fig7

Figure 7. PFPIM membranes in redox flow battery. (A) Schematic diagram of ion exchange in aqueous organic redox flow batteries; (B) Chemical structure of AOPIM-1; (C) Pore size distribution of AOPIM-1; (D) The position of PIMs with other ion-change membranes at the upper bound of K⁺/Mg²⁺ separation; (E) long-term stability of the cells assembled with AOPIM-1 membrane at a current density of 40 mA·cm^-2[99]; (F) Schematic illustration of membrane microstructure; (G) Structure of the SPX-BP membrane; (H) A plot illustrating the relationship between proton conductivity and IEC of SPX-BP, Nafion 117, and some classic phase-separated membranes; (I) Long-term stability of cells assembled with SPX-BP-0.95 at a current of 60 mA·cm^-2[80]. PFPIM: Polar groups-functionalized polymers of intrinsic microporosity; AOPIM-1: amidoxime-functionalized polymers of intrinsic microporosity-1; PIMs: polymers of intrinsic microporosity; IEC: ion exchange capacity.