TiO <sub>2</sub> ‐coated LiNi <sub>0.9</sub> Co <sub>0.08</sub> Al <sub>0.02</sub> O <sub>2</sub> cathode materials with enhanced cycle performance for Li‐ion batteries
Weiwei Li, Xiangjun Zhang, Jiangju Si, Jie Yang, Xueyi Sun
Abstract
Abstract Ni‐rich cathode material is one of the most promising materials for Li‐ion batteries in electric vehicles. However, fading capacity, poor cyclic stability and high pH value are still major challenges, which suppress its practical application. In this study, spherical LiNi 0.9 Co 0.08 Al 0.02 O 2 powders with 0.4 wt% TiO 2 coating layer were prepared by impregnation–hydrolysis method. Scanning electron microscopy (SEM), high‐resolution transmission electron microscopy (HRTEM) and X‐ray diffraction (XRD) results show that TiO 2 is uniformly coated on the surface of LiNi 0.9 Co 0.08 Al 0.02 O 2 particle and slightly embedded into LiNi 0.9 Co 0.08 Al 0.02 O 2 particles. After 100 cycles at 2.0C, 0.4 wt% TiO 2 ‐coated LiNi 0.9 Co 0.08 Al 0.02 O 2 electrode delivers much higher discharge capacity retention (77.0%) than the pristine LiNi 0.9 Co 0.08 Al 0.02 O 2 electrode (63.3%). The excellent cycling performance of 0.4 wt% TiO 2 ‐coated LiNi 0.9 Co 0.08 Al 0.02 O 2 electrode at a high discharge ratio is due to a TiO 2 coating layer which can effectively reduce the direct contact between cathode material and electrolyte, suppress the oxidation of electrolyte, improve electrical conductivity of the electrode and increase the stability of the structure.