Patent ID: 8216720

Claim:
A negative electrode for a rechargeable lithium battery which includes a conductive metal foil current collector and an active material layer provided on a surface of the current collector and comprising a polyimide binder and particles of active material containing silicon and/or a silicon alloy; said negative electrode characterized in that said current collector has mechanical properties of at least 80 N/mm 2 tensile strength, at least 30 N/mm 2 proportional limit, at least 1.0% elongation at break and at least 0.03% elastic elongation limit and said binder has mechanical properties of at least 50 N/mm 2 tensile strength, at least 10% elongation at break, at least 2.5 ×10 −3 J/mm 3 strain energy density and up to 10,000 N/mm 2 elastic modulus; after provision of said active material layer on the surface of said current collector, heat treatment being carried out at a temperature higher than a glass transition temperature and lower than a decomposition temperature of said binder to improve adhesion of the binder to the current collector.