Direct Seawater Electrolysis using Polybenzimidazole Membranes
Abstract
The objective of this research proposal is the efficient direct electrolysis of seawater to produce hydrogen and oxygen gases in high purities. To accomplish this goal, we propose the use of a polybenzimidazole-based proton exchange membrane water electrolyzer (PBI-PEMWE). PBI membranes are well-known for their oxidative stability, thermal stability, and tolerance to impurities in water. We have shown in previous work that PBI membranes enable the direct electrolysis of both anhydrous and aqueous HCl reactions that are applicable to the electrolysis of seawater. The use of PBI membranes will simplify the issue of water management, will facilitate a wider operating temperature range, resulting in higher efficiencies at higher operating temperatures, and will enable the ready separation of hydrogen and oxygen.Anticipated outcomes of this research are the demonstration of a direct seawater electrolyzer at currentdensities (# 0.1 A cm-2) that will meet or exceed ONR#s stated production threshold of 600 grams of hydrogen gas per day with a volumetric footprint of less than or equal to 0.6 cubic meters, an experimentally-derived technoeconomic model and analysis that evaluates the technical and economic feasibility of the proposed electrolysis process, including balance of plant components, and will give guidance on the required design of the electrolyzer, and a computational fluid dynamics (CFD) model that will not only provide insight into the transport phenomena that govern the overall performance of the electrolyzer but also enable parametric studies of operating conditions and optimization of hardware parameters such as the flow field design.The major impact of this research on DoD capabilities is the ability for naval vessels to produce hydrogen on-demand from an abundant and ever-present resource using equipment that has a small physical footprint, could reasonably be powered by batteries and/or renewable energy sources like solar and wind power, and requires little maintenance due to few or no moving parts. The hydrogen could be used to produce ammonia for long-term energy storage, run through a fuel cell to produce power and clean water for drinking, or burned directly for power generation.Approved for Public Release
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 08, 2024
- Source ID
- N000142412390
Entities
People
- Benjamin Meekins
Organizations
- Office of Naval Research
- United States Navy
- University of South Carolina