碳包覆对Li/CuV_2O_6电池性能的影响

Influences of C-Coating on the Properties of Li/CuV_2O_6 Batteries

用溶胶-凝胶法制备了锂离子电池正极材料CuV2O6,XRD衍射证明制备的材料无杂质且结晶度良好.通过球磨技术在制备的CuV2O6表面包覆乙炔黑,用XRD、SEM对包覆前后CuV2O6材料的结构和表面形貌进行对比,应用循环伏安、交流阻抗及恒电流充放电技术研究了包覆前后材料电化学性能.结果发现,包覆在CuV2O6表面的乙炔黑疏松多孔,具有较强的吸附电解液的能力,可以显著降低电极的表面阻抗和电化学阻抗,减少电极的极化并提高电池的放电电压和放电比容量,对于提高电池的循环稳定性也具有重要的作用.

The CuV2O6 was synthesized via sobgel method. It was proved by XRD that the as-prepared sample was high-purified and well-crystallized. Carbon-coated CuV2O6 materials were manufactured through ball-milling technique. The structure and morphology of the CuV2O6 materials were examined by XRD and SEM techniques. The electrochemical performances of the CuV2O6 materials before and after coating carbon were evaluated by cyclic voltammetry, AC impedance and galvanostatic charge/discharge experiment. It was found that the acetylene black coated on the surhce of the CuV2O6 material was fluey and porous. It could markedly decrease the surface impedance and electrochemical impedance. Besides, the porous acetylene black coated on the surface of the CuV2O6 material was favourable to absorb more electrolytes, lower the polarization of the electrode and increase the discharge voltage plateau and specific discharge capacity, at the same time it will play an important role to improve the cycle performance of the battery.