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将无定型MnO2在1 mol/L NaOH水溶液中150℃水热处理12 h后,得到了具有线团形貌的层状二氧化锰。利用XRD、SEM和低温N2吸-脱附等手段对样品的形貌和结构进行了表征。采用循环伏安、恒流充放电以及交流阻抗技术对样品的电化学性质进行了研究。研究结果表明,在三电极体系中,线团状MnO2在0~1.0 V(vs.SCE)的电压范围内具有较好的电容性质,其质量比电容为154 F/g。利用线团状MnO2为正极,石墨烯为负极以及1 mol/L Na2SO4水溶液为电解液组装了不对称型的电化学电容器。电化学测试表明,该电容器可在0~1.8 V的电压范围内可逆循环,其能量密度为21.6 W·h/kg,远远高于基于线团状MnO2(4.86 W·h/kg)和石墨烯(4.3 W·h/kg)的对称型电容器。
Amorphous MnO2 was hydrothermally treated in a 1 mol / L NaOH aqueous solution at 150 ℃ for 12 h to obtain a layered manganese dioxide with a coil morphology. The morphology and structure of the samples were characterized by XRD, SEM and N2 adsorption-desorption. The electrochemical properties of the samples were studied by cyclic voltammetry, constant current charge-discharge and AC impedance techniques. The results show that in the three-electrode system, the mass-like MnO2 has a good capacitance property in the voltage range of 0-1.0 V (vs.SCE), and the mass specific capacitance is 154 F / g. Asymmetric electrochemical capacitors were assembled by using SnO2 as anode, graphene as anode and 1 mol / L Na2SO4 as electrolyte. Electrochemical tests show that the capacitor can be reversibly cycled in the voltage range of 0-1.8 V with an energy density of 21.6 W · h / kg, which is much higher than that of graphite based on wire-like MnO2 (4.86 W · h / kg) Propylene (4.3 W · h / kg) symmetrical capacitor.