Researchers at the University of California, Santa Barbara, have developed functionalized porous inorganic materials for use in PEMs. In preparing these new membranes, hydrophilic moieties are incorporated along the pore surfaces of the inorganic framework to increase conductivity in the membrane and enhance water retention properties. The hydrophilic nature of the porous inorganic films specifically strengthens the conductive areas of the membranes. Functionalized porous inorganic films such as these are capable of maintaining their water retention and ion-conductivity properties at elevated temperatures.
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8808807
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Background
One of the major focuses of research on proton exchange membranes (PEMs) has been improving proton conductivity at elevated temperatures, above 100˚ C. PEMs conventionally operate at 80˚ C or below in order for the membranes to remain hydrated and maintain their proton conductivity properties. The low limit on operating temperature has a detrimental effect on the efficiency of the electrodes due to diminished oxygen reduction kinetics and increased carbon monoxide (CO) poisoning of the electrodes. Furthermore, CO poisoning is also temperature-dependent and CO tolerance of the electrodes is raised ten-fold by increasing the operating temperature of PEMs to 150˚ C. Maintaining hydration in the fuel cell membrane at high temperatures would enhance performance and eliminate costly production steps.
