Synthesis and basic properties of sulfonated polysulfone/phosphotungstic acid (H3O40PW12) composite proton exchange membrane

Li, Weidong; Fei, Guoping; Zhao, Ji

doi:10.1515/epoly.2009.9.1.829

Cited by 2 publications

(2 citation statements)

References 7 publications

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“…This increase in wavenumber suggests an increased bond strength induced by the hydrogen-bond formation between SO 3 H groups and water molecules in LDH-Ac or by the electrostatic interaction between SO 3 H groups and LDH-Ac. The increased bond strength is expected to make the polymer structure rigid and probably the cation exchange capacity lowered, [37][38][39][40] and, consequently, the WU and excessive swelling of the membrane are suppressed. This leads to the enhanced chemical stability of the SPEEK/LDH-Ac membranes described below.…”

Section: Resultsmentioning

confidence: 99%

Proton-Conducting Properties of Sulfonated Poly(etheretherketone) with Layered Double Hydroxides at Intermediate Temperatures

Kozawa

Suzuki

Miyayama

et al. 2010

J. Electrochem. Soc.

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MgAl layered double hydroxide treated in a ͑CH 3 COO͒ 2 Mg aqueous solution ͑LDH-Ac͒ and composite membranes consisting of sulfonated poly͑etheretherketone͒ ͑SPEEK͒ and the LDH-Ac in various volume ratios of 0-50 vol % were prepared. Their proton conductivities were examined at 40-150°C under 100 or 35% relative humidity ͑RH͒. The composite membrane with 12 vol % LDH-Ac showed a relatively high conductivity of 8.0 ϫ 10 −3 S cm −1 at 150°C under 100% RH and a better dry resistance than the SPEEK membrane. The SPEEK/LDH-Ac composites were promising membranes for use above 100°C.The polymer electrolyte membrane fuel cell ͑PEMFC͒, which uses a polymer as its electrolyte, is one of the most promising candidate devices for high efficiency energy conversion systems and is expected to be used as the automotive and stationary power sources owing to its operating temperature below 100°C. However, PEMFC has the following problems: ͑i͒ the poisoning of the platinum-based catalyst in electrodes by CO included in reformed fuel gas, ͑ii͒ the decrease in the effective area of electrodes by liquid H 2 O, and ͑iii͒ the high cost of perfluorosulfonic acid ͑PFSA͒ membranes and platinum-based catalysts. The first two problems are solved by operating PEMFC at intermediate temperatures ͑100-200°C͒. However, PFSA membranes cannot be used at these temperatures owing to their heat resistance limitation. Thus, the development of polymer electrolyte membranes ͑PEMs͒ with a high proton conductivity and a high chemical stability at intermediate temperatures is desired. [1][2][3][4][5] Sulfonated hydrocarbon polymers have attracted attention as PEMs for use at intermediate temperatures owing to their high chemical stability. 6-11 Among these polymers, sulfonated poly͑etheretherketone͒ ͑SPEEK͒ is promising for PEMFC application in terms of its chemical stability and proton conductivity. The proton conductivity of SPEEK membranes increases by increasing the degree of the sulfonation ͑DS͒, accompanied with an increase in water uptake ͑WU͒. However, a high WU leads to excessive swelling of the membranes, consequently reducing their chemical stability. Therefore, it is necessary to use a SPEEK with a high DS as a PEM for an improved chemical stability. The chemical stability of PEMs is improved by the addition of an inorganic compound to a polymer matrix. 7,12,13 This improvement in chemical stability has been suggested to be attributed to hydrogen bonds formed between an inorganic compound and an organic polymer, as has been reported for the SPEEK/Sn͑HPO 4 ͒ 2 ·nH 2 O ͑SnP͒ membrane systems. [12][13][14] Layered compounds with interlayer water, such as tungsten trioxide dihydrate ͑WO 3 ·2H 2 O͒ and layered metal phosphate ͑MP͒ hydrate ͓M͑HPO 4 ͒ 2 ·nH 2 O ͑MP:M = Sn, Zr, Ti͔͒, exhibit proton conductivities. 15-20 WO 3 ·2H 2 O exhibits proton conductivity that remains unchanged even with decreasing water vapor pressure until interlayer water has been completely removed. 15 The MPs also show a relatively high proton conductivity at intermediate temp...

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Section: Resultsmentioning

confidence: 99%

Proton-Conducting Properties of Sulfonated Poly(etheretherketone) with Layered Double Hydroxides at Intermediate Temperatures

Kozawa

Suzuki

Miyayama

et al. 2010

J. Electrochem. Soc.

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“…12,13 Several composites of SPESs with inorganic compounds have been investigated as materials for PEMs. [15][16][17][18][19][20] It has been reported that SPES/boron phosphate (BPO 4 ) composite membranes show a increased stability and a greater proton conductivity of 5 × 10 −2 S cm −1 at 150 • C under saturated vapor pressure in comparison with the pure SPES membrane. 19 It is known that the permeability of methanol in a direct methanol fuel cell (DMFC) is reduced by the presence of an inorganic filler in the organic matrix.…”

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confidence: 99%

Proton Conduction in Composite Membranes of Sulfonated Hydrocarbon Electrolyte and Layered Tin Phosphate Hydrates

Yoshimune

Sugata

Suzuki

et al. 2011

J. Electrochem. Soc.

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The characteristics and mechanism of proton conduction in organic/inorganic composite membranes composed of sulfonated poly(ether sulfone) (SPES) and layered tin phosphate hydrates Sn(HPO 4 ) 2 · nH 2 O (SnP) were examined. SPES/SnP membranes were prepared by mixing 0-50 vol% of SnP with SPES solution and casting the mixture. Fourier-transform infrared, Raman, and solid-state 1 H NMR spectroscopy and thermogravimetric analysis showed that hydrogen-bond networks are formed between SPES and SnP in the composite membranes. At intermediate temperatures up to 150 • C, the membranes showed good proton-conducting properties, high chemical stability (low water solubility), and high thermal stability as a result of the formation of hydrogen bonds between SPES and SnP. The membrane containing 35 vol% SnP showed the highest conductivity of 8.1 × 10 −2 S cm −1 at 130 • C under saturated water vapor pressure. The membrane containing 25 vol% SnP showed a conductivity of 5.3 × 10 −2 S cm −1 at 130 • C under saturated water vapor pressure, despite its low water uptake. This membrane retained a high conductivity of 2.6 × 10 −3 S cm −1 at 130 • C at a low relative humidity of 40%, indicating that SPES/SnP membrane is a promising proton conductor at intermediate temperatures.The proton-exchange membrane fuel cell (PEMFC) is one of the most promising sources of alternative energy for transportation, stationary power, and portable electrical devices. For these diverse applications, it is important to enhance the kinetics of fuel oxidation and to suppress poisoning of the platinum electrocatalyst by carbon monoxide. 1 One approach to solving these problems is to increase the operating temperature to above 100 • C. Current industry-standard perfluorosulfonic polymers, such as Nafion, have a low heat resistance and a low glass-transition temperature, and their use is therefore limited to temperatures below 100 • C. Alternative sulfonated polymer membranes for use at intermediate temperatures have been widely studied, particularly sulfonated hydrocarbon polymers, such as sulfonated poly(ether ether ketone) (SPEEK) and sulfonated poly(ether sulfone) (SPES, including sulfonated polysulfone), which have high proton conductivities at intermediate temperatures, high thermal stabilities, and low costs. 2-6 It is known that the sulfonic acid (SO 3 H) groups in SPES have a high acidity because of the stronger electronwithdrawing nature of the SO 2 group in these polymers in comparison with those in other sulfonated hydrocarbon polymers, 7-9 which leads to a high proton conductivity. However, most such polymers exhibit marked decreases in proton conductivity under conditions of low relative humidity (RH) as a result of dehydration. 2, 3 Therefore, the attainment of a high proton conductivity (σ > 10 −2 S cm −1 ) at intermediate temperatures (above 100 • C) under conditions of low RH, in conjunction with a high chemical stability, is an important goal in the development of novel proton-conducting membranes.One possible approach to this goal is tha...

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Synthesis and basic properties of sulfonated polysulfone/phosphotungstic acid (H3O40PW12) composite proton exchange membrane

Cited by 2 publications

References 7 publications

Proton-Conducting Properties of Sulfonated Poly(etheretherketone) with Layered Double Hydroxides at Intermediate Temperatures

Proton-Conducting Properties of Sulfonated Poly(etheretherketone) with Layered Double Hydroxides at Intermediate Temperatures

Proton Conduction in Composite Membranes of Sulfonated Hydrocarbon Electrolyte and Layered Tin Phosphate Hydrates

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