Secondary batteries

Abstract

To improve charge and discharge characteristics. [Solution] The secondary battery comprises a positive electrode, a negative electrode, and an electrolyte. The positive electrode comprises 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. The electrolyte comprises an electrolyte, a solvent, and an additive. The electrolyte contains a bis(fluorosulfonyl)imide salt. The solvent contains at least one from the first group consisting of ethylene carbonate, propylene carbonate, fluoroethylene carbonate, dimethyl carbonate, and gamma butyrolactone. The additive contains at least one from lithium fluorophosphate, sulfinyl compounds, and dinitrile compounds. The intrinsic molar ratio of the solvent to lithium ions, calculated from the vibrational spectroscopy spectrum of the electrolyte, is greater than 0 and 1.78 or less.

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