Crown Ethers in Nonaqueous Electrolytes for Lithium/Air Batteries

Crown ethers can significantly affect the discharge performance of nonaqueous electrolytes in Li/air batteries. A small amount ( < 10 wt % ) of crown ethers reduces battery performance, and a minimum discharge capacity appears at ca. 5 wt % of crown ether in the electrolytes. When the content increases to 15 wt %, both 12-crown-4 and 15-crown-5 improve the capacity of Li/air cells by about 28% and 16%, respectively. The 15-crown-5-based electrolytes even show a maximum discharge capacity in the crown ether content range of 10–15 wt %. However, increasing the amount of 18-crown-6 in the electrolytes continuously lowers the cell performance.