Structural, electronic, elastic, and thermal properties of CaNiH ₃ perovskite obtained from first-principles calculations

Abstract

A theoretical study of the structural, elastic, electronic, mechanical, and thermal properties of the perovskite-type hydride CaNiH 3 is presented. This study is carried out via first-principles full potential (FP) linearized augmented plane wave plus local orbital (LAPW+lo) method designed within the density functional theory (DFT). To treat the exchangecorrelation energy/potential for the total energy calculations, the local density approximation (LDA) of Perdew-Wang (PW) and the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) are used. The three independent elastic constants (C 11 , C 12 , and C 44 ) are calculated from the direct computation of the stresses generated by small strains. Besides, we report the variation of the elastic constants as a function of pressure as well. From the calculated elastic constants, the mechanical character of CaNiH 3 is predicted. Pertaining to the thermal properties, the Debye temperature is estimated from the average sound velocity. To further comprehend this compound, the quasi-harmonic Debye model is used to analyze the thermal properties. From the calculations, we find that the obtained results of the lattice constant (a 0 ), bulk modulus (B 0 ), and its pressure derivative (B 0 ) are in good agreement with the available theoretical as well as experimental results. Similarly, the obtained electronic band structure demonstrates the metallic character of this perovskite-type hydride.

CaXH 3 (X = Mn, Fe, Co) perovskite‐type hydrides for hydrogen storage applications

“…The given parameters in Table were also reported previously for CaNiH 3 and CaPdH 3. The related velocities of CaNiH 3 were calculated closer to revealed values in Table . Minimum and maximum discrepancies between presented and reported values are around 1.0 and 9.6%, respectively.…”

“…At this point, it would be worthwhile to compare calculated elastic constants with those of similar compounds. Two Ca‐based ternary hydrides, CaNiH 3 and CaPdH 3 , were previously investigated by first‐principles calculations . The B , G , and E values of CaNiH 3 were reported as 113.1, 43.87, and 116.5 GPa while those of CaPdH 3 were calculated as 89.02, 43.87, and 116.5 GPa, respectively .…”

“…Some of the compounds of this structural group are CaCoH 3 , CaNiH 3 , LiTH 3 (T: Fe, Co, Ni, Cu), SrPdH 3 , and SrLiH 3 . ABH 3 perovskite‐type hydrides have been studied in recent years with regard to experimental and theoretical methods to get detailed information about their possible applications . The hydrogen storage techniques should satisfy some necessary conditions like suitable gravimetric and volumetric hydrogen storage capacities, reversibility, and good kinetics in order to get a suitable hydrogen storage material.…”

“…In literature, according to hydrogen stability in the structure and limited combinations of cations, the works have been developed on oxides than hydrides . However, the hydrides containing lightweight elements have received considerable attention with their high thermal stability and absorption/desorption capacity in the process of hydrogen storage . As an alternative material in use of hydrogen storage, this work presents structural, mechanical, electronic, and lattice dynamical characteristics of CaXH 3 compounds with different X elements.…”

“…[16][17][18][19] Among them, the perovskite-type hydrides have been promising candidate for solid-state type of future hydrogen storage materials. [20][21][22][23][24][25][26][27][28] There are numerous number of perovskite compounds that can be obtained as carbides, nitrides, fluorides, chlorides, bromides, oxides, hydrides, and iodides. 29,30 On the other hand, oxides and hydrides are the most prominent structures which may be applicable in the use of hydrogen storage.…”