Self-Catalyzing Hydrogen-Storage Material Yang, Jun; Sudik, Andrea; Siegel, Donald J ...
Angewandte Chemie (International ed.),
01/2008, Letnik:
47, Številka:
5
Journal Article
Recenzirano
Greater than the sum of its parts: Hydrogen storage in complex hydrides is accelerated by using the ternary composite 2 LiNH2/LiBH4/MgH2, which exhibits a “self‐catalyzing” reaction pathway that ...results in faster H2 desorption, lower desorption temperatures, and suppression of NH3 release in comparison to the constituent binary composites (see diagram). The enhanced properties arise from the incorporation of an ionic liquid phase (Li4BH3H10) and from ancillary‐reaction seeding of a reversible H2 storage reaction.
We have investigated the ternary mixture of complex hydrides with stoichiometry 2LiNH2+LiBH4+MgH2, and have identified a set of novel hydrogen storage reactions. One of these reactions involves the ...known reversible reaction Mg(NH2)2+2LiH{left-right arrow}Li2Mg(NH)2+2H2. Previous studies have shown that initiating this reaction from the binary mixture 2LiNH2+MgH2 results in poor hydrogen desorption kinetics and a small amount of NH3 release. In contrast to this behavior, here we demonstrate that by starting from the ternary mixture 2LiNH2+LiBH4+MgH2, the above reaction can proceed at lower temperatures and with improved kinetics, while maintaining reversibility. The advantage of starting with the ternary mixture can be traced to the subsequent formation, melting, and reaction of Li4BH4(NH2)3 with MgH2 to form the mixed imide phase Li2Mg(NH)2, which acts as a seed for the reversible reaction, and is at least partly responsible for the improved kinetic response.
Mehr als die Summe der Teile: Das ternäre Komposit 2 LiNH2/LiBH4/MgH2 unterstützt einen „selbstkatalysierenden“ Reaktionspfad, der eine schnellere H2‐Desorption, niedrigere Desorptionstemperaturen ...und eine effektivere Unterdrückung der NH3‐Freisetzung als bei den binären Komponenten bewirkt (siehe Diagramm). Die verbesserten Eigenschaften werden auf die Entstehung einer ionischen Flüssigphase (Li4BH3H10) zurückgeführt, die die Bildung von Impfkeimen für eine zusätzliche reversible Wasserstoffspeicherreaktion vermittelt.
