12-crown-4(EOCT, Ethylene oxide cyclic tetramer) is an effective phase-transfer catalyst and complexing agent for lithium, facilitating the dissolution of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) without requiring acetonitrile. It selectively binds to lithium ions and forms stable complexes, significantly improving electrolyte conductivity in lithium batteries, and positively influencing ion mobility and overall battery performance.