Poly tris (1-imidazolyl) benzene ionic liquids/Poly (2,6-dimethyl phenylene oxide) composite membranes for anion exchange membrane fuel cells

To improve the conductivity of anion exchange membranes without reducing the mechanical properties, a series of poly ionic liquids (PILs) with precursors of 1,3,5-tris(1-imidazolyl)benzene (TIB) containing tri-conduct groups were synthesized and incorporated into quaternized poly (2,6-dimethyl phenylene oxide) (QPPO) membranes. The new poly ionic liquids we designed contain ternary conduct groups in one monomer which are advantageous to form ionic channels and thus dramatically increase the conductivity of membranes. Various alkyl chains were introduced into TIB during polymerization to tune the distance between two tri-conduct groups. The resulting PILs/QPPO composite membranes showed good thermal stability, appropriate mechanical properties, enhanced conductivity and fuel cell performance. When the numbers of –CH₂– between two tri-conduct groups reached 12, the composite membrane showed the highest conductivity and fuel cell performance (55.5 mS/cm at 80 °C and 168.9 mW/cm²). The composite membranes we prepared show potential application in anion exchange membrane fuel cells (AEMFCs).