A scalable dry chemical method for lithium borate coating to improve the performance of LiNi0.90Co0.06Mn0.04O2 cathode material

The washing process is an important working procedure for the industrial production of Ni-rich layered cathode materials. By washing, the most of residual lithium could be removed efficiently, but the surface corrosion of the cathode materials would be apparent. Therefore, coating is necessary to repair the surfaces of the cathode materials. In this study, we introduce a dry chemical process for LBO coating to improve the surface properties of Ni-rich materials (LiNi0.90Co0.06Mn0.04O2) after washing. Particularly, the effect of subsequent sintering temperature on the structure and uniformity of the coating layer as well as the electrochemical performance of as-prepared cathodes is investigated systematically. When the coating temperature is 300 °C, a uniform LBO coating layer is easily formed on the surface of the cathodes, helping to repair unstable surface of the washed LiNi0.90Co0.06Mn0.04O2 material. The coated LiNi0.90Co0.06Mn0.04O2 material shows a discharge capacity of 222.0 mAh g−1 with 88.1% of capacity retention after 100 cycles at 1C. The thermal stability can also be improved. The improved performance of LiNi0.90Co0.06Mn0.04O2 material should be ascribed to the LBO coating layer which can restrain the structure deterioration and surface impedance by diminishing the direct contact of the cathode materials and the electrolyte.