Synergistic Catalysis of the Lattice Oxygen and Transition Metal Facilitating ORR and OER in Perovskite Catalysts for Li-O-2 Batteries

Abstract

The role of catalysts in aprotic Li-O-2 batteries remains unclear. To identify the exact catalytic nature of oxide catalysts, a precisely surface-engineered model catalyst, perovskite (LaMnO3), was investigated for oxygen reduction reaction/oxygen evolution reaction (ORR/OER) in both aqueous and aprotic solutions. By using integrated theoretical and experimental approaches, we explicitly show that H+-ORR/OER catalytic activity on transition-metal sites fails to completely describe the electrochemical performance of LaMnO3 catalysts in aprotic Li-O-2 batteries, whereas the collective redox of the lattice oxygen and transition metal on the catalyst surface during initial Li2O2 formation determines their discharge capacity and charge overpotential. This work applies oxide catalyst design to tailor both the surface lattice oxygen and the transition-metal arrangement for an aprotic Li-O-2 battery. The optimized model catalyst shows good performance for Li-O-2 batteries under both oxygen and ambient air (real air) conditions.