Sulfonated titania submicrospheres-doped sulfonated poly(ether ether ketone) hybrid membranes with enhanced proton conductivity and reduced methanol permeability

Xu, Tao; Hou, Weiqiang; Shen, Xiaohui; Wu, Hong; Li, Xicheng; Wang, Jingtao; Jiang, Zhongyi

doi:10.1016/j.jpowsour.2011.02.017

Cited by 79 publications

(44 citation statements)

References 32 publications

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“…The methanol permeability of the membrane is affected by both hydrophilicity of membranes, associated to water uptake and λ values, and the presence of micro channels in polymer matrix. 2,11,16 It was observed that the methanol permeability had a linear relationship with the number of water molecules per ion exchange sites ( Figure S10), which was in line with expectation. Also, in general, the methanol permeability remained unchanged or increased with increasing proton conductivities ( Figure 6).…”

Section: Resultssupporting

confidence: 84%

Microstructure-Property Relationships in Sulfonated Polyether Ether Ketone/Silsesquioxane Composite Membranes for Direct Methanol Fuel Cells

Yun

Parrondo

Zhang

et al. 2014

J. Electrochem. Soc.

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The synthesis, structural characterization, and performance evaluation of silsesquioxane -based sulfonated polyether ether ketone (SPEEK) composite membranes for direct methanol fuel cell (DMFC) applications are presented. 3-(trihydroxysilyl)-1-propanesulfonic acid (TPS) was used as a silsesquioxane (SQO) precursor. Two batches of SPEEK membranes with ion exchange capacities (IEC) of 1.06 ± 0.02 meq/g (denoted by SPEEK11) and 1.34 ± 0.05 meq/g (denoted by SPEEK13) were prepared. The SQO loadings in the composite membranes ranged from 5 wt% to 30 wt%. The ionic conductivity of the SPEEK13 membrane (at 60 • C) increased by up to 15 mS/cm (27%) upon incorporation of 15 wt% TPS-derived SQO, while the methanol permeability was at best slightly lowered (5-10%). The morphological changes in the composite membranes resulting from the introduction of SQO was studied by small angle X-ray scattering. The sharp decrease in conductivity with TPS loading was attributed to these changes in the membrane ionic domains. The performance of DMFCs with these SPEEK/SQO composite membranes was governed more by the proton conductivity than the methanol crossover. Compared to pristine SPEEK, the improved DMFC performance (at 60 • C using air and 3M methanol) of SPEEK11+5 wt% TPS and SPEEK13+5 wt% TPS composite membranes (187 mA cm −2 and 240 mA cm −2 at 0.4 V, respectively) was observed. The crossover of methanol from the anode to cathode through the ionic membrane remains one of the challenging obstacles in direct methanol fuel cells (DMFC). Methanol crossover to the cathode leads to a reduction in the operating voltage due to depolarization and mixed potential, and concurrent contamination of the Pt catalyst.1 Perfluorinated membranes such as Nafion have traditionally been used for DMFC systems. However, even though Nafion provides high conductivity and chemical stability, it exhibits large methanol permeability, resulting in relatively poor DMFC performance.2-6 Composite membranes, prepared by adding inorganic materials to an ion conducting polymer matrix, have been proposed and studied in an attempt to reduce methanol crossover.7 Sulfonated polyether ether ketone (SPEEK) is a good choice as a matrix for DMFC applications because it is relatively inexpensive and has lower methanol permeability compared to Nafion. It also exhibits good thermal stability, good mechanical strength and reasonable ionic conductivity.

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Section: Resultssupporting

confidence: 84%

Microstructure-Property Relationships in Sulfonated Polyether Ether Ketone/Silsesquioxane Composite Membranes for Direct Methanol Fuel Cells

Yun

Parrondo

Zhang

et al. 2014

J. Electrochem. Soc.

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“…56 The mechanical properties of Naon 117, SPEEK, S/GO 2 and S/GO 3 membranes are presented in Table 2. The breaking strength of the S/GO composite membranes increases with the GO content.…”

Section: Mechanical Properties and Thermal Analysismentioning

confidence: 99%

SPEEK/Graphene oxide nanocomposite membranes with superior cyclability for highly efficient vanadium redox flow battery

et al. 2014

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A series of novel composite membranes, based on sulfonated poly(ether ether ketone) (SPEEK) with various graphene oxide (GO) loadings, were employed and investigated in vanadium redox flow battery (VRFB) for the first time. The scanning electron microscopy images of the composite membranes revealed the uniform dispersion of GO nanosheets in the polymer matrix due to the interaction between GO and SPEEK, as confirmed by Fourier transform infrared spectra. The mechanical and thermal parameters of the composite membranes increased, while the VO 2+ permeability decreased with increasing GO content.Random embedding of GO nanosheets in the membranes can serve as effective barriers to block the transport of vanadium ion, resulting in a significant decrease of vanadium ion permeability. The VRFB assembled with the composite membrane exhibited highly improved cell parameters and strikingly long cycling stability compared with commercial Nafion 117 membrane. With the protection of porous PTFE substrate, the pore-filling SPEEK/GO composite membrane based on VRFB ran for 1200 cycles with relatively low capacity decline.

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“…This result demonstrates that the rigidity of the inorganic fillers in the SPAES restricted the polymer chain segmental mobility and enhanced the rigidity of the resulting membranes. 21 Nafion ® 1135 had a much higher elongation value than the prepared membranes.…”

Section: Resultsmentioning

confidence: 80%

“…With increases of the grafting amount in the MMT layers, the polymer chain mobility and swelling of the networks in the methanol solution decreased due to the reduced free volume of the hybrid membrane, which reduced the channels for passing the methanol molecules resulting in the resistance to the diffusion of methanol being increased. 21 In addition, methanol molecules have a high affinity with water molecules. The presence of SMMT15 (2.0 wt%) in the membranes can reduce the permeability to 3.8×10 -8 cm 2 /s in comparison with 3.0×10 -8 cm 2 /s for that of Nafion ® 1135.…”

Section: Resultsmentioning

confidence: 99%

Characterization of a composite membrane based on SPAES/sulfonated montmorillonite for DMFC application

et al. 2011

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Sulfonated poly(arylene ether sulfone) (SPAES)/sulfonated montmorillonite (SMMT) hybrid membranes were fabricated to evaluate their potential for use as direct methanol fuel cells (DMFCs). To minimize the loss of proton conductivity while reducing methanol permeability, an ion exchange method was used to prepare the SMMT including a sulfonic acid group. The SPAES/NMMT(-Na + ) and SPAES/SMMT(-SO 3 H) hybrid membranes were prepared using a solution casting and evaporation method, and the NMMT/SMMT content in the composite membranes was controlled at 0.5-2.0 wt% based on the SPAES. The performances of the hybrid membranes for the DMFCs in terms of their mechanical and thermal properties, water uptake, water retention, methanol permeability, and proton conductivity were investigated. The mechanical and thermal properties of the SPAES membranes were improved with introduction of the NMMT and SMMT. Methanol permeability reduction was also obtained when the SMMT content and the sulfonation degree increased. The SPAES/SMMT composite membrane showed increased proton conductivity compared with the non-modified MMT composite membrane under the 100% relative humidity condition. As the modified MMT content increased, the proton conductivity increased and the methanol permeability decreased due to the monovalent ions located between the MMT layers. The ratio of methanol permeability to proton conductivity for the SPEAS/SMMT (2.0 wt%) composite membrane was higher than that of Nafion ® 1135. This property makes hybrid membranes potential candidates for DMFC applications.

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Sulfonated titania submicrospheres-doped sulfonated poly(ether ether ketone) hybrid membranes with enhanced proton conductivity and reduced methanol permeability

Cited by 79 publications

References 32 publications

Microstructure-Property Relationships in Sulfonated Polyether Ether Ketone/Silsesquioxane Composite Membranes for Direct Methanol Fuel Cells

Microstructure-Property Relationships in Sulfonated Polyether Ether Ketone/Silsesquioxane Composite Membranes for Direct Methanol Fuel Cells

SPEEK/Graphene oxide nanocomposite membranes with superior cyclability for highly efficient vanadium redox flow battery

Characterization of a composite membrane based on SPAES/sulfonated montmorillonite for DMFC application

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