Effect of oxidant on morphology and electrochemistry of polypyrrole-coated graphite fiber

The morphology of polypyrrole films produced on graphite fiber substrate is affected by hydrous/anhydrous oxidants. Variation in the morphology was monitored from observation of electronic microscopy images and Brunauer-Emmett-Teller measurements, and the proposed mechanism of film formation is discussed. It was found that the morphology of polypyrrole prepared from hydrous oxidant showed a more porous structure than that of films prepared from anhydrous oxidant. In the case of polypyrrole films with a porous structure, the specific redox charge of the films was substantially enhanced by increasing the contact area between the polymer chain and electrolyte. In addition, their power characteristics were also improved by decreasing the ion diffusion resistance. These films have potential applicability to electrochemical capacitors. (c) 2008 The Electrochemical Society.