Surface coating and doping of single-crystal LiNi0.5Co0.2Mn0.3O2 for enhanced high-voltage electrochemical performances via Chemical Vapor Deposition

•The Al2O3 is applied on the surface of single-crystal LiNi0.5Co0.2Mn0.3O2 (NCM) by Chemical Vapor Deposition (CVD).•The optimum CVD operation time for Al2O3 is 30 min.•The electrochemical performance of NCM can be significantly improved by the Al2O3 coating prepared by CVD.•The Al2O3 is chemically bonded with the NCM substrate and a trace of Al exists as the dopant on the top surface of NCM.