The influence of the electrochemical and thermal stability of mixtures of ionic liquid and organic carbonate on the performance of high power lithium-ion batteries

In this work we report on the use of 0.3 M LiTFSI in PC–PYR14TFSI (50:50 wt.%) as electrolyte in lithium-ion batteries (LIBs). Conductivity, viscosity and electrochemical stability of this electrolyte were investigated and compared with those of the electrolytes 1 M LiPF6 in PC and 0.3 M LiTFSI in PC. The thermal stability of these electrolytes at 60 °C was also investigated. LIBs containing LTO as anode and LFP as cathode were assembled and tested in the three electrolytes at room temperature and 60 °C. The results of these tests show that the use of 0.3 M LiTFSI in PC–PYR14TFSI (50:50 wt.%) allows the realization of LIBs able to deliver high capacity and to display high cycling stability at both temperatures.