ADDITIVE FOR NEGATIVE ELECTRODE, NEGATIVE ELECTRODE, FORMATION METHOD OF NEGATIVE ELECTRODE PROTECTIVE FILM, LITHIUM SECONDARY BATTERY, AND LITHIUM ION CAPACITOR

摘要

PROBLEM TO BE SOLVED: To provide a lithium secondary battery or an additive for a lithium ion capacitor whose output characteristics can be improved and cycle characteristics are excellent.SOLUTION: An additive (B) for a negative electrode contains a polyalkylene imine resin (A) including a polymerizable unsaturated bond (g) and/or an aromatic ring (f), preferably including a polyethylene imine resin (A1). The total content of the polymerizable unsaturated bond (g) and the aromatic ring (f) is preferably 0.1 to 20 mmol/g. The number average molecular weight of (A) is preferably 300 to 100,000.