Metal-borohydrides M(BH4)n (M = Mg, Se, 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 T d of M(BH4)n as candidates for advanced hydrogen storage materials with high gravimetric hydrogen densities and low desorption temperatures.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering