Electronic structures and thermodynamic stabilities of aluminum-based deuterides from first principles calculations

• Published in: Chinese physics B 2011, Vol.20 (1), p.534-540
• Main Author: 叶小球 罗德礼 桑革 敖冰云
• Format: Article
• Language: English
• Subjects: 储氢材料; 化合物; 热力学稳定性; 电子结构; 相互作用; 第一原理计算
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/20/1/017102

The alanates （complex aluminohydrides） have relatively high gravimetric hydrogen densities and are among the most promising solid-state hydrogen-storage materials. In this work, the electronic structures and the formation enthalpies of seven typical aluminum-based deuterides have been calculated by the plane-wave pseudopotential method, these being A1D3, LiA1D4, Li3A1D6, BaA1D5, Ba2A1D7, LiMg（A1D4）3 and LiMgA1D6. The results show that all these compounds are large band gap insulators at 0 K with estimated band gaps from 2.31 eV in A1D3 to 4.96 eV in LiMg（A1D4）3. The band gaps are reduced when the coordination of A1 varies from 4 to 6. Two peaks present in the valence bands are the common characteristics of aluminum-based deuterides containing A1D4 subunits while three peaks are the common characteristics of those containing A1D6 subunits. The electronic structures of these compounds are determined mainly by aluminum deuteride complexes （A1D4 or A1D6） and their mutual interactions. The predicted formation enthalpies are presented for the studied aluminum-based deuterides.