Tailoring Stabilized Multilevel Dynamic Structure Evolution Enables 4.6 V High-Voltage Single-Crystal Ni-Rich Cathode

Ni-rich layered oxides (Li[Ni_xCo_yMn_{1- x - y}]O₂ (NCM, x≥0.8)) are promising cathodes for high-energy lithium-ion batteries but suffer from the inherent chemomechanical, structural, and interfacial instability, leading to severe dynamic structural degradation, especially under high-voltage operation. Herein, a self-engineered lattice modification has been developed for a single-crystal Ni-rich cathode by simultaneously incorporating Zr and Al via a facile thermal treatment. The mechanism of high-voltage stable performance and the optimized multilevel dynamic structure evolution in cation diffusion, microstructure, and interfaces are systematically unraveled by in situ measurement and theory calculation/simulation. The Al/Zr co-doping effectively suppresses the harmful phase transition and mitigates anisotropic lattice distortions, thus alleviating the formation of intragranular cracking and particle gliding. Moreover, it also reduces the Li/Ni cation mixing, facilitates stable Li⁺-diffusion, and prevents inhomogeneous Li⁺-distribution, effectively suppressing internal stress. Additionally, the irreversible bulk lattice rearrangement and interfacial parasitic reaction are efficiently mitigated, facilitating the stable interface. As anticipated, it demonstrates a notably improved capacity retention rate of 96.8% after 100 cycles at 1C at 3.0-4.5 V, significantly surpassing the pristine cathode (76.0%). Even at a high cutoff voltage of 4.6 V, it retains 87.8% capacity, realizing a high energy density of 774.1 Wh kg^-1 cathode. This research offers valuable insights into stabilizing the bulk lattice and surface chemistry of single-crystal Ni-rich cathodes, paving the way for the large-scale development of advanced durable LIBs.