Electrochemical properties of size-controllable polypyrrole/porous carbon for supercapacitor electrodes

Polypyrrole (PPy)/activated carbon (AC) composite (SPPyC) with different PPy particle size are prepared without formation of chemical bonding between PPy and AC. The PPy particles were deposited on AC by miniemulsion polymerization and the size of PPy particles could be controlled by different surfactant amounts. The surface characteristics of SPPyC were characterized by fourier transform infrared spectroscopy (FT-IR). The morphology of SPPyC was examined by scanning electron microscopy (SEM). The electrochemical performance of SPPyC was determined by cyclic voltammetry (CV) and galvanostatic charge/discharge characteristics in 6 M KOH electrolyte. The specific capacitances of SPPyC were higher than those of AC and the highest specific capacitance (125 F/g) of the S3PPyC was obtained at a current density of 0.5 A/g. This improved electrochemical performance of SPPyC was attributed to redox reaction by controlled PPy particle size.