Titanium oxide (TiOx) coating was treated on a surface of LiNi a Co b Al1-a-b O2 (a > 0.85, NCA) cathode material, which exhibited high capacity of 200 mAhg−1, but the charge/discharge capacity of which degraded seriously after contacting with water, to use the NCA with a water-based binder in the cathode preparation of lithium ion battery. The formation of TiOx layer on the NCA surface was conducted using a wet method and the TiOx layer formed was characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS): The TiOx coating layer is 2–3 nm in thickness and Ti atoms are distributed over the whole NCA particle surface. The cathode electrode fabricated with TiOx-coated NCA and water-based TRD202A binder was found to compete in terms of cycle and rate performance with the cathode composed of pristine NCA particle and organic solvent-based PVdF binder even after it was exposed in the water-based slurry for 7 days in the cathode preparation. The results demonstrate that TiOx-coated NCA particles are promising as cathode materials with a water-resistant property and therefore water can be used as solvent for preparing the cathode slurry solution in the fabrication of lithium ion battery cathodes.