DMFCs用SPEEK/SiOx-S复合质子交换膜

A sulfonated poly(ether ether ketone) (SPEEK) membrane with a fairly high degree of sulfonation (DS) can swell excessively and even dissolve at high temperature. To solve these problems, insolvable functionalized silica powder with sulfonic acid groups (SiOx-S) was added into the SPEEK matrix (DS 55.1%) to prepare SPEEK/ SiOx-S composite membranes. The decrease in both the swelling degree and the methanol permeability of the membranes was a dose-dependent result of addition of the SiOx-S powder. Pure SPEEK membrane swelled 52.6% at 80°C, whereas the SPEEK/SiOx-S (15%, by mass) membrane swelled only 27.3% at the same temperature. From room temperature to 80℃, all SPEEK/SPEEK/SiOx-S composite membranes had methanol permeability of about one order of magnitude lower than that of Nafion115. Compared with pure SPEEK membranes, the addition of the SiOx-S powder not only leads to higher proton conductivity, but also increases the dimensional stability at higher temperatures, and greater proton conductivity can be achieved at higher temperature. The SPEEK/SiOx-S (20%, by mass) membrane could withstand temperature up to 145°C, at which in 100% relative humidity (RH) its proton conductivity exceeded slightly that of Nafion115 membrane and reached 0.17 S•cm－1, while pure SPEEK mem-brane dissolved at 90°C. The SPEEK/SiOx-S composite 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)(SPEEK)/SiOx-s composite membranes in direct methanol fuel cells

A sulfonated poly(ether ether ketone)(SPEEK)membrane with a fairly high degree of SUl fonation (DS)can swell excessively and even dissolve at high temperature.To solve these problems,insolvable functionalized silica powder with suIlbnic acid groups(SiOx-S)was added into the SPEEK matrix(DS=55.1%) to prepare SPEEK/SiOx-S composite membranes.The decrease in both the swelling degree and the methanol permeability of the membranes was a dose-dependent result of addition of the SiOx-S powder.Pure SPEEK membrane swelled 52.6%at 80°C,whereas the SPEEK/SiOx-S(1 5%,by mass)membrane swelled only 27.3%at the same temperature.From room temperature to 80℃,all SPEEK/SPEEK/SiOx-S composite membranes had methanol petea-bility of about one order of magnitude lower than that of Nafion r 115.Compared with pure SPEEK membranes,the addition of the SiOx-S powder not only leads to higher proton conductivity,but also increascs the dimensional stability at higher temperatures,and grcater proton conductivity can bc achieved at higher temperature.The SPEEK/SiOx-S(20%,by mass)membrane could withstand temperature up to 145°C,at which in 100%relative humidity(RH) its proton branc dissolved at 90°C.The SPFEk/SiOx-S composite membranes are promising for use in direct methanol fuel cells because of their good dimensional stability,high proton conductivity,and low methanol permeability.