2018 年 86 巻 5 号 p. 254-259
Lithium bis(oxalato)borate (LiBOB) has attracted much attention as an alternative lithium salt in lithium-ion batteries. At positive electrodes, LiBOB is considered to form a protective surface-film. However, its protection-ability is not understood in detail. In this study, the surface-film formation behavior and the protection-ability on a LiMn2O4 thin-film electrode in LiBOB/propylene carbonate (PC) was investigated using spectroscopic methods and a redox reaction of ferrocene. The surface film formed in LiBOB/PC at 55°C is much thinner than that in LiClO4/PC. The redox reaction of ferrocene on cycled LiMn2O4 showed that the electronic passivation did not occur during cycling even at 55°C. On the basis of the results, a degradation behavior of LiMn2O4 was discussed.