LITHIUM ION SECONDARY CELL

摘要

PURPOSE: A lithium ion secondary cell capable of preventing reductions of a capacity and charge and discharge efficiencies even though an electrolyte having a carbonate is used is provided. CONSTITUTION: In a lithium ion secondary cell, a cathode includes a cathode which has an active cathode material having a boron system compound. The active cathode material includes a boron system compound of 0.1 through 5 weight %. The boron system compound is a material selected from the group consisting of B4C, B2O3, and H3BO3. An anode includes a lithium transfer metal oxide capable of performing a reversible coming in and out operation of the lithium. A separator is present between the cathode and anode. An electrolyte is saturated in the cathode, anode, and separator. The electrolyte includes more than an annular carbonate 51 volume % and a chain carbonate.