LITHIUM ION SECONDARY BATTERY

摘要

A lithium ion secondary battery that is furnished with a positive electrode with high thermostability and that even in a nail penetration test, markedly reduces the possibility of falling into thermal runaway. There is provided a lithium ion secondary battery comprising a positive electrode in which a composite lithium oxide is contained and a porous membrane bonded to at least one selected from among a positive electrode surface and a negative electrode surface, wherein the porous membrane comprises an inorganic oxide filler and a membrane binding agent and wherein the composite lithium oxide is represented by the formula: Lia(Co1-x-yM<1>xM<2>y)bO2 (in the formula, the element M<1> is at least one member selected from the group consisting of Mg, Sr, Y, Zr, Ca and Ti; the element M<2> is at least one member selected from the group consisting of Al, Ga, In and Tl; and 0