Electrolyte performance of LiFTA-CsFTA molten salt for lithium secondary battery

摘要

Introducing the Cs cation into a perfluorosulfonylamide lithium salt composed of (fluorosulfonyl)(trifluoromethylsulfonyl)amides (FTA_-) effectively reduced both the melting point and viscosity. Especially, their eutectic mixture (Li_(0.4)Cs_(0.6)[FTA]) exhibited a wide liquid temperature range (33 ~ 200 °C), a wide electrochemical window (> 5.1 V), and the highest lithium ion partial conductivity among the Li-Cs mixtures. Furthermore, intercalation and deintercalation of lithium in and out of LiCoO_2 and LiFePO_4 positive electrodes could be observed in the eutectic melt with a high coulombic efficiency.