Improving electrochemical performance of Ni-rich LiNi_0.8Co_0.1Mn_0.1O₂ cathode for Li-ion batteries by dual-conductive coating layer of PPy and LiAlO₂

Ni-rich LiNi_0.8Co_0.1Mn_0.1O₂ (NCM) as a high capacity cathode material is the most promising candidate for lithium-ion batteries. However, NCM still suffers from poor rate capability and insufficient cycle stability owing to the poor conductivity as well as side reactions. Here, a dual-conductive coating strategy is employed to address these issues. The PPy-LiAlO₂ coated NCM composites (PPy-LA) are synthesized by hydrolysis–hydrothermal approach and in-situ chemical polymerization method. The LiAlO₂ coating can suppress side reactions and enhance ionic conductivity, and the PPy coating can increase electronic conductivity. As a result, the PPy-LA sample delivers superior cycling stability and rate capability compared to NCM sample. The capacity retention of PPy-LA is 92.8% after 100 loops and a high capacity of 128 mAh/g is obtained at 2 A/g. This effective surface modification method could shed light on other cathode materials.