The Capacitor Properties of KOH Activated Porous Carbon Beads Derived from Polyacrylonitrile

Polyacrylonitrile (PAN)-derived carbon beads with uniform size and high surface area were successfully prepared by the carbonization of PAN and activation by KOH. Physicochemical analysis revealed that the PAN-derived carbon beads activated by KOH possessed larger pore volume and pore width than the same types of carbon beads activated by CO2 and commercially available activated carbon powder. Even if the PAN-derived carbon beads were made into an electrode without any conducting supplements, the electrode possessed a higher specific capacitance than an electrode composed of commercially available activated carbon in the presence of conducting acetylene black powders. Origins of such desirable properties as carbon materials used for electric double layer capacitors were investigated by AC impedance measurements in both aqueous and non-aqueous electrolyte solutions. Polyacrylonitrile (PAN)-derived carbon beads with uniform size and high surface area were successfully prepared by carbonization of PAN and activation by KOH. Since ionic diffusion resistance in the pores of particles, as well as electric resistance between particles, was low, PAN-derived carbon beads exhibited desirable properties as an electrode material for electric double layer capacitors.