Murata Manufacturing Co., Ltd.

Swati Devi

Takaaki Matsui

Yuta Hirano

Shinichi Katayama

Tomoyo Ooyama

A secondary battery includes: a positive electrode; a negative electrode including a negative electrode active material layer on which a film including an organic substance is formed; and an electrolytic solution including a sulfur-containing cyclic compound, a fluorinated cyclic carbonic acid ester, an unsaturated cyclic carbonic acid ester, and a multi-nitrile chain compound. According to a mass analysis of the electrolytic solution using gas chromatography-mass spectrometry, a content of the sulfur-containing cyclic compound, a content of the fluorinated cyclic carbonic acid ester, a content of the unsaturated cyclic carbonic acid ester, and a content of the multi-nitrile chain compound in the electrolytic solution each satisfy the following relation: the content of the multi-nitrile chain compound>the content of the fluorinated cyclic carbonic acid ester>the content of the sulfur-containing cyclic compound>the content of the unsaturated cyclic carbonic acid ester, and the total sum of those contents is greater than or equal to 5.0 wt % and less than or equal to 11.0 wt %.

Secondary battery

A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode active material layer. The positive electrode active material layer includes N-methyl-2-pyrrolidone. Where the positive electrode active material layer is divided equally in a width direction into two end regions and two middle regions located between the two end regions, a ratio of a content of N-methyl-2-pyrrolidone in the two middle regions to a content of N-methyl-2-pyrrolidone in the two end regions is greater than or equal to 4 and less than or equal to 8.

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Kyoto, Japan

Swati Devi