Interfacial Electron Transfer in Strategically Engineered Pt₃Rh/C Ultrafine Alloy Nanoparticle Catalysts Facilitates Exceptional Performance in Li-O₂ Batteries

A major challenge for Li-O₂ batteries is the slow kinetics of oxygen reduction (ORR) and evolution (OER) reactions. This work presents a high-performance Pt₃Rh/C composite cathode where Pt-Rh nanoalloys are uniformly dispersed on 3D nanoporous carbon. The bimetallic architecture demonstrates significantly enhanced ORR/OER activity compared to conventional catalysts. Super P, with a large specific surface area and omnipresent pores with diverse size distribution, provided sufficient storage space for Li₂O₂ and facilitated transport channels for Li⁺ and O₂, while the highly conductive Pt₃Rh NPs optimized catalytic efficiency. XPS reveals a prominent electron transfer process between Pt and Rh; the Rh sites in Pt₃Rh/C alloy can effectively act as electron donors to improve the oxygen/lithium peroxide (O₂/Li₂O₂) redox chemistry in LOB. Therefore, the Pt₃Rh/C electrode shows the minimum overpotential (0.60 V) for efficient oxygen reduction and evolution under an upper-limit capacity of 2000 mAh g⁻¹. This work introduces a Pt₃Rh/C nanoalloy synthesis method that boosts Li-O₂ battery efficiency by accelerating oxygen reaction kinetics.