Electrochemical and thermal investigations and Al current collector dissolution studies of three di-lithium salts in comparison to LiPF6 containing electrolytes

Murmann P, Schmitz R, Nowak S, Gores H, Ignatiev N, Sartori P, Passerini S, Winter M, Schmitz RW

Abstract

Electrolyte solutions containing the di-lithium cation salts Li 2CF(SO2NSO2CF3)2 (abbreviated bisimide), Li2(SO2NSO2CF 3)(SO3) (imide-sulfonate), Li2CF 2(SO2NSO2CF3)(SO 2C(SO2CF3)2 (imide-methanide) dissolved in carbonate solvents were electrochemically investigated on graphite and LiFePO4 electrodes and compared to the electrolyte salt LiPF 6. An electrochemical characterization containing the conductivity, the electrochemical stability window, the anodic dissolution behavior of aluminum as well as the thermal behavior at 60°C was performed for these electrolyte solutions. Constant current cycling experiments proved the potential applicability of the investigated salts for use in lithium ion batteries. The order of the salts in regard to their cycling performance reaches from methanide-imide showing the best results over bisimide to imide-sulfonate which is the worst among the investigated salts. © 2013 The Electrochemical Society.