Polymer Electrolyte Membranes Based on Nafion and a Superacidic Inorganic Additive for Fuel Cell Applications (original) (raw)
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18th World Hydrogen Energy Conference, 2010
In the present study, Nafion/Titanium dioxide (TiO 2) nanocomposite membranes for use in proton exchange membrane fuel cells (PEMFC) were investigated. Nafion/TiO 2 membranes were prepared using the recasting procedure. The composite membranes have been characterized by thermal analysis, XRD, SEM, proton conductivity measurements and single cell performance. Thermal analysis results showed that the composite membranes have good thermal properties. The introduction of the inorganic filler supplies the composite membrane with a good thermal resistance. The physico-chemical properties studied by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques have proved the uniform and homogeneous distribution of TiO 2 and the consequent enhancement of crystalline character of these membranes. The energy dispersive spectra (EDS) analysis indicated that the distribution of Ti element on the surface of the composite membrane was uniform. Performances of fabricated Membrane electrode assembly (MEA)'s measured via the PEMFC test station built at METU Fuel Cell Technology Laboratory. A single cell with a 5 cm 2 active area was used in the experiments. These results should be conducive to the preparation of membranes suitable for PEMFC. We believe that Nafion/TiO 2 nano composite membranes have good prospects for use in PEMFC.
Nafion/Analcime and Nafion/Faujasite composite membranes for polymer electrolyte membrane fuel cells
Chemical Engineering Research & Design, 2010
The Nafion/zeolite composite membranes were synthesized for polymer electrolyte fuel cells (PEMFCs) by adding zeolite in the matrix of Nafion polymer. Two kinds of zeolites, Analcime and Faujasite, having different Si/Al ratio were used. The physico-chemical properties of the composite membranes such as water uptake, ion-exchange capacity, hydrogen permeability, and proton conductivity were determined. The fabricated composite membranes showed the significant improvement of all tested properties compared to that of pure Nafion membrane. The maximum proton conductivity of 0.4373 S cm−1 was obtained from Nafion/Analcime (15%) at 80 °C which was 6.8 times of pure Nafion (0.0642 S cm−1 at 80 °C). Conclusively, Analcime exhibited higher improvement than Faujasite.
Composite Nafion-CaTiO3-δ Membranes as Electrolyte Component for PEM Fuel Cells
Polymers, 2020
Manufacturing new electrolytes with high ionic conductivity has been a crucial challenge in the development and large-scale distribution of fuel cell devices. In this work, we present two Nafion composite membranes containing a non-stoichiometric calcium titanate perovskite (CaTiO3−δ) as a filler. These membranes are proposed as a proton exchange electrolyte for Polymer Electrolyte Membrane (PEM) fuel cell devices. More precisely, two different perovskite concentrations of 5 wt% and 10 wt%, with respect to Nafion, are considered. The structural, morphological, and chemical properties of the composite membranes are studied, revealing an inhomogeneous distribution of the filler within the polymer matrix. Direct methanol fuel cell (DMFC) tests, at 110 °C and 2 M methanol concentration, were also performed. It was observed that the membrane containing 5 wt% of the additive allows the highest cell performance in comparison to the other samples, with a maximum power density of about 70 mW...
Journal of Power Sources, 2002
Composite polymer electrolyte membranes were prepared by impregnating Nafion solution into the porous expanded PTFE (ePTFE) films as a substrate and their single cell performance, gas permeability, water flux, and water uptake were investigated. Although the nitrogen permeability of the composite membrane was higher than that of Nafion 112, there was not the serious cross-over of gases to diminish cell performance and it was seen that the cell performance could be improved by reduced thickness of the composite membrane. It was also seen that water uptake and water flux of the composite membrane were dependent on the Nafion loading amount on the substrate and, therefore, the thickness of the membrane. The water uptake as well as the water flux of the composite membrane increased as the Nafion loading amount increased and the increase rate of water uptake with temperature for the composite membranes was found to be larger than Nafion 112. #
2008
Nafion-Silica oxide (SiO2)-Phosphotungstic acid (PWA) composite membrane have been synthesized using solution phase sol-gel method. The effect of the weight ratio of Nafion:SiO2:PWA to the electrochemical properties of composite membrane when applies as electrolyte in the PEMFC was investigated using Fuel Cell Test System (FCTS) at temperature of range of 80 – 90 oC and 40% relative humidity (RH). The weight ratio of the composite membrane samples varied in the range of 100:2.88:1.15, 100:4.33:1.73 and 100:5.76:2.30 and designated as NS10W, NS15W and NS20W, respectively. The aim of the experiment was to insert the inorganic hygroscopic and high conductivity filler like PWA and SiO2 in the Nafion matrix to order to improve the water retention, proton conductivity (σ), hydrogen crossover (β), and thermal stability in addition to increase PEMFC performance at elevated temperature and low RH condition. The result showed when appropriately embeded in the Nafion cluster, the hydrated PWA ...
Critical Filler Concentration in Sulfated Titania-Added Nafion™ Membranes for Fuel Cell Applications
Energies, 2016
In this communication we present a detailed study of Nafion™ composite membranes containing different amounts of nanosized sulfated titania particles, synthesized through an optimized one-step synthesis procedure. Functional membrane properties, such as ionic exchange capacity and water uptake (WU) ability will be described and discussed, together with thermal analysis, atomic force microscopy and Raman spectroscopy data. Also electrochemical properties such as proton conductivity and performances in hydrogen fuel cells will be presented. It has been demonstrated that a critical concentration of filler particles can boost the fuel cell performance at low humidification, exhibiting a significant improvement of the maximum power and current density delivered under 30% low-relative humidity (RH) and 70˝C with respect to bare Nafion™-based systems.
2008
Investigation of the single cell Proton Exchange Membrane Fuel Cell (SCPEMFC) using a series of Nafion-SiO2-PWA composite membranes as electrolyte have been carried out using the Arbin Fuel Cell Test System (FCTS). PEMFC performance and proton conductivity of the composite membrane have been determined over a temperature range of 30-90 o C at pressure 1-1.7 atm at 40% RH. Analysis with FCTS showed that higher current density was yielded by composite membrane (82 mAcm -2 at 0.6 V for NS15W) than with the Nafion membrane (30 mAcm -2 at 0.2 V) at 90 o C. Hence the composite is potentially a good candidate to substitute Nafion membrane especially for the electrolyte of PEMFC operating at higher temperature range and lower RH.
International Journal of Hydrogen Energy, 2012
Nafion Polymer electrolyte membrane fuel cells Dynamical mechanic analyses Vibrational spectroscopy Fabrication and testing of membrane-electrode assemblies a b s t r a c t In this report, three hybrid inorganic-organic proton-conducting membranes based on a novel fluorinated titania labeled TiO 2 F dispersed in Nafion were prepared. The mass fraction of TiO 2 F nanofiller ranged between 0.05 and 0.15. The water uptake and the proton exchange capacity of the membranes were determined; the membranes were further characterized by TG, DMA and FT-IR ATR investigations. Finally, the hybrid membranes were used in the fabrication of membrane-electrode assemblies (MEAs), which were tested in operating conditions as a function of the back pressure and of the hydration degree of the reagents streams. It was demonstrated that, with respect to pristine recast Nafion, at 25%RH the MEA fabricated with the membrane including a mass fraction of TiO 2 F equal to 0.10 yielded a higher maximum power density (0.206 W cm À2 vs. 0.121 W cm À2 ). Finally, it was proposed a coherent structural model of this family of hybrid membranes accounting for both the properties determined from "ex-situ" characterizations and for the performance obtained from measurements in a single fuel cell in operating conditions.
Chemistry of Materials, 2006
Metal-oxide-recast Nafion composite membranes were studied for operation in hydrogen/oxygen protonexchange membrane fuel cells (PEMFC) from 80 to 130°C and at relative humidities ranging from 75 to 100%. Membranes of nominal 125 µm thickness were prepared by suspending a variety of metal oxide particles (SiO 2 , TiO 2 , Al 2 O 3 , and ZrO 2) in solubilized Nafion. The composite membranes were characterized using electrochemical, X-ray scattering, spectroscopic, mechanical, and thermal analysis techniques. Membrane characteristics were compared to fuel cell performance. These studies indicated a specific chemical interaction between polymer sulfonate groups and the metal oxide surface for systems that provide a good elevated-temperature (i.e., fuel-cell operation above 120°C) performance. Composite systems that incorporate either a TiO 2 or a SiO 2 phase produced superior elevated-temperature, lowhumidity behavior compared to that of a simple Nafion-based fuel cell. Improved temperature tolerance permits the introduction of at least 500 ppm CO contaminant in the H 2 fuel stream without cell failure, in contrast to standard Nafion-based cells, which fail below 50 ppm of carbon monoxide.
Electrochimica Acta, 2000
Several new cation exchange membranes of different thicknesses (15-500 mm) based on a Nafion ® solution and silicotungstic acid with and without thiophene (named NASTATH and NASTA respectively) were synthesized by a simple chemical route for PEM fuel-cell applications. The optimum parameters for the preparation of the membranes have been determined: 10 ml of 5% of the Nafion ® 117 solution was reduced by 50% and mixed with 10 − 3 -10 − 5 M-STA to produce a NASTA membrane. If liquid thiophene (0.5% by volume) is added to the above solution, a NASTATH membrane is produced. The water uptake and ionic conductivity of NASTA and NASTATH were compared with those of Nafion ® 117. The effect of membrane thickness and the concentrations of STA and thiophene used during the preparation of NASTA and NASTATH on their water uptake and ionic conductivity were determined. It was shown that the water uptake of the NASTA membrane (60%) was significantly better than that of Nafion ® 117 (27%), while the water uptake of NASTATH (40%) was higher than that of Nafion ® 117 (27%). The ionic conductivity of both the NASTA (10.10 × 10 − 2 V − 1 cm − 1 ) and the NASTATH (9.5×10 − 2 V − 1 cm − 1 ) was found to be significantly higher than that of the Nafion ® 117 (1.23 ×10 − 2 V − 1 cm − 1 ). The membrane performances were also determined by chemical stability studies. The membranes fabricated with Nafion ® and silicotungstic acid with and without thiophene still exhibited good mechanical strength and stability after they had been dipped in an acid or a basic medium for at least 10 months. The voltage-current characteristics of solid polymer electrolyte fuel cells were determined for Nafion ® 117, NASTA and NASTATH based membranes. The fuel cell parameters were correlated to the membrane water uptake and ionic conductivity. The current density at 0.600 V of the solid polymer electrolyte fuel cells (SPEFCs) based on NASTATH (810 mA cm − 2 ) membranes was higher than that of SPEFCs based on Nafion ® 117 (640 mA cm − 2 ). It was shown that the better fuel cell parameters were not obtained with the modified membranes having the higher water uptake.