【摘要】 本文采用水热法,通过调节高锰酸钾(KMnO4)和硫酸锰(MnSO4)原料配比控制MnO2的晶体结构和形貌。当KMnO4与MnSO4物质的量比为6∶1时,制备出由纳米片构成的球形δ-MnO2,形似海胆,直径约为0.5～1μm;当两者物质的量比2∶3时,所得α-MnO2纳米线粗细均匀,直径约为30～50 nm,长度为1μm;当两者物质的量比减小到1∶3时,则合成出直径约为50～100 nm,长度为2～4μm的短棒状β-MnO2。采用循环伏安法和恒电流充放电法对上述电极材料进行电化学性能研究,结果表明海胆状δ-MnO2具有优良的超电容性能,1 A/g充放电时,其放电比电容为162 F/g,远高于α-MnO2(62 F/g)纳米线和棒状β-MnO2(8 F/g)的比电容。更多还原

【Abstract】 Manganese oxides with different structures and morphologies were synthesized by hydrothermally treating KMnO4 and MnSO4 with varying molar ratio.As the molar ratio of KMnO4 and MnSO4 is 6∶ 1,the urchin-like δ-MnO2 superstructures with the diameter of 0.5-1 μm were prepared,which consist of agglomerate petal-shaped thin nanosheet.By adjusting the molar ratio of KMnO4 and MnSO4 to 2∶ 3,the uniform α-MnO2 nanowires were fabricated with the diameter of 30 to 50 nm and the length up to 1 μm.With a decrease molar ratio of 1∶ 3,the short rod-like β-MnO2 were obtained with the diameter of 500 nm and the length ranging from 2 to 4 μm.The electrochemical properties of obtained MnO2 samples as supercapacitor electrode materials were examined by cyclic voltammetry and galvanostatic charge-discharge in a three electrode system,the results indicated that spherical urchin-like δ-MnO2 possessed excellent supercapacitive performance.The specific capacitance of δ-MnO2 was about 162 F/g at a constant current of 1 A/g,which was much higher than the specific capacitance of α-MnO2 nanowires(62 F/g) and β-MnO2 nanorods(8 F/g).更多还原