Synthesis of water-resistant thin TiOx layer-coated high-voltage and high-capacity LiNiaCobAl1-a-bO2 (a > 0.85) cathode and its cathode performance to apply a water-based hybrid polymer binder to Li-Ion batteries

Titanium oxide (TiOx) coating was treated on a surface of LiNiaCobAl1-a-bO2 (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. (C) 2017 Elsevier Ltd. All rights reserved.