A Dual-Functional Synergetic Strategy Enhances the Interfacial and Structural Stability of LiCoO₂ at High Voltage

With the advent of the 5G era, the widespread application of various smart devices and cutting-edge technologies has imposed stringent requirements on the battery lifespan and durability. This study proposes a synergistic modification strategy combining Mg²⁺ and Y³⁺ dual doping with Li₃PO₄ coating. Herein, Mg²⁺ exhibits a gradient distribution near the surface and a uniform distribution inside, enhancing electronic conductivity while facilitating the penetration of the Y element into the particle interior. What is more, the addition of Y³⁺ significantly widens the Li⁺ transmission channels, greatly enhancing the rapid charge-discharge performance. The synergistic interaction of Mg²⁺ and Y³⁺ stabilizes the internal structure, while the Li₃PO₄ coating serves to effectively block a direct interaction between the electrolyte and the cathode surface, stabilizing the surface structure and improving the long-term cycling performance. The findings indicate that the synergistic approach adjusts the Co 3d and O 2p energy bands, effectively suppressing the hybridization phenomenon of Co and O orbitals. Remarkably, the proposed strategy maintains a superb capacity retention rate of nearly 80% after 300 cycles at 4.6 V, and it exhibits an excellent reversible capacity of 109.6 mAh·g^-1 even at 10 C, thus demonstrating the superior overall performance and vast application potential of this approach.