Redox functionalization of carbon electrodes of electrochemical capacitors

Abstract

It is shown that the liquid oxidative treatment of microporous active carbon (AC) of the Norit DLC Supra 30 grade by nitric acid in the presence of carbamide results in an increase in the content of hydroxy groups on the AC surface at the practically unchanged content of carboxyl groups. Redox functionalization and appearance of pseudocapacity result in an increase in the carbon electrode capacity by 26%. The surface state of the carbon material is characterized using the infrared spectroscopy and Boehm titrimetry techniques, while the electrochemical characteristics are studied using the method of cyclic voltammetry in 3 M sulfuric acid solution. Studies of degradation of the electrodes of the initial and modified active carbons show that capacity decreases by 3 and 8%, accordingly, after 1 thousand charging–discharge cycles.