Página 1 dos resultados de 98 itens digitais encontrados em 0.001 segundos

Synthesis and electrochemical properties of vanadyl phosphate di-hydrate/polyaniline derivatives hybrid films

ZAMPRONIO, Elaine C.; FERREIRA, Joao Paulo L.; OLIVEIRA, Herenilton P.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
49.962427%
Vanadyl phosphate and its hybrid compounds have proven to undergo electrochemical intercalation and de-intercalation of lithium ions, which enables its use as cathode material for Li ion rechargeable batteries. In this context, vanadyl phosphate di-hydrate/polyaniline derivatives hybrid films were synthesized via the exfoliation and reconstruction approach in order to evaluate their potential use as cathode in ion lithium batteries. X-ray diffraction patterns indicate that the lamellar structure of the inorganic matrix is maintained, consistent with the topotactic process. In the scanning electron micrographs, hybrid films exhibit rough surface consisting of warped and cracked crystallites, quite different from vanadyl phosphate di-hydrate square platelets crystallites. Electrochemical evaluation using cyclic voltammetry and charge-discharge galvanostatic techniques shows small differences between the charge and the discharge curves, indicating an irreversibility of the hybrid systems. (C) 2009 Elsevier B.V. All rights reserved.; FAPESP[05/58934-2]; CNPq[484137/2006-9]

Development of new organic electroactive materials for rechargeable batteries

Furtado, Olívia; Rangel, C. M.
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em 10/11/2011 ENG
Relevância na Pesquisa
60.848945%
The need for a clean and sustainable energy supply in the transportation sector have prompted electric vehicles as one of the options to reduce fossil fuel dependency and greenhouse gases emissions. Furthermore, electric vehicles are seen as enablers of the storage capacity of electric grids. In this context, the reasobnable energy density and cyclability reached by lithium-ion batteries based on inorganic cathodes have placed them in considerable advantage regarding energy conversation and storage [1, 2]. For higher energy density, lower cost and more environmentally acceptable batteries research efforts are presently focus on organic-based electrodes as a new approach to conventional inorganic cathodes. [3]. In his work, we carried out the development of a derivative of polymide (PI) for use as electrochemically active cathode material in rechargeable lithium batteries. Even though the application of polyimide as electrode material is scarcely found due to its insulating character, its aromatic imide group can be electrochemically oxidized and reduced in a reversible manner [4, 5]. This paper will present the studies on the synthesis and chemical characterization of a polyimide derivate and its evaluation as cathode organic polymer after electrochemical characterization. Test half-cell testing and battery constitution are being planned. The use of polyimide derivates is considered promising because of the potentiial increase in specific discharge capacity...

An Aqueous Rechargeable Lithium Battery Using Coated Li Metal as Anode

Wang, Xujiong; Hou, Yuyang; Zhu, Yusong; Wu, Yuping; Holze, Rudolf
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 07/03/2013 EN
Relevância na Pesquisa
49.96512%
New energy industry including electric vehicles and large-scale energy storage in smart grids requires energy storage systems of good safety, high reliability, high energy density and low cost. Here a coated Li metal is used as anode for an aqueous rechargeable lithium battery (ARLB) combining LiMn2O4 as cathode and 0.5 mol l−1 Li2SO4 aqueous solution as electrolyte. Due to the “cross-over” effect of Li+ ions in the coating, this ARLB delivers an output voltage of about 4.0 V, a big breakthrough of the theoretic stable window of water, 1.229 V. Its cycling is very excellent with Coulomb efficiency of 100% except in the first cycle. Its energy density can be 446 Wh kg−1, about 80% higher than that for traditional lithium ion battery. Its power efficiency can be above 95%. Furthermore, its cost is low and safety is much reliable. It provides another chemistry for post lithium ion batteries.

Advanced aqueous rechargeable lithium battery using nanoparticulate LiTi2(PO4)3/C as a superior anode

Sun, Dan; Jiang, Yifan; Wang, Haiyan; Yao, Yan; Xu, Guoqing; He, Kejian; Liu, Suqin; Tang, Yougen; Liu, Younian; Huang, Xiaobing
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 02/06/2015 EN
Relevância na Pesquisa
59.639097%
Poor cycling performance arising from the instability of anode is still a main challenge for aqueous rechargeable lithium batteries (ARLB). In the present work, a high performance LiTi2(PO4)3/C composite has been achieved by a novel and facile preparation method associated with an in-situ carbon coating approach. The LiTi2(PO4)3/C nanoparticles show high purity and the carbon layer is very uniform. When used as an anode material, the ARLB of LiTi2(PO4)3/C//LiMn2O4 delivered superior cycling stability with a capacity retention of 90% after 300 cycles at 30 mA g−1 and 84% at 150 mA g−1 over 1300 cycles. It also demonstrated excellent rate capability with reversible discharge capacities of 115 and 89 mAh g−1 (based on the mass of anode) at 15 and 1500 mA g−1, respectively. The superior electrochemical properties should be mainly ascribed to the high performance of LiTi2(PO4)3/C anode, benefiting from its nanostructure, high-quality carbon coating, appropriate crystal structure and excellent electrode surface stability as verified by Raman spectra, electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements.

Electrode-Electrolyte Interfaces in Solid Polymer Lithium Batteries

Hu, Qichao
Fonte: Harvard University Publicador: Harvard University
Tipo: Thesis or Dissertation
EN_US
Relevância na Pesquisa
80.83385%
This thesis studies the performance of solid polymer lithium batteries from room temperature to elevated temperatures using mainly electrochemical techniques, with emphasis on the bulk properties of the polymer electrolyte and the electrode-electrolyte interfaces. Its contributions include: 1) Demonstrated the relationship between polymer segmental motion and ionic conductivity indeed has a Vogel-Tammann-Fulcher (VTF) dependence, and improved the conductivity of the graft copolymer electrolyte (GCE) by almost an order of magnitude by changing the ion-conducting block from poly(oxyethylene) methacrylate (POEM) to a block with a lower glass transition temperature ((T_g)) poly(oxyethylene) acrylate (POEA). 2) Identified the rate-limiting step in the battery occurs at the cathode-electrolyte interface using both full cell and symmetric cell electrochemical impedance spectroscopy (EIS), improved the battery rate capability by using the GCE as both the electrolyte and the cathode binder to reduce the resistance at the cathode-electrolyte interface, and used TEM and SEM to visualize the polymer-particle interface (full cells with (LiFePO_4) as the cathode active material and lithium metal as the anode were assembled and tested). 3) Applied the solid polymer battery to oil and gas drilling application...

Toward commercializable microphase-separating copolymer electrolytes for rechargeable lithium batteries

Trapa, Patrick E. (Patrick Ervin), 1976-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 113 p.; 9074637 bytes; 9074390 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
49.853604%
Microphase-separating copolymers have been shown to possess the electrical properties of a polymer liquid and the mechanical properties of a solid. In the past, these materials had to be produced via anionic methods that are not easily scalable. To circumvent this problem, two approaches were adopted. In one, atom transfer radical polymerization (ATRP) was used to create the block copolymer, poly(oligo(oxyethylene) methacrylate)-b-poly(butyl methacrylate) [POEM-b-PBMA], which when doped with LiCF₃SO₃ (lithium triflate) exhibited good conductivity at room temperature ([sigma] [approximately] 3 x 10⁻⁶ S/cm at 23C̊). The other approach used free radical techniques to prepare the graft copolymer, POEM-g-PDMS, starting with commercially available high molecular weight poly(dimethyl siloxane) [PDMS] monomethacrylate-terminated macromonomer. When doped with lithium triflate this material exhibited a conductivity of [sigma] [approximately] 8 x 10⁻⁶ S/cm at 23° C.This material was found to be stable up to [approximately] 300° C and flow resistant below an applied pressure of [approximately] 60 psi. In an effort to achieve single-ion conduction by Li⁺, the anionic charge was incorporated into the polymer backbone as a carboxylate. To prevent undesirable ion-pairing interactions two approaches were adopted: (1) tethering the anionic charge outside the conducting block of a block copolymer; (2) reacting the Lewis acid BF3 with the carboxylate to delocalize the negative charge. Both approaches produced materials with T[sub]Li⁺ = 1 while retaining conductivity ([sigma] <[or equal to] 7 x 10⁻⁶ S/cm) nearly identical to that observed in salt-doped systems. The self-doped electrolytes...

LiCo1−yMyO2 positive electrodes for rechargeable lithium batteries: II. Nickel substituted materials grown by the citrate method

Julien, C.; Amdouni, A.; Castro García, Socorro; Selmane, M.; Rangan, S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
60.40998%
The layered LiCo1−yNiyO2 microcrystalline powders were synthesized by a sol–gel method using citric acid as a chelating agent in the range 0.2 ≤ y ≤ 0.8. Submicron-sized particles of the precursor were obtained at temperature below 400 °C and microcrystalline powders were grown by thermal treatment at 700 °C for 5 h in air. The carboxylic-based acid functioned such as a fuel, decomposed the homogeneous precipitate of metal complexes at low temperature, and yielded the free impurity LiCo1−yNiyO2 single-phases suitable for electrochemical applications. The synthesized products were characterized by structural, spectroscopic and thermal analyses. FT-IR measurements provide information on the growth process and the final local environment in the cationic sublattice of LiCo1−yNiyO2 solid solution. The electrochemical performance of the synthesized products in rechargeable Li cells was evaluated using non-aqueous solution 1 M LiPF6 in EC-DMC as electrolyte. The electrochemical features of a series of LiCo1−yNiyO2 compounds (0.2 ≤ y ≤ 1.0) are discussed in relation with their synthesis procedure and substitutive amount. The substitution of Ni3+ for Co3+ in LiCo1−yNiyO2 for y = 0.75 shows improvement of the specific capacity at ca. 187 mAh/g upon 32 cycles.

Lithium vanadium phosphate as cathode material for lithium ion batteries

Tao, D.; Wang, S.; Liu, Y.; Dai, Y.; Yu, J.; Lei, X.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2015 EN
Relevância na Pesquisa
50.231523%
Lithium vanadium phosphate (Li₃V₂(PO₄)₃) has been extensively studied because of its application as a cathode material in rechargeable lithium ion batteries due to its attractive electrochemical properties, including high specific energy, high working voltage, good cycle stability, and low price. In this review, the preparation of technology, structure, Li⁺ insertion/extraction mechanism, and electrochemical properties of Li₃V₂(PO₄)₃ are introduced, and with particular focus on the relationship of these topics each other. The synthetic techniques of Li₃V₂(PO₄)₃, such as high-temperature solid-state method, sol–gel method, hydrothermal method, etc. And progress of techniques in modification, such as coating and elemental doping, is reviewed. Finally, the directions for further development and prospective applications for the material are proposed.; Du Tao, Shengping Wang, Yongchao Liu, Yu Dai, Jingxian Yu, Xinrong Lei

Graphene-Wrapped Sulfur Particles as a Rechargeable Lithium-Sulfur-Battery Cathode Material with High Capacity and Cycling Stability

Wang, Hailiang; Yang, Yuan; Liang, Yongye; Robinson, Joshua Tucker; Li, Yanguang; Jackson, Ariel; Cui, Yi; Dai, Hongjie
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/07/2011
Relevância na Pesquisa
59.639097%
We report the synthesis of a graphene-sulfur composite material by wrapping polyethyleneglycol (PEG) coated submicron sulfur particles with mildly oxidized graphene oxide sheets decorated by carbon black nanoparticles. The PEG and graphene coating layers are important to accommodating volume expansion of the coated sulfur particles during discharge, trapping soluble polysulfide intermediates and rendering the sulfur particles electrically conducting. The resulting graphene-sulfur composite showed high and stable specific capacities up to ~600mAh/g over more than 100 cycles, representing a promising cathode material for rechargeable lithium batteries with high energy density.; Comment: published in Nano Letters

LiMn1-xFexPO4 Nanorods Grown on Graphene Sheets for Ultra-High Rate Performance Lithium Ion Batteries

Wang, Hailiang; Yang, Yuan; Liang, Yongye; Cui, Li-Feng; Casalongue, Hernan Sanchez; Li, Yanguang; Hong, Guosong; Cui, Yi; Dai, Hongjie
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/07/2011
Relevância na Pesquisa
49.962427%
Following the successful utilization of LiFePO4 as a novel cathode material for rechargeable lithium batteries, interest and efforts have grown in the research of another olivine structured material LiMnPO4 due to its higher operating potential voltage and energy density. However, high rate performance for LiMnPO4-based cathode materials has been challenging due to its extremely low electrical and ionic conductivities. Here, we develop a synthesis of Fe-doped LiMnPO4 (LiMn0.75Fe0.25PO4) nanorods directly bonded on graphene sheets (reduced from graphene oxide) to render LiMn0.75Fe0.25PO4 nanorods superior electrical conductivity. The LiMn0.75Fe0.25PO4 nanorod morphology is unique to materials grown on graphene over those grown in free solution, and is ideal for fast Li+ diffusion with the diffusion path of [010] crystallographic axis along the short radial direction (~20-30nm) of the nanorods. These together lead to ultrafast discharge within ~30-40 seconds without using a high carbon content. With high columbic efficiency above 99.5% at a high operating voltage, our LiMn0.75Fe0.25PO4 nanorods/graphene hybrid exhibits the best rate performance among all doped LiMnPO4 cathode materials for Lithium ion batteries.; Comment: published in Angewandte Chemie International Edition

Estudios de materiales de cátodos híbridos y ánodos vítreos. Caracterización en celdas de ion litio; Study of Hybrid Cathode Materials and Vitreous Anodes. Characterization in Lithium Ion Cells

Jurado Egea, José Ramón; Cuentas Gallegos, A. K.; Colomer, María T.; Palacín, M. R.; Gómez-Romero, P.
Fonte: Sociedad Española de Cerámica y Vidrio Publicador: Sociedad Española de Cerámica y Vidrio
Tipo: Artículo Formato: 1109521 bytes; application/pdf
SPA
Relevância na Pesquisa
70.086626%
[ES] Como parte de nuestros estudios de nuevos materiales de electrodos para aplicación en celdas reversibles de litio, hemos abordado el estudio de materiales vítreos e híbridos [1] como posibles alternativas a los materiales activos cristalinos, que ven frecuentemente limitada su capacidad como resultado de transiciones de fase irreversibles. Dentro de este trabajo se presentan aquí los resultados recientes sobre cátodos híbridos de PPi/MnO2 (PPi= polipirrol) y de PAni/V2O5 (PAni= polianilina), y de ánodos basados en vidrios en el sistema V-Ni-Te-O, así como de su combinación en celdas reversibles de ion litio. Hemos logrado obtener mediante reacción directa de pirrol con permanganato el híbrido PPi/MnO2, y hemos observado que en la síntesis de PAni/V2O5 existen factores que influyen positivamente en su comportamiento electroquímico.; [EN] This paper is based on new materials applied as electrodes in rechargeable lithium batteries. We have approached the study of glassy and hybrid materials as an alternative to crystalline active materials, which capacity is frequently limited by irreversible phase transitions. We present here our latest results on hybrid cathodes, PPy/MnO2 (PPy= PPi= polypirrol) and PAni/V2O5 (PAni= polyaniline)...

Electrochemically Functionalized Carbon Nanotubes and their Application to Rechargeable Li Batteries

Baibarac, Mihaela; Gómez-Romero, P.; Lira-Cantú, Monica; Casañ Pastor, Nieves; Oró Solé, Judith
Fonte: John Wiley & Sons Publicador: John Wiley & Sons
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
Relevância na Pesquisa
59.69865%
Electrochemical polymerization of N-vinyl carbazole (VC) on carbon nanotube (CNT) films was studied by cyclic voltammetry (CV) in LiClO4/acetonitrile solutions. Comparing the cyclic voltammograms recorded on a blank Pt electrode with those obtained when single- or multi-walled carbon nanotube (SWNT or MWNT) films were previously deposited onto the Pt electrode, a downshift of the VC reduction peak potential is observed in the latter case. The influences of monomer concentration, type of solvent, and supporting electrolyte on the polymerization conditions and electrochemical properties of these composite materials are also investigated. The morphological aspects of poly(N-vinyl carbazole) (PVC)-functionalized CNTs are revealed by transmission electron microscopy (TEM) studies. A covalent functionalization of carbon nanotubes with PVC is invoked as a result of attenuated total reflection infrared (ATR-IR) spectroscopic studies. Using PVC-functionalized CNTs as a positive electrode and an electrolytic solution containing LiPF6, the charge-discharge characteristics of the rechargeable lithium cells are determined. High specific discharge capacity (45 and 115 mA h g-1) is reported for PVC-functionalized single- and multi-walled carbon nanotubes...

In-Situ Synthesis of Polypyrrole-MnO2−x Nanocomposite Hybrids

Cuentas Gallegos, A. K.; Gómez-Romero, P.
Fonte: Ecole polytechnique (Montréal, Québec) Publicador: Ecole polytechnique (Montréal, Québec)
Tipo: Artículo Formato: 344581 bytes; application/pdf
ENG
Relevância na Pesquisa
60.28578%
This work centers on hybrid materials based on MnO2-x and conducting polymers and their possible application as electrodes in rechargeable lithium batteries. We approached the study of these hybrids as an alternative to crystalline manganese oxides, which capacity is frequently limited by irreversible phase transitions. We followed the approach of forming simultaneously the organic and inorganic components in an attempt to get nanocomposite materials. PPy/MnO2-x nanocomposite hybrids were prepared by direct one-pot reaction of pyrrole and potassium permanganate, obtaining hybrids with different amounts of the inorganic phase. The results on the chemical, spectroscopic and electrochemical characterization of the PPy/MnO2-x hybrids indicated that as the MnO2-x content increases, so does the initial specific charge in lithium rechargeable cells, reaching values as high as 134 Ah/Kg.5; Partial financial support from the Ministry of Science and Technology (Spain) (GrantMAT2002-04529-C03) and from CONACYT (México) (fellowship to A.K. Cuentas-Gallegos) are gratefully acknowledged; Peer reviewed

The Organic-Inorganic Polyaniline/V2O5 System. Application as a High-Capacity Hybrid Cathode for Rechargeable Lithium Batteries

Lira-Cantú, Monica; Gómez-Romero, P.
Fonte: Electrochemical Society Publicador: Electrochemical Society
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
Relevância na Pesquisa
80.494116%
Texto completo disponible en la web del autor: http://www.cienciateca.com/PAniV2O5%20J%20Electrochem%20Soc%201999%20146_6_2029_2033.pdf; The application of a hybrid polyaniline/V2O5 cathode material in reversible lithium electrochemical cells is reported. We have studied the influence of synthesis conditions and subsequent treatments of this hybrid electrode under oxygen in order to optimize its performance as a lithium-insertion cathode. The temperature and duration of this treatment are key parameters in determining the final specific charge of the cathode. The optimal material yielded a specific charge as high as 302 Ah/kg measured at a low discharge rate (C/48) corresponding to the insertion of 2.72 lithium ions per formula unit (C6H4N)0.6V2O5·0.3H2O). Higher scan rates of C/12 lead to specific capacities of 200 Ah/kg. The thermal and electrochemical stability of the hybrid electrode, especially in relation to the decomposition of the organic polymer and its effect on battery performance and cyclability, are also discussed. ©1999 The Electrochemical Society. All rights reserved.; This work was partially supported by CICYT (Spain, MAT98- 0807-C02-02). We also thank the Ministerio de Educación y Ciencia (Spain, MEC-AECI) and CONACYT (Mexico) for a predoctoral fellowship to M.L.C.; Peer reviewed

Materiales híbridos basados en fosfato de vanadilo y polímeros conductores como cátodos en baterias reversibles de litio; Hybrid Materials Based on Vanadyl Phosphate and Conducting Polymers as Cathodes in Rechargeable Lithium Batteries

Casañ Pastor, Nieves; Gómez-Romero, P.; Cuentas Gallegos, A. K.; Vijayaraghavan, V.
Fonte: Sociedad Española de Cerámica y Vidrio Publicador: Sociedad Española de Cerámica y Vidrio
Tipo: Artículo Formato: 283533 bytes; application/pdf
SPA
Relevância na Pesquisa
69.853604%
[ES] El fosfato de vanadilo es bien conocido como una fase inorgánica laminar capaz de intercalar una gran variedad de moléculas orgánicas. Mediante la polimerización in-situ, de anilina o pirrol, en la fase inorgánica es posible preparar materiales híbridos orgánico-inorgánicos en los que el polímero queda intercalado. Se describe la síntesis y caracterización de este tipo de híbridos y algunos resultados preliminares de su aplicación como materiales activos de cátodo en celdas reversibles de litio.; [EN] Vanadyl phosphate is a well known layered inorganic phase, capable of intercalating a great variety of organic molecules. By means of an in-situ polymerisation of aniline or pyrrole between the layers of the inorganic phase, it is possible to obtain organic-inorganic hybrids. We describe the synthesis and characterization of these type of hybrids, and some preliminary results of their application as active cathodic materials for positive electrodes in reversible lithium cells.; Agradecemos la financiación de este trabajo a través de los proyectos MAT2001-709-C04-01 y MAT2002-04529-C03, y al Consejo Nacional de Ciencia y Tecnología de México (CONACYT) por la concesión de una beca predoctoral a A.KCuentas-Gallegos.; Peer reviewed

Integration of Hexacyanoferrate as Active Species in a Molecular Hybrid Material. Transport Properties and Application of PAni/HCF as Cathode in Rechargeable Lithium Batteries

Torres-Gómez, G.; Tejada Rosales, E. M.; Gómez-Romero, P.
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
Relevância na Pesquisa
80.577217%
Especial Issue on Nanocomposite Materials.; The hybrid organic-inorganic material formed by polyaniline and the hexacyanoferrate anion (PAni/HCF) constitutes a molecular hybrid where the anchoring of the electroactive anion within the polymer leads to its application as a functional material that harnesses the activity of the molecular species. Transport measurements of the hybrid have been carried out, both by cyclic voltammetry at different scan rates and ac impedance spectroscopy. An apparent diffusion coefficient of 5 10-8 cm2/s and an activation energy of 15.5 kJ/mol (0.16 eV) have been obtained. The particular application of these hybrids to energy storage is shown here through their use as cathodes in lithium rechargeable cells. In this respect, the PAni/HCF hybrids show very good cyclabilities and high specific charges of up to 140 A.h/ kg, unprecedented for this type of hybrid materials; This work was funded by CICYT (Spain) (MAT98-0807-C02-02). We thank the Ministry of Education and Culture (Spain) for predoctoral fellowships awarded to G.T.G. and E.M.T.R.; Peer reviewed

Molecular Batteries. Harnessing Fe(CN)63- Electroactivity in Hybrid Polyaniline-Hexacyanoferrate Electrodes

Gómez-Romero, P.; Torres-Gómez, G.
Fonte: John Wiley & Sons Publicador: John Wiley & Sons
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
Relevância na Pesquisa
59.518696%
Texto completo disponible en la web del autor: http://www.cienciateca.com/PAni-HCF_AdvMater%202000.pdf; Hybrid materials useful as electrodes in plastic batteries are investigated by these authors. The electroactive species hexacyanoferrate (HCF) and the conducting organic polymer polyaniline (PAni) are combined to create hybrid materials that show promise as cathode materials in rechargeable lithium batteries. The chemical and electrochemical synthesis of PAni/HCF as well as the material's electrochemical properties are reported. It is demonstrated that this material has not only a high specific charge and efficiency but also good cyclability.; Peer reviewed

Poly(N-vinyl carbazole) and carbon nanotubes based composites and their application to rechargeable lithium batteries

Baibarac, Mihaela; Lira-Cantú, Monica; Oró Solé, Judith; Baltog, Ioan; Casañ Pastor, Nieves; Gómez-Romero, P.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
Relevância na Pesquisa
59.639097%
In order to prepare poly(N-vinyl carbazole) (PVK) and carbon nanotube (CNs) based composites, electrochemical polymerization of N-vinyl carbazole (NVK) was studied by cyclic voltammetry (CV) in LiClO4/acetonitrile solutions. Cyclic voltammograms recorded on a blank Pt electrode and those obtained when single or multi-walled carbon nanotubes (SWNTs or MWNTs) films were previously deposited onto the Pt electrode show a down-shift of the VK reduction peak potential in the latter case. The influence of monomer concentration and supporting electrolyte on the polymerization conditions and electrochemical properties of these composite materials were also investigated. Morphologic aspects as well as the photoluminescence properties of the PVK/CNs composite were also investigated. A covalent functionalization of carbon nanotubes with PVK is suggested on the basis of infrared (IR) spectroscopic studies. Using the PVK/CN composite as a positive electrode and an electrolytic solution containing LiPF6, a higher specific discharge capacity of the rechargeable lithium cells, 45 and 115 mA h g−1, are reported for PVK functionalized SWNTs and MWNTs, respectively.; A post-doctoral fellowship to M.B. by the Spanish Ministry of Science is gratefully acknowledged. Partial funding from the Spanish Ministry of Science and Technology (Grant No. MAT 2002-04529-C03) is also acknowledged.; Peer reviewed

Electrodos híbridos a base de Polianilina/V2O5 para el desarrollo de baterías plásticas de litio; Hybrid Electrodes based on Polyaniline/V2O5 for the development of plastic lithium batteries

Cuentas Gallegos, A. K.; Gómez-Romero, P.; Lira-Cantú, Monica; Torres-Gómez, G.
Fonte: Sociedad Española de Cerámica y Vidrio Publicador: Sociedad Española de Cerámica y Vidrio
Tipo: Artículo Formato: 486462 bytes; application/pdf
SPA
Relevância na Pesquisa
80.17076%
[ES] Presentamos la síntesis y caracterización del híbrido PAni/V2O5 y su aplicación como cátodo en baterías reversibles de litio. La síntesis se realizó directamente a partir del hidrogel de V2O5. Observamos una relación directa entre las condiciones de síntesis y la carga específica (Ah/Kg) obtenida durante el análisis del material como cátodo en baterías recargables de litio. Por otro lado, se llevaron a cabo tratamientos con oxígeno para aumentar el estado de oxidación del V2O5 en el material híbrido. El uso de mayores temperaturas y tiempos de reacción provoca la descomposición de la parte orgánica del híbrido PAni/V2O5. La carga específica y tratamientos posteriores de los híbridos obtenidos son muy sensibles a las condiciones de síntesis. Se observaron valores tan elevados como 302 Ah/Kg a baja velocidad de descarga (C/48) y 200-238 Ah/Kg a una velocidad de descarga de C/12, valores que corresponden a la inserción de 2.7 y 2.08 iones litio respectivamente. Estos valores demuestran la respuesta sinérgica entre PAni y el material óxido V2O5.; [EN] We present the synthesis and characterization of the hybrid PAni/V2O5 and its performance as cathode in reversible lithium cells. The synthesis was made directly from the V2O5 gel. We observe a direct relationship between the synthesis conditions and the specific charge (Ah/Kg) obtained during the analysis of the material as cathode in lithium batteries. On the other hand...

Materiales híbridos moleculares orgánicos-inorgánicos: síntesis y aplicación como electrodos en baterías recargables de litio; Molecular Organic-Inorganic Hybrid Materials : Synthesis and Application as Electrodes in Lithium Rechargeable Batteries

Torres-Gómez, G.; Lira-Cantú, Monica; Gómez-Romero, P.
Fonte: Sociedad Española de Cerámica y Vidrio Publicador: Sociedad Española de Cerámica y Vidrio
Tipo: Artículo Formato: 291755 bytes; application/pdf
SPA
Relevância na Pesquisa
60.28578%
[ES] Se describe la síntesis y aplicación como electrodos para el almacenamiento o conversión de energía de materiales híbridos basados en la dispersión de especies inorgánicas electroactivas en el seno de polímeros orgánicos conductores. Polianilina y polipirrol son dopados con polioxometalatos electroactivos ([PMo12O40]3-) o aniones ferricianuro ([(FeCN)6]3-) como únicas especies dopantes. La elevada carga y tamaño de estos aniones evitan, en la mayoría de los casos, su desintercalación durante la reducción. Estos híbridos se han sintetizado por métodos químicos y electroquímicos, siendo la relación anillos de anilina o de pirrol por anión de [PMo12O40]3- de nueve, de manera que el anión permanece en el interior de la matriz polimérica incluso después de reducir el material a -0.4V (vs Ag/AgCl, 2.6V vs Li). En el caso del híbrido Polipirrol/Fe(CN)6 la relación anillos de pirrol/anión oscila entre 10 y 12 dependiendo de la temperatura de síntesis. La temperatura también afecta a su conductividad eléctrica, oscilando los valores más elevados alrededor de 60 Scm-1 (preparado a 0ºC). El anión permanece en el interior de la matriz polimérica cuando se reduce en medio orgánico. Los híbridos con PMo12 pueden intercalar hasta 5.3 Li+ durante la descarga (52Ah/Kg). El híbrido con Fe(CN)6 intercala 2.7 iones litio por fórmula unidad (69Ah/Kg).; [EN] A novel family of molecular hybrid materials based on electroactive inorganic species dispersed in conducting organic polymers is reported as electrodes for energy storage or conversion. Polyaniline and polypyrrole are effectively doped with electroactive polyoxometalates ([PMo12O40]3-) or ferricyanide ([(FeCN)6]3-) anions as the only doping species. The high charge and size of these anions prevents their deintercalation during reduction in most cases. The synthesis of these hybrids can be made by chemical (bulk powders) and electrochemical (films) methods. For [PMo12O40]3-...