Secondary battery

Abstract

The present invention improves charge / discharge characteristics. This secondary battery is provided with a positive electrode, a negative electrode, and an electrolyte solution. The positive electrode comprises: a positive electrode current collector containing aluminum; and a positive electrode active material layer provided to the positive electrode current collector. The positive electrode active material layer contains a lithium-containing compound. The electrolyte solution contains an electrolyte, a solvent, and an additive. The electrolyte includes a bis(fluorosulfonyl)imide salt. The surface of the positive electrode current collector contains sulfur. The additive includes at least one of lithium fluorophosphate, a sulfinyl compound, and a dinitrile compound. A photoelectron spectrum of the surface of the positive electrode current collector obtained by XPS has a first signal that has a peak in the range of 164.1 eV to 164.5 eV inclusive, and a second signal that has a peak in the range of 168.9 eV to 169.3 eV inclusive. The ratio of the sum of the signal intensity of the first signal and the signal intensity of the second signal to the sum of the signal intensities of the S2p spectrum is 0.97 or less.

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