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Electrochemical Kinetics of Nanostructured Nb2O5 Electrodes

Come, Jérémy and Augustyn, Veronica and Kim, Jong Woung and Rozier, Patrick and Taberna, Pierre-Louis and Gogotsi, Pavel and Long, Jeffrey W. and Dunn, Bruce and Simon, Patrice Electrochemical Kinetics of Nanostructured Nb2O5 Electrodes. (2014) Journal of The Electrochemical Society (JES), 161 (5). A718-A725. ISSN 0013-4651

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Official URL: http://dx.doi.org/10.1149/2.040405jes

Abstract

Pseudocapacitive charge storage is based on faradaic charge-transfer reactions occurring at the surface or near-surface of redox-active materials. This property is of great interest for electrochemical capacitors because of the substantially higher capacitance obtainable as compared to traditional double-layer electrode processes. While high levels of pseudocapacitance have been obtained with nanoscale materials, the development of practical electrode structures that exhibit pseudocapacitive properties has been challenging. The present paper shows that electrodes of Nb2O5 successfully retain the pseudocapacitive properties of the corresponding nanoscale materials. For charging times as fast as one minute, there is no indication of semi-infinite diffusion limitations and specific capacitances of 380 F g−1 and 0.46 F cm−2 are obtained in 40-μm thick electrodes at a mean discharge potential of 1.5 V vs Li+/Li. In-situ X-ray diffraction shows that the high specific capacitance and power capabilities of Nb2O5 electrodes can be attributed to fast Li+ intercalation within specific planes in the orthorhombic structure. This intercalation pseudocapacitance charge-storage mechanism is characterized as being an intrinsic property of Nb2O5 that facilitates the design of electrodes for capacitive storage devices. We demonstrate the efficacy of these electrodes in a hybrid electrochemical cell whose energy density and power density surpass that of commercial carbon-based devices.

Item Type:Article
Additional Information:Thanks to the Electrochemical Society. The definitive version is available at http://ecsdl.org The original PDF of the article can be found at Journal of The Electrochemical Society website : http://jes.ecsdl.org/content/161/5/A718
HAL Id:hal-00976993
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Other partners > United States Navy - USNavy (USA)
Other partners > Réseau de stockage électrochimique de l’énergie - Energie RS2E (FRANCE)
Other partners > University of California-Los Angeles - UCLA (USA)
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Deposited By: cirimat webmestre
Deposited On:10 Apr 2014 14:21

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