电解液对二氧化锰电化学性能的影响

Effect of electrolyte on electrochemical performance of manganese dioxide

利用水热法分别制备了MnO2纳米线和纳米球。通过场发射扫描电子显微镜(FESEM)和X射线衍射仪(XRD)对两种形貌的MnO2粉末进行表征,并使用循环伏安法(CV)、恒流充放电(GCD)和交流阻抗测试研究MnO2电极材料在KOH和Na2SO4电解液下的电化学行为。结果表明,MnO2纳米球形成机理为:先溶解后聚集并呈各向异性生长状态。在2 mol/L KOH或3 mol/L Na2SO4电解液中的MnO2纳米球性能均优于纳米线,比电容分别为756.44 F/g和333.65 F/g;与MnO2纳米线对比,MnO2纳米球的比电容分别提高了59.06%和52.14%。经分析可知,MnO2材料与电解液之间存在一定的匹配性关系。

MnO2 nanowires and nanospheres were prepared by hydrothermal method. The surface morphology and crystal structure of MnO2 were characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The formation mechanism of MnO2 nanospheres was dissolved, aggregated and anisotropically grown. The electrochemical behavior of the electrode materials in KOH and Na2SO4electrolytes was studied by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). The results show that the specific capacitances of MnO2 nanospheres in 2 mol/L KOHand3mol/LNa2SO4electrolytesare756.44F g-1and333.65F g-1,respectively,whichis59.06%and52.14%higher than that of MnO2 nanowires. It is concluded that there is a certain match up between the electrolyte and MnO2nanomaterial.