Novel Sulfonated Block Copolymers for Efficient Electrochemical Hydrogen Compression

According to a report by the Hydrogen Council, a global lobby set up in January 2017 by Toyota and Air Liquide that includes 27 members such as automakers Audi, BMW, Daimler, Honda and Hyundai, and energy firms Shell and Total, increasing the use of hydrogen in power, transport, heat and industry could deliver around one fifth of the total carbon emissions cuts needed to limit global warming to safe levels by mid-century. Electrochemical hydrogen separation and compression (EHSC) technology can recycle and purify waste hydrogen and compress hydrogen to high pressures required for vehicle fuel storage, addressing needs facing the large and growing industry for hydrogen supply and use as a process gas or energy carrier. EHSC systems that are able to reach ultra- high pressures at low energy requirements can better meet the needs of the hydrogen vehicle fueling industry. Electrochemical systems offer the potential for hydrogen compression with greater reliability and lower costs than conventional mechanical systems due to their elimination of moving parts. The use of electrochemical cells in compressors is challenged by membrane stability under high pressure differentials, membrane tolerance to impurities, capital cost of membranes and catalysts, and risks of cell flooding due to membrane hydration requirements. Perfluorosulfonic acid ionomers such as Nafion have been the most widely tested proton exchange membrane (PEM) material. Recently, Dr. Chulsung Bae’s group at Rensselaer Polytechnic Institute (RPI) has developed a new controlled polymer functionalization method based on functionalization of C-H bonds in polymer. This new synthetic method has allowed Bae’s group to incorporate various types of ionic functional groups into polymers. Synthesis and characterization of these new ionic polymers has advanced understanding of relationships between chemical structure and performance of the materials at molecular level. The proposed DOE program will focus on the development of next-generation PEMs that enable hydrogen compression in SI’s electrochemical hydrogen separation and compression system at the DOE goals of > 1 kg/hour at 875 bar with an energy consumption of 1.4 kWh/kg, given hydrogen input at 100 bar.