Chemical modification of carbon edge sites using trimethylaluminum to enhance the oxidation resistance of carbon materials

Abstract

As the oxidation of carbon materials proceeds from chemically reactive carbon edge sites, increasing the chemical stability of carbon edge sites is expected to increase the oxidation resistance. In this study, we developed a method for enhancing the chemical stability of carbon materials by modifying the carbon edge sites with chemically stable metal oxides. We focused on aluminol as a potentially stable metal oxide and introduced it to the carbon edge sites by modifying them with trimethylaluminum (TMA). Moreover, we investigated the effect of this introduction on the electrochemical oxidation resistance of the carbon material. A detailed structural analysis of the TMA-treated carbon samples indicated that TMA reacts one-to-one with the hydroxyl groups at the edge sites and modifies them with aluminol. An investigation of the effect of TMA treatment on the electrochemical oxidation resistance of carbon samples revealed that TMA treatment increases the oxidation resistance only when the ratio of TMA-modified sites to total carbon edge sites is ≥ 60%.