Enhancing Long‐Term Cycling Stability of Co‐Free Ultrahigh‐Ni Layered Cathode Materials via Synergistic Structure/Interface Engineering

Abstract The development of Co‐free ultrahigh‐Ni (Ni > 0.9) layered oxide cathode materials holds immense promise for addressing electric vehicle range limitations and cost efficiency, though substantial obstacles persist in structural durability, thermal stability, and safety. To concurrently enhance the structural integrity and interfacial stability of LiNi 0.95 Mn 0.05 O 2 , a dual‐functional co‐regulation strategy integrating Zr/Al bulk doping with Li 6 Zr 2 O 7 surface coating is implemented. Controlled Zr 4+ /Al 3+ co‐incorporation expands interlayer spacing, strengthens transition metal–oxygen bonding, and stabilizes the oxygen framework, thereby improving Li + diffusion kinetics while suppressing cation disorder. Concurrently, the epitaxially Li 6 Zr 2 O 7 coating effectively passivates the surface by eliminating residual lithium species, inhibiting grain coarsening, and suppressing interfacial side reactions. These coupled bulk‐surface modifications synergistically inhibit mechanical stress‐induced crack propagation and deleterious phase transformations. Therefore, the optimized cathode achieves 96.9% capacity retention after 100 cycles at 1 C, while maintaining stable operation under extreme electrochemical conditions (4.5 V cutoff voltage) and thermal extremes (−10 °C/60 °C). This work demonstrates a synergistic modification paradigm for designing robust ultrahigh‐Ni cathodes, thereby propelling the advancement of next‐generation high‐energy density lithium‐ion batteries.