| Full text | |
| Author(s): |
Total Authors: 2
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| Affiliation: | [1] Univ Sao Paulo, Inst Quim, BR-05508000 Sao Paulo - Brazil
Total Affiliations: 1
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| Document type: | Journal article |
| Source: | Electrochimica Acta; v. 278, p. 236-244, JUL 10 2018. |
| Web of Science Citations: | 1 |
| Abstract | |
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 Opportunities: | Research Projects - Thematic Grants |