Effect of Pore Structure of Activated Carbon on its Electrochemical Performance in Non-Aqueous Electrolyte

Abstract

The surface area and pore distribution of activated carbons (ACs) were characterized by nitrogen adsorption isotherms at 77 K, and double layer capacitors were assembled to demonstrate the electrochemical performance. With 1 mol·L-1 tetraethylammonium tetrafluoroborate dissolved in acetonitrile (Et4NBF4/AN) as electrolyte, electrochemical methods including cyclic voltammetry (CV) and galvanostatic charge-discharge tests were used to evaluate the capacitors. Results show that the surface area has a limited effect on the specific capacitance of ACs and the increaing of mesoporous content can decrease the capacitance decay rate at large discharge current. When current increases from 0.15A·g-1 to 9.6A·g-1, the minimum specific capacitance decay rate of mesoporous ACs is 10.93%, while that of the microporous ACs is 15.21%;the contributions of mesoporous surface area to the specific capacitance drop from 10.10 to 9.95μF·cm-2, while that of microporous surface area drop from 5.68 to 4.21μF·cm-2.