No abstract

The present work reports the synthesis of polybenzimidazole (PBI)/BaCe0.85Y0.15O3-δ nanocomposite membrane. The obtained membranes were investigated to use as novel electrolytes in high-temperature proton exchange fuel cells. The PBCYx membranes were prepared with dispersing BaCe0.85Y0.15O3-δ into the polyimidazole membrane by solution casting method. The obtained membranes were used as novel proton conductors. The thermal stability and structural properties were investigated. The conductivity and morphology of the obtained materials were studied using impedance spectroscopy AC (IS) and a scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDX). The maximum phosphoric acid adsorption (175%) and protonic conductivity (0.092 S/cm at 180 °C under dry conditions) were observed for all of the PBI nanocomposite membranes containing 5 wt.% of BaCe0.85Y0.15O3-δ in the membrane matrix. The polarization and power density curves were studied at 150 and 180 °C operating temperatures. The power density of about 0.42 W/cm2 and current density of about 0.84 A/cm at 0.5 V and 180 °C were achieved under dry conditions. The data obtained from our studies showed that the physicochemical properties of the novel nanocomposites were enhanced for using in the high-temperature proton transfer fuel cells.

Pure and ytterbium-doped BaCeO3 nanostructures were synthesized by solid-state reaction with the mixtures of Ba(NO3)2, BaCO3, (NH4)2Ce(NO3)6, and Yb2O3 at 800 °C for 10 and 24 h. Doping of ytterbium ions in the BaCeO3 host matrix has been studied and confirmed using powder X-ray diffraction. The results from the Rietveld analysis indicated that the sample has a main BaCeO3 structure with the space group of [Formula: see text]. Through intensive experiments and analysis, optimum reaction conditions for the synthesis of doped nanoparticles including the crystal phase impurity and reaction time are proposed. The results of the study showed that for the reaction time of 24 h, BaCO3 reacted more effectively with (NH4)2Ce(NO3)6 than Ba(NO3)2 did. On the other hand, the purity values of 97% and 95% were obtained for pure and Yb3+ doped BaCeO3 samples, respectively. Field emission scanning electron microscope images revealed that the synthesized BaCeO3 nanomaterials have mono-shaped sphere morphology. Furthermore, ytterbium-doped nanoparticles were incorporated into the matrix of sulfonated poly(ether ether ketone) (SPEEK) membranes (SPYb) with the aim of enhancing proton conductivity. The prepared SPYb nanocomposite membrane containing 1.7 wt.% of BaCe0.85Yb0.15O3-δ nanoparticles exhibited a high proton conductivity (67 mS/cm) at 80 °C.