多次聚合法制备多孔聚吡咯厚膜及其电化学容量性能

Capacitance Properties of Porous Polypyrrole Thick Films Prepared Electrochemically by Multi-step Polymerization

为了得到高面积比容量的聚吡咯(PPy)膜超级电容器电极材料,用多次聚合法合成了PPy厚膜,聚合电量分别为8、10和12mAh·cm-2,掺杂离子分别为氯离子和对甲基苯磺酸根离子(TOS-).PPy膜的电化学性能采用恒电流充放电、循环伏安(CV)和电化学阻抗谱(EIS)等方法测试.研究表明,多次聚合法可以制备表面平整且内部均匀多孔的PPy厚膜.在聚合电量为12mAh·cm-2时,用Cl-、TOS-两种离子掺杂的PPy厚膜的面积比容量高达5F·cm-2,并表现出理想的电化学容量性能.同时PPy-Cl厚膜的质量比容量达到330F·g-1,PPy-TOS厚膜的质量比容量略低(191F·g-1),但具有更快的充放电速率.与一次聚合法合成的PPy薄膜相比,多次聚合法合成的PPy厚膜的质量比容量没有降低.通过场发射扫描电镜(SEM)观察了一次聚合法和多次聚合法制备的PPy厚膜的截面形貌,并讨论了多次聚合法的合成机理.

To obtain polypyrrole （PPy）fllms with high area specific capacitance as electrode material for supercapacitors, the multi-step polymerization method was proposed for preparing PPy thick films with polymerization charge of 8, 10, and 12 mAh·cm^-2, doped with Cl^- and p-toluenesulfonate （TOS^-）, respectively. The capacitance properties of the PPy films were investigated by galvanostatic charge/discharge, cyclic voltammetry （CV）, and electrochemical impedance spectrum （EIS） technologies. The section morphology of the PPy films was observed by using field emission electron scanning microscope （SEM）. The results showed that two kinds of even porous PPy films with area specific capacitance up to 5 F·cm^-2 could be obtained by multi-step method. Moreover, the mass specific capacitance （referring to the masses of polymer and doping ions） of PPy-Cl could reach 330 F·g^-1, and the value of PPy-TOS could reach 191 F·g^-1, which were similar with that of PPy thin films. However, the discharge rate of the PPy-TOS film was more rapid than that of the PPy-Cl film. In addition, the growth processes of PPy films from one-step polymerization method and multi-step polymerization method were discussed.