LITHIUM ION SECONDARY BATTERY

A lithium ion secondary battery that includes: a positive electrode having a positive electrode active material capable of storing and releasing lithium ions, the positive electrode active material containing positive electrode active material grains having a coating layer containing a carbon compound having an acid functional group, and an amount of the acid functional group in a composite including the positive electrode active material and the coating layer is 0.004 mmol/g to 0.0062 mmol/g; a negative electrode having a negative electrode active material capable of storing and releasing lithium ions; a separator interposed between the positive electrode and the negative electrode; and a non-aqueous electrolyte containing a polar solvent having a relative permittivity of 20 or more.