Lithium ion secondary battery
Provided is a lithium ion secondary battery including a positive electrode, a negative electrode, a separator, and an electrolyte solution, in which the separator contains 0.02 to 0.11 wt % of sulfur relative to the weight of the separator.
1. A lithium ion secondary battery comprising:
a positive electrode;
a negative electrode;
a separator; and
an electrolyte solution,
wherein the separator contains 0.02 to 0.11 wt % of sulfur relative to a weight of the separator, and
wherein the separator comprises an olefin resin layer and a heat-resistant microparticle layer.
2. The lithium ion secondary battery according to claim 1 , wherein the sulfur is contained in the heat-resistant microparticle layer.
3. The lithium ion secondary battery according to claim 1 , wherein the heat-resistant microparticle layer includes at least one of alumina and boehmite.
4. The lithium ion secondary battery according to claim 1 , wherein a positive electrode active material layer included in the positive electrode includes a lithium nickel cobalt manganese composite oxide having a layered crystal structure and represented by general formula Li x Ni y Co z Mn (1−y−z) O 2 (where “x” is a numeral satisfying 1≤x≤1.2, “y ” and “z” are positive numerals satisfying y+z<1, and “y” is a numeral of 0.5 or less).