We use a combination of first-principles density functional calculations along with the recently developed grand canonical linear programing method to predict a novel, high-capacity hydrogen storage reaction with thermodynamics suitable for near-ambient reversible storage. Unlike the vast majority of previously proposed complex hydrides, which typically rely on a hydrogen-containing anionic unit, our reaction is based on an ammonium-containing hydride, (NH4)2B12H 12, which contains increased storage capacity due to both anionic and cationic hydrogen-containing complexes. The predicted decomposition of this hydride is a two-step reaction sequence: (NH4)2B 12H12 → 2BN + 1/2B20H16 + 6H2 →2BN + 10B + 10H2, which possesses a theoretical gravimetric capacity of 11.3 wt% H2, a single-crystal volumetric density of 52 g H2/L, and T=300 K reaction enthalpies of 17 and 33 kJ/mol H2, respectively, which are well-suited for near-ambient reversible storage. The combination of these three attributes in a single material makes this decomposition reaction sequence highly promising.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Feb 11 2011|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics