论文部分内容阅读
采用熔盐法在不同温度下制备了MnO2粉体。X射线衍射仪分析表明:粉体样品为α-MnO2和γ-MnO2晶混合物,反应温度越高样品的结晶程度越好。将MnO2粉体与石墨、乙炔黑、聚四氟乙烯、羧甲基纤维素按质量比为75:10:10:2:3进行混合,在10MPa压力下压制成电极。在2mol/L(NH4)2SO4溶液中,用三电极体系对MnO2电极样品进行电化学性能测试。结果表明:制备粉体的反应温度是影响MnO2粉体制备的电极的电化学性能的重要因素,反应温度为450℃的粉体制备的电极样品电容性能最好。循环伏安测试表明该样品在0～1.0V电位窗口范围内具有较好的矩形特征;交流阻抗测试结果显示样品具有典型的电容阻抗特性,其等效串联电阻和电极反应电阻分别为0.064Ω和2.825Ω。在电流密度为2mA/cm2,恒流充放电时测得其放电比容量可达246.46F/g。
The molten salt method was used to prepare MnO2 powder at different temperatures. X-ray diffraction analysis showed that the powder sample was a mixture of α-MnO2 and γ-MnO2 crystals. The higher the reaction temperature, the better the crystallinity of the sample. The MnO2 powder and graphite, acetylene black, polytetrafluoroethylene, carboxymethyl cellulose mass ratio of 75: 10: 10: 2: 3 were mixed, pressed under pressure of 10MPa into an electrode. In 2mol / L (NH4) 2SO4 solution, the electrochemical performance of MnO2 electrode was tested by three-electrode system. The results showed that the reaction temperature of the powders was an important factor affecting the electrochemical performance of the electrodes prepared by MnO2 powders. The samples prepared by the reaction at 450 ℃ had the best capacitance. Cyclic voltammetry test showed that the sample has good rectangular characteristics in the 0-1.0V potential window. The results of AC impedance show that the sample has a typical capacitance impedance with equivalent series resistance and electrode reaction resistance of 0.064Ω and 2.825Ω. In the current density of 2mA / cm2, constant current charge and discharge measured when the discharge capacity of up to 246.46F / g.