Optimize the surface of the Li-rich cathode materials with lithium phosphate and polyaniline to improve the electrochemical performance

Li-Rich cathode materials are a very promising cathode material for lithium-ion batteries due to its high energy density and low cost, and being environmentally friendly. However, there will be some defects such as lower initial coulomb efficiency, poor cycle stability, and poor rate performance that make the material difficult to commercialize so far. In this paper, we use Li1.2Mn0.54Ni0.13Co0.13O2 (LMNC) as the raw cathode material, lithium phosphate (Li3PO4) and polyaniline (PANI) are constructed as surface modifiers of LMNC, and the electrochemical performance of the modified material has been significantly improved. Compared with the raw material, the initial coulomb efficiency is increased from 64.5 to 82.3%. After 100 cycles at 1C, the capacity retention rate reaches 94.1% (raw material is 81.3%) and the specific capacity can reach 109.57 mAh g−1 under the high current density of 5C (raw material is 73.27 mAh g−1). As a result, the hybrid coating layer not only can be used as a protective layer to protect electrode materials from HF corrosion, but also has excellent electrical conductivity to promote the exchange of ions and electrons.