The electrochemical characteristics of polypyrrole doped with either perchlorate or Nafion are determined. Polypyrrole doped with Nafion ions or perchlorate ions exhibits a specific capacitance of 344 or 355 F g−1, respectively. Cycle life experiments reveal that the Nafion-doped material retains 98% of the original capacitance after 3000 cycles whereas that doped with perchlorate retains only 70% over this period. Scanning electron microscopy (SEM) before and after long-term cycling, reveals some mechanical degradation.