Sulfonated poly(ether ether ketone)/zirconium tricarboxybutylphosphonate composite proton-exchange membranes for direct methanol fuel cells |
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Authors: | Qijun GAO Mianyan HUANG Yuxin WANG Yuquan CAI Li XU |
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Affiliation: | (1) State Key Laboratory of Chemical Engineering, Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China |
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Abstract: | Sulfonated poly(ether ether ketone) (SPEEK) is a very promising alternative membrane material for direct methanol fuel cells.
However, with a fairly high degree of sulfonation (DS), SPEEK membranes can swell excessively and even dissolve at high temperature.
This restricts membranes from working above a high tolerable temperature to get high proton conductivity. To deal with this
contradictory situation, insolvable zirconium tricarboxybutylphosphonate (Zr(PBTC)) powder was employed to make a composite
with SPEEK polymer in an attempt to improve temperature tolerance of the membranes. SPEEK/Zr(PBTC) composite membranes were
obtained by casting a homogeneous mixture of Zr(PBTC) and SPEEK in N,N-dimethylacetamide on a glass plate and then evaporating
the solvent at 60°C. Many characteristics were investigated, including thermal stability, liquid uptake, methanol permeability
and proton conductivity. Results showed significant improvement not only in temperature tolerance, but also in methanol resistance
of the SPEEK/Zr(PBTC) composite membranes. The membranes containing 30 wt-% ∼ 40 wt-% of Zr(PBTC) had their methanol permeability
around 10−7 cm2·s−1 at room temperature to 80°C, which was one order of magnitude lower than that of Nafion?115. High proton conductivity of
the composite membranes, however, could also be achieved from higher temperature applied. At 100% relative humidity, above
90°C the conductivity of the composite membrane containing 40 wt-% of Zr(PBTC) exceeded that of the Nafion?115 membrane and
even reached a high value of 0.36 S·cm−1 at 160°C. Improved applicable temperature and high conductivity of the compositemembrane indicated its promising application
inDMFC operations at high temperature.
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Translated from Acta Polymerica Sinica, 2007, (4): 337–342 译自:高分子学报] |
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Keywords: | sulfonated poly(ether ether ketone) zirconium phosphonate composite membrane direct methanol fuel cell |
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