Spatially confined sub-nanometer Pt in RuO₂ nanosheet as robust bifunctional oxygen electrocatalyst for stabilizing Li-O₂ batteries

Developing a highly active and durable bifunctional oxygen catalyst is the key to boosting lithium-oxygen batteries, but it remains a grand challenge. Herein, we demonstrate a remarkably active and durable bifunctional electrocatalyst (Pt/RuO₂/G) with highly exposed active sites for stabilizing Li-O₂ batteries by synergistically coupling the advanced oxygen reduction reaction (ORR) catalyst Pt with the oxygen evolution reaction (OER) catalyst RuO₂, strongly anchored on graphene. The combined merits, including 2D porous morphology, ultrathin thickness (∼2.5 nm), and a well-dominated (110) plane of ultrasmall RuO₂, originating from the efficient spatial confinement, provide the bifunctional Pt/RuO₂/G electrocatalyst an extremely narrow OER/ORR voltage gap of only 0.633 V. Moreover, the as-designed Pt/RuO₂/G-based Li-O₂ batteries deliver a low initial charge-discharge mid-capacity overpotential (0.78 V) and remarkable lifetime (2,200 h) at 200 mA g⁻¹, outperforming most Ru-based catalysts for Li-O₂ batteries. This work provides a reliable practical approach for high-performance Li-O₂ batteries.