Abstract text

A non-aqueous electrolyte secondary battery includes: a positive electrode including a transition metal oxide capable of absorbing and desorbing lithium ions; a negative electrode capable of absorbing and desorbing lithium ions; a separator; and a non-aqueous electrolyte. A polyamide film or a porous film containing an inorganic oxide is disposed at least between the positive electrode and the negative electrode, and an unsaturated sultone is added to the non-aqueous electrolyte. This can suppress deterioration in the rate characteristics of the non-aqueous electrolyte secondary battery after storage at a high temperature and improve the storage characteristics of the battery, while maintaining the initial rate characteristics of the battery.