A Phosphate Thermal Barrier Coating Endows Ni‐Rich Cathode 4.8 V‐Tolerant and Thermal Oxidation Stability Enabling High‐Energy Lithium‐Ion Batteries
Hangyu Zhang, Yanxue Wu, Y.D. Kuang, Xijun Xu, Fangkun Li, Jiahe Chen, Sihuan Tang, Jing-Wei Zhao, Jun Liu, Yanping Huo
Abstract
Abstract Ni‐rich layered oxide cathode (LiNi x Co y Mn 1‐ x ‐ y O 2 , 0.8 < x < 1) possesses a high theoretical specific capacity (≈270 mAh g −1 ) and stimulated considerable attention for high energy density lithium‐ion batteries (LIBs). However, the unstable cathode electrolyte interfaces (CEI) resulting in terrible thermal endurance and awful high voltage tolerance (>4.5 V) and thermal instability significantly hinder their practical applications. Herein, a thermodynamically stable InPO 4 interface is constructed on the LiNi 0.83 Co 0.12 Mn 0.05 O 2 (NCM83@InPO 4 ), which achieves excellent cyclic stability (≈85.7% capacity retention after 500 cycles at 10 C in 2.7–4.6 V, ≈80.0% after 200 cycles at 1 C in 2.8–4.8 V). Advanced characterizations confirm that the InPO 4 coating layer stabilizes the Ni 4+ /O α− (α < 2), and forms a stable CEI that prevents side reactions with electrolytes under high‐voltage operation. In situ characterizations reveal that the InPO 4 layer suppresses the harmful H2‐H3 phase transition and maintains the layered structure under thermal shock from 25 to 400 °C. Density functional theory (DFT) calculation validates that the modified NCM83@InPO 4 not only enhances mechanical strength but also reduces the Li⁺ migration energy, facilitating rapid Li + /electron transfer. This polyanionic thermal barrier coating strategy effectively improves cycling stability and enhances thermal stability, thus shedding light on designing reinforced high‐voltage tolerant cathodes for high‐energy LIBs.