Study of Aluminoborane Compound AlB₄H₁₁ for Hydrogen Storage

Abstract

Aluminoborane compounds AlB4H11, AlB5H12, and AlB6H13 were reported by Himpsl and Bond in 1981, but they have eluded the attention of the worldwide hydrogen storage research community for more than a quarter of a century. These aluminoborane compounds have very attractive properties for hydrogen storage: high hydrogen capacity (i.e., 13.5, 12.9, and 12.4 wt % H, respectively) and attractive hydrogen desorption temperature (i.e., AlB4H11 decomposes at ∼125 °C). We have synthesized AlB4H11 and studied its thermal desorption behavior using temperature-programmed desorption with mass spectrometry, gas volumetric (Sieverts) measurement, infrared (IR) spectroscopy, and solid state nuclear magnetic resonance (NMR). Rehydrogenation of hydrogen-desorbed products was performed and encouraging evidence of at least partial reversibility for hydrogenation at relatively mild conditions is observed. Our chemical analysis indicates that the formula for the compound is closer to AlB4H12 than AlB4H11.

Synthesis of amorphous Mg(BH4)2 from MgB2 and H2 at room temperature

“…In the range from 20 to −30 ppm a very broad signal is observed, with two shoulders at 0.53 ppm and −15.57 ppm (∼32% signal). In earlier work, this signal has been attributed to a mixture of several Mg(B n H m ) y species which were observed during the decomposition process of Mg(BH 4 ) 2 or similar M(BH 4 ) n materials [15][16][17].…”

Search for the global minimum structures of AlB3H2n(n = 0 − 6) clusters

“…[2][3][4][5][6][7][8] Group 13 hydrides are of importance in the chemistry of materials, organic synthesis, organometallic catalysis, hydrogen storage applications, [9,10] and jet fuel. [16,17]. Hence, aluminoborane compounds may be good candidates for hydrogen storage due to their very high hydrogen capacity, moderate stability in terms of a decomposition temperature, fast hydrogen recharging kinetics, and attractive hydrogen fragmentation temperature, see Refs.…”

Synthesis, structural analysis, and thermal decomposition studies of [(NH3)2BH2]B3H8

“…The gaseous decomposition products (except for H 2 ) were condensed into the flask cooled by liquid nitrogen. The condensed products were then analysed using 11 B NMR spectroscopy. The high sensitivity of 11 B allows for an easy and accurate identification of these B containing products.…”

“…For example, the synthesis of AlB 4 H 11 requires diborane (B 2 H 6 ), which is highly flammable and consequently necessitates high quality vacuum apparatus and strong experience. 11,14 To make a compound interesting for hydrogen storage, its synthetic ease and availability are apparently of great importance.…”