Redox-crosslinked graphene networks with enhanced electrochemical capacitance

A facile and effective method for the synthesis of redox-crosslinked graphene networks is reported. This method involves the polyphosphoric acid-catalyzed cyclization reaction between the carboxylic groups on graphene oxide and the hydroxyl, amino groups on 4,6-diaminoresorcinol hydrochloride, as well as a subsequent reduction process. The obtained benzobisoxazole-crosslinked graphene networks (BBO-GNs) show a high BET surface area of 357 m² g^-1 in comparison with the reduced graphene oxide (rGO) (117 m ² g^-1), due to the presence of benzobisoxazole groups that prevent the irreversible restacking or agglomeration of graphene sheets during the reduction. Another immediate and more practically meaningful benefit of introducing benzobisoxazole groups is that such functional groups could effectively provide an extra contributing channel to the specific capacity by pseudocapacitance. As a consequence, the improved performance such as significantly enhanced electrochemical capacitance is clearly demonstrated in the supercapacitor with the electrodes of BBO-GNs.