磺化聚醚醚酮/三羧基丁烷膦酸锆复合质子交换膜的研究

通过在磺化聚醚醚酮(SPEEK)中掺杂1,2,4-三羧基丁烷-2-膦酸锆(Zr(PBTC))制备出SPEEK/Zr(PBTC)复合质子交换膜.结果表明,与纯SPEEK膜相比,Zr(PBTC)的掺杂能降低复合膜的吸液量及甲醇透过系数,且随着Zr(PBTC)含量的增加,这种作用越趋明显.在室温至80℃范围内,复合膜的甲醇透过系数在10-7cm2.s-1数量级上,远小于Nafion115膜.在饱和湿度下,当温度大于90℃时,含40wt%Zr(PBTC)的复合膜电导率超过Nafion115膜,并在160℃时达到0.36S.cm-1.使用温度的提高及在高温下的高电导率表明该复合膜适合在高温DMFC中使用.

SULFONATED POLY(ETHER ETHER KETONE)/ZIRCONIUM TRICARBOXYBUTYL-PHOSPHONATE COMPOSITE PROTON_EXCHANGE MEMBRANES FOR DIRECT METHANOL FUEL CELLS

Sulfonated poly(ether ether ketone) (SPEEK) is a very promising alternative membrane material for direct methanol fuel cells.However,with fairly high degree of sulfonation (DS) SPEEK membranes can excessively swell or even dissolve at high temperatures.This restricts the membranes from working above a high tolerable temperature to get the high proton conductivity.To deal with this contradictory,insolvable zirconium tricarboxybutylphosphonate (Zr(PBTC))powder was employed to make composite with SPEEK polymerwith the attempt to improve the temperature tolerance of membranes.SPEEK/Zr(PBTC) composite membranes were obtained by casting homogeneous mixtures of Zr(PBTC)and SPEEK in N,N-dimethylacetamide on glass plates and then evaporating solvent at 60℃.Many characteristics of composite membranes were investigated,including thermal stability,liquid uptake,methanol permeability and proton conductivity.Results show that not only the temperature tolerance but also the methanol resistance of the SPEEK/Zr(PBTC) composite membranes was improved.The composite membranes with 30 wt%～40 wt% of Zr(PBTC) have their methanol permeability around 10~ -7 cm~25s~-1 ,which is one order of magnitude lower than that of Nafion~115.High proton conductivity of the composite membranes can be also achieved because of the increased high tolerable temperature.Under 100% relative humidity the conductivity of the composite membrane with 40 wt% of Zr(PBTC) exceeded that of the Nafion~ 115 membrane at 90℃ and reached a high value of 0.36 S5cm~ -1 at 160℃.Improved applicable temperature and high conductivity of the composite membrane indicate its promising application in DMFC operating at high temperature.