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Language: enSubject: High temperature proton exchange

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    Article
    Citation - WoS: 146
    Citation - Scopus: 163
    Polybenzimidazole Based Nanocomposite Membranes With Enhanced Proton Conductivity for High Temperature Pem Fuel Cells
    (Pergamon-elsevier Science Ltd, 2017) Ozdemir, Yagmur; Uregen, Nurhan; Devrim, Yilser
    In this study, phosphoric acid doped PBI nanocomposite membranes were prepared by dispersion of various amounts of inorganic nanoparticles in PBI polymer followed by phosphoric acid (H3PO4) doping for high temperature proton exchange membrane fuel cells (HT-PEMFC). All of the PBI composite membranes were cast from the same FBI polymer with the same molecular weight. Titanium dioxide (TiO2), silicon dioxide (SiO2) and inorganic proton conductor zirconium phosphate (ZrP) were used as inorganic fillers. The PBI based composite membranes were characterized in terms of their acid uptake and acid leaching properties, mechanical properties, chemical stabilities in N-N Dimethylacetamide (DMAc) and impedance analyses. Thermal gravimetric analysis confirmed the improved thermal stability of the PBI composite membranes. The existence of inorganic fillers was improved the acid retention capability. Electrochemical Impedance Spectroscopy (EIS) showed that the introduction of 5 wt. % SiO2 or 5 wt. % ZrP helps to increase proton conductivity. The composite membrane with TiO2 retained low conductivity values than pristine PBI and this is a result of its non-uniform membrane structure. The highest proton conductivity of 0.200 S/cm was obtained for PBI/ZrP composite membrane with the highest value of H3PO4 doping level. Nyquist plots are drawn for all the membranes at different temperatures and the plots showed good fit with Randel's circuit. As a result the experimental results suggested that the PBI based composite membranes may be a promising electrolyte used in HT-PEMFC. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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    Article
    Citation - WoS: 26
    Citation - Scopus: 30
    Micro-Cogeneration Application of a High-Temperature Pem Fuel Cell Stack Operated With Polybenzimidazole Based Membranes
    (Pergamon-elsevier Science Ltd, 2020) Budak, Yagmur; Devrim, Yilser
    High temperature Proton Exchange Membrane Fuel Cells (HT-PEMFC) have attracted the attention of researchers in recent years due to their advantages such as working with reformed gases, easy heat management and compatibility with micro-cogeneration systems. In this study, it is aimed to designed, manufactured and tested of the HT-PEMFC stack based on Polybenzimidazole/Graphene Oxide (PBI/GO) composite membranes. The micro-cogeneration application of the PBI/GO composite membrane based stack was investigated using a reformat gas mixture containing Hydrogen/Carbon Dioxide/Carbon Monoxide (H-2/CO2/CO). The prepared HT-PEMFC stack comprises 12 cells with 150 cm(2) active cell area. Thermo-oil based liquid cooling was used in the HT-PEMFC stack and cooling plates were used to prevent coolant leakage between the cells. As a result of HTPEMFC performance studies, maximum 546 W and 468 W power were obtained from PBI/ GO and PBI membranes based HT-PEMFC stacks respectively. The results demonstrate that introducing GO into the PBI membranes enhances the performance of HT-PEMFC technology and demonstrated the potential of the HT-PEMFC stack for use in micro cogeneration applications. It is also underlined that the developed PBI/GO composite membranes have the potential as an alternative to commercially available PBI membranes in the future. (c) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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    Citation - WoS: 34
    Citation - Scopus: 39
    Development of a One-Dimensional and Semi-Empirical Model for a High Temperature Proton Exchange Membrane Fuel Cell
    (Pergamon-elsevier Science Ltd, 2018) Nalbant, Yagmur; Colpan, C. Ozgur; Devrim, Yilser
    High temperature proton exchange membrane fuel cells (HT-PEMFC), which operate between 160 degrees C and 200 degrees C, can be generally used in portable and stationary power generation applications. In this study, a one-dimensional, semi-empirical, and steady-state model of a HT-PEMFC fed with a gas mixture consisting of hydrogen and carbon monoxide is developed. Some modeling parameters are adjusted using empirical data, which are obtained conducting experiments on a HT-PEMFC for different values of Pt loading and cell temperature. For adjusting these parameters, the total summation of the square of the difference between the cell voltages found using the experimental and theoretical methods is minimized using genetic algorithm. After finding the values of the adjusted parameters, the effects of different cell temperature, Pt loading, phosphoric acid (PA) percentage, and different binders (PBI and PVDF) on the performance of the fuel cell are examined. It was found that, the performance of the fuel cell using PVDF binder exhibited better performance as compared to that using PBI binder. (c) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.