Developing effective electrodes for supercapacitors by grafting of trihydroxybenzene onto activated carbons

The specific capacity of activated carbon electrodes for supercapacitors may be enhanced with additional faradaic redox reactions by grafting of electroactive aromatic molecules with heteroatoms that act as redox centers. Such enrichment was demonstrated recently with anthraquinone and catechol using diazonium chemistry. Here, trihydroxybenzene, which has obvious advantages, was successfully grafted, yielding a mass enrichment of 25%. Electrochemical characterization in acidic aqueous solution after in situ methoxy deprotection demonstrated an initial specific capacity of 65 mAh g⁻¹, which faded only slightly to 55 mAh g⁻¹ after about 2000 cycles and remained stable for over 4500 cycles.