DMFCs用磺化聚醚醚酮/磺化酚酞型聚醚砜共混质子交换膜

A sulfonated poly(ether ether ketone) (SPEEK) membrane with fairly high degree of sulfonation (DS) swells excessively and even dissolves at high temperature. To solve these problems, sulfonated phenolphthalein poly(ether sulfone) (SPES-C, DS 53.7%) is blended with the SPEEK matrix (DS 55.1%, 61.7%) to prepare SPEEK/SPES-C blend membrane. The decrease in swelling degree and methanol permeability of the membrane is dose-dependent. Pure SPEEK (DS 61.7%) membrane dissolves completely in water at 70ºC, whereas the swelling degree of the SPEEK (DS 61.7%)/SPES-C (40%, by mass) membrane is 29.7% at 80ºC. From room temperature to 80ºC, the methanol permeability of all SPEEK (DS 55.1%)/SPES-C blend membranes is about one order of magnitude lower than that of Nafion®115. At higher temperature, the addition of SPES-C polymer increases the dimensional stability and greater proton conductivity can be achieved. The SPEEK (DS 55.1%)/SPES-C (40%, by mass) membrane can withstand temperatures up to 150ºC. The proton conductivity of SPEEK (DS 55.1%)/SPES-C (30%, by mass) membrane approaches 0.16 S•cm－1, matching that of Nafion115 at 140ºC and 100% RH, while pure SPEEK (DS 55.1%) membrane dissolves at 90ºC. The SPEEK/SPES-C blend membranes are promising for use in direct methanol fuel cells because of their good dimensional stability, high proton conductivity, and low methanol permeability.

Proton-exchange Sulfonated Poly(ether ether ketone)/Sulfonated Phenolphthalein Poly(ether sulfone) Blend Membranes in DMFCs

A sulfonated poly(ether ether ketone)(SPEEK) membrane with fairly high degree of sulfonation(DS) swells excessively and even dissolves at high temperature.To solve these problems,sulfonated phenolphthalein poly(ether sulfone)(SPES-C,DS=53.7%) is blended with the SPEEK matrix(DS=55.1%,61.7%) to prepare SPEEK/SPES-C blend membrane.The decrease in swelling degree and methanol permeability of the membrane is dose-dependent.Pure SPEEK(DS=61.7%) membrane dissolves completely in water at 70℃,whereas the swelling degree of the SPEEK(DS=61.7%)/SPES-C(40%,by mass) membrane is 29.7% at 80℃.From room temperature to 80oC,the methanol permeability of all SPEEK(DS=55.1%)/SPES-C blend membranes is about one order of magnitude lower than that of Nafion115.At higher temperature,the addition of SPES-C polymer increases the dimensional stability and greater proton conductivity can be achieved.The SPEEK(DS=55.1%)/SPES-C(40%,by mass) membrane can withstand temperatures up to 150℃.The proton conductivity of SPEEK(DS=55.1%)/SPES-C(30%,by mass) membrane approaches 0.16 S·cm^-1,matching that of Nafion 115 at 140℃ and 100% RH,while pure SPEEK(DS=55.1%) membrane dissolves at 90℃.The SPEEK/SPES-C blend membranes are promising for use in direct methanol fuel cells because of their good dimensional stability,high proton conductivity,and low methanol permeability.