隐钾锰矿型MnO2纳米棒的制备及其电容性能研究

摘要

用乙醇室温还原KMnO4得到MnO2前驱体,通过煅烧制备得到了MnO2,采用X射线衍射(XRD)、场发射扫描电镜(FESEM)对其晶体结构和微观形貌进行了表征,采用循环伏安、恒流充放电和交流阻抗法对其电化学性能进行测试.结果表明,所制备的材料为隐钾锰矿型MnO2,微观形貌呈纳米棒状,煅烧时间为6 h时,产物具有最小的直径和最大的长径比,同时也具有最高的比电容和最低的阻抗.在0.1 A/g的电流密度下,比电容达到327 F/g,经100次充放电比电容几乎没有损耗.%The nano-MnO2 was prepared by calcining the precursor synthesized by reducing the KMnO4 with ethanol at room temperature. The products were characterized by XRD, FESEM, CV, EIS and CCCD. The results show that the MnO2 presents tetragonal cryptomelane structure with the micro-morphology of nano-rod. The product after calcined at 400℃ for 6 h presents the minimum diameter and maximum L/D ratio, and also presents the highest specific capacitance and lowest impedance. At the current density of 0.1 A/g, the specific capacitance is up to 327 F/g and almost free of loss after 100 cycles of charge and discharge.