The global shift towards a low-carbon future and the urgent need to address climate change have put clean energy solutions at the forefront of innovation. In recent years, hydrogen has gained significant attention as a versatile and sustainable energy carrier. To achieve large-scale clean hydrogen production, governments and industries are investing in cutting-edge technologies, such as water electrolysis powered by renewable energy sources. Cost limitations have delayed the adoption of some mature technologies, such as Proton Exchange Membrane Water Electrolysis (PEMWE), which has driven research into Anion Exchange Membrane Water Electrolysis (AEMWE). AEMWE has its own limitations, typically arising from the use of Potassium Hydroxide (KOH) as an electrolyte, which disintegrates membranes and is hard on equipment. However, researchers at Colorado School of Mines have just published a paper illuminating how TuffBrane™, the AEM being commercialized by Spark Ionx, Innosphere Ventures Client Company, may have unlocked an even more scalable solution: Carbonate. AEMWE: Scalable Alternative to PEMWE PEMWE has been favored over carbon-emitting hydrogen production methods, such as steam methane reforming, but has been limited in adoption due to the high cost of Platinum Group Metal (PGM) catalysts, which can account for nearly $400,000 per MW, in addition to Titanium electrodes required to withstand the highly acidic environment. AEMWE has been gaining traction as an alternative, as it uses low-cost stainless steel and Nickel, and a cheap electrolyte, KOH, to boost efficiency and performance. However, KOH is caustic and can cause harm to membranes, pumps, and other equipment, adding operational expense. While AEMWE shows great promise, there are challenges to overcome for its widespread adoption. One significant hurdle lies in finding membrane materials that possess both high hydroxide conductivity and durability in corrosive electrolytes. Research efforts are focused on developing new polymer chemistries and morphologies to address these challenges. By striking a balance between performance and durability, scientists are paving the way for the practical application of AEMWE technology.
Polymer Breakthrough: TuffBrane™ Polymers play a crucial role in AEMWE systems, as they provide the structural framework and facilitate ion conduction. A breakthrough in research has resulted in TuffBrane™, a polyethylene-based triblock copolymer that shows exceptional promise, developed at Colorado School of Mines and commercialized by Spark Ionx. By carefully fine-tuning the hydrophobic polyethylene backbone, TuffBrane™ has demonstrated impressive water uptake values and not only high hydroxide conductivity, but high carbonate conductivity as well. Competing AEMs have touted high hydroxide conductivity, but these values are typically achieved by increasing the Ion Exchange Capacity (IEC) of the membrane, which leads to excessive swelling and eventually membrane failure. In contrast, TuffBrane™ achieves conductivity through both IEC and microphase separation that arises from the use of both hydrophobic and hydrophilic polymers. This interaction creates tiny domains that can absorb water without saturating the polymer chains themselves, thereby increasing conductivity while limiting swelling. There is an added benefit that the polymer chain itself is not subjected to hydroxide attack, further increasing durability. The pockets also allow for transfer of larger ions like carbonate, which is a property absent from most AEMs.
Toward a Sustainable Future "We have always believed TuffBrane™ is a groundbreaking and versatile technology, but it's nice to see confirmation from the academic community, said Sean Daniel, CEO of Spark Ionx. “With such a high carbonate conductivity now possible in an AEM, some electrolyzer manufacturers may be wondering why they even bother with the complications of KOH." As the world strives for a sustainable energy landscape, AEMWE technology holds tremendous potential. The ability to produce clean hydrogen through water electrolysis, without relying on precious metals or perfluorinated compounds, opens up new possibilities for a greener energy transition. AEMWE offers scalability, lower costs, and reduced environmental impact, and now, with TuffBrane™, there is potential for further improvements with the use of carbonate electrolyte. For more information about the full research publication, please visit HERE
See the press release at Innosphere Ventures HERE