First-principles calculations into LiAl(NH2)4 and its derivative hydrides for potential sodium storage

• Main Authors: Yingying Ren, Xiaohan Ren, Rajeev Ahuja, Zhao Qian
• Format: Article
• Language: English
• Published: Elsevier 2020-12-01
• Series: Results in Physics
• Subjects: First-principles physics; Atomic-scale design; Light metal based complex hydrides; Sodium-ion battery; Density Functional Theory; Electronic structures
• Online Access: http://www.sciencedirect.com/science/article/pii/S2211379720318751

In this work, we have employed the first-principles quantum physics method to investigate the light-metal based LiAl(NH2)4 and its modified compounds as conversion electrode materials for sodium-ion batteries on the basis of state-of-the-art Density Functional Theory. The pure LiAl(NH2)4 possesses an average voltage of 0.294 V (versus Na+/Na0) and a theoretical specific capacity of 1093.77 mA h g−1 for sodium storage. Among the modified materials, the Li4AlB3(N4H8)4 has the most excellent electrochemical properties with a theoretical specific capacity of 1249.57 mA h g−1 and a low average voltage of 0.087 V (versus Na+/Na0) for potential anode applications. The diffusion behavior of Na-ion is also improved in Li4AlB3(N4H8)4 whether at 300 K or at 400 K, which indicates the prospective rate capability. The diffusion coefficient of Na-ion is obviously increased to 3.667 × 10−9 m2 s−1 (in modified material) from 1.500 × 10−9 m2 s−1 (in pristine material) at 400 K. The diffusion of Na-ion is calculated to be very fast in Li4AlB3(N4H8)4 with a kinetic barrier of 0.31 eV. This work will provide impetus to the quantum design and experimental development of complex hydride materials for metal-ion battery applications.