Filters

2016 - 201912020 - 20221
Reset filters

Settings

Author: Devrim, YilserSubject: Proton conductivity

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Article
    Citation - WoS: 41
    Citation - Scopus: 42
    Preparation of Polybenzimidazole/Zif-8 and Polybenzimidazole/Uio-66 Composite Membranes With Enhanced Proton Conductivity
    (Pergamon-elsevier Science Ltd, 2022) Eren, Enis Oguzhan; Ozkan, Necati; Devrim, Yilser
    Metal-organic frameworks (MOFs) are considered emerging materials as they further improve the various properties of polymer membranes used in energy applications, ranging from electrochemical storage and purification of hydrogen to proton exchange membrane fuel cells. Herein, we fabricate composite membranes consisting of polybenzimidazole (PBI) polymer as a matrix and MOFs as filler. Synthesis of ZIF-8 and UiO-66 MOFs are conducted through a typical solvothermal method, and composite membranes are fabricated with different MOF compositions (e.g., 2.5, 5.0, 7.5, and 10.0 wt %). We report a significant improvement in proton conductivity compared with the pristine PBI; for example, more than a three-fold increase in conductivity is observed when the PBI-UiO66 (10.0 wt %) and PBI-ZIF8 (10.0 wt %) membranes are tested at 160 degrees C. Proton conductivities of the composite membranes vary between 0.225 and 0.316 S cm(-1) at 140 and 160 degrees C. For the comparison, pure PBI exhibits 0.060 S cm(-1) at 140 degrees C and 0.083 S cm(-1) at 160 degrees C. However, we also report a decrease in permeability and mechanical stability with the composite membranes. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
  • Thumbnail Image
    Conference Object
    Citation - WoS: 91
    Citation - Scopus: 109
    Modeling and Sensitivity Analysis of High Temperature Pem Fuel Cells by Using Comsol Multiphysics
    (Pergamon-elsevier Science Ltd, 2016) Sezgin, Berna; Caglayan, Dilara Gulcin; Devrim, Yilser; Steenberg, Thomas; Eroglu, Inci
    The objective of this study is to observe the effect of the critical design parameters, velocities of inlet gases (hydrogen and air) and the conductivity of polymer membrane, on the performance of a high temperature PEM fuel cell. A consistent and systematic mathematical model is developed in order to study the effect of these parameters. The model is applied to an isothermal, steady state, three-dimensional PEM fuel cell in order to observe concentration profiles, current density profiles and polarization curves. The model includes the transport of gases in anode and cathode gas flow channels, diffusion in the catalyst layers, the transport of water and hydronium ion in the polymer electrolyte and in the catalyst layers, and the transport of electrical current in the solid phase. The model is considered as having a single flow channel. The simulation is performed by using licensed Comsol Multiphysics 5.0, Fuel Cells &Batteries Module. The results compare well with the experimental polarization data obtained at 160 degrees C for ohmic and activation regions. The best match with the experimental data is obtained when the inlet hydrogen gas velocity is 0.133 m/s whereas inlet air velocity is 1.3 m/s for proton conductivity of 10 S/m. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.