Electrochemical study of anatase TiO<inf>2</inf> nanotube array electrode in electrolyte based on 1,3-diethylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid

Abstract

The density, viscosity and electrical conductivity of ionic liquid 1,3-diethylimidazolium bis(trifluoromethylsulfonyl)imide, (C2C2imTFSI), and 0.5-M solution of LiTFSI in C2C2imTFSI were determined at different temperatures. The LiTFSI/C2C2imTFSI system was tested as a possible electrolyte for lithium-ion batteries by using anatase TiO2 nanotube array electrode as anode material for the first time. The electrochemical testing has shown not only the improvement of lithium-ion insertion/deinsertion properties by increasing temperature but also the existence of a decomposition of the electrolyte, detecting the change of colour. The decomposition of electrolyte leads to the formation of a film on the surface of the electrode which improves Coulombic efficiency during cycling.