The evolution of electrochemical functionality of carbons derived from glucose during pyrolysis and activation

The electrokinetics of electrochemical capacitor electrodes composed of either pyrolyzed dextrose or chemically activated pyrolyzed dextrose during progressive steps in the production process were studied under dynamic charging condition by using cyclic voltammetry. Two different sizes and species of aqueous electrolyte anions, SO ₄ ^2- and NO ₃ ^-, were used to probe the relationship between functional species dimension and electrode morphology. Cyclic voltammetry data collected with different scan rates demonstrate the appearance of slow charging process in the non-activated pyrolyzed carbons because of their ultramicroporous properties. The KOH activated material had significant micro-pores, and demonstrated electrokinetics of an ideal electric double layer. The activation on the carbon pyrolyzed at lower temperature is assumed to develop cylindrical pores, while that on the carbon pyrolyzed at higher temperature evolves slit-shaped pores.