Excellent high-rate cyclic performance of LiNi_0.8Co_0.1Mn_0.1O₂ cathodes via dual Li₂SiO₃/PPy coating

LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) has garnered significant research attention as a high-power battery cathode for electric vehicles. However, low-rate capability and poor cyclic performance limit the widespread applications of NCM cathodes. Although surface coating is an effective strategy to suppress these drawbacks, single-phase coating does not meet the application requirements. Herein, Li₂SiO₃ and PPy are used to prepare dual coating and improve both rate capability and cyclic performance. Results reveal that Li₂SiO₃/PPy-coated NCM811 exhibits a specific discharge capacity of 145.1 mAh/g and capacity retention of 96.4% after 100 charge/discharge cycles at 10 C. Various analytical and electrochemical characterization techniques demonstrate that Li₂SiO₃ in the inner layer is helpful to enhance Li⁺ diffusion coefficient and PPy in the outer layer is conducive to improve electronic transmission and decrease polarization. Besides, the dual-phase coating can alleviate adverse side reactions at the interface by acting as a strong barrier between the cathode and electrolyte.