Abstract: Two anthraquinone derivatives with amino acid functional groups were synthesized by two methods: the amide condensation reaction of carboxyl anthraquinone with amino acids by amide bond or urea bond, and the coupling reaction of halogenated anthraquinone with amine, that is, (4,5-dihydroxy-9,10-anthraquinone-2-carbonyl)-glutamic acid (GAAQ) and N, N'-(9,10-anthraquinone- 2,6-dicarboxylic)-di-glycine (GLAQ). The electrochemical properties and single cell cycling performance of two anthraquinone derivatives, GAAQ and GLAQ, and the cycling performance of GLAQ were investigated. Among them, GLAQ was an alkaline flow battery composed of the negative electrode electrolyte active substance and potassium ferrocyanide. Using Nafion as the ion exchange membrane, charge and discharge cycling experiments were conducted at a current density of 200 mA/cm². The results showed when the open circuit voltage was greater than 1 V, the Coulombic efficiency was 92%, the voltage efficiency was higher than 85%, and the energy efficiency was higher than 80%. There was no significant capacity decrease in 200 cycles, which indicated that GLAQ had good application prospects for active substances in flow battery.

Key words: anthraquinone, amino acid, alkaline organic flow battery, cathode electrolyte