Abstract

Due to growing interest to explore and predict potential hydrogen storage materials by adopting theoretical and greatly functional software, research on lightweight materials has taken great attention. From this perspective, this study focuses on investigating electronic, elastic, and anisotropic properties of cubic LiBH₄ and Li(BH)₃ using first principles calculations for the first time. A comprehensive investigation has been carried out to reveal materials’ electronic, elastic, hardness, and anisotropic behaviour. The calculations exhibit that both LiBH₄ and Li(BH)₃ has negative formation energies as − 0.268 eV/atom and − 0.187 eV/atom, respectively which indicate synthesisability and thermodynamic stability. Elastic constants of materials are used to predict mechanical stabilities based on the well-known Born stability criteria. It is seen that both materials are mechanically stable. The electronic band structures indicate band gaps between valence and conduction band as 6 eV for LiBH₄ and 4.58 eV for Li(BH)₃, showing non-metallic nature of both materials. The negative Cauchy pressures and the B/G ratio less than 1.75 indicate brittleness of both materials. The anisotropy factors of both materials display that these materials are anisotropic due to a deviation from unity. The hydrogen desorption temperature is also estimated as \(\sim\) 198.2 K for LiBH₄ and \(\sim\) 138.6 K for Li(BH)₃.

Graphical abstract

中文翻译：

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LiBH4 和 Li(BH)3 作为储氢基质材料的电子和弹性性能立方体

摘要

由于采用理论和功能强大的软件来探索和预测潜在的储氢材料的兴趣日益浓厚，轻质材料的研究受到了极大的关注。从这个角度来看，本研究首次利用第一性原理计算研究立方LiBH ₄和Li(BH) _{3的电子、弹性和各向异性性质。}我们进行了全面的研究，以揭示材料的电子、弹性、硬度和各向异性行为。计算表明LiBH ₄和Li(BH) ₃均具有负形成能，分别为- 0.268 eV/原子和- 0.187 eV/原子，这表明可合成性和热力学稳定性。材料的弹性常数用于根据众所周知的玻恩稳定性标准来预测机械稳定性。可以看出，两种材料都是机械稳定的。电子能带结构表明LiBH _{4 的价带和导带之间的带隙为6 eV，Li(BH) 3}的电子带隙为4.58 eV ，显示出两种材料的非金属性质。负柯西压力和 B/G 比小于 1.75 表明两种材料都是脆性的。两种材料的各向异性因子表明这些材料由于偏离统一而具有各向异性。_{LiBH 4 的}氢解吸温度估计为\(\sim\) 198.2 K ，Li(BH) _{3 的氢解吸温度为}\(\sim\) 138.6 K。

图形概要