Optimization of synthesis condition of water-resistant and thin titanium oxide layer-coated Ni-rich layered cathode materials and their cathode performance

In this study, in order to develop water-resistant LiNi a Co b Al 1− a − b O 2 ( a > 0.85, NCA) cathode materials which exhibit high-rate performance, the surface coating of NCA with titanium oxide (TiO x ) was examined. The synthesis conditions for the TiO x -coated NCA cathode materials were investigated, by taking into account some essential factors in the surface coating of NCA by TiO x , with a view to improving the rate performance. We successfully prepared the TiO x -coated NCA cathode material, the rate performance of which is superior to that of the conventionally prepared NCA cathode materials, typically using a polyvinylidene difluoride (PVdF) binder and N-methyl-2-pyrrolidone (NMP) solvent. Their surface analysis suggested that the specific surface structure of TiO x layer coated on the NCA particle leads to both a water-resistant property and a high permeability of Li + ions through it in the charging/discharging process. Graphical abstract