Surface Spinel and Oxygen Vacancies Induced by Multi‐Gas‐Solid Reactions Enhance the Electrochemical Performance of Lithium‐Rich Manganese‐Based Oxide Cathodes

Abstract Lithium‐rich manganese‐based oxides (LRO) with ultra‐high energy density are regarded as promising candidates for the next generation of cathode materials. However, their commercial application is hindered by challenges such as irreversible oxygen releases, poor rate performance, and limited cycling stability. Here, a synergistic modification strategy involving spinel coating and the formation of oxygen vacancies in LRO induced by multi‐gas‐solid reactions is proposed to enhance the structural stability. The spinel coating provides a 3D channel for Li ⁺ diffusion and suppresses side reactions between the cathode material and the electrolyte. Oxygen vacancies enhance the conductivity of cathode materials while reducing the Li ⁺ migration energy barrier. As a result, the modified material achieved a coulombic efficiency of 94.75% in the first cycle, a discharge‐specific capacity of 199.4 mAh g ⁻¹ at 5C, and a reversible capacity of 211.8 mAh g ⁻¹ after 250 cycles at 1C. This study offers a new approach for the commercialization of lithium‐rich manganese‐based oxides with high energy density.