Patent attributes
Provided is a lithium ion secondary battery including a positive electrode which is capable of storing and releasing lithium, a negative electrode which is capable of storing and releasing lithium, and a nonaqueous electrolyte which contains lithium salts and cyclic disulfonic acid ester, in which as the nonaqueous electrolyte, a nonaqueous electrolyte containing a polymer is used, and as at least a part of the lithium salts, imide lithium salts are used. Here, the content of the cyclic sulfonic acid ester is preferably in a range of 2.0% to 5.0% by mass with respect to a total content of the nonaqueous electrolyte. Also, the proportion of the imide lithium salts is preferably in a range of 10 to 50 mol % with respect to a total amount of lithium salts in the nonaqueous electrolyte.
