B. Bogdanovic, G. Sandrock
Sep 1, 2002
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Influential Citations
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Journal
MRS Bulletin
Abstract
Complex hydrides are mixed ionic–covalent compounds that can serve as reversible H2 storage media only when they are catalyzed by a transition metal such as Ti. As the prime example, the phenomenology of Ti-catalyzed sodium alanate (NaAlH_4) is reviewed from a historical perspective. Dehydriding yields a theoretical 5.6 wt% H_2 during two-step decomposition, NaAlH_4 → Na_3AlH_6 → NaH + Al, although 100% recovery of that H_2 is not currently possible. H_2 can be discharged and recharged at practical rates at 125°C. More work is needed on the alanates, in particular, as well as the identification and optimization of the catalytic mechanism and a broad extension of the concept to other than Na-based alanates. The possibility of an even further extension of the concept to other complex hydrides (e.g., the borohydrides and transition-metal complexes) is discussed.