(562d) 300°C Proton Exchange Membrane-Based Low-Pressure Electrolytic Ammonia Synthesis

The two North Dakota universities are developing a 300°C-capable polymer–inorganic composite (PIC) proton exchange membrane for low-pressure (15-psi) ammonia synthesis. The PIC membrane comprises an inorganic proton conductor strategically composited within a high-temperature polymer to achieve a proton conductivity (PC) at 300°C of 10^-2 S/cm, similar to that of Nafion at 70°C. Integrated with electrodes produced by Nel Hydrogen in a membrane–electrode assembly (MEA), a partially optimized PIC membrane was demonstrated to offer a 300°C PC of 0.9*10^-2 S/cm. Combined with an appropriate cathode catalyst, the PIC membrane is projected to enable ammonia production at a total energy input of 7.1 MWh/ton versus 8.5 MWh/ton for state-of-the-art (2018) Haber Bosch-based ammonia production. The PIC membrane will also have application to high-temperature water electrolysis for lower power-consumption lower-cost high-purity hydrogen production. Data and information regarding PIC membrane properties and deployment for ammonia synthesis will be presented.