Enabling Structural and Interfacial Stability via Coherent Interface Li3BO3 Coating for Lithium-Rich Manganese-Based Cathodes

Despite the high energy density of lithium-rich manganese-based (LR) cathode materials, the practical implementation in batteries has been impeded by the intrinsic issues regarding cycling. Herein, a coherent interface modification strategy is proposed. The LR materials are coated with a lattice-matched Li3BO3 (LBO) layer at the interface. The coating applied to the electrode has two impacts. (1) It reduces interfacial side reactions between the electrode materials and electrolyte, thereby improving structural stability. (2) It mitigates stress between solid particles, which enhances the cycling stability (83% after 500 cycles at 2C) of LR. Furthermore, the LBO coating promotes the development of a spinel-like structure on the electrode materials surface, eliminating unstable oxygen, increasing oxygen vacancy (Ov), consequently enhancing the initial Coulombic efficiency (ICE, 92.18%), and alleviating particle breakage (Young's moduli of LR@S@LBO is 3.26 ± 1.6 GPa) after optimization. Theoretical calculations show that Ov and spinel can improve the diffusion of Li+ and the structural stability of LR materials. This work shows great potential for the rational design of high-energy-density electrode materials.