LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) has gradually become a research hotspot for the high-energy density. However, it is troubled by the residual lithium during the preparation process and its subsequent effect on the electrochemical performance in the following charge and discharge. Polyvinylpyrrolidone (PVP)-assisted LiF-LaF₃ coated NCM811 materials are prepared by in-situ method to reduce the residual lithium, improve the interface and electrochemical performance of the NCM811. Results show that the content of Li₂CO₃ (from 6610 ppm to 2230 ppm) and LiOH (from 3260 ppm to 1870 ppm) is greatly reduced, and the modified NCM811 cathode maintains exceptional capacity retention of 91.17% (159.2 mAh g⁻¹/173.6 mAh g⁻¹) and 81.78% (122.1 mAh g⁻¹/149.3 mAh g⁻¹) at high cut-off voltage of 2.8–4.6 V after 100 cycles, at 5C and 10C, respectively, which are much higher than that of the bare NCM811. The structural and compositional characterization (XRD, XPS and EIS) further reveal the electrochemical mechanism and kinetics of the designed NCM811 cathode, indicate that the improved cycling and rate performance of LiF-LaF₃ coated NCM811 is mainly due to the reduction of residual lithium, the suppression of interfacial side reactions and the enhancement of thermal stability.

LiNi _0.8 Co _0.1 Mn _0.1 O ₂（NCM811）逐渐成为高能量密度的研究热点。然而，在制备过程中残留的锂及其在随后的充电和放电中对电化学性能的后续影响困扰着它。采用原位法制备了聚乙烯吡咯烷酮（PVP）辅助的LiF-LaF ₃包覆的NCM811材料，以减少残余锂，改善NCM811的界面和电化学性能。结果表明，Li ₂ CO ₃的含量（从6610 ppm到2230 ppm）和LiOH（从3260 ppm到1870 ppm）大大降低了，改进的NCM811阴极保持了91.17％（159.2 mAh g ^-1 /173.6 mAh g ^-1）和81.78％的出色容量保持率100循环后在2.8–4.6 V的高截止电压下（122.1 mAh g ^-1 /149.3 mAh g ^-1），分别在5C和10C时，分别高于5 N和裸NCM811的高截止电压。结构和组成特征（XRD，XPS和EIS）进一步揭示了所设计NCM811阴极的电化学机理和动力学，表明LiF-LaF _3的循环和速率性能得到改善 NCM811涂层的主要原因是减少了残留锂，抑制了界面副反应并提高了热稳定性。