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

Funding Information: This research is supported by the National Natural Science Foundation of China ( 21773279 , 22075305 , 52061135110 ), Zhejiang Provincial Natural Science Foundation of China ( LD22E020003 ), the Key Research Program of the Chinese Academy of Sciences (ZDRW_CN_2020-1), and the Ningbo Science & Technology Innovation 2025 Major Project (2019B10050, 2019B10113, 2020Z024, 2020Z101, 2020Z025), and Key Laboratory of Bio-based Polymeric Materials of Zhejiang Province. Publisher Copyright: © 2023 High-nickel ternary cathode materials such as LiNi0.8Co0.1Mn0.1O2 (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.