Kuan-Rong Hao,  Qing-Bo  Yan   Gang Su

Abstract

Graphite is the most commonly used electrode material, which is mainly due to two key advantages, i.e., its layered structure acts a perfect framework for the accommodation and migration of ions, and the light atomic mass of carbon is conducive to obtaining a high specific capacity. As a neighbor of carbon in the periodic table, boron is even lighter than carbon, and it can also form various layered structures. Here, we systematically investigate boron-based layered compounds to explore their potential applications as electrode materials by means of first-principle calculations. Among various types of boron compounds, MXB₄ (M = Li, Na, Mg; X = Al, Ga) with the YCrB₄-type structure are found to be potentially excellent electrode materials for metal-ion batteries. The adsorption and migration of Li/Na/Mg in MXB₄ have been presented, and migration barriers comparable with conventional electrode materials are observed. In particular, Li₂AlB₄ and Li₂GaB₄ are found to exhibit quite high specific capacities of 754 mA h g⁻¹ and 470 mA h g⁻¹ compared to the theoretical value of graphite (372 mA h g⁻¹) as well as low average voltages of 0.71 V and 0.79 V, respectively, revealing that they may be good anode materials for Lithium ion batteries.