Integrated Local‐Microstructure Engineering Toward Mechanochemically Robust Ultra‐High Nickel Cathodes

Abstract

ABSTRACT Ni‐rich layered cathodes show exceptional promise for next‐generation high‐energy‐density lithium‐ion batteries. However, higher nickel utilization in layered cathodes readily exacerbates both bulk mechanical failure and interfacial chemistry instability, significantly hindering their practical application. Herein, a comprehensive local lattice regulation strategy was proposed via Mg/Nb co‐doping, which constructed a chemically and mechanically co‐robust LiNi 0.95 Co 0.03 Mn 0.02 O 2 cathode from surface to bulk. The surface‐reconstructed ultrathin disordered rock‐salt phase effectively stabilized the electrochemical interface. Meanwhile, the bulk cation‐disordered structure integrated with a coherent spinel‐like phase mitigated lattice strain and enhanced structural integrity. Therefore, the modified ultra‐high nickel cathode exhibited excellent long‐term cycling stability, high rate capability, and thermal stability. It exhibited high initial coulombic efficiency of 93.24% and a discharge specific capacity of 240.11 mAh·g −1 at 0.1C. It could also deliver a high initial capacity of 210.44 mAh·g −1 at 1C and retain 97.37% of its capacity after 100 cycles. Moreover, it exhibited outstanding performance during cycling at 3C, delivering a superior capacity retention of 81.65% after 500 cycles. It also delivered a remarkable specific capacity of 147.43 mAh·g −1 even at the rate of 15C. This integrated microstructure regulation strategy would pave the way for commercializing ultra‐high‐nickel cathodes in next‐generation high‐energy‐density batteries.