Decoupling Chemo‐Mechanical Failure for Robust Li‐Rich Cathodes

Abstract

ABSTRACT Despite being renowned for their high specific capacity, Li‐rich Mn‐based layered cathodes (LRMs) are constrained by severe capacity degradation and structural deterioration during cycling. The persistent focus on chemical failure, driven by irreversible anionic redox and transition metal (TM) migration, has left the intimately coupled mechanical degradation largely overlooked, leaving the chemo‐mechanical interplay insufficiently resolved. Herein, we propose a synergistic void‐engineering and doping strategy to decouple this chemo‐mechanical degradation. The in situ formed voids act as stress‐absorbing reservoirs, releasing internal strain and thereby mitigating mechanical failure at its origin. Concurrently, La doping permeates the bulk lattice, strengthening La‐O covalency to rigidify the framework and suppress TM migration. This enhanced covalency further modulates the electronic band structure, depressing the non‐bonding O 2 p orbitals to limit excessive oxygen oxidation, while elevating the antibonding orbitals and optimizing the charge transfer energy, thus promoting highly reversible anionic redox at the atomic scale. The resulting cathodes exhibit exceptional structural and electrochemical reversibility, delivering a high specific energy density of 580.5 Wh kg −1 with 82.1% capacity retention after 300 cycles at 1C. This work shifts focus from chemical to mechano‐electrochemical synergistic stability, providing a viable route for designing robust high‐energy Li‐rich cathodes.