LITHIUM SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a secondary battery with a small capacitance reduction due to high temperature storage and excellent in cycle characteristics and reliability by adding a ligand in a battery at a specific mol ratio with respect to a support salt and by arranging the ligand on the surface of positive and negative electrodes and the interface of an electrolyte layer, the ligand being a cyclic structure having a selectivity to a lithium ion stronger than that to a solvent or an anion and having a specific value or more of a hole diameter. SOLUTION: In this lithium secondary battery, as a solvent of an electrolyte, a cyclic carbonate is mixed with a chain carbonate or a fatty carboxylic ester is mixed with these carbonates to obtain a mixture; the mixture constitutes 80% by volume of the total solvent. A support salt selected from a perchloric acid (ClO4-) and a fluoride borate (BF4-) is used because coordination capacity to the anion is low. A ligand of a cyclic structure having a selectivity to a lithium ion stronger than that to a solvent or an anion and having a hole diameter of 1.7 A or more is added in a battery at a mol ratio ranging in 10-1-10-4 to the support salt and is arranged on the surface of positive and negative electrodes and the interface of an electrolyte layer.