Insights into the influence of pore size distribution and surface functionalities in the behaviour of carbon supercapacitors

In the present study, we report the microstructural characterization and the electrochemical performance of six activated carbons with varied textural properties. Activated carbons were investigated in terms of specific surface area, pore size distribution, surface chemistry and electrochemical behaviour in acidic, neutral and organic electrolytes. For this purpose, N2 adsorption isotherms, thermogravimetric analysis (TGA), infrared spectroscopy (FT-IR) and cyclic voltammetry (CV) techniques were used. Electrochemical properties of symmetric supercapacitors using these carbons were investigated by galvanostatic charge–discharge experiments and electrochemical impedance spectroscopy (EIS).Differences in textural properties of the activated carbons were analysed and correlated with their electrochemical behaviour indicating that mesoporous carbons of high surface area are promising materials for high power applications, whereas microporous carbons with higher specific capacitances would be preferred for high energy and medium power applications.

► Electrochemical performance of 6 carbons with different textural properties in 3 electrolytes.
► We demonstrate the crucial role of porosity, surface functionalities and electrolyte in the capacitance.
► Mesoporous carbons are promising materials for high power applications.
► Microporous carbons are preferred for high energy and medium power applications.