Y.J. Li, Y.G. Li, Y.J. Ding, J.X. Ma, P. Das, B. Zhang, Z.-S. Wu*, X.H. Bao

Chem Catalysis, 2023, 3.

DOI: 10.1016/j.checat.2023.100658 [PDF]

Developing highly active, durable and commercialized bifunctional oxygen catalyst is the key for boosting rechargeable lithium-oxygen batteries, but remains a grand challenge. Herein, a remarkably active and durable bifunctional electrocatalyst (Pt/RuO2/G) with highly exposed active sites for extraordinarily stabilizing Li-O2 batteries is demonstrated by synergistically coupling the advanced oxygen reduction reaction (ORR) catalyst Pt with oxygen evolution reaction (OER) catalyst RuO2, both of which are strongly anchored on graphene. The as-designed Pt/RuO2/G catalyst shows 2D porous morphology, ultrathin thickness of ~2.5 nm, and well-dominated (110) plane of ultrasmall RuO2, originating from the efficient spatial confinement by the O on the surface of RuO2 and monodispersed sub-nanometer Pt. Benefiting from these merits, this bifunctional Pt/RuO2/G electrocatalyst achieves an extremely narrow OER/ORR voltage gap of only 0.633 V, superior to most reported bifunctional oxygen catalysts. Besides, a low initial charge-discharge mid-capacity overpotential of 0.78 V is afforded in our Li-O2 batteries. Notably, its lifetime far exceeds 220 cycles (2200 h) at 200 mA g-1 under cutoff capacity of 1000 mAh g-1, outperforming most Ru-based catalysts for Li-O2 batteries. Theoretical results reveal that the improved conductivity and weakened adsorption of spatially confined Pt/RuO2/G onto the intermediates (e.g., LiO2) lead to lower overpotentials and enhanced stability compared with pure RuO2. This work provides a reliable practical approach for achieving high-performance rechargeable Li-O2 batteries.