Asymmetrical Ru–O–Mn Bridge Active Sites Fully Decouple Bifunctional Oxygen Electrocatalysis for Rechargeable Zinc-Air Batteries

Abstract

A high-performance bifunctional electrocatalyst toward oxygen evolution/reduction reactions (OER/ORR) is critical for rechargeable zinc-air batteries (ZABs). However, the binding energy scaling of reaction intermediates impedes full optimization of the electrocatalyst, leading to poor bifunctional activity and low efficiency. Here, the OER/ORR cycles are effectively decoupled over a Mn 0.3 Ru 0.7 O 2 catalyst by asymmetrical “Ru–O–Mn” dual-bridge active sites, with OER intermediates coordinated over the “Ru–O” site and ORR intermediates over the “Mn” site. Due to the metal–oxygen covalency competition between the two sites, lattice oxygen-mediated O–O coupling on the Ru–O site is promoted, whereas the overbinding of *OOH on the Mn site is mitigated to enhance the OER and ORR, respectively, leading to a low ORR–OER potential gap of 0.63 V. The Mn 0.3 Ru 0.7 O 2 -assembled ZAB exhibits a high-power density of 179 mW cm –2 and a long lifespan of over 800 h, outperforming the [Pt/C||RuO 2 ] benchmark. These findings rationalize the design of Ru–O–Mn dual-bridge sites for bifunctional oxygen electrocatalysis and provide a strategy to enhance the ORR/OER bifunctionality for high-performance ZABs.