LITHIUM ION SECONDARY BATTERY

Deterioration in cycle characteristics and battery swelling are improved. The lithium ion secondary battery of the present invention is characterized in comprising an electrolyte solution comprising a multifunctional monomer comprising two or more epoxy groups and a negative electrode comprising a binder comprising a polymer comprising a monomer unit comprising a functional group selected from the group consisting of —OH, —OM, —COOH, —COOM and —COOCH, wherein M is a metal element, and n is an integer of 1 to 5.