Decoupled Catalysis in Lithium-Oxygen Batteries: Directed Oxygen-Species Spillover Between Dual Single-Atoms to Circumvent Linear Scaling Limit.

Abstract

Oxygen species spillover across sites in heterogeneous catalysis is a core strategy for reconfiguring reaction pathways and overcoming the theoretical limits of the Sabatier volcano plot. The key lies in achieving thermodynamic decoupling and kinetic synergy in multi-step reactions. Based on Hard-Soft Acid-Base (HSAB) theory, this study constructs a series of Co-based Ln (Sm, Eu, Gd, Tb, and Dy) dual single-atom catalytic systems (CoLn-DAC) through selective coordination design, serving as model platforms to decouple the fundamental electron-transfer steps in electrochemical reactions. Directional oxygen species spillover is captured at the dual-single-atom scale: oxygen-philic Ln sites activate O₂ and sequester LiO₂, followed by dynamic lithiation and recombination within accessible migration channels engineered by energy gradients, ultimately localizing at sub-central Co sites for further decomposition and desorption. Through oxygen-shuttling-mediated decoupling of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), a spatially tandem closed-loop catalytic pathway is realized, fundamentally bypassing traditional scaling relationships. Theoretical calculations and experimental results confirm CoGd-DAC as the optimal catalyst with exceptional overall catalytic performance. This work proposes a dynamic cascade catalytic design strategy that extends remote active-site functionality and transcends traditional catalyst-design dimensional constraints.