Dual-modification of WO3-coating and Mg-doping on LiNi0.8Co0.1Mn0.1O2 cathodes for enhanced electrochemical performance at high voltage

Surface coating and ion doping are of great significance for improving the electrochemical performance of cathode materials for lithium-ion batteries. In this study, WO3-coated and Mg2+-doped LiNi0.8Co0.1Mn0.1O2 cathode materials were successfully synthesised by the coprecipitation and wet coating methods. X-ray diffraction and energy-dispersive X-ray spectroscopy confirmed that the synthesised material was NCM811 with a good layered structure and Mg2+ doped into it. X-ray photoelectron spectroscopy revealed that W6+ mainly existed on the surface of the material, while morphological analysis revealed a uniform WO3 coating on the material surface. Electrochemical performance of the material suggested that the modification by suitable materials synergistically stabilised the material structure and suppressed side reactions. Capacity retention of the dual-modified material at 25 °C after 100 cycles at 1 C rate was as high as 73.5%, which is considerably higher than that of the raw materials (53.6%).