Tuning Dual Catalytic Active Sites of Pt Single Atoms Paired with High-Entropy Alloy Nanoparticles for Advanced Li-O<sub>2</sub> Batteries
Lei Li, Minghao Hua, Jiafeng Li, Peng Zhang, Yingjian Nie, Peng Wang, Xiaohang Lin, Zhiwei Zhang, Rutao Wang, Xiaoli Ge, Yuguang Li, Longwei Yin
Abstract
To achieve a long cycle life and high-capacity performance for Li-O 2 batteries, it is critical to rationally modulate the formation and decomposition pathway of the discharge product Li 2 O 2 . Herein, we designed a highly efficient catalyst containing dual catalytic active sites of Pt single atoms (Pt SAs ) paired with high-entropy alloy (HEA) nanoparticles for oxygen reduction reaction (ORR) in Li-O 2 batteries. HEA is designed with a moderate d-band center to enhance the surface adsorbed LiO 2 intermediate (LiO 2 (ads)), while Pt SAs active sites exhibit weak adsorption energy and promote the soluble LiO 2 pathway (LiO 2 (sol)). An optimal ratio between LiO 2 (ads) and LiO 2 (sol) pathway was realized to modulate Pt SAs and HEA active sites via regulating the etching conditions in the dealloying synthesis process for obtaining high-performance Li-O 2 batteries. The ORR kinetics are accelerated, and the parasitic reactions are restrained in the Li-O 2 batteries. As a result, Li-O 2 batteries based on the HEA@Pt-Pt SAs catalyst demonstrate an ultralow overpotential (0.3 V) and ultralong cycling performance of 470 cycles at 1000 mA g –1 . 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 2 batteries.