Synthesis and properties of novel sulfonated polybenzimidazoles from disodium 4,6-bis(4-carboxyphenoxy)benzene-1,3-disulfonate

▶ A series of novel sulfonated polybenzimidazoles (SPBIs) have been synthesized from a new sulfonated dicarboxylic acid monomer, disodium 4,6-bis(4-carboxyphenoxy)benzene-1,3-disulfonate. ▶ The phosphoric acid (PA)-doped SPBI-11 membrane shows high mechanical strength (20 MPa) despite the high PA-doping level (240% (w/w)). ▶ The fuel cell fabricated with the PA-doped SPBI-11 membrane exhibits high performance (the highest output power density: 0.58 W cm-2) at 170 °C with hydrogen-oxygen gases under ambient pressure without any gas humidification.