MnO_2-CNTs复合材料的合成及其超级电容器性能研究

Synthesis and supercapacitor characteristics of MnO_2-CNTs composites

采用液相沉淀法在碳纳米管(CNTs)的表面沉积MnO2纳米颗粒,制得了MnO2-CNTs复合材料。通过扫描电子显微镜(SEM)、X射线衍射(XRD)对材料的微观结构及成分进行了表征。利用电化学循环伏安和恒电流充放电对材料进行电化学性能测试,表明MnO2-CNTs复合材料结合了MnO2较高的质量比电容和CNTs较好的电化学稳定性的优点,质量比电容为220F/g。并将MnO2-CNTs复合材料与活性炭(AC)组装形成非对称超级电容器,发现MnO2-CNTs与AC质量比为0.75:1时,质量比电容达到最高,为306F/g。非对称电容器性能较对称电容器有较大幅度的提高,并且具有良好的电化学稳定性。

MnO2-CNTs（carbon nanotubes）composite material was successfully synthesized by depositing MnO2 nanoparticle onto the surface of CNTs with chemical coprecipitation method.This composite material was characterized by XRD and SEM.The electrochemical properties of MnO2-CNTs composite material were investigated using cyclic voltammetry and galvanostatic charge/discharge.The results showed that MnO2-CNTs composite material combines the higher specific capacitance of MnO2 and the electrochemical stability of CNTs.The specific capacitance of MnO2-CNTs electrode reaches 220F/g.And a MnO2-CNTs/AC（active carbon）asymmetrical supercapacitor was assembled.It was found that,when the mass ratio of positive electrode and negative electrode was 0.75：1,the specific capacitance of the asymmetrical supercapacitor achieved the highest value of 306 F/g which was larger than that of the symmetric supercapacitor,and the asymmetrical supercapacitor has good electrochemical stability.