| abstract |
The invention provides a lithium ion secondary battery, which comprises: a negative electrode having a negative electrode active material layer containing a negative electrode active material and a negative electrode binder in a given proportion, and a negative electrode having a positive electrode active material and a given proportion of a positive electrode binder The positive electrode of the positive electrode active material layer, the electrolyte and the separator, wherein the negative electrode active material is composed of carbonaceous active material, and the negative electrode binder is polymerized containing a given proportion of styrene and ethylenically unsaturated carboxylic acid A polymer made of a monomer composition for the negative electrode, the positive electrode active material contains a given transition metal element, and the positive electrode binder is a positive electrode that polymerizes acrylonitrile and ethylenically unsaturated carboxylic acid in a given proportion The polymer formed from the monomer composition, the swelling degree of the positive electrode binder is 2.0-15.0 times. |