Ionic Liquid Mediated Synthesis of Alane25-000008894
Abstract
A key challenge to the widespread adoption of hydrogen as an energy carrier is the discovery of advanced materials with optimal hydrogen storage properties that offer a higher available energy density alternative to compressed gas hydrogen storage or battery technology. Aluminum hydride (alane) is one of the few hydrides that possess the best combination of properties for practical utilization as hydrogen storage media, with a high hydrogen density (10 wt% H2), high volumetric capacity (148 g H2 /L) and favorable kineticsof hydrogen release at moderate temperatures (<200 oC). However, the commercialization of alane is challenged by the large amounts of solvents (e.g., diethyl ether and toluene) and costly reactants/catalysts (e.g., excess LiAlH4 and LiBH4) utilized in the synthesis and purification process. This problem necessitates the need to develop new, safe, alternate alane synthesis approaches, with concomitant demonstration and evaluation of the effectiveness of the synthesized alane under practical fuel cell power generation conditions. The objective of this work is to demonstrate and evaluate the fuel cell power generation performance of alane materials developed through a novel ionic liquid-mediated synthesis process under simulated Navy-relevant operation conditions, such as for unmanned systems. The ionic liquid-mediated synthesis has the potential to lower costs and improve the scale-up process. To achieve the objective, we will leverage our synthesis and characterization expertise and experiences in hydrogen storage and ionic liquids, as wellas expertise in fuel cell performance testing at Hawaii Natural Energy Institute#s ONR-sponsored Fuel Cell Systems Laboratory to investigate commercial and novel Lewis basic ionic liquids as solvents for alane synthesis. We aim to contribute to the elimination ofthe bottlenecks in the commercialization of alane by (1) eliminating the use of diethyl ether as a solvent for alane synthesis, (2)eliminating the useof costly LiAlH4 in alane synthesis by investigating other alanates such as NaAlH4.The project research plan involves six main tasks: i) Develop Lewis basic ionic liquids; (ii) Evaluate the effectiveness of the basic functionalized ionic liquids in alane synthesis; iii) Characterize the properties of the synthesized alane; iv) Demonstrate and evaluate the alane in fuel cellpower generation at simulated Navy operation conditions relevant to unmanned aerial vehicles (UAVs); v) Design a lab-scale batch reactor for scaling up the alane synthesis; vi) Perform cost analysis of scale-up synthesis of a metric ton of alane.If successful, the project will result in a solid-state hydrogen storage synthesis technology that overcomes the cost and manufacturing challenges ofstate-of-the-art alane synthesis technologies. We envision the new knowledge gained from the synthesis and demonstration activitieswould lead to the rapid commercialization of alane-based technologies for onboard and stationary applications. There is potentiallyhigh demand in the Navy for a hydrogen storage material such as alane, which is maneuverable to fit space, is cheap to manufacture locally at a large scale, and has optimum hydrogen storage properties at close to fuel cell operation conditions. The inherent highenergy density of the alane will entail unique, versatile, and agile power options for the U.S. military, including long-range fuelcell power sources for unmanned systems (unmanned aerial vehicles (UAVs), ground vehicles, unmanned underwater vehicles (UUVs)) andlightweight power generators for Soldier missions.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 10, 2025
- Source ID
- N000142512187
Entities
People
- Godwin Severa
Organizations
- Office of Naval Research
- United States Navy
- University of Hawaiʻi System