纳米MnO2/膨胀石墨复合材料的制备及其电化学性能

Preparation and electrochemical properties of nanostructured MnO_2/ exfoliated graphite composites

采用水热法原位合成二氧化锰(MnO_2)/膨胀石墨(EG)复合材料,利用扫描电子显微镜(SEM)、x-射线衍射仪(XRD)、热重分析仪(TGA)对材料进行表征,并将所制MnO_2/EG复合材料(MEG)作为超级电容器电极,采用循环伏安、恒电流充放电和交流阻抗谱等方法进行电化学性能测试。结果表明,纳米MnO_2沉积填充在EG中,提高了材料导电性和稳定性;与纯MnO_2相比,复合材料不但具有较高的倍率性能,而且在1 000次循环后电容保持率高达100%。

Nanostructured MnO2 /exfoliated graphite（EG） composites were prepared by an in-situ hydrothermal method,and were characterized by scanning electron microscopy,X-ray diffraction and thermal gravimetric analysis.Their electrochemical performance was investigated by cyclic voltammetry,galvanostatic charge-discharge and electrochemical impedance spectroscopy.Results show that the nano structured MnO2 is inserted between the EG layers,and their conductivity and electrochemical stability are significantly improved.The composites have an improved rate performance compared with the pure MnO2.The capacitance retention rate of the composites and pure MnO2 are 100 and 94.3% after 1000 cycles at a current density of 1 A/g,indicating that the stability of the composites is better than that of pure MnO2.