Bifunctional catalytic activity of LaCoO3 perovskite air electrode for rechargeable Zn-air batteries boosted by molybdenum doping

Perovskite oxides are widely regarded as efficient and low-cost catalytic materials for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on the air -electrode side of zinc -air batteries (ZABs). Herein, LaCo1-xMoxO3 (LCM, x = 0, 0.05, 0.1, and 0.15) perovskite electrocatalysts are prepared by selfpropagating high -temperature synthesis and evaluated as the bifunctional electrocatalytic activity for ZABs. Results show that the ORR and OER activities of LaCoO3 (LCO) can be efficiently enhanced simultaneously with the proper substitution of Mo for Co, and the optimal performance is obtained in LaCo0.95Mo0.05O3 (LCM-5). In comparison with LCO, LCM-5 demonstrates significantly enhanced bifunctional catalytic activity, in which a more positive ORR onset potential (0.861 V) at -0.1 mA cm -2 and a lower OER overpotential (405 mV) at 10 mA cm -2 are achieved. When using LCM-5 as an air electrode catalyst for ZABs, it delivers a specific discharge capacity of over 800 mA h g-1, a high power density of 136.1 mW cm -2, and excellent long-term cycle stability (120 h at 10 mA cm -2). This finding is primarily due to the regulation of the B -site Co valence states and the increase in surface oxygen vacancies. This study suggests the possibility of enhancing the bifunctional catalytic activity of LaCoO3 perovskite air electrodes for ZABs by a simple doping process.