Wadsley–Roth Phase Armored Ultra‐Stable Ni‐Rich Cathodes via Synergistic Interfacial Engineering

ABSTRACT Rapid charging triggers phase transitions and interfacial degradation, which results in rapid capacity fading in nickel‐rich layered oxide cathodes (LiNi x Co y Mn z O 2 , NCM) and restricts the realization of their high energy density advantages. Herein, a dual‐modification strategy is developed by employing the Wadsley–Roth phase fast ionic conductor NaNb 13 O 33 (NNO) to achieve simultaneous Nb bulk doping and the construction of an epitaxial coating on LiNi 0.8 Co 0.1 Mn 0.1 O 2 . The lattice‐matched NNO coating, featuring exceptionally wide interlayer spacing and robust structural stability, effectively suppresses phase‐induced structural degradation and enhances interfacial Li + kinetics. Combined analyses from density functional theory (DFT) calculations, in situ X‐ray diffraction (XRD), transmission electron microscopy (TEM), and time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) reveal that the NNO epitaxial layer and Nb doping collaboratively mitigate unit cell volume changes and promote Li + diffusion, even under rigorous cycling conditions. Consequently, the optimized cathode (NCM@NNO‐2) delivers outstanding electrochemical stability, retaining 86.7% of its initial capacity after 300 cycles at a high rate of 7C, and exhibits a high discharge capacity of 149.7 mAh g −1 at an ultrahigh rate of 10C. This work pioneers the atomic‐scale stabilization of NCM materials through lattice‐coherent coatings, offering a novel and effective avenue for designing high‐performance, fast‐charging battery cathodes.