Lithium ion secondary battery

Abstract

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.

1 . A lithium ion secondary battery comprising:
 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, wherein the nonaqueous electrolyte is a nonaqueous electrolyte containing a polymer, and at least a part of the lithium salts are imide lithium salts.   
     
     
         2 . The lithium ion secondary battery according to  claim 1 ,
 wherein a content of the cyclic sulfonic acid ester is in a range of 2.0% to 5.0% by mass with respect to a total content of the nonaqueous electrolyte.   
     
     
         3 . The lithium ion secondary battery according to  claim 1 ,
 wherein a proportion of the imide lithium salts is in a range of 10 to 50 mol % with respect to a total amount of lithium salts in the nonaqueous electrolyte.   
     
     
         4 . The lithium ion secondary battery according to  claim 1 ,
 wherein a content of the polymer in the nonaqueous electrolyte is in a range of 0.5% to 2.0% by mass with respect to the total content of the nonaqueous electrolyte.   
     
     
         5 . The lithium ion secondary battery according to  claim 1 ,
 wherein the positive electrode contains a lithium nickel composite oxide as a positive electrode active material.   
     
     
         6 . The lithium ion secondary battery according to  claim 5 ,
 wherein the lithium nickel composite oxide is a compound represented by Li a Ni x M 1-x O 2  (0<a<1.2, 0.45<x<0.95, M represents at least one or more elements selected from Mn, Co, Fe, Zr, and Al).