SECONDARY BATTERY

A secondary battery is provided and includes a secondary battery including a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode current collector containing aluminum and a positive electrode active material layer provided on the positive electrode current collector. The positive electrode active material layer contains a lithium-containing compound, a lithium carbonate, and a lithium hydroxide. The non-aqueous electrolytic solution contains an electrolyte salt and an organic solvent. The electrolyte contains a bis(fluorosulfonyl)imide salt. The surface of the positive electrode current collector contains sulfur. The photoelectron spectrum obtained in X-ray photoelectron spectroscopy for the surface of the positive electrode current collector has a first signal with a peak in a range of 164.1 eV or more and 164.5 eV or less and a second signal with a peak in a range of 168.9 eV or more and 169.3 eV or less. The ratio of the sum of the signal intensity of the first signal and the signal intensity of the second signal to the sum total of the signal intensities of the S2p spectrum is 0.97 or less.