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New proton exchange membranes were prepared and evaluated as polymer electrolytes for a proton exchange membrane fuel cell (PEMFC). Two types of fluorinated poly(arylene ether)s (FPAEs) were synthesized by nucleophilic aromatic substitution of decafluorobiphenyl (DFBP) with 4,4′-(hexafluoroisopropylidene)diphenol (HFDP) and bisphenol-A (BPA). The FPAEs so prepared were converted into proton exchange polymers by sulfonation with fuming sulfuric acid (30% SO3). The FPAEs and sulfonated-fluorinated poly(arylene ether)s (S-FPAEs) with various sulfonation levels were characterized using 1H NMR, thermogravimetric analysis (TGA) and back titration, and then successfully evaluated as proton exchange membranes (PEM) with unit cell operation. power output measurements of S-DFBP-HFDP carried out at a cell temperature of 80 °C. They exhibited a maximum power density of 425.5 mW/cm2 at 1150 mA/cm2. [Copyright &y& Elsevier]

Abstract: Organic–inorganic composite membranes for operation above 100°C in polymer electrolyte membrane fuel cells (PEMFCs) were prepared, characterized and cell-tested. Composite membranes were obtained by mixing organic polymers, which have a SO3H group as a proton conductor with inorganic material, SiO2, using the sol–gel process. Electron probe micro analyser (EPMA) was used to show the homogeneous and uniform distribution of SiO2. The physico-chemical properties of all membranes were investigated regarding their tensile strength, water uptake and thermogravimetric analyzer (TGA). Due to a higher water uptake and thermal stability of composite membranes, the cell performances at high temperatures above 100°C, were improved. In addition, the SiOH group in the composite membrane was shown to play a major role in capturing water strongly and maintaining proton conductivity even at high temperature. Furthermore, the fuel cell performance of organic–inorganic composite membranes was superior to that of the Nafion membrane at high current density over all ranges of temperature. [Copyright &y& Elsevier]

Sacrificial templating effect of mixed polymer matrix to create surface pores promoting the facile ion flow and close interaction of electrode and electrolyte. • Mixed polymer matrix provided a strong framework to restrict CNT migration. • Hot press proved to have enhance the performance with no structural deformation. • Easy access point for the electrolytes due to the emergence of surface pores. • Exhibited a specific energy of 814 Wh/kg -cell required for electric vehicles. Although Li-air batteries have been recognized as promising next-generation batteries for electric vehicles (EVs), there are still several issues in the development of practical cells that can achieve high specific energies for long driving ranges. In particular, it is important to employ a small amount of electrolyte and prevent it from escaping the cathode material during charging and discharging. Herein, a free-standing web-like mat cathode composed of mixed polymer nanofibers with high CNT loading is reported. High amounts of CNT (ca. 65.8 wt% of the polymer weight) is simultaneously loaded into the as-spun nanofibers with a mixed polymer matrix (consisting of polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP)). The domain occupied by PVP was converted into pores after a simple washing process, while the remaining PAN domain formed a backbone for the nanofibers. Using this cathode, a practical cell with a specific energy of 814 Wh/kg -cell is successfully developed by applying a controlled optimum ratio of electrolyte to CNT in the cathode. With these results, although still lacking, can provide handful insights and new directions towards development of future electrode materials as well as encourage to pursue strategies that requires minimal processing and activation steps while still achieving industrial acceptable performances. [ABSTRACT FROM AUTHOR]