Two phosphonium ionic liquids with high Li+ transport number

Autor(es)

Martins, Vitor L. ^[1] ; Sanchez-Ramirez, Nedher ^[1] ; Ribeiro, Mauro C. C. ^[1] ; Torresi, Roberto M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim, BR-05513970 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Physical Chemistry Chemical Physics; v. 17, n. 35, p. 23041-23051, 2015.
• Citações Web of Science: 20

Resumo

This work presents the physicochemical characterization of two ionic liquids (ILs) with small phosphonium cations, triethylpenthylphosphonium bis(trifluoromethanesulfonyl)imide ({[}P-2225]{[}Tf2N]) and (2-methoxyethyl)trimethylphosphonium bis(trifluoromethanesulfonyl) imide ({[}P-222(201)]{[}Tf2N]), and their mixtures with Li+. Properties such as the electrochemical window, density, viscosity and ionic conductivity are presented. The diffusion coefficient was obtained using two different techniques, PGSE-NMR and Li electrodeposition with microelectrodes. In addition, the Li+ transport number was calculated using the PGSE-NMR technique and an electrochemical approach. The use of these three techniques showed that the PGSE-NMR technique underestimates the diffusion coefficient for charged species. The Li+ transport number was found to be as high as 0.54. Raman spectroscopy and molecular dynamics simulations were used to evaluate the short-range structure of the liquids. These experiments suggested that the interaction between the Li+ and the Tf2N- anion is similar to that seen with other ILs containing the same anion. However, the MD simulations also showed that the Li+ ions interact differently with the cation containing an alkyl ether chain. The results found in this work suggest that these Li+ mixtures have promising potential to be applied as electrolytes in batteries. (AU)

• Processo FAPESP: 14/01987-6 - Estudo da intercalação de lítio em materiais catódicos baseados em óxidos de metais transição nanoestruturados usando como eletrólitos líquidos iônicos (ILs) pouco viscosos sintetizados a partir do fôsfonio e tetracianoborato.
• Beneficiário: Nédher Sánches Ramírez
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 09/53199-3 - Reconhecimento molecular e armazenamento de energia: estudos fundamentais do efeito de geometria, tamanho e síntese na otimização das propriedades químicas de materiais eletroativos
• Beneficiário: Roberto Manuel Torresi
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/22748-7 - Desenvolvimento de Capacitores Eletroquímicos de Alto Desempenho, Baseado em Grafeno e Líquidos Iônicos.
• Beneficiário: Vitor Leite Martins
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 10/08646-9 - Síntese e caracterização de Líquidos iônicos baseados em cátions quaternários de fosfônio
• Beneficiário: Nédher Sánches Ramírez
• Modalidade de apoio: Bolsas no Brasil - Doutorado