POLYMER COMPOUND, INTERMEDIATE COMPOSITION, NEGATIVE ELECTRODE, ELECTRICITY STORAGE DEVICE, SLURRY FOR NEGATIVE ELECTRODES, METHOD FOR PRODUCING POLYMER COMPOUND, AND METHOD FOR PRODUCING NEGATIVE ELECTRODE

A polymer compound, which is used as a binder for a negative electrode of an electricity storage device, is obtained by condensation of a vinyl polymer that contains a carboxyl group and a third compound that is selected from among an aromatic multifunctional amine, phosphorous acid, phosphorous acid ester, trialkoxysilane, and phosphoric acid.