Separated and intermixed phases of borophene as anode material for lithium-Ion batteries

Abstract

In this work, density functional theory calculations along with ab initio molecular dynamics simulations are employed to evaluate the potential of intermixed and separated phases of borophene as anode materials for lithium-ion batteries. The most stable binding positions are identified, followed by a gradual increase of lithium-ion concentration until a maximum value of theoretical specific capacity is achieved. The results indicate that separate phases of striped, β₁₂ and x₃ show adsorption energies of -1.16, -1.42 and -1.25 eV to lithium adatom, respectively. Moreover, the maximum lithium concentration for the mentioned phases are Li₀.₇₅B, Li₀.₈B and Li₀.₅₈₃B with their corresponding specific capacities being 1864, 1983 and 1487 mAh g⁻¹, accordingly. Moreover, the energy barrier for lithium diffusion is calculated along different pathways to determine the performance of each of the discussed phases. As intermixing of the phases is an inevitable phenomenon in the synthesis process of borophene, three possible types of intermixing are analyzed. The predicted capacity for both separated and intermixed phases are well above the highest reported values for common materials, which renders this material a promising candidate for future high capacity lithium-ion batteries.