ELECTROLYTE ADDITIVE AND LITHIUM SECONDARY BATTERY COMPRISING SAME

The present invention provides an electrolyte additive comprising a salt of an anion, derived from a nitrogen-atom-containing compound, with Cs+ or Rb+. Further, the present invention provides an electrolyte additive further comprising lithium difluoro bis(oxalato) phosphate. The present invention provides a non-aqueous electrolyte comprising a lithium salt, a non-aqueous organic solvent, and the electrolyte additive, and may provide a lithium secondary battery comprising: a cathode employing a cathode active material; an anode employing an anode active material; a separator interposed between the cathode and the anode; and the non-aqueous electrolyte.