Suppression of Self-Discharge by a LiPF6/Methyl Difluoroacetate Electrolyte in Li/CuCl2Batteries

Methyl difluoroacetate (MFA) was used as an electrolyte solvent in Li/CuCl 2 batteries, and the LiPF 6 /MFA electrolyte was effective for the suppression of the self-discharge of Li/CuCl 2 batteries. The dependence of self-discharge behavior on LiPF 6 concentration (1.0, 1.4, 1.8, 2.2, and 2.7 mol dm −3 ) in MFA-based electrolytes was investigated. The lowest self-discharge was observed for a 2.2 mol dm −3 LiPF 6 /MFA electrolyte under the described conditions, and an initial discharge capacity of 395 mAh g −1 was maintained after 678 h (4 weeks) of rest. The cycling performance of the LiPF 6 /MFA electrolytes was evaluated, and the discharge capacity for the 2.2 mol dm −3 LiPF 6 /MFA electrolyte was found to be maintained at 183 mAh g −1 (10 th cycle). Therefore, 2.2 mol dm −3 LiPF 6 /MFA electrolyte is confirmed to be effective for the suppression of the self-discharge of Li/CuCl 2 batteries.