以KMnO4为锰源，尿素为还原剂，在水热温度120℃和180℃下分别合成了花状δ-MnO2和线状α-MnO2。利用XRD和SEM对样品的结构和形貌进行了分析；利用循环伏安、交流阻抗和恒流充放电测试研究其电化学性能。测试结果表明， MnO2的晶型和形貌对其电化学性能影响较大，花状δ-MnO2比线状α-MnO2展现出更好的电容性能。在扫速5 mV/s时，花状δ-MnO2和线状α-MnO2电极比电容分别为193．9 F/g和152．0 F/g。在与活性炭组成的非对称超级电容器中， AC//δ-MnO2和AC//α-MnO2电容器初始比电容分别为31．2 F/g和25．4 F/g；1000次充放电循环后， AC//δ-MnO2循环性能更好。因此，花状δ-MnO2更适合做非对称超级电容器的正极活性材料。%Flower-like δ-MnO2 and wire-like α-MnO2 were synthesized at the hydrothermal temperature of 120 ℃and 180 ℃ with adding urea into KMnO4. Their crystal structures and morphologies were analyzed by XRD and SEM. Their capacitive properties were investigated by cyclic voltammeter, electrochemical impedance spectroscopy and galvanostatic charge-discharge test. The results showed that the crystal structure and morphology had an important influence on its electrochemical properties. Flower-like δ-MnO2 showed better capacitive behavior than wire-like α-MnO2. The specific capacitance values ofδ-MnO2 andα-MnO2 electrode were 193. 9 F/g and 152. 0 F/g at the scan rate of 5 mV/s. After asymmetric supercapacitors were fabricated by MnO2 positive electrode and AC negative electrode, the initial specific capacitance values of AC//δ-MnO2 and AC//α-MnO2 supercapacitors were 31. 2 F/g and 25. 4 F/g. After 1000 cycles, AC//δ-MnO2 exhibited better cyclic stability. Therefore, flower-like δ-MnO2 was more suitable for the positive electrode material of the asymmetric supercapacitor.
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