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Published November 8, 2007 | public
Journal Article

Potential and Reaction Mechanism of Li−Mg−Al−N−H System for Reversible Hydrogen Storage

Abstract

Complex metal hydrides are attracting much attention as a class of candidate materials for hydrogen storage. Lithium-based complex hydrides, including lithium aluminum hydrides (LiAlH_4 and Li_3AlH_6), are among the most promising materials, owing to their high hydrogen contents. In the present work, we investigated the dehydrogenation/rehydrogenation reactions of a combined system of Li_3AlH_6 and Mg(NH_2)_2, which has a theoretical hydrogen capacity of 6.5 wt %. Thermogravimetric analysis of hydrogenated 2/3Al−Li_2Mg(NH)2 (doped with 4 wt % TiCl_3) indicated that a large amount of hydrogen (∼6.2 wt %) can be stored under 300 °C and 172 bar of hydrogen pressure. The FT-IR and NMR results showed that the reaction between Li_3AlH_6 and Mg(NH_2)_2 is reversible. Further, a short-cycle experiment has demonstrated that the new combined material system of alanates and amides can maintain its hydrogen storage capacity upon cycling of the dehydrogenation/rehydrogenation reactions.

Additional Information

© 2007 American Chemical Society. Received 20 June 2007. Published online 11 October 2007. Published in print 1 November 2007. This research was supported by the U.S. Department of Energy (DOE) under contract numbers DE-FC36-05GO15069 (U. Utah) and DE-AI-01-06EE11105 (JPL) and was also partially performed at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautical and Space Administration (NASA). The NMR facility at Caltech was supported by the National Science Foundation (NSF) under Grant Number 9724240 and partially supported by the MRSEC Program of the NSF under Award Number DMR-520565. We thank W. Luo and J. W. Reiter for providing several Li−Mg−N−H reference materials.

Additional details

Created:
August 19, 2023
Modified:
October 25, 2023