| This paper summarized the development background and working principle of lithium-ion battery firstly, and overviewed the surface coated modification development and research progress of the LiNi1/3Mn1/3Co1/3O2 lithium ion battery cathode materials. On this basis, glucose was used the source of carbon, zirconium acetate was used the source of ZrO2 and calcium nitrate Ca(NO3)2·4H2O (AR), nitric acid cobalt Co(NO3)2·6H2O (AR) and lanthanum nitrate La(NO3)3·nH2O (AR) were used the source of La0.4Ca0.6CoO3 for the study of surface coating modification, respectively. X-Ray Diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) were applied to characterize the structure, surface morphology and elemental composition of the material of before and after coated. XRD results show that the C, ZrO2 and La0.4Ca0.6CoO3 coating did not change crystal phase structure of LiNi1/3Mn1/3Co1/3O2, but the lattice constant is increased, so the coating not only effectes the surface of the particles, but also impactes on materials within the lattice. XRF results detecte the existence of the cladding material, but are lower than the theoretical value.Electrochemical performance of coated LiNi1/3Mn1/3Co1/3O2 had been measured as positive materials in botton cell, lithium foil is used as anode. AC impedance analysis was carried on the two electrodes. The test results show that:The material of the sintering temperature is 400℃, holding time is 15 min, the carbon content is 2 wt%, solvent type is ethanol have the best electrochemical performance. At the rate of 0.2 C in the voltage range of 4.3 to 2.75 V the first discharge specific capacity is 155.9 mAh g-1,,and the capacity retention is 95.5% and after charge and discharge 50 times which is 10.7% higher than the bare LiNi1/3Mn1/3Co1/3O2 material. At the rate of 2 C in the voltage range of 4.3 to 2.75 V the first discharge specific capacity is 130.8 mAh g-1,and the capacity retention is 86.1% after charge and discharge 50 times which is 5.2% higher than the bare LiNi1/3Mn1/3Co1/3O2 material. At the rate of 4 C and 8 C the capacity retention are 69.9% and 59.8% after charge and discharge 50 times, respectively. Compared with the bare LiNi1/3Mn1/3Co1/3O2 material, the capacity retention are improved, and under the large ratio the discharge specific capacity of carbon coated LiNi1/3Mn1/3Co1/3O2 material were improved. Carbon coating improves the large discharge capacity and cycle stability of the material. AC impedance analysis showes that carbon coated material inhibited the increase of impedance effectively and the diffusion coefficient of lithium ion increased, carbon coating not only improves the electronic conductivity of LiNi1/3Mn1/3Co1/3O2 material, but also improves the ionic conductivity of LiNi1/3Mn1/3Co1/3O2 material, the rate discharge capacity and cycle stability of the the LiNi1/3Mn1/3Co1/3O2 material were improved. Through the study of zirconia content, LiNi1/3Mn1/3Co1/3O2 material whose ZrO2 content is 2 wt% has the better electrochemical comprehensive performance preliminary. At the rate of 0.2 C in the voltage range of 4.3 to 2.75 V the first discharge specific capacity is 157.83 mAh g-1,and the capacity retention is 93.1% after charge and discharge 50 times which is higher than the bare LiNi1/3Mn1/3Co1/3O2 material and the 2 wt% ZrO2 content LiNi1/3Mn1/3Co1/3O2 material. ZrO2 coating improves the cycle stability of the LiNi1/3Mn1/3Co1/3O2 material.The best cycle performance is La0.4Ca0.6CoCO3 coated LiNi1/3Mn1/3Co1/3O2 material among the three coating material and the capacity retention is 98.8% at the rate of 0.2 C in the voltage range of 4.3 to 2.75 V, the same condition of carbon coated LiNi1/3Mn1/3Co1/3CO2 material capacity retention is 95.5%, zirconium oxide coated capacity remain is 93.1%.
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