Improvement of the Stability of LiPF₆ Electrolytes toward Water by the Addition of LiCl

Abstract

It is known that LiPF₆ electrolytes react with water. In this study, LiCl, LiF, LiBr and LiI were added to 1 M LiPF₆/EC + DEC electrolyte with about 5000 ppm water to inhibit the reaction of LiPF₆. When 0.1 M LiCl was added, the LiPF₆ electrolyte did not react with the water for 50 hours. Differential scanning calorimetry (DSC) measurement indicated that the amount of exothermic heat at 265°C, which is related to a reaction with LiPF₆, did not change at all for 48 hours when LiCl was added. Based on this result, we confirmed that LiPF₆ salt did not react with water when LiCl was added.