Enhanced Electrochemical Properties of Gradient Cathode Material By Coating

As lithium-ion batteries vigorously expand into newly emerging application fields such as smart mobile devices, power tools, (hybrid) electric vehicles, and energy storage systems, the demand for high-energy density/high-power density cells is rapidly growing. Among various attempts to meet this stringent requirement, charging cells at a voltage higher than the conventional cut-off at 4.2 V has been suggested as one of the most secured approaches to enhance the energy/power density of cells. Raising the charge cut-off voltage for the cathode material including LiCoO2, LiNi1/3Mn1/3Co1/3O2 (NMC), LiNi0.8Co0.15Al0.05O2 (NCA), LiNi0.5Mn1.5O4, etc, tends to face formidable challenges related to deterioration of cell performance and thermal stability of cathode materials.

One promising approach to resolve these stringent shortcomings of high-voltage cathode materials is the surface modification using inorganic coating materials such as Al2O3 and ZrO₂, ZnO, AlF₃, Ni₃(PO₄)₂, and AlPO₄ on the result products. The process for the material preparation involve calcining the lithium source precursor such as LiOH, Li2CO3, LiNiO2 etc with another precursor such as Co3O4, Co(OH)2, LiNi1/3Mn1/3Co1/3(OH)2, Ni0.8Co0.15Al0.05O2, Ni0.25Mn0.75CO3 etc at high temperature. The coating process happens at results material, which would have a distinctively separation between bulk material with the coating layer. We coat the material on the precursor, and then use the coating precursor to prepare the cathode material.