Polymer-inorganic composite proton-exchange membranes for intermediate temperature electrochemical processes

Fuel cells are the most efficient electrochemical energy conversion devices that directly convert the chemical energy stored in fuels (e.g., hydrogen, natural gas, biogas, methanol, ethanol, etc.) into electricity. Intermediate temperature (IT) proton-exchange membranes (PEMs) carrying high proton conductivity are expected to play the crucial role in a variety of electrochemical processes including PEM fuel cells, electrolytic ammonia synthesis, electrolysis, hydrogen separation, electrolytic CO2 capture, etc. in the mild IT range (e.g., 150-350 oC) due to their improved work conditions and material requirements for durability and high performance. This research is focused on the development of a new type of IT polymer-inorganic composite (PIC) PEMs. Tests showed that the flexible PIC PEMs carried the proton conductivity up to 0.1 S/cm that was measured using a single-cell hydrogen fuel cell unit at humidified conditions and 200 oC. The PIC PEMs also demonstrated sufficient mechanical properties and thermal stability. The experimental results indicate the promising applications of the PIC PEMs in various IT electrochemical energy conversion processes.