Synergy of Bulk Flexible Motif Buffer With Surface Engineering Enabling Mechanochemical Durability for Single‐Crystalline Ni‐Rich Layered Oxides

Abstract

The high specific capacity and cost efficiency of Ni‐rich layered oxides render them promising cathode materials for lithium‐ion batteries (LIBs). Nevertheless, the intrinsic chemicophysical instability of Ni‐rich layered oxides severely limits their application at scale. Herein, a motif buffer strategy coupled with surface engineering is proposed to improve the electrochemical performance of single‐crystalline LiNi0.83Co0.07Mn0.10O2 (MS‐SC‐NCM). The introduced Nb5+ without d electrons in the transition metal site imparts NbO6 octahedron motifs the capacity to buffer the local structural distortion derived from the Jahn‐Teller effect in Ni3+‐O6 octahedrons. In addition, the tenacious Nb‐O bonds with superior bond energy limit the anisotropic volume change of MS‐SC‐NCM and alleviate the irreversible lattice oxygen loss, thereby inhibiting the heterogeneous stress accumulation and uncontrollable structural degradation effectively. Furthermore, the constructed fast ion conductor Li3NbO4 on the surface of MS‐SC‐NCM accelerates the Li+ diffusion kinetics at the electrode‐electrolyte interface and suppresses interfacial parasitic reactions. As a result, MS‐SC‐NCM displays excellent cyclic performance both in coin cell and pouch cell with the capacity retention of 91.54% after 150 cycles and 92.5% after 300 cycles, respectively. This work provides valuable insights for designing advanced electrode materials for next‐generation LIBs.