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Yu Zhang - One of the best experts on this subject based on the ideXlab platform.

  • preparation and characterization of nafion speek layered Composite Membrane and its application in vanadium redox flow battery
    Journal of Membrane Science, 2008
    Co-Authors: Huamin Zhang, Yu Zhang, Qingtao Luo, Jian Chen, Dongjiang You, Chenxi Sun
    Abstract:

    In order to reduce the cost of Membrane used in vanadium redox flow battery (VRB) system while keeping its chemical stability, Nafion/sulfonated poly(ether ether ketone) (SPEEK) layered Composite Membrane (N/S Membrane) consisting of a thin layer of recast Nafion Membrane and a layer of SPEEK Membrane were prepared by chemical crosslink the sulfonic acid groups of different ionomer Membranes. Scanning electron microscopy (SEM) and IR spectra analysis of the Membrane showed that Nafion layer was successfully deposited on the SPEEK Membrane surface and an integral layered Membrane structure was formed. The area resistance and permeability of vanadium ions of Membrane were also measured. It was found that N/S Membrane have a very low permeability of vanadium ions accompanied by a little higher area resistance compared with Nafion Membrane. As a result, the VRB single cell with N/S Membrane exhibited higher coulombic efficiency and lower voltage efficiency compared with VRB single cell with Nafion Membrane. Although N/S Membrane delivered relatively lower energy efficiency compared with Nafion Membrane, its good chemical stability and low cost make it a suitable substitute for Nafion Membrane used in VRB system.

  • a novel h3po4 nafion pbi Composite Membrane for enhanced durability of high temperature pem fuel cells
    Journal of Power Sources, 2007
    Co-Authors: Yunfeng Zhai, Huamin Zhang, Yu Zhang, Danmin Xing
    Abstract:

    Abstract A novel phosphoric acid doped Nafion–polybenzimidazole (H 3 PO 4 /Nafion–PBI) Composite Membrane was prepared and the H 2 /O 2 single cell durability was tested at 150 °C without humidification. The durability was improved 55% compared with that of phosphoric acid doped polybenzimidazole (H 3 PO 4 /PBI). During the durability test, the hydrogen permeability of the Membrane and the internal resistance of the single cell were detected using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS), respectively. Before and after the durability test, the mechanical strength of the Membranes was measured by stress–strain tests. The results of characterization indicated that the enhanced durability of the Membrane attributed to the improved mechanical strength, which benefited from the presence of Nafion in the Nafion and PBI matrix. The preliminary results suggested that the novel H 3 PO 4 /Nafion–PBI Composite Membrane is a good candidate in high temperature PEMFC for achieving longer cell lifetime.

  • A novel H3PO4/Nafion–PBI Composite Membrane for enhanced durability of high temperature PEM fuel cells
    Journal of Power Sources, 2007
    Co-Authors: Yunfeng Zhai, Huamin Zhang, Yu Zhang, Danmin Xing
    Abstract:

    Abstract A novel phosphoric acid doped Nafion–polybenzimidazole (H 3 PO 4 /Nafion–PBI) Composite Membrane was prepared and the H 2 /O 2 single cell durability was tested at 150 °C without humidification. The durability was improved 55% compared with that of phosphoric acid doped polybenzimidazole (H 3 PO 4 /PBI). During the durability test, the hydrogen permeability of the Membrane and the internal resistance of the single cell were detected using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS), respectively. Before and after the durability test, the mechanical strength of the Membranes was measured by stress–strain tests. The results of characterization indicated that the enhanced durability of the Membrane attributed to the improved mechanical strength, which benefited from the presence of Nafion in the Nafion and PBI matrix. The preliminary results suggested that the novel H 3 PO 4 /Nafion–PBI Composite Membrane is a good candidate in high temperature PEMFC for achieving longer cell lifetime.

Maria Skyllas-kazacos - One of the best experts on this subject based on the ideXlab platform.

  • Characterisation of novel Composite Membrane for redox flow battery applications
    Journal of Membrane Science, 1995
    Co-Authors: Toraj Mohammadi, Maria Skyllas-kazacos
    Abstract:

    The preparation and evaluation of a Composite Membrane from a single sheet of a microporous separator, Daramic, by incorporation of Amberlite CG 400 as an anion exchange resin and further crosslinking with divinylbenzene was successfully employed in the vanadium battery as described previously. Further modification and characterisation of the Composite Membrane are now described. A detailed FESEM, TGA, IR and 13C NMR analysis of the Composite Membrane has been carried out. The ion exchange capacity of the Composite Membrane was also evaluated. Formation of a thin layer of poly(divinylbenzene) after crosslinking was confirmed by morphological studies. None of the experiments showed incorporation of the ion exchange resin into the Composite Membrane, although its presence in the monomer/solvent mixture appears to somehow affect the final properties of the Composite Membrane prepared. ?? 1995.

  • Preparation of sulfonated Composite Membrane for vanadium redox flow battery applications
    Journal of Membrane Science, 1995
    Co-Authors: Toraj Mohammadi, Maria Skyllas-kazacos
    Abstract:

    Abstract In the present studies, Daramic, which consits of ultrahighmolecular polyethylene, amorphous silica and mineral oil, was crosslinked with divinylbenzene (DVB) as a crosslinking agent and further sulfonated to obtain a cation exchange Membrane for the vanadium redox cell. It was shown that the average pore size of Daramic was reduced from 0.1 to 0.02 μm after crosslinking [1]. The preparation and characterisation of the modified ion exchange Membrane from the Composite Membrane with subsequent sulfonation are described. The Membrane modification process results in a dramatic reduction in solvent transfer across the Membrane when used in the vanadium redox cell. The ion exchange capacity (IEC) of the sulfonated Composite Membrane was also evaluated. The sulfonation reaction was found to be able to incorporate cation exchange groups into the Composite Membrane. Water transport measurements across the sulfonated Composite Membrane showed promising results compared with those across the Composite Membrane. A detailed FESEM and 13 C NMR analysis of the Composite Membrane and the sulfonated Composite Membrane have been carried out.

Rafiuddin - One of the best experts on this subject based on the ideXlab platform.

  • Preparation, electrochemical characterization and antibacterial study of polystyrene-based magnesium–strontium phosphate Composite Membrane
    Materials Science and Engineering: C, 2012
    Co-Authors: Mohammad Mujahid Ali Khan, Rafiuddin
    Abstract:

    Abstract The electrochemical characterizations of polystyrene-based magnesium–strontium phosphate (MSP) Composite Membrane have been worked on, as a function of Membrane thickness, porosity and moisture content etc. Polystyrene-based magnesium–strontium phosphate Composite Membrane was characterized by XRD, FTIR, SEM, and antibacterial studies. The Membrane was found to be crystalline in nature with uniform arrangement of particles, no sign of visible cracks and shows excellent inhibitory results against Escherichia coli and Pseudomonas aeruginosa bacteria. The Membrane potentials of inorganic Membrane were measured with uni-univalent electrolytes solution using saturated calomel electrodes and followed the order LiCl > NaCl > KCl, thus, the Membrane was found to be cation selective. Membrane potential data have been used to calculate transport number, mobility ratio, distribution coefficient, charge effectiveness, and also to derive the fixed-charge density which is a central parameter governing the Membrane phenomena by utilizing the Teorell, Meyer, and Sievers method. The order of surface charge density for uni-univalent electrolytes solution was found to be LiCl

  • Synthesis, electrochemical characterization, antibacterial study and evaluation of fixed charge density of polystyrene based calcium-strontium phosphate Composite Membrane
    Desalination, 2012
    Co-Authors: Mohammad Mujahid Ali Khan, Rafiuddin
    Abstract:

    Abstract The present work demonstrates the electrochemical characterizations of polystyrene based calcium–strontium phosphate Composite Membranes prepared by sol–gel process. Polystyrene based magnesium-strontium (CSP) Composite Membrane was characterized by XRD, FTIR, SEM, and antibacterial studies. The Membrane was found to be crystalline in nature with uniform arrangement of particles indicating no sign of visible cracks and showed good inhibitory effects against gram positive as well as gram negative bacteria. The IR spectra confirm the binding of the Composites with the polystyrene. The observed Membrane potential of polystyrene based calcium–strontium phosphate Composite Membrane were measured with uni-univalent electrolytes solutions using saturated calomel electrodes and followed the order LiCl > NaCl > KCl. Thus, the Membrane was found to be cation-selective. Membrane potential data have been used to calculate transport number, mobility ratio, distribution coefficient, charge effectiveness, and also to derive the fixed charge density which is a key parameter to govern the Membrane phenomena by utilizing Teorell, Meyer, and Sievers method. The order of surface charge density for uni-univalent electrolytes solution was found to be KCl > NaCl > LiCl.

Xiangguo Teng - One of the best experts on this subject based on the ideXlab platform.

  • nafion organic silica modified tio2 Composite Membrane for vanadium redox flow battery via in situ sol gel reactions
    Journal of Membrane Science, 2009
    Co-Authors: Xiangguo Teng, Yongtao Zhao, Xinping Qiu, Liquan Chen
    Abstract:

    Abstract To improve the selectivity of Nafion Membrane, reduce the crossover of vanadium ions and decrease water transfer across the Membranes used in VRB systems, the sol–gel method was employed to obtain a Composite Membrane of Nafion/organic silica modified TiO 2 (Nafion/Si/Ti hybrid Membrane). The preparation technique and characteristics of the Composite Membrane were described. The water transfer and the permeability of vanadium ions were also measured. Results showed that crossover of vanadium ions and water transfer across the Membrane for the Composite Membrane have a remarkable decrease comparing with the unmodified Nafion Membrane. It has been confirmed by EDX and FT-IR analysis of the modified Membrane that the Si and Ti elements distributed uniformly in the prepared Membrane. As a result, the coulombic efficiency of the VRB single cell with modified Nafion Membrane was higher than that of the VRB single cell with pristine Nafion Membrane. The ion exchange capacity (IEC), the area resistance and the water uptake of the Composite Membrane were also evaluated. Furthermore, the open circuit voltage (OCV) of the VRB with modified and unmodified Nafion Membrane has been carried out and cycle performance of the VRB with modified Membrane proves that it has high stability in strong acid condition.

Qingtao Luo - One of the best experts on this subject based on the ideXlab platform.

  • preparation and characterization of nafion speek layered Composite Membrane and its application in vanadium redox flow battery
    Journal of Membrane Science, 2008
    Co-Authors: Huamin Zhang, Yu Zhang, Qingtao Luo, Jian Chen, Dongjiang You, Chenxi Sun
    Abstract:

    In order to reduce the cost of Membrane used in vanadium redox flow battery (VRB) system while keeping its chemical stability, Nafion/sulfonated poly(ether ether ketone) (SPEEK) layered Composite Membrane (N/S Membrane) consisting of a thin layer of recast Nafion Membrane and a layer of SPEEK Membrane were prepared by chemical crosslink the sulfonic acid groups of different ionomer Membranes. Scanning electron microscopy (SEM) and IR spectra analysis of the Membrane showed that Nafion layer was successfully deposited on the SPEEK Membrane surface and an integral layered Membrane structure was formed. The area resistance and permeability of vanadium ions of Membrane were also measured. It was found that N/S Membrane have a very low permeability of vanadium ions accompanied by a little higher area resistance compared with Nafion Membrane. As a result, the VRB single cell with N/S Membrane exhibited higher coulombic efficiency and lower voltage efficiency compared with VRB single cell with Nafion Membrane. Although N/S Membrane delivered relatively lower energy efficiency compared with Nafion Membrane, its good chemical stability and low cost make it a suitable substitute for Nafion Membrane used in VRB system.