This secondary battery comprises a positive electrode, a negative electrode, a separator positioned between the positive electrode and the negative electrode, and an electrolyte. The positive electrode has a positive electrode current collector, a positive electrode mixture layer containing a positive electrode active material, and an additional layer containing an inactive material. The inactive material is an Li-containing transition metal oxide having a crystal structure belonging to one space group from among Fm3m, C2/M, Immm, and P3m1. The inactive material content of the additional layer is 60 mass % or greater, and the basis weight of the additional layer is 3.8 g/m2 to 50 g/m2 (inclusive).