsuo, Yutaka

    2016-08-01

    Organic solar cells are flexible and inexpensive, and expected to have a wide range of applications. Many transparent organic solar cells have been reported and their success hinges on full transparency and high power conversion efficiency. Recently, carbon nanotubes and graphene, which meet these criteria, have been used in transparent conductive electrodes. However, their use in top electrodes has been limited by mechanical difficulties in fabrication and doping. Here, expensive metal top electrodes were replaced with high-performance, easy-to-transfer, aerosol-synthesized carbon nanotubes to produce transparent organic solar cells. The carbon nanotubes were p-doped by two new methods: HNO3 doping via ‘sandwich transfer’, and MoOx thermal doping via ‘bridge transfer’. Although both of the doping methods improved the performance of the carbon nanotubes and the photovoltaic performance of devices, sandwich transfer, which gave a 4.1% power conversion efficiency, was slightly more effective than bridge transfer, which produced a power conversion efficiency of 3.4%. Applying a thinner carbon nanotube film with 90% transparency decreased the efficiency to 3.7%, which was still high. Overall, the transparent solar cells had an efficiency of around 50% that of non-transparent metal-based solar cells (7.8%).

  12. Dry-Deposited Transparent Carbon Nanotube Film as Front Electrode in Colloidal Quantum Dot Solar Cells.

    Science.gov (United States)

    Zhang, Xiaoliang; Aitola, Kerttu; Hägglund, Carl; Kaskela, Antti; Johansson, Malin B; Sveinbjörnsson, Kári; Kauppinen, Esko I; Johansson, Erik M J

    2017-01-20

    Single-walled carbon nanotubes (SWCNTs) show great potential as an alternative material for front electrodes in photovoltaic applications, especially for flexible devices. In this work, a press-transferred transparent SWCNT film was utilized as front electrode for colloidal quantum dot solar cells (CQDSCs). The solar cells were fabricated on both glass and flexible substrates, and maximum power conversion efficiencies of 5.5 and 5.6 %, respectively, were achieved, which corresponds to 90 and 92 % of an indium-doped tin oxide (ITO)-based device (6.1 %). The SWCNTs are therefore a very good alternative to the ITO-based electrodes especially for flexible solar cells. The optical electric field distribution and optical losses within the devices were simulated theoretically and the results agree with the experimental results. With the optical simulations that were performed it may also be possible to enhance the photovoltaic performance of SWCNT-based solar cells even further by optimizing the device configuration or by using additional optical active layers, thus reducing light reflection of the device and increasing light absorption in the quantum dot layer.

  13. Nanoporous Carbide-Derived Carbon Material-Based Linear Actuators

    Directory of Open Access Journals (Sweden)

    Janno Torop

    2009-12-01

    Full Text Available Devices using electroactive polymer-supported carbon material can be exploited as alternatives to conventional electromechanical actuators in applications where electromechanical actuators have some serious deficiencies. One of the numerous examples is precise microactuators. In this paper, we show for first time the dilatometric effect in nanocomposite material actuators containing carbide-derived carbon (CDC and polytetrafluoroetylene polymer (PTFE. Transducers based on high surface area carbide-derived carbon electrode materials are suitable for short range displacement applications, because of the proportional actuation response to the charge inserted, and high Coulombic efficiency due to the EDL capacitance. The material is capable of developing stresses in the range of tens of N cm-2. The area of an actuator can be dozens of cm2, which means that forces above 100 N are achievable. The actuation mechanism is based on the interactions between the high-surface carbon and the ions of the electrolyte. Electrochemical evaluations of the four different actuators with linear (longitudinal action response are described. The actuator electrodes were made from two types of nanoporous TiC-derived carbons with surface area (SA of 1150 m2 g-1 and 1470 m2 g-1, respectively. Two kinds of electrolytes were used in actuators: 1.0 M tetraethylammonium tetrafluoroborate (TEABF4 solution in propylene carbonate and pure ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf. It was found that CDC based actuators exhibit a linear movement of about 1% in the voltage range of 0.8 V to 3.0 V at DC. The actuators with EMITf electrolyte had about 70% larger movement compared to the specimen with TEABF4 electrolyte.

  14. Graphene-based materials for supercapacitor electrodes – A review

    Directory of Open Access Journals (Sweden)

    Qingqing Ke

    2016-03-01

    Full Text Available The graphene-based materials are promising for applications in supercapacitors and other energy storage devices due to the intriguing properties, i.e., highly tunable surface area, outstanding electrical conductivity, good chemical stability and excellent mechanical behavior. This review summarizes recent development on graphene-based materials for supercapacitor electrodes, based on their macrostructural complexity, i.e., zero-dimensional (0D (e.g. free-standing graphene dots and particles, one-dimensional (1D (e.g. fiber-type and yarn-type structures, two-dimensional (2D (e.g. graphenes and graphene-based nanocomposite films, and three-dimensional (3D (e.g. graphene foam and hydrogel-based nanocomposites. There are extensive and on-going researches on the rationalization of their structures at varying scales and dimensions, development of effective and low cost synthesis techniques, design and architecturing of graphene-based materials, as well as clarification of their electrochemical performance. It is indicated that future studies should focus on the overall device performance in energy storage devices and large-scale process in low costs for the promising applications in portable and wearable electronic, transport, electrical and hybrid vehicles.

  15. Electrochemical Impedance Characterization of Nafion-Coated Carbon Film Resistor Electrodes for Electroanalysis

    OpenAIRE

    Gouveia-Caridade, Carla; Brett, Christopher M. A.

    2005-01-01

    Carbon film disk electrodes with Nafion coatings have been characterized by electrochemical impedance spectroscopy (EIS) with a view to a better understanding of their advantages and limitations in electroanalysis, particularly in anodic stripping voltammetry of metal ions. After initial examination by cyclic voltammetry, spectra were recorded over the full potential range in acetate buffer solution at the bare electrodes, electrodes electrochemically pretreated in acid solution, and Nafion-c...

  16. Anthocyanin-sensitized solar cells using carbon nanotube films as counter electrodes

    Science.gov (United States)

    Zhu, Hongwei; Zeng, Haifeng; Subramanian, Venkatachalam; Masarapu, Charan; Hung, Kai-Hsuan; Wei, Bingqing

    2008-11-01

    Carbon nanotube (CNT) films have been used as counter electrodes in natural dye-sensitized (anthocyanin-sensitized) solar cells to improve the cell performance. Compared with conventional cells using natural dye electrolytes and platinum as the counter electrodes, cells with a single-walled nanotube (SWNT) film counter electrode show comparable conversion efficiency, which is attributed to the increase in short circuit current density due to the high conductivity of the SWNT film.

  17. Electrocatalytic Study of Paracetamol at a Single-Walled Carbon Nanotube/Nickel Nanocomposite Modified Glassy Carbon Electrode

    OpenAIRE

    Koh Sing Ngai; Wee Tee Tan; Zulkarnain Zainal; Ruzniza Mohd Zawawi; Joon Ching Juan

    2015-01-01

    A rapid, simple, and sensitive method for the electrochemical determination of paracetamol was developed. A single-walled carbon nanotube/nickel (SWCNT/Ni) nanocomposite was prepared and immobilized on a glassy carbon electrode (GCE) surface via mechanical attachment. This paper reports the voltammetry study on the effect of paracetamol concentration, scan rate, pH, and temperature at a SWCNT/Ni-modified electrode in the determination of paracetamol. The characterization of the SWCNT/Ni/GCE w...

  18. Preparation and characterization of platinum/carbon and ruthenium/platinum/carbon nanocatalyst using the novel rotating disk-slurry electrode (RoDSE) technique

    Science.gov (United States)

    Santiago de Jesus, Diana

    An effort to develop electrochemically smaller and well-dispersed catalytic material on a high surface area carbon material is required for fuel cell applications. In terms of pure metal catalysts, platinum has shown to be the most common catalyst used in fuel cells, but suffers from poisoning when carbon monoxide is strongly adsorbed on its surface when used for direct methanol fuel cell applications. The addition of a metal with the ability to form oxides, such as ruthenium, helps to oxidize the carbon monoxide, freeing the platinum surface for new methanol oxidation. The deposition of catalysts of PtRu onto a carbon support helps to increase the active surface area of the catalyst. Vulcan X is the most commonly used of the amorphous carbon materials for fuel cell applications. Also, a high-surface-area carbon material of interest is carbon nano-onions (CNOs), also known as multilayer fullerenes. The most convenient synthetic method for CNOs is annealing nanodiamond particles, thus retaining the size of the precursors and providing the possibility to prepare very small nanocatalysts using electrochemical techniques. A rotating disk-slurry electrode (RoDSE) technique was developed as a unique method to electrochemically prepare bulk Pt/Carbon and PtRu/Carbon nanocatalysts avoiding a constant contact of the carbon support to an electrode surface during the electrodeposition process. The nanocatalysts were prepared by using a slurry that was saturated with functionalized Vulcan XC-72R and the metal precursor in sulfuric acid. The electrochemically prepared Pt/C and PtRu/C catalysts were characterized by using TEM, STEM, XRD, XRF, TGA, XPS and electrochemical techniques. A computational analysis also was done.

  19. Electrolytic aminated carbon materials for the electrocatalytic redox reactions of inorganic and organic compounds.

    Science.gov (United States)

    Hayashida, Eriko; Takahashi, Yuichi; Nishi, Hideki; Uchiyama, Shunichi

    2011-06-01

    Some kinds of amine groups can be introduced to the glassy carbon surface by the electrode oxidation of the carbon electrode surface in ammonium carbamate solution, and this amine groups modified electrode is named as an aminated glassy carbon electrode. The existences of not only primary amine but also secondary and tertially amines were confirmed by X ray photoelectron spectroscopy. The applications of the aminated carbon material for the electrocatalytic reductions of oxygen, hydrogen peroxide, and organic compounds such as quinones were carried out, and the effects of amination on the formation of electrocatalytic sites for many species were revealed. The electrocatalyzed cyclic voltammograms of metal ions and metal chelate compounds obtained by aminated glassy carbon electrodes are also discussed. Moreover, we intend to describe that the aminated carbon electrode can exhibit the large reduction waves of inorganic oxoacids such as N02- or bromide ion. The introduced functional groups containing nitrogen atom can change the distribution of the electron densities of the graphite carbon surface, and this specific electron distribution environment may generate the various electrocatalytic activities. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  20. Carbon nanotube modification of microbial fuel cell electrodes.

    Science.gov (United States)

    Yazdi, Alireza Ahmadian; D'Angelo, Lorenzo; Omer, Nada; Windiasti, Gracia; Lu, Xiaonan; Xu, Jie

    2016-11-15

    The use of carbon nanotubes (CNTs) for energy harvesting devices is preferable due to their unique mechanical, thermal, and electrical properties. On the other hand, microbial fuel cells (MFCs) are promising devices to recover carbon-neutral energy from the organic matters, and have been hindered with major setbacks towards commercialization. Nanoengineered CNT-based materials show remarkable electrochemical properties, and therefore have provided routes towards highly effective modification of MFC compartments to ultimately reach the theoretical limits of biomass energy recovery, low-cost power production, and thus the commercialization of MFCs. Moreover, these CNT-based composites offer significant flexibility in the design of MFCs that enable their use for a broad spectrum of applications ranging from scaled-up power generation to medically related devices. This article reviews the recent advances in the modification of MFCs using CNTs and CNT-based composites, and the extent to which each modification route impacts MFC power and current generation.

  1. Freestanding hierarchically porous carbon framework decorated by polyaniline as binder-free electrodes for high performance supercapacitors

    Science.gov (United States)

    Miao, Fujun; Shao, Changlu; Li, Xinghua; Wang, Kexin; Lu, Na; Liu, Yichun

    2016-10-01

    Freestanding hierarchically porous carbon electrode materials with favorable features of large surface areas, hierarchical porosity and continuous conducting pathways are very attractive for practical applications in electrochemical devices. Herein, three-dimensional freestanding hierarchically porous carbon (HPC) materials have been fabricated successfully mainly by the facile phase separation method. In order to further improve the energy storage ability, polyaniline (PANI) with high pseudocapacitance has been decorated on HPC through in situ chemical polymerization of aniline monomers. Benefiting from the synergistic effects between HPC and PANI, the resulting HPC/PANI composites as electrode materials present dramatic electrochemical performance with high specific capacitance up to 290 F g-1 at 0.5 A g-1 and good rate capability with ∼86% (248 F g-1) capacitance retention at 64 A g-1 of initial capacitance in three-electrode configuration. Moreover, the as-assembled symmetric supercapacitor based on HPC/PANI composites also demonstrates good capacitive properties with high energy density of 9.6 Wh kg-1 at 223 W kg-1 and long-term cycling stability with 78% capacitance retention after 10 000 cycles. Therefore, this work provides a new approach for designing high-performance electrodes with exceptional electrochemical performance, which are very promising for practical application in the energy storage field.

  2. Arsenic removal from groundwater using low-cost carbon composite electrodes for capacitive deionization.

    Science.gov (United States)

    Lee, Ju-Young; Chaimongkalayon, Nantanee; Lim, Jinho; Ha, Heung Yong; Moon, Seung-Hyeon

    2016-01-01

    Affordable carbon composite electrodes were developed to treat low-concentrated groundwater using capacitive deionization (CDI). A carbon slurry prepared using activated carbon powder (ACP), poly(vinylidene fluoride), and N-methyl-2-pyrrolidone was employed as a casting solution to soak in a low-cost porous substrate. The surface morphology of the carbon composite electrodes was investigated using a video microscope and scanning electron microscopy. The capacitance and electrical conductivity of the carbon composite electrodes were then examined using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively. According to the CV and EIS measurements, the capacitances and electrical conductivities of the carbon composite electrodes were in the range of 8.35-63.41 F g(-1) and 0.298-0.401 S cm(-1), respectively, depending on ACP contents. A CDI cell was assembled with the carbon composite electrodes instead of with electrodes and current collectors. The arsenate removal test included an investigation of the optimization of several important operating parameters, such as applied voltage and solution pH, and it achieved 98.8% removal efficiency using a 1 mg L(-1) arsenate solution at a voltage of 2 V and under a pH 9 condition.

  3. Electrochemical detection of nitrite based on the polythionine/carbon nanotube modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Chunyan, E-mail: dengchunyan@csu.edu.cn [College of Chemistry and Chemical Engineering, Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha 410083 (China); College of Pharmaceutical Science, Central South University, Changsha 410083 (China); Chen, Jinzhuo [College of Chemistry and Chemical Engineering, Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha 410083 (China); Nie, Zhou [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Yang, Minghui, E-mail: yangminghui@csu.edu.cn [College of Chemistry and Chemical Engineering, Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha 410083 (China); Si, Shihui [College of Chemistry and Chemical Engineering, Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha 410083 (China)

    2012-09-30

    In this paper, thionine was electro-polymerized onto the surface of carbon nanotube (CNT)-modified glassy carbon (GC) to fabricate the polythionine (PTH)/CNT/GC electrode. It was found that the electro-reduction current of nitrite was enhanced greatly at the PTH/CNT/GC electrode. It may be demonstrated that PTH was used as a mediator for electrocatalytic reduction of nitrite, and CNTs as an excellent nanomaterial can improve the electron transfer between the electrode and nitrite. Therefore, based on the synergic effect of PTH and CNTs, the PTH/CNT/GC electrode was employed to detect nitrite, and the high sensitivity of 5.81 {mu}A mM{sup -1}, and the detection limit of 1.4 Multiplication-Sign 10{sup -6} M were obtained. Besides, the modified electrode showed an inherent stability, fast response time, and good anti-interference ability. These suggested that the PTH/CNT/GC electrode was favorable and reliable for the detection of nitrite. - Highlights: Black-Right-Pointing-Pointer Polythionine (PTH) was used as a mediator for electrocatalytic reduction of nitrite. Black-Right-Pointing-Pointer Carbon nanotubes (CNTs) improve electron transfer between the electrode and nitrite. Black-Right-Pointing-Pointer The PTH/CNT/glassy carbon electrode showed excellent nitrite detection performance.

  4. IMPROVED SELECTIVE ELECTROCATALYTIC OXIDATION OF PHENOLS BY TYROSINASE-BASED CARBON PASTE ELECTRODE BIOSENSOR

    Science.gov (United States)

    Tyrosinase-based carbon paste electrodes are evaluated with respect to the viscosity and polarity of the binder liquids. The electrodes constructed using a lower viscosity mineral oil yielded a greater response to phenol and catechol than those using a higher viscosity oil of s...

  5. Spinel LiMn2O4 nanohybrid as high capacitance positive electrode material for supercapacitors

    Science.gov (United States)

    Wang, F. X.; Xiao, S. Y.; Zhu, Y. S.; Chang, Z.; Hu, C. L.; Wu, Y. P.; Holze, R.

    2014-01-01

    A LiMn2O4 nanohybrid consisting of nanotubes, nanorods and nanoparticles has been synthesized using α-MnO2 nanotubes from hydrothermal reaction as a precursor. It is characterized with X-ray diffraction, field emission scanning electron and transmission electron microscopy. A formation mechanism is proposed. As a positive electrode material for supercapacitors, it exhibits a high specific discharge capacitance of 415 F g-1 at 0.5 A g-1 in 0.5 mol l-1 Li2SO4 aqueous solution. Even at 10 A g-1, it still has a specific discharge capacitance of 208 F g-1. The energy density of the asymmetric supercapacitor using activated carbon as the negative electrode and LiMn2O4-nanohybrid as the positive electrode in the aqueous solution in the voltage range of 0-1.8 V presents 29.8 Wh kg-1 at power density of 90 W kg-1. In addition, the cycling behavior of the asymmetric supercapacitor is good.

  6. Ultrasonic modification of carbon materials for electrochemical capacitors

    Science.gov (United States)

    Rachiy, Bogdan I.; Nykoliuk, Marian O.; Budzulyak, Ivan M.; Kachmar, Andrii I.

    2017-01-01

    The paper is devoted to study the ultrasonic impact on the biomass of natural raw materials, which were used for the creation a nanoporous carbon material (NCM), which was used as electrode material for electrochemical capacitors (EC). The dry shells of apricot seeds were a feedstock, which were modified by the chemical treatment in the phosphoric acid and part of them were impacted by ultrasonic waves for 25 minutes. The NCM, which were obtained by carbonization at 550 °C, were modified by chemical treatment in the nitric acid. Thus, the different of modification NCM was obtained to compare their capacitance characteristics for EC. From experimental data we can do a conclusion, that ultrasonic modification and chemical treatment in nitric acidare improvecapacitance characteristics of NCM for EC.

  7. Electrochemical Investigation of Carbon as Additive to the Negative Electrode of Lead-Acid Battery

    Directory of Open Access Journals (Sweden)

    Fernandez Matthew M.

    2015-01-01

    Full Text Available The increasing demand of cycle life performance of Pb-acid batteries requires the improvement of the negative Pb electrode’s charge capacity. Electrochemical investigations were performed on Pb electrode and Pb+Carbon (Carbon black and Graphite electrodes to evaluate the ability of the additives to enhance the electrochemical faradaic reactions that occur during the cycle of Pb-acid battery negative electrode. The electrodes were characterized through Cyclic Voltammetry (CV, Potentiodynamic Polarization (PP, and Electrochemical Impedance Spectroscopy (EIS. CV revealed that the addition of carbon on the Pb electrode increased anodic and cathodicreactions by tenfold. The kinetics of PbSO4 passivation measured through PPrevealed that the addition of Carbon on the Pb electrode accelerated the oxide formation by tenfold magnitude. The Nyquist plot measured through EIS suggest that the electrochemical mechanism and reaction kinetics is under charge-transfer. From the equivalent circuit and physical model, Pb+CB1 electrode has the lowest EIS parameters while Pb+G has the highest which is attributed to faster faradaic reaction.The Nyquist plot of the passivated Pb+CB1 electrode showed double semicircular shape. The first layer represents to the bulk passive PbSO4 layer and the second layer represents the Carbon+PbSO4 layer. The enhancements upon addition of carbon on the Pb electrode were attributed to the additive’s electrical conductivity and total surface area. The electrochemical active sites for the PbSO4 to nucleate and spread increases upon addition of electrical conductive and high surface area carbon additives.

  8. Nanostructured core-shell electrode materials for electrochemical capacitors

    Science.gov (United States)

    Jiang, Long-bo; Yuan, Xing-zhong; Liang, Jie; Zhang, Jin; Wang, Hou; Zeng, Guang-ming

    2016-11-01

    Core-shell nanostructure represents a unique system for applications in electrochemical energy storage devices. Owing to the unique characteristics featuring high power delivery and long-term cycling stability, electrochemical capacitors (ECs) have emerged as one of the most attractive electrochemical storage systems since they can complement or even replace batteries in the energy storage field, especially when high power delivery or uptake is needed. This review aims to summarize recent progress on core-shell nanostructures for advanced supercapacitor applications in view of their hierarchical architecture which not only create the desired hierarchical porous channels, but also possess higher electrical conductivity and better structural mechanical stability. The core-shell nanostructures include carbon/carbon, carbon/metal oxide, carbon/conducting polymer, metal oxide/metal oxide, metal oxide/conducting polymer, conducting polymer/conducting polymer, and even more complex ternary core-shell nanoparticles. The preparation strategies, electrochemical performances, and structural stabilities of core-shell materials for ECs are summarized. The relationship between core-shell nanostructure and electrochemical performance is discussed in detail. In addition, the challenges and new trends in core-shell nanomaterials development have also been proposed.

  9. Integration of UV-cured Ionogel Electrolyte with Carbon Paper Electrodes

    Directory of Open Access Journals (Sweden)

    Stephanie Flores Zopf

    2014-02-01

    Full Text Available A test bed with a coplanar architecture is employed to investigate the integration of an in situ cross-linked, polymer-supported ionogel with several commercially available, high surface area carbon paper electrodes. Specifically, a UV-cured poly(ethylene glycol diacrylate (PEGDA-supported ionogel electrolyte film is formed in situ against a variety of porous electrodes comprising: a carbon fiber paper, a carbon aerogel paper, and four carbon nanotube-based papers. Electrochemical impedance spectroscopy measurements reveal that the relative performance of a particular carbon paper with the neat ionic liquid is not necessarily indicative of its behavior when integrated with the solid ionogel electrolyte. The coplanar test bed can therefore serve as a useful tool to help guide the selection of suitable carbon-based electrode structures for supercapacitors that incorporate UV-cured ionogels created in situ for wearable energy storage applications.

  10. The dependence of the electronic conductivity of carbon molecular sieve electrodes on their charging states.

    Science.gov (United States)

    Pollak, Elad; Genish, Isaschar; Salitra, Gregory; Soffer, Abraham; Klein, Lior; Aurbach, Doron

    2006-04-13

    The dependence of the electronic conductivity of activated carbon electrodes on their potential in electrolyte solutions was examined. Kapton polymer films underwent carbonization (1000 degrees C), followed by a mild oxidation process (CO(2) at 900 degrees C) for various periods of time, to obtain carbons of different pore structures. A specially designed cell was assembled in order to measure the conductivity of carbon electrodes at different potentials in solutions. When the carbon electrodes possessed molecular sieving properties, a remarkable dependence of their conductivity on their charging state was observed. Aqueous electrolyte solutions containing ions of different sizes were used in order to demonstrate this phenomenon. As the average pore size of the activated carbons was larger, their molecular sieving ability was lower, and the dependence of their conductivity on their charging state regained its classical form. This behavior is discussed herein.

  11. Platinum-polyaniline-modified carbon fiber electrode for the electrooxidation of methanol

    Institute of Scientific and Technical Information of China (English)

    WU Kezhong; MENG Xu; WANG Xindong; LI Jingling

    2005-01-01

    Platinum was electrodeposited onto a polyaniline-modified carbon fiber electrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in the level of platinum u tilization currently achieved in electrocatalyric systems. This electrode preparation consists of a two-step procedure: first electropolymerization of aniline onto carbon fiber and then electrodeposition of platinum. The catalytic activity of the platinum-polyaniline-modified carbon fiber electrode (Pt/PAni/C) was compared with that of a bare carbon fiber electrode (Pt/C) by the oxidation of methanol. The maximum oxidation current of methanol on Pt/PAni/C is 50.7 mA.cm-2, which is 6.7 times higher than 7.6 mA.cm-2 on the Pt/C.Scanning electron microscopy was used to investigate the dispersion of the platinum particles of about 0.4 μm.

  12. Electrocatalysis of chemically synthesized noble metal nanoparticles on carbon electrodes

    DEFF Research Database (Denmark)

    Zhang, Ling; Ulstrup, Jens; Zhang, Jingdong

    Noble metal nanoparticles (NPs), such as platinum (Pt) and palladium (Pd) NPs are promising catalysts for dioxygen reduction and oxidation of molecules such as formic acid and ethanol in fuel cells. Carbon nanomaterials are ideal supporting materials for electrochemical catalysts due to their good...... microscopy (AFM) which have proved to be highly efficient techniques to map the in situ structures of selfassembled molecular monolayers at molecular or sub-molecular resolution. Electrocatalysis of the Pd NPs immobilized on atomically flat, highly oriented pyrolytic graphite (HOPG) will be investigated...

  13. Gradation of mechanical properties in gas-diffusion electrode. Part 2: Heterogeneous carbon fiber and damage evolution in cell layers

    Science.gov (United States)

    Poornesh, K. K.; Cho, C. D.; Lee, G. B.; Tak, Y. S.

    In PEM fuel cell, gas-diffusion electrode (GDE) plays very significant role in force transmission from bipolar plate to the membrane. This paper investigates the effects of geometrical heterogeneities of gas-diffusion electrode layer (gas-diffusion layer (GDL) and catalyst layer (CL)) on mechanical damage evolution and propagation. We present a structural integrity principle of membrane electrode assembly (MEA) based on the interlayer stress transfer capacity and corresponding cell layer material response. Commonly observable damages such as rupture of hydrophobic coating and breakage of carbon fiber in gas-diffusion layer are attributed to the ductile to brittle phase transition within a single carbon fiber. Effect of material inhomogeneity on change in modulus, hardness, contact stiffness, and electrical contact resistance is also discussed. Fracture statistics of carbon fiber and variations in flexural strength of GDL are studied. The damage propagation in CL is perceived to be influenced by the type of gradation and the vicinity from which crack originates. Cohesive zone model has been proposed based on the traction-separation law to investigate the damage propagation throughout the two interfaces (carbon fiber/CL and CL/membrane).

  14. Ionic liquid modified carbon paste electrode and investigation of its electrocatalytic activity to hydrogen peroxide

    Indian Academy of Sciences (India)

    Erhan Canbay; Hayati Türkmen; Erol Akyilmaz

    2014-05-01

    This paper reports on the preparation and advantages of novel amperometric biosensors in the presence of hydrophobic ionic liquid (IL), 1-methyl-3-butylimidazolium bromide ([MBIB]). Carbon paste bio-sensor has been constructed by entrapping horseradish peroxidase in graphite and IL mixed with paraffin oil as a binder. The resulting IL/graphite material brings new capabilities for electrochemical devices by combining the advantages of ILs composite electrodes. Amounts of H2O2 were amperometrically detected by monitoring current values at reduction potential (–0.15 V) of K3Fe(CN)6. Decrease in biosensor responses were linearly related to H2O2 concentrations between 10 and 100 M with 2 s response time. Limit of detection of the biosensor were calculated to be 3.98 M for H2O2. In the optimization studies of the biosensor some parameters such as optimum pH, optimum temperature, enzyme amount, interference effects of some substances on the biosensor response, reproducibility and storage stability were carried out. The promising results are ascribed to the use of an ionic liquid, which forms an excellent charge-transfer bridge and wide electrochemical windows in the bulk of carbon paste electrode.

  15. Antipulverization Electrode Based on Low-Carbon Triple-Shelled Superstructures for Lithium-Ion Batteries.

    Science.gov (United States)

    Zu, Lianhai; Su, Qingmei; Zhu, Feng; Chen, Bingjie; Lu, Huanhuan; Peng, Chengxin; He, Ting; Du, Gaohui; He, Pengfei; Chen, Kai; Yang, Shihe; Yang, Jinhu; Peng, Huisheng

    2017-09-01

    The realization of antipulverization electrode structures, especially using low-carbon-content anode materials, is crucial for developing high-energy and long-life lithium-ion batteries (LIBs); however, this technology remains challenging. This study shows that SnO2 triple-shelled hollow superstructures (TSHSs) with a low carbon content (4.83%) constructed by layer-by-layer assembly of various nanostructure units can withstand a huge volume expansion of ≈231.8% and deliver a high reversible capacity of 1099 mAh g(-1) even after 1450 cycles. These values represent the best comprehensive performance in SnO2 -based anodes to date. Mechanics simulations and in situ transmission electron microscopy suggest that the TSHSs enable a self-synergistic structure-preservation behavior upon lithiation/delithiation, protecting the superstructures from collapse and guaranteeing the electrode structural integrity during long-term cycling. Specifically, the outer shells during lithiation processes are fully lithiated, preventing the overlithiation and the collapse of the inner shells; in turn, in delithiation processes, the underlithiated inner shells work as robust cores to support the huge volume contraction of the outer shells; meanwhile, the middle shells with abundant pores offer sufficient space to accommodate the volume change from the outer shell during both lithiation and delithiation. This study opens a new avenue in the development of high-performance LIBs for practical energy applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Gyroidal mesoporous carbon materials and methods thereof

    Energy Technology Data Exchange (ETDEWEB)

    Wiesner, Ulrich B.; Werner, Joerg G.

    2017-07-25

    The present invention relates to, inter alia, gyroidal mesoporous carbon materials and methods of use and manufacture thereof. In one embodiment, the present invention relates to a mesoporous carbon composition comprising a gyroidal mesoporous carbon having an ordered gyroidal structure and mesopores having a pore size of greater than 2 nanometers (nm) in diameter, and more particularly greater than 11 nm in diameter.

  17. Preparation of magnetic TNT-imprinted polymer nanoparticles and their accumulation onto magnetic carbon paste electrode for TNT determination.

    Science.gov (United States)

    Alizadeh, Taher

    2014-11-15

    In this study, the TNT-imprinted polymer shell was created on nano-sized Fe3O4 cores in order to construct the nano-sized magnetic molecularly imprinted polymer (nano-MMIP). For this purpose, the surface of the synthesized magnetic nanoparticles was modified with methacrylic acid. The modified particles were then utilized as the core on which the TNT-imprinted polymeric shell was synthesized. The synthesized materials were then characterized by scanning electron microscopy, FT-IR and thermal gravimetric analysis (TGA). The resulting nano-MMIP particles were suspended in TNT solution and then collected on the surface of a carbon paste electrode via a permanent magnet, situated within the CP electrode. The extracted TNT was analyzed on the CP electrode by applying square wave voltammetry (SWV). It was found that the oxidative signal of TNT is much favorable for TNT detection on the resulting magnetic carbon paste electrode. The electrode with nano-MMIP showed distinctly higher signal to TNT, compared to that containing magnetic non-imprinted polymer (MNIP) nanoparticles. All parameters influencing the method performance including extraction pH, extraction time and sorbent amount were evaluated and optimized. The developed method showed a dynamic linear concentration range of 1.0-130.0 nM for TNT measurement. The detection limit of the method was calculated to be 0.5 nM. The method showed appropriate capability for TNT analysis in real water samples.

  18. Effects of the transcutaneous electrode temperature on the accuracy of transcutaneous carbon dioxide tension

    DEFF Research Database (Denmark)

    Sørensen, Line C; Brage-Andersen, Lene; Greisen, Gorm

    2011-01-01

    The harmful effect of hypocapnia on the neonatal brain emphasizes the importance of monitoring arterial carbon dioxide tension (PaCO2). Transcutaneous monitoring of carbon dioxide (tcPCO2) reduces the need for arterial blood sampling. Drawbacks are high electrode temperature causing risks of skin...... burning. The aim was to determine the accuracy and precision of tcPCO2 at reduced electrode temperature....

  19. Cathodic stripping voltammetry of trace Mn(II) at carbon film electrodes

    OpenAIRE

    Filipe, Olga M. S.; Brett,Christopher M.A.

    2003-01-01

    A sensitive voltammetric method is presented for the determination of tract levels of Mn (II) using carbon film electrodes fabricated from carbon resistors of 2 [Omega]. Determination of manganese was made by square wave cathodic stripping voltammetry (CSV), with deposition of manganese as manganese dioxide. Chronoamperometric experiments were made to study MnO2 nucleation and growth. As a result, it was found to be necessary to perform electrode conditioning at a more positive potential to i...

  20. Potential electrode materials for symmetrical Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Ruiz Morales, J. C.

    2008-08-01

    Full Text Available Chromites, titanates and Pt-YSZ-CeO2 cermets have been investigated as potential electrode materials for an alternative concept of Solid Oxide Fuel Cell (SOFC, the symmetrical SOFCs (SFC. In this configuration, the same electrode material is used simultaneously as anode and cathode. Interconnector materials, such as chromites, could be considered as potential SFC electrodes, at least under pure hydrogen-fed at relatively high temperatures, as they do not exhibit significant catalytic activity towards hydrocarbon oxidation. This may be overcome by partially substituting Cr in the perovskite B-sites by other transition metal cations such as Mn. La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCM is a good candidate for such SFCs, rendering fuel cell performances in excess of 500 and 300mW/cm2 using pure H2 and CH4 as fuel, at 950 oC. Similarly, typical n-type electronic conductors traditionally regarded as anode materials, such as strontium titanates, may also operate under oxidising conditions as cathodes by substituting some Ti content for Fe to introduce p-type conductivity. Preliminary electrochemical experiments on La4Sr8Ti12-xFexO38-δ-based SFCs show that they perform reasonably well under humidified H2, at high temperatures. A third group of materials is the support material of any typical cermet anode, i.e. YSZ, CeO2 plus a current collector. It has been found that this combination could be optimised to operate as SFC electrodes, rendering performances of 400mW/cm2 under humidified pure H2 at 950oC.

    Cromitas, titanatos y cermets de Pt-YSZ-CeO2 han sido investigados como potenciales materiales de electrodo para un concepto alternativo de Pilas de Combustible de Óxidos Sólidos (SOFC, las pilas SOFC simétricas (SFC. En

  1. Electrochemical Reduction of Oxygen on Anthraquinone/Carbon Nanotubes Nanohybrid Modified Glassy Carbon Electrode in Neutral Medium

    Directory of Open Access Journals (Sweden)

    Zheng Gong

    2013-01-01

    Full Text Available The electrochemical behaviors of monohydroxy-anthraquinone/multiwall carbon nanotubes (MHAQ/MWCNTs nanohybrid modified glassy carbon (MHAQ/MWCNTs/GC electrodes in neutral medium were investigated; also reported was their application in the electrocatalysis of oxygen reduction reaction (ORR. The resulting MHAQ/MWCNTs nanohybrid was characterized by scanning electron microscope (SEM and transmission electron microscope (TEM. It was found that the ORR at the MHAQ/MWCNTs/GC electrode occurs irreversibly at a potential about 214 mV less negative than at a bare GC electrode in pH 7.0 buffer solution. Cyclic voltammetric and rotating disk electrode (RDE techniques indicated that the MHAQ/MWCNTs nanohybrid has high electrocatalytic activity for the two-electron reduction of oxygen in the studied potential range. The kinetic parameters of ORR at the MHAQ/MWCNTs nanohybrid modified GC electrode were also determined by RDE and EIS techniques.

  2. Voltammetric determination of theophylline at a Nafion/multi-wall carbon nanotubes composite film-modified glassy carbon electrode

    Indian Academy of Sciences (India)

    Suling Yang; Ran Yang; Gang Li; Jianjun Li; Lingbo Qu

    2010-11-01

    A Nafion/multi-wall carbon nanotubes (MWNTs) composite film-modified electrode was fabricated and applied to the sensitive and convenient determination of theophylline (TP). Multi-wall carbon nanotubes (MWNTs) were easily dispersed homogeneously into 0.1% Nafion methanol solution by sonication. Appropriate amount of Nafion/MWNTs suspension was coated on a glassy carbon electrode. After evaporating methanol, a Nafion/MWNTs composite film-modified electrode was achieved. TP could effectively accumulate at Nafion/MWNTs composite film-modified electrode and cause a sensitive anodic peak at around 1180 mV (vs SCE) in 0.01 mol/L H2SO4 medium (pH 1.8). In contrast with the bare glassy carbon electrode, Nafion film-modified electrode, Nafion/MWNTs film-modified electrode could remarkably increase the anodic peak current and decreased the overpotential of TP oxidation. Under the optimized conditions, the anodic peak current was proportional to TP concentration in the range of 8.0 × 10-8-6.0 × 10-5 mol/L, with a detection limit of 2.0 × 10-8 mol/L. This newly developed method was used to determine TP in drug samples with good percentage of recoveries.

  3. Fabrication of a three-electrode battery using hydrogen-storage materials

    Science.gov (United States)

    Roh, Chi-Woo; Seo, Jung-Yong; Moon, Hyung-Seok; Park, Hyun-Young; Nam, Na-Yun; Cho, Sung Min; Yoo, Pil J.; Chung, Chan-Hwa

    2015-04-01

    In this study, an energy storage device using a three-electrode battery is fabricated. The charging process takes place during electrolysis of the alkaline electrolyte where hydrogen is stored at the palladium bifunctional electrode. Upon discharging, power is generated by operating the alkaline fuel cell using hydrogen which is accumulated in the palladium hydride bifunctional electrode during the charging process. The bifunctional palladium electrode is prepared by electrodeposition using a hydrogen bubble template followed by a galvanic displacement reaction of platinum in order to functionalize the electrode to work not only as a hydrogen storage material but also as an anode in a fuel cell. This bifunctional electrode has a sufficiently high surface area and the platinum catalyst populates at the surface of electrode to operate the fuel cell. The charging and discharging performance of the three-electrode battery are characterized. In addition, the cycle stability is investigated.

  4. Determination of Zinc, Cadmium, Lead, Copper and Silver Using a Carbon Paste Electrode and a Screen Printed Electrode Modified with Chromium(III Oxide

    Directory of Open Access Journals (Sweden)

    Zuzana Koudelkova

    2017-08-01

    Full Text Available In this study, the preparation and electrochemical application of a chromium(III oxide modified carbon paste electrode (Cr-CPE and a screen printed electrode (SPE, made from the same material and optimized for the simple, cheap and sensitive simultaneous determination of zinc, cadmium, lead, copper and the detection of silver ions, is described. The limits of detection and quantification were 25 and 80 µg·L−1 for Zn(II, 3 and 10 µg·L−1 for Cd(II, 3 and 10 µg·L−1 for Pb(II, 3 and 10 µg·L−1 for Cu(II, and 3 and 10 µg·L−1 for Ag(I, respectively. Furthermore, this promising modification was transferred to the screen-printed electrode. The limits of detection for the simultaneous determination of zinc, cadmium, copper and lead on the screen printed electrodes were found to be 350 µg·L−1 for Zn(II, 25 µg·L−1 for Cd(II, 3 µg·L−1 for Pb(II and 3 µg·L−1 for Cu(II. Practical usability for the simultaneous detection of these heavy metal ions by the Cr-CPE was also demonstrated in the analyses of wastewaters.

  5. Carbon nanohorns-coated microfibers for use as free-standing electrodes for electrochemical power sources

    Energy Technology Data Exchange (ETDEWEB)

    Aissa, Brahim; Hamoudi, Zehira; Mohamedi, Mohamed; Khakani, My Ali El [Institut National de Recherche Scientifique, Energie, Materiaux et Telecommunications, 1650 Blvd. Lionel Boulet, Varennes, Quebec (Canada); Takahashi, Hiro; Tohji, Kazuyuki [Department of Environmental Studies, Graduate School of Environmental Studies, Tohoku University, Aza-aoba 6-6-11, Aramaki, Aoba-ku, Sendai 9808579 (Japan)

    2009-04-15

    We report the first direct laser based synthesis of carbon nanohorns onto carbon microfibrous, for the straightforward fabrication, of free-standing (binderless) electrodes. These carbon nanohorns have diameters as small as 2-4 nm and were found to cover uniformly the microfibrous substrates. The carbon nanohorns-based electrodes developed here are shown to open new prospects for the development of advanced electrochemical power sources. In particular, their possible applications in either lithium-ion batteries or supercapacitors or fuel cell technologies are demonstrated. (author)

  6. Nanostructured carbon electrodes for laccase-catalyzed oxygen reduction without added mediators

    Energy Technology Data Exchange (ETDEWEB)

    Stolarczyk, Krzysztof; Nazaruk, Ewa [Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland); Rogalski, Jerzy [Department of Biochemistry, Maria Curie Sklodowska University, Sklodowskiej Sq 3, Lublin 20-031 (Poland); Bilewicz, Renata [Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland)], E-mail: bilewicz@chem.uw.edu.pl

    2008-04-20

    Reduction of dioxygen catalyzed by laccase was studied at carbon electrodes without any added mediators. On bare glassy carbon electrode (GCE) the catalytic reduction did not take place. However, when the same substrate was decorated with carbon nanotubes or carbon microcrystals the dioxygen reduction started at 0.6 V versus Ag/AgCl, which is close to the formal potential of the laccase used. Four different matrices: lecithin, hydrophobin, Nafion and lipid liquid-crystalline cubic phase were employed for hosting fungal laccase from Cerrena unicolor. The carbon nanotubes and nanoparticles present on the electrode provided electrical connectivity between the electrode and the enzyme active sites. Direct electrochemistry of the enzyme itself was observed in deoxygenated solutions and its catalytic activity towards dioxygen reduction was demonstrated. The stabilities of the hosted enzymes, the reduction potentials and ratios of catalytic to background currents were compared. The boron-doped diamond (BDD) electrodes prepolarized to high anodic potentials exhibited behavior similar to that of nanotube covered GCE pointing to the formation of nanostructures during the anodic pretreatment. BDD is a promising substrate in terms of potential of dioxygen reduction, however the catalytic current densities are not large enough for practical applications, therefore as shown in this paper, it should be additionally decorated with carbon particles being in direct contact with the electrode surface.

  7. Study on electroactive and electrocatalytic surfaces of single walled carbon nanotube-modified electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Salinas-Torres, David [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain); Huerta, Francisco [Departamento de Ingenieria Textil y Papelera, Universidad Politecnica de Valencia, Plaza Ferrandiz y Carbonell, 1. E-03801 Alcoy (Spain); Montilla, Francisco, E-mail: francisco.montilla@ua.e [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain); Morallon, Emilia [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain)

    2011-02-01

    An investigation of the electrocatalysis of single-walled carbon nanotubes modified electrodes has been performed in this work. Nanotube-modified electrodes present a surface area much higher than the bare glassy carbon surfaces as determined by capacitance measurements. Several redox probes were selected for checking the reactivity of specific sites at the carbon nanotube surface. The presence of carbon nanotubes on the electrode improves the kinetics for all the reactions studied compared with the bare glassy carbon electrode with variations of the heterogeneous electron transfer rate constant up to 5 orders of magnitude. The most important effects are observed for the benzoquinone/hydroquinone and ferrocene/ferricinium redox couples, which show a remarkable improvement of their electron transfer kinetics on SWCNT-modified electrodes, probably due to strong {pi}-{pi} interaction between the organic molecules and the walls of the carbon nanotubes. For many of the reactions studied, less than 1% of the nanotube-modified electrode surface is transferring charge to species in solution. This result suggests that only nanotube tips are active sites for the electron transfer in such cases. On the contrary, the electroactive surface for the reactions of ferrocene and quinone is higher indicating that the electron transfer is produced also from the nanotube walls.

  8. Direct electrochemistry and electrochemical catalysis of myoglobin-TiO2 coated multiwalled carbon nanotubes modified electrode.

    Science.gov (United States)

    Zhang, Lei; Tian, Dan-Bi; Zhu, Jun-Jie

    2008-11-01

    TiO(2) nanoparticles were homogeneously coated on multiwalled carbon nanotubes (MWCNTs) by hydrothermal deposition, and this nanocomposite might be a promising material for myoglobin (Mb) immobilization in view of its high biocompatibility and large surface. The glassy carbon (GC) electrode modified with Mb-TiO(2)/MWCNTs films exhibited a pair of well-defined, stable and nearly reversible cycle voltammetric peaks. The formal potential of Mb in TiO(2)/MWCNTs film was linearly varied in the range of pH 3-10 with a slope of 48.65 mV/pH, indicating that the electron transfer was accompanied by single proton transportation. The electron transfer between Mb and electrode surface, k(s) of 3.08 s(-1), was greatly facilitated in the TiO(2)/MWCNTs film. The electrocatalytic reductions of hydrogen peroxide were also studied, and the apparent Michaelis-Menten constant is calculated to be 83.10 microM, which shows a large catalytic activity of Mb in the TiO(2)/MWCNTs film to H(2)O(2). The modified GC electrode shows good analytical performance for amperometric determination of hydrogen peroxide. The resultant Mb-TiO(2)/MWCNTs modified glassy carbon electrode exhibited fast amperometric response to hydrogen peroxide reduction, long term life and excellent stability. Finally the activity of the sensor for nitric oxide reduction was also investigated.

  9. Water Desalination Using Capacitive Deionization with Microporous Carbon Electrodes

    NARCIS (Netherlands)

    Porada, S.; Weinstein, L.; Dash, R.; Wal, van der A.F.; Bryjak, M.; Gogotsi, Y.; Biesheuvel, P.M.

    2012-01-01

    Capacitive deionization (CDI) is a water desalination technology in which salt ions are removed from brackish water by flowing through a spacer channel with porous electrodes on each side. Upon applying a voltage difference between the two electrodes, cations move to and are accumulated in electrost

  10. Preparation of porous carbon nanofibers derived from PBI/PLLA for supercapacitor electrodes

    Science.gov (United States)

    Jung, Kyung-Hye; Ferraris, John P.

    2016-10-01

    Porous carbon nanofibers were prepared by electrospinning blend solutions of polybenzimidazole/poly-L-lactic acid (PBI/PLLA) and carbonization. During thermal treatment, PLLA was decomposed, resulting in the creation of pores in the carbon nanofibers. From SEM images, it is shown that carbon nanofibers had diameters in the range of 100-200 nm. The conversion of PBI to carbon was confirmed by Raman spectroscopy, and the surface area and pore volume of carbon nanofibers were determined using nitrogen adsorption/desorption analyses. To investigate electrochemical performances, coin-type cells were assembled using free-standing carbon nanofiber electrodes and ionic liquid electrolyte. cyclic voltammetry studies show that the PBI/PLLA-derived porous carbon nanofiber electrodes have higher capacitance due to lower electrochemical impedance compared to carbon nanofiber electrode from PBI only. These porous carbon nanofibers were activated using ammonia for further porosity improvement and annealed to remove the surface functional groups to better match the polarity of electrode and electrolyte. Ragone plots, correlating energy density with power density calculated from galvanostatic charge-discharge curves, reveal that activation/annealing further improves energy and power densities.

  11. Preparation of porous carbon nanofibers derived from PBI/PLLA for supercapacitor electrodes.

    Science.gov (United States)

    Jung, Kyung-Hye; Ferraris, John P

    2016-10-21

    Porous carbon nanofibers were prepared by electrospinning blend solutions of polybenzimidazole/poly-L-lactic acid (PBI/PLLA) and carbonization. During thermal treatment, PLLA was decomposed, resulting in the creation of pores in the carbon nanofibers. From SEM images, it is shown that carbon nanofibers had diameters in the range of 100-200 nm. The conversion of PBI to carbon was confirmed by Raman spectroscopy, and the surface area and pore volume of carbon nanofibers were determined using nitrogen adsorption/desorption analyses. To investigate electrochemical performances, coin-type cells were assembled using free-standing carbon nanofiber electrodes and ionic liquid electrolyte. cyclic voltammetry studies show that the PBI/PLLA-derived porous carbon nanofiber electrodes have higher capacitance due to lower electrochemical impedance compared to carbon nanofiber electrode from PBI only. These porous carbon nanofibers were activated using ammonia for further porosity improvement and annealed to remove the surface functional groups to better match the polarity of electrode and electrolyte. Ragone plots, correlating energy density with power density calculated from galvanostatic charge-discharge curves, reveal that activation/annealing further improves energy and power densities.

  12. Electrochemical Oxidation of Paracetamol Mediated by MgB2 Microparticles Modified Glassy Carbon Electrode

    OpenAIRE

    Mohammed Zidan; Tan Wee Tee; A. Halim Abdullah; Zulkarnain Zainal; Goh Joo Kheng

    2011-01-01

    A MgB2 microparticles modified glassy carbon electrode (MgB2/GCE) was fabricated by adhering microparticles of MgB2 onto the electrode surface of GCE. It was used as a working electrode for the detection of paracetamol in 0.1 M KH2PO4 aqueous solution during cyclic voltammetry. Use of the MgB2/GCE the oxidation process of paracetamol with a current enhancement significantly by about 2.1 times. The detection limit of this modified electrode was found to be 30 μM. The sensitivity under conditio...

  13. Effect of acid oxidization of carbon nanotube electrode on the capacitances of double layer capacitors

    Institute of Scientific and Technical Information of China (English)

    LI; Chensha; WANG; Dazhi; LIANG; Tongxiang; WANG; Xiaofen

    2004-01-01

    Polarizable electrode of electric double layer capacitor was made from carbon nanotubes. The effect of acid oxidation of electrode on the specific capacitance was studied. Oxidation removed the redundant carbon, expanded the pore size and introduced some kinds of functional groups on the surface of CNTs. The specific capacit ance of the electrodes with organic electrolyte was increased from 21.4 to 49.6 F/gafter being oxidized at a volume ratio of H2SO4 to HNO3 of 3:1.

  14. Detection of Guanine and Adenine Using an Aminated Reduced Graphene Oxide Functional Membrane-Modified Glassy Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Di Li

    2017-07-01

    Full Text Available A new electrochemical sensor based on a Nafion, aminated reduced graphene oxide and chitosan functional membrane-modified glassy carbon electrode was proposed for the simultaneous detection of adenine and guanine. Fourier transform-infrared spectrometry (FTIR, transmission electron microscopy (TEM, and electrochemical methods were utilized for the additional characterization of the membrane materials. The prepared electrode was utilized for the detection of guanine (G and adenine (A. The anodic peak currents to G and A were linear in the concentrations ranging from 0.1 to 120 μM and 0.2 to 110 μM, respectively. The detection limits were found to be 0.1 μM and 0.2 μM, respectively. Moreover, the modified electrode could also be used to determine G and A in calf thymus DNA.

  15. Performance and Stability of Supercapacitor Modules based on Porous Carbon Electrodes in Hybrid Powertrain

    Institute of Scientific and Technical Information of China (English)

    GONG Xuan; XIE Changjun; ZOU Yaohui; QUAN Shuhai; PIOTR Bujlo; SHEN Di

    2014-01-01

    Hybrid power sources have attracted much attention in the electric vehicle area. Particularly, electric-electric hybrid powertrain system consisting of supercapacitor modules and lithium-ion batteries has been widely applied because of the high power density of supercapacitors. In this study, we design a hybrid powertrain system containing two porous carbon electrode-based supercapacitor modules in parallel and one lithium ion battery pack. With the construction of the testing station, the performance and stability of the used supercapacitor modules are investigated in correlation with the structure of the supercapacitor and the nature of the electrode materials applied. It has been shown that the responding time for voltage vibration from 20 V to 48.5 V during charging or discharging process decreases from about 490 s to 94 s with the increase in applied current from 20 A to 100 A. The capacitance of the capacitor modules is nearly independent on the applied current. With the designed setup, the energy efficiency can reach as high as 0.99. The results described here provide a guidance for material selection of supercapacitors and optimized controlling strategy for hybrid power system applied in electric vehicles.

  16. Synthesis and characterization of high performance electrode materials for lithium ion batteries

    Science.gov (United States)

    Hong, Jian

    Lithium-ion batteries have revolutionized portable electronics. Electrode reactions in these electrochemical systems are based on reversible intercalation of Li+ ions into the host electrode material with a concomitant addition/removal of electrons into the host. If such batteries are to find a wider market such as the automotive industry, less expensive and higher capacity electrode materials will be required. The olivine phase lithium iron phosphate has attracted the most attention because of its low cost and safety (high thermal and chemical stability). However, it is an intriguing fundamental problem to understand the fast electrochemical response from the poorly electronic conducting two-phase LiFePO4/FePO 4 system. This thesis focuses on determining the rate-limit step of LiFePO4. First, a LiFePO4 material, with vanadium substituting on the P-site, was synthesized, and found that the crystal structure change may cause high lithium diffusivity. Since an accurate Li diffusion coefficient cannot be measured by traditional electrochemical method in a three-electrode cell due to the phase transformation during measurement, a new method to measure the intrinsic electronic and ionic conductivity of mixed conductive LiFePO 4 was developed. This was based on the conductivity measurements of mixed conductive solid electrolyte using electrochemical impedance spectroscopy (EIS) and blocking electrode. The effects of ionic/electronic conductivity and phase transformation on the rate performance of LiFePO4 were also first investigated by EIS and other electrochemical technologies. Based on the above fundamental kinetics studies, an optimized LiFePO4 was used as a target to deposit 1mum LiFePO4 thin film at Oak Ridge National Laboratory using radio frequency (RF) magnetron sputtering. Similar to the carbon coated LiFePO4 powder electrode, the carbon-contained RF LiFePO4 film with no preferential orientation showed excellent capacity and rate capability both at 25°C and -20