LiTiO2 coating toward enhanced nickel-rich LiNi0.815Co0.15Al0.035O2 cathode in lithium-ion batteries

Lithium-nickel-cobalt-aluminum (NCA) material coated by a 10-nm thick LiTiO2 (LTO) layer was prepared using a method based on hydrolysis combined with a solvothermal process. The effects of LTO modifications on the structure, morphology, gas generation, and electrochemical performance of this NCA material were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Gas Chromatography-Mass Spectrometer, and electrochemical tests. The results vividly showed that the LTO layer was uniformly coated on NCA surfaces and titanium addition (1 wt%) for these modified results was crucial. The residual lithium on the surface of NCA material was efficiently resumed by LTO synthesis reaction without extra effects on the morphology and structure of NCA material. LTO treatment can significantly improve the processability, gas production performance, and the electrochemical properties of NCA material. After cycling 100 times at 25 °C with the current rate of 1C, optimized NCAT1 electrodes maintained a high discharge capacity at 164.6 mA·h·g−1 compared to NCA electrodes at 152.3 mA·h·g−1. On the other hand, the high-rate discharge capacity of NCAT1 electrodes at 10 C was also maintained at 135.0 mA·h·g−1, contrasted with NCA electrodes at only 125.0 mA·h·g−1. The enhancement of electrochemical performance was ascribed to the LTO-coating layer, which improved ionic conductivity, reduced interface resistance, and protected the core NCA material.