NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY

A non-aqueous electrolyte secondary battery according to one aspect of the present invention includes: a positive electrode plate in which a positive electrode mixture layer containing a positive electrode active material is formed on a positive electrode current collector; a negative electrode plate in which a negative electrode mixture layer containing a negative electrode active material is formed on a negative electrode current collector; a separator; a non-aqueous electrolyte; a sealing member; and an outer casing. The negative electrode active material contains graphite and a silicon material. The silicon material contains silicon oxide represented by SiO(0.5≤x