Single‐Atom Immobilization Boosting Oxygen Redox Kinetics of High‐Entropy Perovskite Oxide Toward High‐Performance Lithium‐Oxygen Batteries

Abstract

AbstractUnderstanding and modulating the unique electronic interaction between single‐metal atoms and high entropy compounds are of great significance to enable their high‐efficiency oxygen electrocatalysis for aprotic lithium‐oxygen (Li‐O2) batteries. Herein, a novel bi‐functional electrocatalyst is for the first time created by immobilizing single‐atom ruthenium (Ru) on lanthanum‐based high entropy perovskite oxide La(Mn0.2Co0.2Fe0.2Ni0.2Cr0.2)O3 (Ru@HEPO), which demonstrates high activity and stability in Li‐O2 batteries. The heteronuclear coordination between single‐atom Ru and HEPO facilitates fast electron transfer from Ru to HEPO by establishing Ru‐O‐M (M stands for Mn, Co, Fe, Ni) bridges, which well redistributes electrons within the Ru@HEPO hence significantly improving its interfacial charge transfer kinetics and electrocatalytic activity. Additionally, the strong electron coupling between Ru and Mn atoms enhances the hybridization between Mn 3d and O 2p orbitals, which promotes the inherent affinity of Ru@HEPO toward the LiO2 intermediate, thereby reducing the reaction energy barrier of the oxygen electrode. As a result, the Ru@HEPO‐based Li‐O2 batteries deliver remarkable electrochemical performances, such as high energy efficiency (87.3% at 100 mA g−1), excellent rate capability (low overpotential of 0.52 V at 100 mA g−1) and durable cyclability (345 cycles at 300 mA g−1). This work opens up a promising avenue for the development of high entropy‐based electrocatalysts for Li‐O2 batteries by precisely tailoring the electronic distributions at an atomic scale.