无定型氧化锰超级电容器电极材料

Amorphous MnO_2 as electrode material for supercapacitor

采用化学共沉淀法制备超级电容器用氧化锰电极材料,借助X射线衍射(XRD)、扫描电子显微镜(SEM)、红外光谱(FT-IR)和BET比表面积分析手段对样品进行表征。结果表明,产物为无定型结构,粒径分布较均匀,约在40～50nm,BET比表面积达到160.5m2/g。在0.5mol/LK2SO4水溶液中,电位窗口为0～0.8V(vs.SCE)内,通过循环伏安和恒流充放电测试,显示该材料制备的电极具有良好的电容行为和功率特性。在扫描速度为4mV/s时,单电极的比容量达到140F/g。

α-MnO2·nH2O as electrode material for supercapacitor was prepared by chemical coprecipitation. The material was characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), surface area analysis (BET) and Fourier transform infrared spectroscopy (FT-IR). The results show that the material has amorphous structure with particle diameter range from 40 nm to 50 nm, and the BET specific surface area reaches 160.5 m2/g. Electrochemical characterizations were earned out by using cyclic voltammetry (CV) and constant current charge/discharge with a three-electrode system. The results show that within the potential window range from 0 to 0.8 V (vs. SCE) amorphous α-MnO2·nH2O exhibits excellent capacitance and high power characteristics in 0.5 mol/L K2SO4 aqueous electrolyte. A maximum specific capacitance of 140 F/g is obtained at the sweep rate of 4 mV/s. Effect of different sweep rates on the specific capacitance of α-MnO2·nH2O was also studied.