Two-Dimensional B5Al2 as a Potential Electrode Material for Lithium-Ion Batteries

Abstract

In order to meet the requirements of advanced mobile electronic devices and electric vehicles, it is urgent to develop efficient energy storage technique. Lithium-ion (Li-ion) battery is one of most prospected candidates for such a technique. Note that, for the achievement of efficient Li-ion battery, two-dimensional (2D) electrode materials received scientists’ attention. In this work, we on the basis of density functional theory (DFT) successfully predicted a new 2D material of B5Al2 and evaluated its potential as an electrode material for Li-ion battery. Our results shown that intrinsic B5Al2 is metallic and its stability is well confirmed by its ab initio molecular dynamic (AIMD) simulation and phonon spectra calculation. Interestingly, calculated theoretical specific capacity of B5Al2 can reach up to 993 mA h/g, and AIMD simulation further confirmed that geometry of B5Al2 is well kept at this specific capacity. Meanwhile, we observed that B5Al2 always displays a metallic characteristic when it is absorbed by Li ions with various concentrations, which indicates an excellent electrical conductivity during charge and discharge processes. Moreover, we revealed that B5Al2 can display a low diffusion energy barrier of 0.05 eV, which is favorable for fast charge and discharge processes. In addition, we also revealed that B5Al2 can exhibit a low open-circuit voltage (OCV) with a range from 0.06 to 0.54 V. All of these findings successfully disclose a new 2D metallic material and its superior performances endow it with a promising electrode material for Li-ion battery application.