Two-step carbon coating onto nickel-rich LiNi0.8Co0.1Mn0.1O2 cathode reduces adverse phase transition and enhances electrochemical performance.

• A two-step carbon coating process is developed to modify high nickel cathode. • Li/Ni cation mixing and adverse phase transition are suppressed by carbon coating. • Dissolution of transition metals is inhibited by carbon coating. • Improved cyclic stability and enhanced rate performance are achieved. High-nickel ternary cathode materials such as LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) are among the most promising cathode materials due to their high capacity and low cost. However, irreversible phase transition and interfacial side reactions over cycles remain critical concerns. In this paper, a two-step carbon coating process is developed to suppress the adverse phase transition and excessive side reactions at the electrode-electrolyte interface. Sucrose is melted firstly at mild temperature to be coated onto the particle surface, which is converted into carbon in situ at elevated temperature under oxygen atmosphere. Both the cyclic (96.7% capacity retention after 100 cycles at 1 C) and rate performance (130 mAh g−1 at 5 C) of the NCM811 cathode are effectively improved by the carbon coating treatment. [Display omitted] [ABSTRACT FROM AUTHOR]