Oxidative chemical vapor deposition of polypyrrole onto carbon fabric for flexible supercapacitive electrode material

Polypyrrole has been a promising conjugated polymer for application in electrochemical energy storage devices. One primary feature is its pseudocapacitive behavior, which makes it suitable for hybridization with traditional carbon-based electrical double layer capacitive materials. The processing condition for such a hybridization is a critical aspect for the electrode performance in long term. Oxidative chemical vapor deposition was used to deposit polypyrrole onto 3D carbon fiber fabric. This allowed uniform and conformal deposition of polypyrrole on individual fibers as well as a control over its thickness depending on the reaction time. The obtained composite was characterized for electrochemical energy storage application using cyclic voltammetry and galvanostatic charge discharge measurements. Additionally, the stability of the polypyrrole-carbon fiber electrode was tested using microscopy and energy dispersive spectroscopy in order to obtain insights into physical and chemical degradation of polypyrrole during electrochemical aging. Results showed thickness-dependence of electrode stability, tuning of which in the correct voltage window is necessary for optimal long-term performance.