Enhancement on the electrochemical properties of commercial coconut shell-based activated carbon by H2O dielectric barrier discharge plasma

Commercial coconut shell-based activated carbon (CSAC) has low specific capacitance and specific capacitance retention owing to its undeveloped pore structure and low proportion of heteroatoms. In this study, dielectric barrier discharge (DBD) plasma was used to enhance the specific capacitance and rate capability of CSAC. H2O was used as excited medium to introduce oxygen functional groups. The physicochemical properties of CSAC and CSAC modified by H2O plasma (HCSAC) were revealed by automated surface area and pore size analysis, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy (Raman). Electrochemical workstation was applied to investigate the electrochemical properties of CSAC and HCSAC. Obtained results showed that plasma modification improved the specific capacitance of CSAC by 64.8% (current density, 1 A g-1; electrolyte, 6 M KOH solution) within 100 seconds. This result is ascribed to the oxygen functional groups intro...