| dc.description.abstract | Proton exchange membrane (PEM) fuel cells and PEM reverse fuel cell dehumidifiers (or PEM electrolytic dehumidifiers) are zero emission, high efficiency electrochemical energy devices. However, the high cost associated with their material components, e.g., platinum (Pt) electrocatalysts, perfluorinated PEMs, hinders wide scale commercialization. In this work, fundamental mechanisms and strategies were explored in ultra-low Pt PEM fuel cells and low-cost PEM electrolytic dehumidifiers. For ultra-low Pt PEM fuel cells, a series of organized hexagonally patterned electrodes (diameters of 40, 80, 160, and 360 µm) were fabricated via template-assisted electrospinning/electrospraying (E/E), and the 80 µm pattern resulted in 42% Pt utilization enhancement compared to its random analog (without template-assisted). For low-cost PEM electrolytic dehumidifiers, i.e., to reduce the cost of conventional perfluorinated Nafion membrane, a series of commercial sulfonated pentablock terpolymer membranes (i.e., NEXAR® with ion exchange capacities (IECs) of 1.0 and 2.6 meq g-1) were evaluated in a PEM electrolytic dehumidifier. Water vapor transmission rates (WVTRs) and energy efficiency were measured at various humidity gradients and potential directions for membrane electrode assemblies (MEAs). NEXAR® (at 1.0 meq g-1 IEC) showed the highest energy efficiency, serving as a cost-effective alternative to Nafion. Additionally, a fundamental investigation in electrospun sulfonated pentablock terpolymers and poly(ionic liquid)s was explored for future application to advanced low-cost electrodes in electrochemical energy devices. Overall, this work demonstrates nanoscale engineering of polymer electrolytes as electrodes and membranes in both PEM fuel cells and PEM reverse fuel cells that results in lower cost for high performance zero emission electrochemical energy devices. | |
