The effect of surface modification on high capacity Li_(1.375)Ni_(0.25)Mn_(0.75)O_(2+γ) cathode material for lithium-ion batteries

摘要

Li_(1.375)Ni_(0.25)Mn_(0.75)O_(2+γ) exhibits an obviously enhanced electrochemical performance after AlF_3 surface modification, including the high initial discharge capacities of 276.8 mA h g(-1) and high coulombic efficiency of 93.6%. The results from powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma (ICP) and galvanostatical test confirm that its electrochemical improvement can be mainly attributed to the appearance of spinel-like structure on the surface of the layered material induced by AlF_3-modified. Moreover, the reduced charge transfer resistance (R_(ct) during cycling contributes to a better cycle stability of AlF_3-modified Li_(1.375)Ni_(0.25)Mn_(0.75)O_(2+γ).