Bifunctional Membrane Electrode Assemblies for Unitized Regenerative Fuel Cells
Abstract
Abstract:Enabling autonomous unmanned systems that perform critical missions, enable decisive capabilities, and mitigate tactical-level risk represents a priority for the Navy. Towards this end, the Navy is developing Unmanned Undersea Vehicles (UUVs) that can perform critical intelligence, surveillance and reconnaissance (ISR) and other missions. Increasing the operationalendurance of UUV propulsion systems is a key priority to improve mission capabilities. Air independent hydrogen/oxygen fuel cell energy systems provide UUVs with longer endurance than current rechargeable batteries. The ability to refuel fuel cell-powered UUV from forward deployed positions remains a significant challenge and need for the Navy. Unitized regenerative fuel cells(URFCs) provide a single device that can power the UUV in fuel cell mode and convert back the on-board product water to re-charge the hydrogen and oxygen storage vessels in electrolysis mode. Current URFCs have significant catalyst degradation and water management issues that substantially limit the performance and durability of URFCs.The proposed project will develop URFC membrane electrode assemblies (MEAs) with advanced bifunctional oxygen electrodes and components to provide higher performance and durability in both fuel cell and electrolyzer modes compared with baseline URFC MEAs. The project objectives are to (i) evaluate factors affecting URFC MEA performance and stability to develop effective MEA architectures for URFCs, and (ii) develop and test URFC MEAs withefficient, robust bifunctional oxygen catalysts. The project will evaluate the effects of MEA fabrication method, catalyst composition, catalyst loading, gas diffusion media/porous transport layer, and operating conditions on URFC MEA performance and stability. The performance and stability of URFC MEAs will be tested as single cells in both fuel cell and electrolyzer modes andwill be compared with MEAs containing baseline catalysts and electrodes.The project will significantly benefit the Navy by providing a key enabling technology for URFC development that can enable refueling of autonomous/self-sustaining long endurance UUVs from forward deployed recharging/refueling docking stations. The development of URFCs will allow hydrogen and oxygen production at the time and location of deployment and therefore avoid the requirement for long-term fuel/oxidant storage. The project will address key challenges of catalyst degradation and water management to provide URFC MEAs with improved performance and durability. Texas State University is classified as a Minority Institution (MI), and this effort will increase participation of underrepresented minorities in research relevant to theNavy.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 24, 2019
- Source ID
- N000141912071
Entities
People
- Christopher P Rhodes
Organizations
- Office of Naval Research
- Texas State University
- United States Navy