New insights into dry-coating-processed surface engineering enabling structurally and thermally stable high-performance Ni-rich cathode materials for lithium ion batteries

Nickel-rich layered oxides with high capacity and acceptable cost have established their critical status as cathode materials in high energy density lithium ion batteries. However, their mass production and application are still challenged by rapid capacity fading and poor thermal stability, which drives the research on surface protective coating techniques in both academic and industrial fields. Intensively investigated techniques like wet method or atomic layer deposition coatings are time-consuming and complicated, which may cause negative effects like surface lithium deficiency and phase reconstruction. Herein, a feasible and economic powder dry coating strategy assisted by high-energy mixer is proposed. Ni-rich LiNi0.8Co0.1Mn0.1O2 cathodes with Al(OH)3 nanoparticles are selected as the model case to reveal the distinct chemical evolution on cathode surface by elucidating the specific mechanism nuances between samples under different coating amounts in this process. Instructively under the good tuning of LiAlO2/Al2O3 role, coated cathode exhibits significant improvement in cycling stability, rate capability, attributed to proper surface protection against side reactions and lithium ion transferring enhancement. Moreover, the ambient storage stability and thermal stability are also improved successfully. This work attempts to remedy the research gap between lab research and industry engineering, and provides universal insights into simplified and controllable strategies for wider range of cathode material and their coatings under practical application scenarios.