Patent ID: 7445872

Claim:
A lithium sulfur battery comprising: a cathode; an anode; a separator interposed between the cathode and the anode; and an organic electrolytic solution comprising: a lithium salt; an organic solvent; and an oxalate compound of formula (1) below: where R 1 and R 2 are independently selected from hydrogen atom, halogen atom, a hydroxy group, a substituted or unsubstituted C 1 -C 20 alkyl group, a substituted or unsubstituted C 1 -C 20 alkoxy group, a substituted or unsubstituted C 1 -C 20 alkenyl group, a substituted or unsubstituted C 6 -C 30 aryl group, a substituted or unsubstituted C 6 -C 30 arylalkyl group, a substituted or unsubstituted C 6 -C 30 aryloxy group, a substituted or unsubstituted C 2 -C 30 heteroaryl group, a substituted or unsubstituted C 2 -C 30 heteroarylalkyl group, a substituted or unsubstituted C 2 -C 30 heteroaryloxy group, a substituted or unsubstituted C 5 -C 20 cycloalkyl group, and a substituted or unsubstituted C 2 -C 20 heterocycloalkyl group, wherein the amount of the oxalate compound of said formula (1) is in a range of 0.001-10 parts by weight with respect to 100 parts by weight of the organic solvent, and wherein during use in said lithium sulfur battery said oxalate compound of formula (1) chelates with lithium ions and bonding between lithium ions and sulfide anions is blocked so that the solubility of sulfide ions is improved.