ELECTROLYTE COMPOSITION AND SECONDARY BATTERY USING SAME

An electrolyte composition contains a propane sultone compound substituted with a specific substituent, a cyclic fluorocarbonate-based compound and a nonaqueous solvent. A secondary battery containing the electrolyte composition is disclosed. The electrolyte composition has excellent SEI film-forming ability and HF-removing ability by containing the cyclic fluorocarbonate-based compound together with the propane sultone compound substituted with a specific substituent, so that the lifespan characteristic and stability at high temperature can be improved.