ATOMIC LAYER DEPOSITION OF Al₂O₃ OR AlF₃ COATINGS ON LiNi_0.6Co_0.2Mn_0.2O₂ AND LiNi_0.5Co_0.2Mn_0.3O₂ Ni - RICH CATHODE MATERIALS: THE EFFECT OF THEIR ELECTROCHEMICAL BEHAVIOR IN Li CELLS

One of the major challenges in lithium batteries technology is the further improvement of battery components – electrodes, solutions, and separators. Among several modern strategies to improve electrochemical performance and structural characteristics of materials for positive electrodes coatings have attracted much attention of the researches. Another approach to improve energy density, safety, and cost is using nickel-rich oxide cathode materials of layered structure (R-3m s. g). These materials have a general formula of Li(Ni_xCo_yMn_1-x-y)O₂. Increasing nickel content increases the capacity but lowers the cathode stability, thus the amount of transition metals needs to be optimized for the best performance of the material.

In this research, we investigated Ni-rich cathode materials: Li(Ni_0.6Co_0.2Mn_0.2)O₂ (NCM-622) and Li(Ni_0.5Co_0.2Mn_0.3)O₂ (NCM-523), bare and surface coated using atomic layer deposition (ALD) with Al₂O₃ or AlF₃, in aspects of their electrochemical and thermal behavior and structural stability. It was established that the Al₂O₃ coated NCM 523 and NCM 622 demonstrated more stable cycling behavior and lower mean voltage fade.