fig1

Figure 1. Structure formula of some low-cost organic electrode materials. (A) 9, 10-anthraquinone-2, 7-disulphonic acid for flow battery. (B) A redox-active triangular phenanthrenequinone-based macrocycle. (C) 4, 4 -(phenazine-5,10-diyl) dibenzoate. (D) The phenazine material for Zn-organic battery.