Raman probing carbon&aqueous electrolytes interfaces and molecular dynamics simulations towards understanding electrochemical properties under polarization conditions in supercapacitors
Raman probing carbon ＆ aqueous electrolytes interfaces and molecular dynamics simulations towards understanding electrochemical properties under polarization conditions in supercapacitors作者机构：Advanced Energy Storage DivisionCarbon Sci-Tech LabsUniversity of CampinasAv Albert Einstein 400CampinasSP 13083-852Brazil Department of ChemistryFederal University of Jequitinhonha and Mucuri’s ValleyRodovia MGT 367km 5835000Alto da Jacuba39.100-000 DiamantinaMGBrazil Advanced Energy Storage DivisionCenter for Innovation on New EnergiesLaboratory of Advanced BatteriesSchool of Chemical EngineeringUniversity of Campinas(UNICAMP)CampinasSP 13083-852Brazil Department of ChemistryFederal University of Mato GrossoICET-UFMT78060-900 CuiabáMTBrazil Departamento de FísicaICExUniversidade Federal de Minas GeraisBelo HorizonteMG 31270-901Brazil
出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)
年 卷 期：2021年第30卷第9期
页 面：279-292页
核心收录：
学科分类：0820[工学-石油与天然气工程] 080801[工学-电机与电器] 0808[工学-电气工程] 07[理学] 08[工学] 0817[工学-化学工程与技术] 0807[工学-动力工程及工程热物理] 070302[理学-分析化学] 0827[工学-核科学与技术] 0703[理学-化学]
基 金：the financial support from the Brazilian funding agencies CNPq(301486/2016-6) the FAEPEX(2426/17),the FAPESP(2016/25082-8,2017/11958-1,2014/02163-7,2018/20756-6,2018/02713-8)and CAPES(1740195) the‘‘Funda??o ao AmparoàPesquisa do Estado de Minas Gerais-FAPEMIG”(Project CEX112-10) the‘‘Secretaria de Estado de Ciência,Tecnologia e Ensino Superior de Minas Gerais-SECTES/MG”(Support for the LMMA Laboratory) the‘‘Conselho Nacional de Desenvolvimento Científico e Tecnológico–CNPq”(PQ-2 grant) support Shell and the strategic importance of the support given by ANP(Brazil’s National Oil,Natural Gas and Biofuels Agency)through the R&D levy regulation the Center for Research Computing(CRC)at the University of Notre Dame for the computational resources,and the Brazilian agencies CNPq(Reference Number 203393/2018-0)and CAPES(Finance Code 001)for the financial support financial support from the FAPEMIG,CNPq(307742/2017-2 and 432384/2018-9) Brazilian Institute of Science and Technology in Carbon Nanomaterials(INCTNanocarbono)。
主 题：Defect reorganization in graphite Surface excess of charge Operando Raman studies Electrical double-layer capacitors
摘 要：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 2.31μF cm^(-2)μm 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~3 to 7μF 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 p H 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.
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