Efficient Li₂O₂ Formation via Aprotic Oxygen Reduction Reaction Mediated by Quinone Derivatives

Abstract

Since the oxygen reduction reaction (ORR) in aprotic Li ion electrolytes accompanied by Li₂O₂ formation is a crucial reaction for the discharge of nonaqueous aprotic Li–air batteries, there is a strong demand for a reduction in the overpotential of the reaction in order to improve the discharge performance. In the present work, we investigated the effect of the addition of quinone derivatives for ORR on carbon materials in aprotic Li⁺–electrolytes. Detailed electrochemical analysis revealed that the semiquinone species catalyze the aprotic ORR, resulting in the efficient Li₂O₂ formation. Among the quinone derivatives, benzoquinone exhibited the best catalytic performance, with an overpotential for the Li₂O₂ formation of less than 100 mV