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Ternary electrolyte composed of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid (PYR 14 TFSI), γ-butyrolactone (GBL) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and anatase TiO 2 nanotube arrays (NTAs) electrode are investigated for the application in new generation of lithium-ion batteries (LIBs). The electrical conductivity and viscosity are measured in the whole composition range at several temperatures. Also, cyclic voltammetry experiments are performed at different temperatures and scan rates. At all scan rates, up to 100 mV · s −1 Ti 4+ /Ti 3+ redox peaks appear designating exceptionally fast intercalation/deintercalation reaction. At the end of cycling the intercalation/deintercalation capacity was 144.8/140.7 mAh · g −1 at current rate 3 C. The diffusion coefficient for Li + extraction from TiO 2 nanotubes (NTs) have been calculated for temperatures from (25 to 55) • C. Activation energy for diffusion was found to be 54.7 kJ/mol (0.57 eV The rapid development of portable electronic devices and technologies significantly increased demand for the next generation of energy storage systems.1 Because of enhanced energy and power density, efficiency and long life, LIBs are currently one of the most promising energy storage devices.2,3 Improvement of safety standards and low impact on human health and environment is essential for large-scale application of LIBs. 4 Safety concerns related to utilization of highly volatile and flammable organic solvents in commercial cells can be addressed by introducing ionic liquids (ILs) as emerging class of fluids.5 Numerous advantages of ILs such as negligible vapor pressure and high chemical and thermal stability make them ideal candidates for their application in LIBs. Potential application of ILs based on a combination of the pyrrolidinium (PYR + ) cation and bis(trifluoromethanesulfonyl)imide (TFSI -) anion as electrolytes in LIBs with long term cycling stability and very good capacity utilization, has been confirmed by several research groups. [6][7][8][9][10][11][12] Nevertheless, the utilization of IL-based electrolytes is usually limited by their high viscosity, which reduces transport capabilities and slows down the chemical processes that occur in these solvents. Mixing of ionic liquids with molecular solvents such as organic carbonates or lactones can reduce viscosity of applied electrolyte. 12-15Among other aprotic solvents, γ-butyrolactone (GBL) is usually applied in new generation of LIBs and other electrochemical devices. Besides its low cost, GBL has wide liquidus range and better thermal stability comparing to alkyl carbonate solvents. 16 In our previous papers we demonstrated that binary mixture of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, (IM 14 TFSI), and GBL has around 20% higher specific conductivity at low IL mole fractions compared to IM 14 TFSI + propylene carbonate (PC) binary mixture.15,17 Xu et al. observed similar trend in the case of 1-ethyl-3-methylimidazolium dicyanamide (IM 12 DC...

The structure of an ionic liquid at an electrode interface was studied by a combination of neutron reflectometry measurements and molecular dynamics simulations.

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