Polypyrrole doped with dodecyl benzene sulfonate electrodeposited on carbon fibers for flexible capacitors with high-performance

Abstract Polypyrrole (PPy) doped with large counter anion of dodecyl benzene sulfonate (DBS) has been electrodeposited on carbon fibers to obtain the composite of PPy/DBS/CF, and the preparation conditions for the flexible composites have also been optimized. The microstructures of PPy/DBS/CF composites are observed by scanning electron microscope, and the electrochemical properties of the composites are investigated by using electrochemical techniques. The flexible wire-shaped electrochemical capacitors can be fabricated conveniently by using the composites of PPy/DBS/CF as electrodes, and the performances of the flexible capacitors are evaluated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy methods in different polyvinyl alcohol (PVA)-based gel electrolytes. The results show that the electrolytes have significant influence on the capacitors’ performances. The specific capacitance of PPy/DBS/CF can reach to about 29.0 mF cm −1 when LiClO 4 /PVA and LiCl/PVA are used as electrolytes. The energy density and power density of the capacitors based on LiCl/PVA electrolyte can get 1.20 mWh cm −3 and 0.59 W cm −3 at discharge current density of 1.50 A cm −3 . Furthermore, the flexible capacitors based on LiCl/PVA electrolyte have excellent cyclic stability, which can retain 90.5 % of the initial capacitance after 5000 cycles, while the capacitors based on LiClO 4 /PVA only retains about 80.1 % of their initial capacitance.