Thermally Processible AEMs from Stereospecific Polypropylene

Currently there are several anion exchange membranes that have been developed for commercial use that have demonstrated high performance and durability. However, all the membranes that are currently available are not thermally processible, like perfluorinated membrane are for proton exchange membrane devices, therefore MEA fabrication is more laborious and not currently scalable and the MEAs fabricated from the commercial polymers donĺt have the same intimate contact between the membrane and catalyst layers as perfluornated membranes. The decreased contact tends to lead to lower performance, durability and the necessity of supporting electrolyte i.e. KOH. Our proposed research aims to solve the stated challenges through the development of thermally processible, high performance AEMs. The AEMs are being developed from stereospecific polypropylene and will have a high degree of functionalization resulting in membranes with performance competitive with SOA perfluorinated materials, high durability and thermal processability enabling MEA manufacturing at scale. During the ongoing Phase I program we have demonstrated the several key aspects of the proposed work. Ziegler-Natta polymer chemistry based on titanium catalysts has been shown to capable of predictive syntheses, e.g. prepare copolymers of desired composition, materials are readily functionalized, and the catalyst system is sufficiently active. The copolymers have been thermally fabricated into thin film and woven PEEK supported films, thus eliminating solvent processing. Functionalized thin films/membranes have been successfully utilized in thermal electrode decal transfer. To date we have demonstrated a single cell AEM water electrolyzer cell operating at 0.9 A/cm2 achieving 1.75V at 80 °C. Our proposed Phase II project will further our membrane architecture and functionalization strategy to achieve > 100 mS/cm hydroxide conductivity. Achieving the conductivity target will enable achievement of our AEM water electrolyzer performance and durability milestones. Finally, our Phase II program will begin to scale up the polymer synthesis to > 100 g batches of copolymer to then be fabricated in to membranes and MEAs. The anticipated benefits from our proposed AEM development will include less expensive alkaline exchange membrane water electrolyzers to contribute to lowering the cost of green hydrogen to = $1 per kg. Furthermore, the membrane will have applications in alkaline fuel cells, carbon capture, green chemical synthesis and water desalination. This system will enable the technologies listed to utilize platinum group metal free electrodes and eliminate the use of perfluoroalkyl substances (PFAS) from membrane production. Ultimately, our technology will enable, for the first time, AEM MEA manufacturing at commercial scale.