| abstract |
(57) [Problem] When a mixed solvent of a cyclic carbonate and a chain carbonate is used as a non-aqueous electrolyte, a transesterification reaction by the chain carbonate occurs, and a methoxy group or ethoxy is used as an intermediate thereof. An alkoxide radical, which is a strong nucleophilic reagent such as a group, is generated to promote ring opening and decomposition of ethylene carbonate, which is a cyclic ester, to generate gas. Alternatively, the metal is dissolved in the positive electrode active material to destroy the crystal structure, thereby deteriorating the characteristics. SOLUTION: As an electrolyte solvent, two or more compounds selected from the group consisting of cyclic esters, cyclic ethers, cyclic acid anhydrides and derivatives of these compounds are used, at least one of which has a melting point of -20 ° C or lower. A supporting electrolyte having lithium as a cation and a surfactant were dissolved in a solvent of a certain compound. |