Evaluation of stability of hydrogen in alloys using energy density formalism

Abstract We apply the energy density formalism with density functional theory for hydrogen storage alloys, which provides the decomposition of the total energy of a system into the contributions of constituent atoms. Since hydrogen atomic energies in an alloy can be obtained from a single total-energy calculation, the stabilities of individual hydrogen atoms are efficiently evaluated. For (Ti10V11Cr11)H64, it is found that hydrogen atomic energies are correlated well with the stabilities determined by conventional total-energy difference calculations. The substitution effect is also investigated for VH2. The energy density calculation reproduces the results of the conventional approach.