| Texto completo | |
| Autor(es): |
Vicentini, Rafael
[1]
;
Da Silva, Leonardo M.
[2]
;
Franco, Debora V.
[2]
;
Nunes, Willian G.
[1]
;
Fiates, Juliane
[3]
;
Doubek, Gustavo
[3]
;
Franco, Luis F. M.
[3]
;
Freitas, Renato G.
[4]
;
Fantini, Cristiano
[5]
;
Zanin, Hudson
[1]
Número total de Autores: 10
|
| Afiliação do(s) autor(es): | [1] Univ Estadual Campinas, Adv Energy Storage Div, Carbon Sci Tech Labs, Av Albert Einstein 400, BR-13083852 Campinas, SP - Brazil
[2] Fed Univ Jequitinhonha & Mucuris Valley, Dept Chem, Rodovia MGT 367, Km 583, BR-39 10000 Diamantina, MG - Brazil
[3] Univ Campinas UNICAMP, Lab Adv Batteries, Adv Energy Storage Div, Ctr Innovat New Energies, Sch Chem Engn, BR-13083852 Campinas, SP - Brazil
[4] Univ Fed Mato Grosso, Dept Chem, ICET UFMT, BR-78060900 Cuiaba, MT - Brazil
[5] Univ Fed Minas Gerais, Dept Fis, ICEx, BR-31270901 Belo Horizonte, MG - Brazil
Número total de Afiliações: 5
|
| Tipo de documento: | Artigo Científico |
| Fonte: | JOURNAL OF ENERGY CHEMISTRY; v. 60, p. 279-292, SEP 2021. |
| Citações Web of Science: | 7 |
| Resumo | |
Raman probing of carbon electrode and electrolyte under dynamic conditions is performed here using different aqueous electrolytes to elucidate the fundamental events occurring in electrochemical supercapacitor during charge-discharge processes. The areal capacitance ranges from 1.54 to 2.31 mF cm(-2) and it is determined using different techniques. These findings indicate that the Helmholtz capacitance governs the overall charge-storage process instead of the space charge (quantum) capacitance commonly verified for HOPG electrodes in the range of similar to 3 to 7 mu F cm(-2). Molecular dynamics simulations are employed to elucidate the origin of the reversible Raman spectral changes during the charge-discharge processes. A correlation is verified between the reversible Raman shift and the surface excesses of the different ionic species. A theoretical framework is presented to relate the effect of the applied potential on the Raman shift and its correlation with the surface ionic charge. It is proposed that the Raman shift is governed by the interaction of solvated cations with graphite promoted by polarization conditions. It is the first time that a comparative study on different aqueous electrolyte pH and cation ion size has been performed tracking the Raman spectra change under dynamic polarization conditions and contrasting with comprehensive electrochemistry and dynamic molecular simulations studies. This study shines lights onto the charge-storage mechanism with evidence of Kohn anomaly reduction in the carbon electrode during the reversible adsorption/desorption and insertion/extraction of ionic species. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved. (AU) | |
| Processo FAPESP: | 17/11958-1 - CINE - Divisão para Armazenamento de Energia Avançado |
| Beneficiário: | Rubens Maciel Filho |
| Modalidade de apoio: | Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia |
| Processo FAPESP: | 18/02713-8 - Dinâmica molecular de fluidos confinados: propriedades de equilíbrio e de transporte |
| Beneficiário: | Luís Fernando Mercier Franco |
| Modalidade de apoio: | Auxílio à Pesquisa - Jovens Pesquisadores |
| Processo FAPESP: | 16/25082-8 - Desenvolvimento de protótipo armazenador e fornecedor de energia |
| Beneficiário: | Lenon Henrique da Costa |
| Modalidade de apoio: | Bolsas no Brasil - Mestrado |
| Processo FAPESP: | 14/02163-7 - Desenvolvimento de dispositivos supercapacitores a partir de grafenos, nanotubos de carbono e diamantes |
| Beneficiário: | Hudson Giovani Zanin |
| Modalidade de apoio: | Auxílio à Pesquisa - Jovens Pesquisadores |
| Processo FAPESP: | 18/20756-6 - Desenvolvimento de pseudocapacitores a partir de compósitos de óxidos metálicos e carvão ativado |
| Beneficiário: | Willian Gonçalves Nunes |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |