Potassium-Substituted LaMnO₃ as a Highly Active and Exceptionally Stable Electrocatalyst toward Bifunctional Oxygen Reduction and Oxygen Evolution Reactions

Abstract

Efficient, low-cost, and long-lasting electrocatalysts that accelerate sluggish oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) kinetics are highly desirable for a variety of applications, including metal–air batteries and fuel cells, but they are uncommon. Such bifunctional catalysts are primarily harmed by either low catalytic activity or degradation during prolonged cycling. We devise a relatively low-temperature hydrothermal strategy for producing a perovskite oxide-based catalyst composed of potassium-substituted LaMnO3. In an alkaline environment, the catalyst performs admirably, with improved kinetics and activity for the ORR (half-wave potential of 0.78 V) and OER (potential at the current density of 10 mA cm–2 is 1.66 V). Furthermore, as a two-electrode cell, this catalyst renders the potential for use as an electrode in zinc–air batteries with unprecedented stability (no visible sign of degradation even after 1000 cycles of charge–discharge).