Abstract text

An all solid-state polymer battery uses: 1) a lithium based negative electrode active material including crystal grains and crystal grain boundaries, wherein at least part of the crystal grain boundaries are exposed on a surface of the lithium-based negative electrode active material, and the area of the exposed surface of the crystal grain boundaries is 0.02 to 0.5 cm² per square centimeter of surface; 2) a dry polymer electrolyte including a specific ethylene glycol ether, a polymer containing electron-donating oxygen atoms in the skeleton, and a lithium salt; or 3) an amorphous lithium nitride layer formed between the negative electrode and the polymer electrolyte. This reduces the resistance at the interface between the negative electrode and the polymer electrolyte, thereby providing an all solid-state polymer battery with high capacity and excellent cycle characteristics. This also suppresses an increase in internal resistance during storage, thereby providing an all solid-state polymer battery with excellent high-rate discharge characteristics after storage.