Ionic liquid-modified TiO2 to enhance polybenzimidazole for high-temperature proton exchange membranes

Increasing the retention of phosphoric acid (PA) may significantly boost the performance of proton exchange membranes (PEMs). In this work, mesoporous titanium dioxide (TiO 2 ) nanoparticles were introduced into polybenzimidazole (PBI) membranes and crosslinked using a silane coupling agent–modified ionic liquid (IL). TiO 2 nanoparticles with high specific volume were combined with ILs to enhance PA retention and inhibit leaching, thereby improving the performance of PEMs. Strong proton conductivity (0.092 S cm −1 , 140 °C) combined with saturated electron transport and outstanding PA retention is made possible by a special proton transfer channel with a silane-bonded titanium dioxide structure. At 140 °C, having an excellent stabilizing current demand of 200 mA cm −2 during 110 h of operation, a hydrogen/oxygen (H 2 /O 2 ) cell founded on the as-fabricated membrane demonstrated outstanding long-term stability and a maximum power density up to 668 mW cm −2 . A high-temperature PEM (HT-PEM) that can function across an extensive temperature spectrum of 80 °C to 200 °C without the need for external humidification is created when stabilized PBI chains are coupled with hydrogen-bonded proton transport channels.