石墨烯/富锂三元正极复合材料的制备及电化学性能研究

通过水热法制备了石墨烯包覆量不同的石墨烯/富锂三元正极复合材料。采用X射线衍射仪、扫描电子显微镜和电化学交流阻抗等对包覆后富锂三元正极复合材料的物相结构、形貌及电化学性能进行了研究。结果表明:石墨烯包覆量为2%(质量分数)时,包覆效果较好,石墨烯/富锂三元正极复合材料首次库仑效率为89.6%,比富锂三元正极材料提高了17.16%,放电比容量为226.41mAh/g,比原材料提高了21.38mAh/g;以0.5C循环100次后石墨烯/富锂三元正极复合材料放电比容量可保持在154mAh/g,容量保持率为88%,比富锂三元正极材料提高了5.3%;石墨烯/富锂三元正极复合材料阻抗为75Ω,比富锂三元正极材料阻抗低50Ω。

Preparation of Li1.2 Ni0.133 Co0.33 Mn0.533O2 anode material and its electrochemical performance

Lithium-rich anode material Li1.2Ni0.133Co0.133Mn0.533O2 was prepared by hydrothermal method and coated with graphene.The phase structure,morphology and electrochemical properties of the coated materials were investigated by X-ray diffraction(XRD),scanning electron microscopy(SEM)and electrochemical impedance spectroscopy(EIS).The results shown that when the coating amount was 2 wt%,the Li-rich material had a good coating effect.Its first Coulomb efficiency was 89.6%,which was 17.16% higher than the original material.The discharge specific capacity was 226.41 mAh/g,which was 21.38 mAh/g higher than the original material.The discharge specific capacity after 100 cycles of 0.5 Ccan be maintained at 154 mAh/g,its capacity retention rate was 88%,which was 5.3% higher than the original material.The impedance was 75Ω,which was much smaller than the 125Ωof the raw material.