Surface modification of carbon black by anodic oxidation and electrochemical characterization

The purpose of the work reported here is to give carbon black with a high functional surface, especially for use in battery electrodes. The authors have investigated the surface properties, such as wettability, electric conductivity, and rate constant of H2O2 decomposition of surface modified carbon black (CB) by anodic oxidation processing. This work also describes the relationships between the surface properties and the electrochemical behavior of the electrodes with anodically modified CB in an aqueous KOH solution. The results are as follows: the CB surface changes from hydrophobic to hydrophilic; the conductivity of CB decreases with the processing; and the processing enhances the H2O2 decomposition ability of CB. From experiments using a rotating disk electrode, it can be concluded that oxygen electrode reaction on CB surface is a two-electron reduction forming H2O2 as an intermediate. The polarization behavior of an oxygen electrode with CB has been much improved by the anodic oxidation. This can be attributed to the formation of the stable three-phase zone owing to adequate wettability, high H2O2 decomposition ability, and highly developed fine pores of the CB electrode.