Theoretical calculation of the energy of formation of LiBH4

Abstract

We report density functional theory calculations on the energy of LiBH 4, relative to solid B and LiH and gaseous H2. The calculated energy is -71.3 (-76.1) kJ/mol H2 which can be approximately corrected for zero-point energy to give an enthalpy of -52 (-57) kJ/mol H2 at the PW91 (LDA) level, smaller than but similar to the experimental value of -68.9 kJ/mol H2. Calculations on four different LiBH4 phases indicate that alternative phases are not accessible at low temperatures without applying high pressures. These results indicate that complete decomposition to H2, B and LiH is not an attractive means of obtaining a reversible hydrogen storage system based on LiBH4.