Electrochemical investigation of carbon aerogels and their activated derivatives

摘要

Carbon aerogels are highly porous materials prepared via pyrolysis of resorcinol-formation-dehyde aerogels. Depending on the mixing ratio of the ingredients entering the sol-gel-process hte porosity and pore size distribution of the carbon network can be varied. The major part of the pores is accessible to ionic conductors. For that reason the application of carbon aerogels as electrodes for supercapacitors is promising. In the present paper aerogel electrodes are modified via thermal and electrochemical activation procedures, e.g. oxidation in CO_2-atmosphere and anodic oxidation in sulfuric acid, respectively. The electro-chemical double layer of activated and non-activated aerogels is investigated using cyclic voltammetry and impedance spectroscopy. In combination with BET-measurements these methods provide a detailed insight in the surface structure and charging process of carbon aerogels.