Phosphorylated graphene oxide-reinforced polybenzimidazole composite membrane for high-temperature proton exchange membrane fuel cell

A novel phosphorylated graphene oxide (PGO)-reinforced polybenzimidazole (PBI) composite membrane was prepared for high-temperature proton exchange membrane fuel cell (HT-PEMFC). PGO was prepared by phosphorylation of graphene oxide (GO) with phosphoric acid (PA), and its structure was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometry (EDS), and ion exchange capacity (IEC) measurement. Then, PGO was added into PBI to prepare composite membranes, with excellent oxidation and thermal stability, outstanding mechanical properties, strong PA uptake and high proton conductivity. The PBI composite membrane with 1.5 wt.% of PGO exhibits the highest tensile strength (38.4 MPa) and excellent proton conductivity (17.6 mS·cm−1 at 180 ℃ without moisture) after immersion in PA aqueous solution, which is 1.31 and 1.15 times higher than that of pure PBI and PBI/GO composite membranes, respectively. Thus, PGO-reinforced PBI composite membranes have promising applications in HT-PEMFC.