Acta Phys. -Chim. Sin. ›› 2007, Vol. 23 ›› Issue (01): 44-49.doi: 10.3866/PKU.WHXB20070109

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Methanol Resistant Poly(Ether Sulfone)/Sulfonated Poly(Ether Ether Ketone) Blend Proton Exchange Membrane for DMFC

HUANG Mian-Yan;CHEN Hua-Yan;GUO Jian-Zhao;WANG Zhi-Tao;XU Li;WANG Yu-Xin   

  1. State Key Laboratory of Chemical Engineering, Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University , Tianjin 300072, P. R. China
  • Received:2006-07-12 Revised:2006-08-28 Published:2007-01-08
  • Contact: WANG Yu-Xin

Abstract: 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), which enables high proton conductivity, SPEEK membranes can excessively swell or even dissolve. To deal with this contradictory, poly(ether sulfone) (PES) was blended into SPEEK to prepare PES/SPEEK blend membranes by solvent evaporating. Characteristics of the blend membranes, including thermal property, swelling degree, methanol permeability, proton conductivity and single cell performance, were investigated. DSC results reveal that the two polymers show good miscibility, which results in the homogeneity of the blend membranes. Methanol permeability and swelling degree of the blend membranes are both improved efficiently. The membranes with 20%−30%(w) of PES present the methanol permeability in the order of 1×10−7 cm2•s−1, which is an order of magnitude lower than that of Nafion 115. High proton conductivity of the blend membranes can also be achieved because of increased applicable temperature of membranes. Under 100% relative humidity, the conductivity of blend membrane with 30%(w) PES shows to be 0.078 S•cm−1 at 80 ℃. The single cell performance of blend membrane with 30%(w) PES is better than that of Nafion 115 membrane for its reduced thickness and thereby the resistance.

Key words: Direct methanol fuel cell, Sulfonated poly(ether ether ketone), Poly(ether sulfone), Blend membrane