▎ 摘　　要

A commercial perfluorinated sulfonic acid (PFSA) membrane, Nafion, shows outstanding conductivity under conditions of a fully humidified surrounding. Nevertheless, the use of Nafion membranes that operate only at low temperature (<100 degrees C) can lead to some disadvantages in PEMFC systems, such as a low impurity tolerance and slow kinetics. To overcome the above problems, this study introduces a highly durable composite membrane with an inorganic filler for a high-temperature proton exchange membrane fuel cell (HT-PEMFC) applications under anhydrous conditions. In this work, polybenzimidazole (PBI) is used as a polymer electrolyte membrane with the addition of a sulfonated graphene oxide (SGO) inorganic filler. The amount of SGO filler was varied (0.5-6 wt.%) to study its influence on proton conductivity at elevated temperature, mechanical stability as well as phosphoric acid doping level. In particular, PBI-SGO composite membranes exhibited higher the level of acid dopant and proton conductivities than those of the pure PBI membranes. The PBI-SGO 2 wt.% composite membrane displayed the highest proton conductivity, with a value of 9.142 mS cm(-1) at 25 degrees C, and it increased to 29.30 mS cm(-1) at 150 degrees C. The PBI-SGO 2 wt.% also displayed the maximum values in the acid doping level (11.63 mol of PA/PBI repeat unit) and mechanical stability (48.86 MPa) analyses. In the HT-PEMFC test, compared with a pristine PBI membrane, the maximum power density was increased by 40% with the use of a PBI composite membrane with 2 wt.% SGO. These results show that the PBI-SGO membrane has a great potential to be applied as an alternative membrane in HT-PEMFC applications, offering the possibility of improving impurity tolerance and kinetic reactions. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.