Patent ID: 8349496

Claim:
A non-aqueous electrolyte secondary battery comprising: a negative electrode, a non-aqueous electrolyte comprising a carbonate-based solvent containing a lithium salt, and a positive electrode having a positive electrode active material comprising sodium oxide, characterized in that: the sodium oxide is represented by the general formula Na a Li b M x O 2±α , where 0.5≦a≦1.0, 0<b<0.5, 0.6≦a+b≦1.1, 0.90≦x≦1.10, and 0≦α≦0.1, and M is at least one element selected from the group consisting of manganese, iron, cobalt, and nickel; and the sodium oxide has a main peak at 2θ=15.9° to 16.9° as determined by X-ray powder crystal diffraction (Cukα).