Acta Phys. -Chim. Sin. ›› 2007, Vol. 23 ›› Issue (03): 299-304.doi: 10.1016/S1872-1508(07)60023-0

• ARTICLE • Previous Articles     Next Articles

Effect of Doping Ions on Electrochemical Capacitance Properties of Polypyrrole Films

WANG Jie;XU You-Long;CHEN Xi;DU Xian-Feng;LI Xi-Fei   

  1. School of Electronic and Information Engineering, Xi′an Jiaotong University, Xi′an 710049, P. R. China
  • Received:2006-10-18 Revised:2006-11-21 Published:2007-03-07
  • Contact: XU You-Long

Abstract: Conducting polypyrrole films (PPy) doped with p-toluenesulfonate (TOS-), ClO-4, and Cl- were electro- chemically prepared, respectively. The electrochemical capacitance properties of the PPy films were investigated with cyclic voltammetry (CV), galvanostatic charge/discharge, and electrochemical impedance spectroscope (EIS) techniques. The morphology observation and structure analysis of PPy films were performed by scanning electron microscope (SEM) and X-ray diffraction (XRD). The results showed that PPy-Cl and PPy-TOS were characterized with a highly porous and ordered structure, which led to their fast ion switch processes. Moreover, they exhibited a rectangle-like shape of voltammetry characteristics even at a scanning rate of 50 mV·s-1, a linear variation of the voltage with respect to time in charge/discharge process and almost ideal capacitance behavior in low frequency even on deeply charged/discharged states in 1 mol·L-1 KCl solution. Furthermore, specific capacitance of PPy-Cl (polymerization charge of 2 mAh·cm-2) would reach 270 F·g-1 (scanning rate of 5 mV·s-1) or 175 F·g-1 (scanning rate of 200 mV·s-1) and its specific energy could reach 35.3 mWh·g-1. Moreover, with heavier doping ion (TOS-), PPy-TOS (polymerization charge of 2 mAh·cm-2) had a slightly smaller specific capacitance (146 F·g-1, scanning rate of 5 mV·s-1) but very rapidly charge/discharge ability (specific capacitance of 123.6 F·g-1 at scanning rate of 200 mV·s-1) and its specific power could reach 10 W·g-1. In addition, both PPy-TOS and PPy-Cl had a good cycleability. All of the above implied that the PPy-Cl and PPy-TOS were two kinds of promising electrode material for supercapacitors.

Key words: Polypyrrole, Capacitance, Electrochemical polymerization, Doping ion, Supercapacitor