Design of stable and durable polymer electrolyte membrane fuel cells by embedding hydrophobic cage-structured material in cell components

Performance stability and durability of polymer electrolyte membrane fuel cells (PEMFCs) depend on many factors of cell assembly that in turn determines the commercial applicability of PEMFC technology. In this study, an economically viable solution to improve the stability of PEMFCs at variable power is achieved with tailored membrane electrode assemblies (MEAs) by the incorporation of hydrophobic, cage-structured octasilane polyhedral oligomeric silsesquioxanes, (OSP) to Nafion™ in the MEA construction. In the Durability and Stability Dynamic Stress Testing (DST) studies over an operating time of 250 h; OSP modified MEAs exhibited a higher peak power density of 0.60 W cm−2 which dropped only 45%, compared to peak power density of neat Nafion™ which dropped 70% from the initial peak power density of 0.37 W cm−2. The H+ conductivity of OSP/Nafion™ composite MEAs remains stable during the full course of study and demonstrated sustained performance in harsh DST environment. The results illustrated that small amount of OSP (∼3%) in the MEA does prevent excess water accumulation in MEA and simultaneously allocate enough humidity for transporting H+, thus it advances the stability and durability of Nafion™ for manufacturing PEMFC and Direct Methanol Fuel Cells (DMFC).