Tuning Dual Catalytic Active Sites of Pt Single Atoms Paired with High-Entropy Alloy Nanoparticles for Advanced Li-O Batteries.

To achieve a long cycle life and high-capacity performance for Li-O batteries, it is critical to rationally modulate the formation and decomposition pathway of the discharge product LiO. Herein, we designed a highly efficient catalyst containing dual catalytic active sites of Pt single atoms (Pt) paired with high-entropy alloy (HEA) nanoparticles for oxygen reduction reaction (ORR) in Li-O batteries. HEA is designed with a moderate d-band center to enhance the surface adsorbed LiO intermediate (LiO(ads)), while Pt active sites exhibit weak adsorption energy and promote the soluble LiO pathway (LiO(sol)). An optimal ratio between LiO(ads) and LiO(sol) pathway was realized to modulate Pt and HEA active sites via regulating the etching conditions in the dealloying synthesis process for obtaining high-performance Li-O batteries. The ORR kinetics are accelerated, and the parasitic reactions are restrained in the Li-O batteries. As a result, Li-O batteries based on the HEA@Pt-Pt catalyst demonstrate an ultralow overpotential (0.3 V) and ultralong cycling performance of 470 cycles at 1000 mA g. The insights into the synthetic strategies and the importance of balancing the ORR pathways will offer guidance for devising multisite synergistic catalysts to accelerate redox-reaction kinetics for Li-O batteries.