A study on enhanced cycle life of Li-air batteries by synergistic effect of blended electrolytes

Abstract

Despite the exceptionally large specific capacities, the use of Li-O2 batteries have been limited due to their poor cycle lives originating from irreversible reaction processes during each cycle. Recent investigations have found electrolyte decomposition as one of the most critical reasons for the capacity decay. Herein, this paper demonstrates that a blended electrolyte consisting of a carbonate solvent and an ionic liquid improves the cycle lives of Li-O2 batteries remarkably by engaging a synergistic effect from both components. Both electrolyte components perform complementary functions to each other, as the ionic liquid suppresses the decomposition of the carbonate solvent, while the carbonate solvent resolves the poor ionic conductivity of the ionic liquid. This study confirms the importance and opportunities of utilizing electrolytes in Li-O2 batteries.