2006 Volume 47 Issue 8 Pages 1898-1901
Metal-borohydrides M(BH4)n (M=Mg, Sc, Zr, Ti, and Zn; n=2–4) were synthesized by mechanical milling process according to the following reaction; MCln+nLiBH4/nNaBH4→M(BH4)n+nLiCl/nNaCl. Then the thermal desorption properties of M(BH4)n were investigated by gas-chromatography and mass-spectroscopy combined with thermogravimetry. The results indicate that the hydrogen desorption temperature Td of M(BH4)n correlates with the Pauling electronegativity χP of M; that is, Td decreases with increasing value of χP. The components of desorbed gas for M=Mg, Sc, Zr and Ti (χP≤1.5) are hydrogen only, while that for M=Zn (χP=1.6) contains borane besides hydrogen. The Pauling electronegativity χP of M is an indicator to estimate Td of M(BH4)n as candidates for advanced hydrogen storage materials with high gravimetric hydrogen densities and low desorption temperatures.