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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Spectroelectrochemical study of the lithium insertion in vanadium(V) oxide xerogels

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Huila, Manuel F. G. [1] ; Toma, Henrique E. [1]
Total Authors: 2
[1] Univ Sao Paulo, Inst Quim, BR-05508000 Sao Paulo - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Electrochimica Acta; v. 278, p. 236-244, JUL 10 2018.
Web of Science Citations: 1

Vanadium-oxide gels and xerogels are currently explored as versatile materials in lithium ion batteries. They consist of V2O5 nanoribbons composed by doubly-layered slabs joint by a strongly bond H3O+/H2O intercalated layer. Their thin films exhibit a complex electrochemical behavior encompassing four reduction waves at 0.38, 0.22, -0.42 and -0.81 V vs Ag/AgNO3 (0.503 vs SHE). In order to improve the understanding of such processes, a detailed spectroelectrochemical investigation was carried out based on visible-UV and confocal Raman spectroscopy. Accordingly, the first two waves were ascribed to the partial reduction of non-equivalent, localized V-V=O centers, keeping most of the representative vanadium-oxide vibrational features. At -0.4 V, a transition to a delocalized mixed-valence configuration became apparent in the optical and Raman spectra, leading to a dramatic current increase coupled with the insertion of lithium ions into the lamellar structure. At -0.8 V a complete conversion into the vanadium (IV) oxide form was observed from the spectroelectrochemical profiles. The nanoribbons doublylayered structure seems to be preserved, sustaining a reversible and reproducible electrochemical behavior along several repetitive voltammetric cycles. (C) 2018 Elsevier Ltd. All rights reserved. (AU)

FAPESP's process: 13/24725-4 - Supramolecular chemistry and nanotechnology
Grantee:Henrique Eisi Toma
Support type: Research Projects - Thematic Grants