| abstract |
In a lithium ion secondary battery using a positive electrode active material comprising a lithium manganese-based oxide containing a lithium (Li) element and a tetravalent manganese (Mn) element and having a layered rock salt crystal structure, Suppresses deterioration due to redox decomposition. By adding 2-pyrone-4,6-dicarboxylic acid to the electrolyte, the additive is oxidized before the organic solvent is oxidized on the surface of the positive electrode during activation treatment or high temperature storage. It is considered that a film is formed, and the storage capacity and the recovery capacity are improved, and an increase in internal resistance is suppressed. [Selection figure] None |