Interactive effects of pore size control and carbonization temperatures on supercapacitive behaviors of porous carbon/carbon nanotube composites

Porous carbon-based electrodes were prepared by carbonization with poly(vinylidene fluoride) (PVDF)/carbon nanotube (CNT) composites to further increase the specific capacitance for supercapacitors. The specific capacitance, pore size distribution, and surface area of the PVDF/CNT composites were measured, and the effect of the carbonization temperatures was examined. The electrochemical properties were examined by cyclic voltammetry, impedance spectroscopy, and galvanostatic charge-discharge performance using a two-electrode system in TEABF(4) (tetraethylammonium tetrafluoroborate)/acetonitrile as a non-aqueous electrolyte. The highest specific capacitance of ～101 Fg(-1) was obtained for the samples carbonized at 600 °C. The pore size of the samples could be controlled to below 7 nm through the carbonization process. This suggests that micropores make a significant contribution to the specific capacitance due to improved charge transfer between the pores of the electrode materials and the electrolyte.