Abstract
Nafion® was introduced into a polypyrrole (PPy) matrix, and the redox performance of the PPy/Nafion electrode was investigated in a poly(ethylene oxide) 
electrolyte. A rougher interface between polymer cathode and polymer electrolyte is usually needed for an all‐solid battery, however, the PPy/Nafion cathode works well regardless of the flat surface of the PPy/Nafion film. When compared to a PPy film doped with 
anions with a similar morphology, the PPy/Nafion film showed better redox performance. The results of ac impedance spectroscopy and potential‐step chronoamperometry confirmed that the improvement in the redox reaction of the PPy/Nafion film was due to the enhancement of the ion diffusion rate in the film. Thus, the PPy/Nafion film showed good charging‐discharging properties in a rechargeable 
battery.