Crosslinked Sulfonated Polyphenylsulfone (CSPPSU) Membranes for Elevated-Temperature PEM Water Electrolysis (original) (raw)
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Chemically Crosslinked Sulfonated Polyphenylsulfone (CSPPSU) Membranes for PEM Fuel Cells
Membranes
Sulfonated polyphenylsulfone (SPPSU) with a high ion exchange capacity (IEC) was synthesized using commercially available polyphenylsulfone (PPSU), and a large-area (16 × 18 cm2) crosslinked sulfonated polyphenylsulfone (CSPPSU) membrane was prepared. In addition, we developed an activation process in which the membrane was treated with alkaline and acidic solutions to remove sulfur dioxide (SO2), which forms as a byproduct during heat treatment. CSPPSU membranes obtained using this activation method had high thermal, mechanical and chemical stabilities. In I-ViR free studies for fuel cell evaluation, high performances similar to those using Nafion were obtained. In addition, from the hydrogen (H2) gas crossover characteristics, the durability is much better than that of a Nafion212 membrane. In the studies evaluating the long-term stabilities by using a constant current method, a stability of 4000 h was obtained for the first time. These results indicate that the CSPPSU membrane ob...
Investigation of a PEM Water Electrolyzer Based on a Sulfonated Polysulfone Membrane
ECS Transactions, 2013
A sulfonated polysulfone (SPSf) membrane was prepared and used as polymer electrolyte in water electrolysis cell. The behaviour of SPSf in PEMWE was investigated by polarization, electrochemical impedance spectroscopy and chrono-amperometry. The performance was compared to a commercial Nafion 115 membrane. A low series resistance of 0.13 Ω·cm 2 was measured for the SPSf membrane at 80 °C under water electrolysis. At the same potential value, 1.8 V, the current density values in the polarization curves were 1.29 A·cm -2 and 1.08 A·cm -2 for the cells with Nafion and SPSf membrane, respectively. During a chrono-amperometric measurement, the current density remained constant throughout the test, indicating a suitable stability of the SPSf based cell. The good performance, low cost and excellent lifetime stability of SPSf make this polymer a promising solid electrolyte for the application in PEM electrolyzers. 10.1149/05801.0615ecst ©The Electrochemical Society ECS Transactions, 58 (1) 615-620 (2013) 615 ecsdl.org/site/terms_use address. Redistribution subject to ECS license or copyright; see 150.145.66.3 Downloaded on 2014-02-05 to IP
Journal of Membrane Science, 2013
A polymer electrolyte membrane (PEM) based on a non-perfluorinated polymer as an alternative to Nafion was investigated for application in a water electrolyzer. The sulfonated polysulfone (SPSf) was synthesized using trimethyl silyl chlorosulfonate as the sulfonating agent. The SPSf polymer was used for the preparation of a proton conducting membrane. A single cell (5 cm 2 geometrical area) PEM electrolyzer based on SPSf membrane, IrO 2 anode and Pt/C cathode electrocatalysts was investigated by polarization, impedance spectroscopy, chrono-amperometry and gas crossover measurements. The performance was compared to that of an electrolyzer based on a standard Nafion 115 membrane. The electrolyzer based on SPSf showed polarization and hydrogen permeation characteristics similar to those of Nafion. After 35 h potentiostatic operation at 1.8 V, the sulfonated polysulfone MEA reached a current density of 1.35 A cm À 2 . The results indicate promising performance of the sulfonated polysulfone polymer electrolyte membrane for application in a PEM electrolyzer.
Sulfonated polysulfone as promising membranes for polymer electrolyte fuel cells
Journal of Applied Polymer Science, 2000
A new, milder sulfonation process was used to produce ion-exchange polymers from a commercial polysulfone (PSU). Membranes obtained from the sulfonated polysulfone are potential substitutes for perfluorosulfonic acid membranes used now in polymer electrolyte fuel cells. Sulfonation levels from 20 to 50% were easily achieved by varying the content of the sulfonating agent and the reaction time. Ion-exchange capacities from 0.5 to 1.2 mmol SO 3 H/g polymer were found via elemental analysis and titration. Proton conductivities between 10 Ϫ6 and 10 Ϫ2 S cm Ϫ1 were measured at room temperature. An increase in intrinsic viscosity with increasing sulfonation degree confirms that the sulfonation process helps to preserve the polymer chain from degradation. Thermal analysis of the sulfonated polysulfone (SPSU) samples reveals higher glass transition temperatures and lower decomposition temperatures with respect to the unsulfonated sample (PSU). Amorphous structures for both PSU and SPSU membranes were detected by X-ray diffraction analysis and differential scanning calorimetry. Preliminary tests in fuel cells have shown encouraging results in terms of cell performance.
Journal of Power Sources, 2007
A new and facile approach has been developed for the preparation of cross-linked sulfonated poly(sulfide sulfone) (SPSSF) membranes. The cross-linking reaction was performed by immersing the SPSSF membranes into polyphosphoric acid at 180 • C for 1.5 h and the cross-linking bond was the very stable sulfonyl group. Cross-linking significantly improved the membrane performance, i.e., the cross-linked membranes showed better mechanical properties, lower water uptake and lower methanol permeability than the corresponding uncross-linked ones, while reasonably high proton conductivity was maintained. For example, for the membrane containing 40 mol% sulfonated moiety, by cross-linking the tensile strength increased from 39 MPa (dry) or 21 MPa (wet) to 44 MPa (dry) or 30 MPa (wet) and the elongation at break from 17% (dry) or 18% (wet) to 65% (dry) or 21% (wet), while the water uptake was reduced from 74 to 38 wt% and the methanol permeability from 7.0 × 10 −7 to 1.6 × 10 −7 cm 2 s −1
New highly phosphonated polysulfone membranes for PEM fuel cells
Journal of Membrane Science, 2010
This paper reports the development and characterization of phosphonated poly(arylene ether sulfone) polymer electrolytes for direct methanol fuel cells. The synthesis of phosphonated polysulfone was performed by a post-phosphonation method via chloromethylation of the polysulfone backbone followed by phosphonation utilizing the Michaels-Arbuzov reaction. High degree of phosphonation up to 150% was achieved without crosslinking side reactions. The obtained membranes/polymers in the ester form were hydrolyzed to the corresponding phosphonic acid by refluxing in aqueous hydrochloric acid. The modified polymers were characterized by nuclear magnetic resonance, infrared spectroscopy, ion exchange capacity, differential scanning calorimetry and thermal gravity analysis. The high level of phosphonic acid content 150% led to high water uptake level 52 wt% which is necessary to reach high proton conductivity values. The synthesized membranes with the highest phosphonic acid content 150% reached 12 mS/cm at 100 • C under fully hydrated conditions and showed low methanol crossover (9.12 × 10 −8 cm 2 /s) compared to Nafion 117 membranes. Also, membranes with 150% phosphonic acid content exhibit high thermal stability up to 252 • C under air which entitle them as future candidates for proton exchange membrane fuel cells PEMFCs.
Thermal analysis of sulfonated polymers tested as polymer electrolyte membrane for PEM fuel cells
An aromatic polymer, poly(2,6-dimethyl-1,4phenylene oxide) (PPO) was sulfonate with different sulfonation degrees (30, 50, and 75 % theoretical degree) to obtain an electrolytic polymer suitable as proton exchange membrane for fuel cells. Thermal behaviors of sulfonated PPO were tested by differential scanning calorimetry and thermogravimetry. The sulfonation degrees were correlated with glass transitions temperatures (T g ) and the percent of weight loss. One notices a good fitting between sulfonation degree and the percent of weight loss thanks splitting of sulfonic moieties but it is not the same for glass transition temperatures that have a random variation.
Macromolecular Chemistry and Physics, 2016
Sulfonated poly(ether sulfone)s (SPESs) are developed which have different sulfonation level as a polymer electrolyte membrane for high-temperature operation. The sulfonation level of SPESs is calculated by 1 H NMR, and the molecular structure and crystalline structure of SPESs are evaluated by Fourier transform infrared and X-ray diffraction. SPES membranes are thermally stable up to 250 °C. SPES membranes can keep their shapes at 120 °C and 23%RH. Water uptake at 120 °C and 23%RH is 5.7-6.4 wt%, while Nafion 212 shows 2.4 wt%. Proton conductivity measurements of SPESs are carried out from 30 to 120 °C at different relative humidity. With increasing sulfonation level of SPES, proton conductivity increases in all humidity. The proton conductivity obtained from all SPESs is more than 100 mS cm-1 at 120 °C in high humidity (>90%RH), and high-sulfonation SPES shows higher conductivities than Nafion 212 at 120 °C, 20%RH. devices into wider society, demonstrating their role as a key technology for next-generation energy systems. There are several types of fuel cells categorized by the constituent components and the operating temperature. Polymer electrolyte membrane fuel cells (PEFCs) offer a broad range of benefits, including: (1) high efficiency, (2) nonpolluting (no CO 2 emission), (3) compact design. [1] In addition, PEFCs can be installed without any concerns of
Evaluation of a sulfophenylated polysulfone membrane in a fuel cell at 60 to 110 °C
Solid State Ionics, 2007
A novel sulfophenylated polysulfone membrane material has been evaluated in a hydrogen/oxygen fuel cell using Nafion-impregnated commercial electrodes. Comparative measurements were performed with Nafion membranes to distinguish between different sources of potential losses. The operational temperatures in the experiments ranged from 60 to 110°C, and the effect of different humidifying conditions was investigated. Membranes that were operated over 300 h under fully humidified conditions showed a slight increase in the cell resistance. At lower humidification levels the cell resistance increased significantly. No difference in the membrane composition between active areas and areas not subjected to ionic currents could be detected by ATR-IR or Raman spectroscopy after fuel cell testing. The best fuel cell performance for these membranes was found at 90°C and 100°C. The current density at a cell voltage of 0.5 V ranged between 100 and 200 mA cm − 2 depending on the operating conditions. The relatively low current densities found when using the new membrane material are explained by high ionic contact resistances between the electrodes and the membrane.