Synthesis and characterization of carbon-coated LiNi1/3Co1/3Mn1/3O2 cathode material prepared by polyvinyl alcohol pyrolysis route

Carbon-coated LiNi1/3Mn1/3Co1/3O2 cathode materials for lithium ion battery were synthesized by the pyrolysis of polyvinyl alcohol (PVA) to improve the electrochemical performance of LiNi1/3Mn1/3Co1/3O2 and the carbon content was optimized. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses indicated that the crystal structure of LiNi1/3Co1/3Mn1/3O2 was not destroyed during the carbon coating process. Transmission electron microscope (TEM) images confirmed that amorphous carbon existed on the surface of LiNi1/3Co1/3Mn1/3O2 particles. Charge and discharge tests showed that the cycle performance and the rate capability of LiNi1/3Co1/3Mn1/3O2 were improved by carbon coating. The LiNi1/3Co1/3Mn1/3O2/C composite with the optimal carbon content of 1.0 wt.% showed the highest capacity retention of 96.3% after 40 cycles at the current density of 20 mA g−1 (C/8), and the highest initial discharge capacity of 150 mAh g−1 at 160 mA g−1 (1C). The electrochemical impedance spectroscopy (EIS) results showed that the improved electrochemical performance caused by carbon coating was mainly attributed to the decrease of the charge transfer resistance.