| CPC H01M 10/0568 (2013.01) [H01M 4/362 (2013.01); H01M 10/0525 (2013.01); H01M 10/0563 (2013.01); H01M 2004/028 (2013.01)] | 12 Claims | 

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               1. A lithium-ion secondary battery comprising: 
              a positive electrode that includes a positive electrode active material; 
                a negative electrode; and 
                an electrolytic solution that includes a cyclic sulfuric acid ester compound represented by Formula (1), a cyclic ether compound represented by Formula (2), and a chain alkyl dinitrile compound represented by Formula (3), 
                wherein a ratio of a weight in milligrams of the cyclic sulfuric acid ester compound to a weight in grams of the positive electrode active material is from 0.01 to 2, 
              ![]() wherein 
                each of R1 to R6 represents one of a hydrogen group and a monovalent hydrocarbon group, and 
                n1 is an integer of 0 or greater, 
              ![]() wherein 
                each of R7 to R12 represents one of a hydrogen group and a monovalent hydrocarbon group, and 
                each of n2 and n3 is an integer of 1 or greater, and 
              ![]() wherein 
                each of R13 to R16 represents one of a hydrogen group and a monovalent hydrocarbon group, and 
                n4 is an integer of 0 or greater. 
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