Abstract: An electrolytic solution for a secondary battery includes a lithium salt, a sulfonyl compound, and a fluorinated ether compound. The sulfonyl compound includes two or more selected from cyclic compounds and chain compounds. The sulfonyl compound includes at least one of the cyclic compounds. Each of the cyclic compounds is represented by Formula (1). Each of the chain compounds is represented by Formula (2). The fluorinated ether compound is represented by Formula (3). A concentration of the lithium salt is higher than or equal to 1.159 mol/L and lower than or equal to 3.592 moles per liter. A ratio of a number of moles of the sulfonyl compound to a number of moles of the lithium salt is greater than or equal to 2 and less than or equal to 4.

Abstract: A production method for a cathode material of a lithium sulfur battery includes, in sequence: a step of preparing a first dispersed solution in which a carbon particle is dispersed in a lithium sulfate solution; a step of adding a solvent in the first dispersed solution, the solvent being a solvent in which lithium sulfate is insoluble; a step of separating a precursor particle from the first dispersed solution in which the solvent is added; and a step of changing the precursor particle into a cathode active material particle by heating the precursor particle under an inert atmosphere.

Abstract: A carbon material according to an embodiment contains: 2% by mass or more and 15% by mass or less of nitrogen and 0.3% by mass or more and 2.5% by mass or less of sulfur, and 40% by mass or more of the nitrogen is a graphitic nitrogen.

Abstract: A production method for a cathode material of a lithium sulfur battery includes, in sequence: a step of preparing a first dispersed solution in which a carbon particle is dispersed in a lithium sulfate solution; a step of adding a solvent in the first dispersed solution, the solvent being a solvent in which lithium sulfate is insoluble; a step of separating a precursor particle from the first dispersed solution in which the solvent is added; and a step of changing the precursor particle into a cathode active material particle by heating the precursor particle under an inert atmosphere.

Abstract: An alkali metal-sulfur-based secondary battery, in which coulombic efficiency is improved by suppressing a side reaction during charge, and a reduction in discharge capacity by repetition of charge and discharge is suppressed and which has a long battery life and an improved input/output density, includes a positive electrode or a negative electrode containing a sulfur-based electrode active material; an electrolyte solution containing an ether compound such as THF and glyme and a solvent such as a fluorine-based solvent, wherein at least a part of the ether compound and the alkali metal salt forms a complex; and a counter electrode.

Abstract: A carbon material according to an embodiment contains: 2% by mass or more and 15% by mass or less of nitrogen and 0.3% by mass or more and 2.5% by mass or less of sulfur, and 40% by mass or more of the nitrogen is a graphitic nitrogen.

Abstract: An alkali metal-sulfur-based secondary battery, in which coulombic efficiency is improved by suppressing a side reaction during charge, and a reduction in discharge capacity by repetition of charge and discharge is suppressed and which has a long battery life and an improved input/output density, includes a positive electrode or a negative electrode containing a sulfur-based electrode active material; an electrolyte solution containing an ether compound such as THF and glyme and a solvent such as a fluorine-based solvent, wherein at least a part of the ether compound and the alkali metal salt forms a complex; and a counter electrode.