Anthraquinone-2,6-disulfamidic acid: an anolyte with low decomposition rates at elevated temperatures

A new sulfamidic acid anthraquinone derivative was synthesized from 2,6-diaminoanthraquinone with high yields, designed for utilization in redox flow batteries. The active material was investigated with cyclic voltammetry, revealing a reversible redox reaction at approximately -0.65 V <i>vs.</i> Ag/AgCl at pH-values above 12. A stress test in a redox flow battery was applied with hold times at critical states of charge and at 32 °C as well as at 60 °C. Furthermore, the stability was investigated at the maximum concentration of the anolyte. All in all, the material showed the lowest decomposition rates at 60 °C reported so far for an organic anolyte in a redox flow battery.