Dependence of Mg, Be and Al substitution on the hydrogen storage characteristics of ZrNiH ₃

Abstract

Summary The effect of Zr substitution by alkaline earth metals Mg, Be and post‐transition metal Al on the evolution of hydrogen storage properties of ZrNiH3 has been investigated by ab‐initio calculations based on density functional theory. The stability of the quaternary hydrides is studied by the determination of the formation enthalpy and the desorption temperature. The obtained results indicate a reduction of the formation enthalpy as well as the desorption temperature, hence reflecting the enhancement of hydrogen storage properties of ZrNiH3. Interestingly, each dopant (Mg, Be and Al) achieved its optimum substitution effect at a particular concentration, with Al and Be elements are found to exhibit the lowest substituting content ~17% and ~23% respectively and Mg with the highest concentration ~85%, to achieve an ideal formation enthalpy (ΔH = −40 kJ/mol.H2) and desorption temperatures (289 to 393 K), as required for practical use of proton exchange membrane fuel cells (PEMFC) without affecting the hydrogen storage capacity as seen in pure ZrNiH3.Moreover, the electronic structure investigated by partial density of states (PDOS), reveals the metallic nature of Zr1−xAMxNiH3 (AM = Mg, Be and Al) hydrides. Highlights The ZrNiH3 hydride presents high stability and high decomposition temperature. The stability decreases significantly when doping ZrNiH3 with Mg, Be and Al. The density of states reveals the metallic nature of Zr1−xAMxNiH3 hydrides.

Influence of N‐vacancy on the electronic and optical properties of bulk GaN from first‐principles investigations

“…During the structural optimization, all atomic positions and lattice parameters of a system were fully relaxed. [51][52][53]…”

“…The k meshes of 9 × 9 × 5, 11 × 6 × 11 and 12 × 6 × 12 were adopted for the hexagonal GaN, the cubic ( F‐43m ) GaN and the cubic ( Fm‐3m ) GaN, respectively. During the structural optimization, all atomic positions and lattice parameters of a system were fully relaxed 51‐53 …”

Thermodynamic characterisation and application of the ZrNi–H metal hydride system in the low-pressure regime

“…Among all known hydride-forming metal materials, ZrNi was in 1958 the rst demonstration 13 of an intermetallic compound reacting reversibly with hydrogen to form the ternary AB-type hydride ZrNiH 3 . On account of its distinctive propertieshigh storage capacity (theoretically almost 2 wt%), fast absorption/ desorption kinetics, but low equilibrium pressure at room temperature (<1 Pa), high desorption temperature (∼300 °C for ambient pressure 14 ) and high thermodynamic stability which leads to a lower useable capacity (∼68.8 kJ per mol H 2 ) 14,15 -ZrNi alloys are utilized in rather specic applications instead of large-scale technologies: 16 hydrogen isotopes handling and storage in thermonuclear fusion devices, [17][18][19][20] formation of negative electrode in nickel-metal hydride (Ni-MH) batteries, 21,22 vacuum getter materials, [23][24][25] hydrogenation catalysts, [26][27][28][29] closed-cycle solid hydrogen Joule-Thomson cryocoolers, [30][31][32] isotope separation and hydrogen purication 33,34 or thermal switch components. [35][36][37][38][39] ZrNi-H applicationgas pressure adjustment A thermal switch is an interesting and emerging technology in the context of energy transition, since it allows for a controlled manipulation of thermal transmittance without an additional heat transfer uid.…”

Tailoring the Electrochemical Performance of Olivine Phosphate Cathode Materials for Li-Ion Batteries by Strain Engineering: Computational Experiments

“…To date, one of the major challenges facing our society is the dramatic increase in energy demand around the world. − This increase is accompanied by dwindling fossil fuel reserves, rising costs, the pollution caused by their use, and geopolitical concerns. To solve these problems, seeking alternative energy sources is imperative. − Such a move requires significant scientific and technological advances in renewable energy, clean energy sources, and electric propulsion such as electric vehicles .…”