Systematic First-Principles Study of Binary Metal Hydrides

Abstract

First-principles calculations were systematically performed for 31 binary metal-hydrogen (M-H) systems on a set of 30 potential crystal structures selected on the basis of experimental data and possible interstitial sites. For each M-H system, the calculated enthalpies of formation were represented as functions of H composition. The zero-point energy correction was considered for the most stable hydrides via additional harmonic phonon calculations. The sequence of stable hydrides (ground-state) given by the convex hull was found in satisfactory agreement with the experimental data. In addition, new high pressure dihydrides and trihydrides were predicted, providing orientations for new materials synthesis. The overall results provide a global overview of hydride relative stabilities and relevant input data for thermodynamic modeling methods.

Effects of alloying elements (Al, Mn, Ru) on desorption plateau pressures of vanadium hydrides: An experimental and first-principles study

“…ZPE correction influenced the formation energies of hydrides more significantly than formation energies of V-3A alloys with no hydrogens. Because the atomic weight of hydrogen is small, its contribution to ZPE was significant [28,39]. As shown in Fig.…”

“…All the newly generated alloys and hydrides were fully optimized until the total forces acting on each atom were smaller than 0.01 eV/Å. The zero-point energy (ZPE), particularly for compounds that contain lightweight elements such as hydrogen, is not negligible [26][27][28][29][30]. Therefore, in addition to the formation energy of the hydrides, here we also report the ZPE corrected formation energies.…”

An x-ray study of palladium hydrides up to 100 GPa: Synthesis and isotopic effects

“…Here, we thus observed an inverse isotope effect. The isotopic effect should be canceled when the hydrogen atom contribution to the hydride's Zero-Point Energy (ZPE) is equal to half of the H 2 molecule's ZPE 38,39 .…”

Light Weight Complex Metal Hydrides for Reversible Hydrogen Storage

“…A new ternary complex metal hydride Zn(BH 4 ) 2 , was formulated for the low temperature hydrogen decomposition by reacting either NaBH 4 or LiBH 4 with ZnCl 2 salt in a mechanochemical process at room temperature according to the Equation [24,25]. 4 2 42…”

“…Complex metal hydrides are basically composed of various light weight elements and compounds that bonded with the hydrogen atom in binary, ternary, or quaternary structures [1][2][3]. The binary hydrides are made of light-weight elements and compounds, for example, LiH and MgH 2 often releases the absorbed hydrogen at very high temperatures (>400°C) and are irreversible in nature [4,5]. The reversibility of hydrogen absorption and desorption can be improved by bringing either the cationic or anionic substitution to form a ternary compound for example, LiBH 4 , Mg 2 FeH 6 , or Zn(BH 4 ) 2 [6,7].…”