Tailoring Intergranular Interfaces through Zirconium Solubility‐Controlled Segregation for Optimized LiNiO 2 Cathodes

Abstract Structural instability and interfacial degradation pose critical challenges in the design of Ni‐rich layered cathodes for high energy density lithium‐ion batteries. Here, an intergranular interface engineering of LiNi 0.996 Zr 0.004 O 2 (LNO‐Zr) cathode is proposed and realized on a kilogram‐scale by in situ doping, promoting the preferential growth of electrochemically active facets and inducing the segregation of Zr at intergranular interfaces. The incorporation of Zr 4+ into Ni(OH) 2 precursors effectively modulates surface energy, guiding crystal growth toward preferential {010}/{101} facets and promoting the formation of ultrafine primary particles with enhanced Li + pathways. During calcination, a conformal Li 2 ZrO 3 nanolayer forms at intergranular interfaces due to the limited solubility threshold of Zr in the cathode lattice, acting as a grain growth inhibitor to preserve the radially oriented structure. This engineered architecture mitigates lattice strain, suppresses microcrack propagation, and reduces parasitic reactions. Consequently, the LNO‐Zr cathode delivers a high specific capacity of 239.1 mAh g −1 , excellent cycling retention of 78.3% after 200 cycles at 1C, and improved Li + diffusion kinetics with suppressed H2–H3 phase transitions. This work introduces a scalable strategy for intergranular interface engineering of LiNiO 2 cathodes, providing valuable insights into defect chemistry and mechanical stabilization in high‐performance Ni‐rich cathodes.