LITHIUM SECONDARY BATTERY

摘要

Charge-discharge cycle performance is improved in a lithium secondary battery that uses a material that occludes lithium by alloying with lithium as its negative electrode active material. A lithium secondary battery comprises a negative electrode having a negative electrode active material thin film provided on a negative electrode current collector, a positive electrode including a positive electrode active material, and a non-aqueous electrolyte, in which the negative electrode active material is a material that occludes lithium by alloying with lithium, the ratio of the discharge capacity per unit area of the negative electrode to the discharge capacity per unit area of the positive electrode is from 1.5 to 3, and the ratio of the thickness (mum) of the negative electrode active material to the arithmetical mean roughness Ra (mum) of the surface of the negative electrode current collector is 50 or less.