▎ 摘　　要

The Li1.2Mn0.54Ni0.13Co0.13O2 particles were modified by graphene to improve the electrochemical properties. The graphene-coated materials have been synthesised by spray drying method and show crystal structure similar to that of pristine. The structure, morphology and electrochemical performances of the pristine and graphene-coated materials have been investigated by Scanning electron microscopy, Transmission electron microscope, as well as charge-discharge measurements. At 250 mA g(-1), the pristine and graphene-coated samples deliver capacities of 156-178 mA h g(-1) with capacity retention of 80-90% in 100 cycles, respectively. An analysis of the charge-discharge capacity values and Ac impedance spectroscopy reveals that the improved electrochemical performances of the graphene-coated sample are due to the suppression of charge-transfer resistance and the enhancement of diffusion coefficients (D) of lithium ions.