Hybrid polymers based on sulfonated polynorbornene with enhanced proton conductivity for direct methanol fuel cells

2012 ◽  
Vol 24 (8) ◽  
pp. 756-764 ◽  
Author(s):  
Rong Zeng ◽  
Shuqin Xiao ◽  
Lie Chen ◽  
Yiwang Chen

Sulfonated polynorbornene (SPNB) and 3-aminopropyltriethoxysilane (KH550) hybrid cross-linked proton exchange membranes doped with different weight ratio of phosphotungstic acid (PWA) were prepared by a simple sol-gel process. The cross-linked structures led to low methanol permeability and good stability of the nanocomposites. Incorporation of PWA has significantly improved the proton conductivity of the hybrid membrane due to an extra provided conductive proton-conduction pathway to facilitate proton transportation. In particular, the conductivity of SPNB/KH550/PWA25 reached the maximum of 0.02 S.cm−1 at 80°C under the 100% relative humidity condition, and this value is on the same order of magnitude as that of Nafion117. Furthermore, SPNB /KH550/PWA20 owns the lowest proton transport activation energy (8.39 kJ.mol−1).

2012 ◽  
Vol 503-504 ◽  
pp. 625-628 ◽  
Author(s):  
Chun Hua Yuan ◽  
Gui Bao Guo ◽  
Sheng Li An

Polyvinyl alcohol(PVA) modified by SiO2/poly 2-acrylamido 2-methylpropane sulfonic acid (PAMPS) electrolyte membrane (SiO2/PVA-PAMPS ) was prepared by a Sol-gel synthesis in situ technique for DMFC. The influence of the different ratio of AMPS and SiCl4 on the proton conductivity and methanol permeability of these membranes was studied using an impedance analyzer and a gas chromatograph. The results showed that with increasing of the content of silicon dioxide, the SiO2 was homogeneously distributed in the membrane. As the AMPS content increased, the proton conductivity of the SiO2/PVA-PAMPS membranes also increased. The swelling degree of the SiO2/PVA-PAMPS membrane with 30wt% SiCl4 and 20wt% AMPS was 28.79% at 25°C. The membranes possess a methanol permeability of around 10-7 cm2•S-1, which is about one order of magnitude lower than that of Nafion115. These membranes have high selectivity and are promising for use in direct methanol fuel cells (DMFC).


2021 ◽  
pp. 095400832110394
Author(s):  
Yan Ma ◽  
Kaixu Ren ◽  
Ziqiu Zeng ◽  
Mengna Feng ◽  
Yumin Huang

To improve the performances of sulfonated poly (arylene ether nitrile) (SPEN)–based proton exchange membranes (PEMs) in direct methanol fuel cells (DMFCs), the copper phthalocyanine grafted graphene oxide (CP-GO) was successfully prepared via in situ polymerization and subsequently incorporated into SPEN as filler to fabricate a series of SPEN/CP-GO-X (X represents for the mass ratio of CP-GO) composite membranes. The water absorption, swelling ratio, mechanical properties, proton conductivity, and methanol permeability of the membranes were systematically studied. CP-GO possesses good dispersion and compatibility with SPEN matrix, which is propitious to the formation of strong interfacial interactions with the SPEN, so as to provide more efficient transport channels for proton transfer in the composite membranes and significantly improve the proton conductivity of the membranes. Besides, the strong π–π conjugation interactions between CP-GO and SPEN matrix can make the composite membranes more compact, blocking the methanol transfer in the membranes, and significantly reducing the methanol permeability. Consequently, the SPEN/CP-GO-1 composite membrane displayed outstanding tensile strength (58 MPa at 100% RH and 25°C), excellent proton conductivity (0.178 S cm−1 at 60°C), and superior selectivity (5.552 × 105 S·cm−3·s). This study proposed a new method and strategy for the preparation of high performance PEMs.


2006 ◽  
Vol 6 (11) ◽  
pp. 3594-3598
Author(s):  
Jung-Eun Yang ◽  
Young Taik Hong ◽  
Jae-Suk Lee

The polystyrene-poly(arylene ether sulfone)-polystyrene (PS-PAES-PS) coil-semirod-coil triblock copolymer was synthesized by the condensation reaction of PS-COCl and H2N-PAES-NH2 telechelic polymers. The reaction was facile characterized by high yields with a perfect control over the block lengths. Following a known reaction protocol it was possible to selectively sulfonate the PS block of the triblock copolymer that led to the sulfonated copolymer sPS-PAES-sPS. Studies on its proton conductivity and methanol permeability were carried out to evaluate its use as the proton exchange membrane in direct methanol fuel cells. Proton conductivity of the membranes was increased depending on the sulfonic acid group content in the sulfonated polymer. The membranes exhibited good dimensional and thermal stability, and low methanol permeability compared to Nafion 117.


Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1037 ◽  
Author(s):  
Hang Wang ◽  
Xiangxiang Li ◽  
Xiaojie Li ◽  
Xi Feng ◽  
Weimin Kang ◽  
...  

In this work, we reported a novel proton exchange membrane (PEM) with an ion-conducting pathway. The hierarchical nanofiber structure was prepared via in situ self-assembling 1,3:2,4-dibenzylidene-d-sorbitol (DBS) supramolecular fibrils on solution-blown, sulfonated poly (ether sulfone) (SPES) nanofiber, after which the composite PEM was prepared by incorporating hierarchical nanofiber into the chitosan polymer matrix. Then, the effects of incorporating the hierarchical nanofiber structure on the thermal stability, water uptake, dimensional stability, proton conductivity, and methanol permeability of the composite membranes were investigated. The results show that incorporation of hierarchical nanofiber improves the water uptake, proton conductivity, and methanol permeability of the membranes. Furthermore, the composite membrane with 50% hierarchical nanofibers exhibited the highest proton conductivity of 0.115 S cm−1 (80 °C), which was 69.12% higher than the values of pure chitosan membrane. The self-assembly allows us to generate hierarchical nanofiber among the interfiber voids, and this structure can provide potential benefits for the preparation of high-performance PEMs.


2014 ◽  
Vol 11 (3) ◽  
Author(s):  
Vahid Mazinani ◽  
SeyedHadi Tabaian ◽  
Milad Rezaei ◽  
Mahdiyeh Mallahi ◽  
Mohsen Mohammadijoo ◽  
...  

Nafion-CaO, Nafion-ZrOH, and Nafion-CaO-ZrOH membranes are fabricated in order to improve proton conductivity, thermal stability, and mechanical properties as well as decrease methanol crossover in direct methanol fuel cells. The ion exchange method is utilized to incorporate Ca and Zr into Nafion membranes. Prepared membranes are characterized by using absorption transmission reflectance (ATR) and energy dispersive X-ray spectroscopy (EDS) techniques. Methanol crossover decreases significantly for all fabricated membranes. Nafion-CaO and Nafion-CaO-ZrOH membranes exhibit a 10 and 6 time increase in proton conductivity compared to Nafion (0.08 Scm–1), while the proton conductivity of Nafion-ZrOH decreases. The elastic modulus enhance from 48 MPa for Nafion to 60, 78, and 90 MPa for Nafion-CaO, Nafion-ZrOH, and Nafion-CaO-ZrOH membranes. In addition, the thermal stability of Nafion (360 °C) increases to 407, 457, and 470 °C for fabricated membranes.


Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1292 ◽  
Author(s):  
Gutru Rambabu ◽  
Santoshkumar D. Bhat ◽  
Filipe M. L. Figueiredo

A membrane electrolyte that restricts the methanol cross-over while retaining proton conductivity is essential for better electrochemical selectivity in direct methanol fuel cells (DMFCs). Extensive research carried out to explore numerous blends and composites for application as polymer electrolyte membranes (PEMs) revealed promising electrochemical selectivity in DMFCs of carbon nanomaterial-based polymer composites. The present review covers important literature on different carbon nanomaterial-based PEMs reported during the last decade. The review emphasises the proton conductivity and methanol permeability of nanocomposite membranes with carbon nanotubes, graphene oxide and fullerene as additives, assessing critically the impact of each type of filler on those properties.


2009 ◽  
Vol 81 (12) ◽  
pp. 2309-2316 ◽  
Author(s):  
Yong Fang ◽  
Ruiying Miao ◽  
Tongtao Wang ◽  
Xindong Wang

A series of novel composite membranes was prepared by using poly(vinyl alcohol) (PVA) with polyimide (PI) as base material and 8-trimethoxysilylpropyl glycerine ether-1,3,6-pyrenetrisulfonic acid (TSGEPS) as proton conductor for direct methanol fuel cells (DMFCs). The parameters of membranes, including water sorption, hydrolysis stability, dimensional stability, proton conductivity, and methanol permeability were studied. The proton conductivity of the membranes is in the order of 10–2 S/cm, and the membranes show better resistance to methanol permeability (1.51 × 10–7 cm2 s–1) and better selectivity (20.6 × 104 S cm–3 s) than those of Nafion115 under the same measurement conditions.


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