分散剂对MnO_2/AC电化学电容性能的影响

Influence of dispersant on capacitance performance of manganese dioxide/activated carbon composites

添加不同系列的聚乙二醇(PEG)分散剂,采用化学混合法制备了MnO2/AC(活性炭)复合材料。应用X射线衍射、恒流充放电、交流阻抗和循环伏安等方法研究了各分散剂对产物结构与电化学性能的影响。实验结果表明,分散剂聚乙二醇(PEG)的聚合度对MnO2/AC复合材料的比电容和循环寿命有显著的影响,其中PEG400作为分散剂制备的复合材料具有最好的电化学电容行为。以PEG400制得的复合材料为正极,活性炭为负极组成超级电容器,在电流密度为100mA/g条件下,MnO2/AC复合材料的比电容达366F/g,且经500次充放电循环后容量仍保持在94%以上,显示出该复合材料具有良好的超电容特性。

The amorphous manganese dioxide/activated carbon composites were synthesized with the addition of different series of PEG dispersants by a chem-mixed method. The influence of different dispersants on the performance of MnO2/AC was studied using X-ray diffraction, constant current charge-discharge, alternate current impendence and cyclic voltammetry. The experimental results show that the polymerization degree of the PEG dispersants has an obvious effect on the electrochemical capacitance performance of MnOdAC materials. The electrochemical hybrid supercapacitor was assembled with the PEG400 composite material as the positive electrode and activated carbon as the negative electrode, with a maximum specific capacitance of the composites being 366 F/g in 100 mA/g current density. The capacitance of the capacitor was still kept more than 94% after 500 charge-discharge cycles in 6 mol/L KOH aqueous solutions. The composite materials exhibit good supercapacitance behaviors, such as high reversible characteristics and excellent cycle stability.