Theoretical prediction of borophene monolayer as anode materials for high-performance lithium-ion batteries

Three morphologies of two-dimension Boron with metallicity have been successfully synthetized by experiments. To access the potential of β12 borophene (□) and χ3 borophene monolayer (◇) as anode materials for lithium ion batteries, first-principles calculations based on density functional theory (DFT) are performed. Lithium atom is preferentially absorbed over the center of the hexagonal B atom hollow of β12 and χ3 borophene monolayer. The fully lithium storage phase of β12 and χ3 borophene monolayer corresponds to Li8B10 and Li8B16 with a theoretical specific capacity of 1983 and 1240 mA h g−1, respectively, much larger than other two-dimension materials. Interestingly, lithium ion diffusion on β12 borophene (□) monolayer is extremely fast with a low-energy barrier of 41 meV. Meanwhile, lithiated-borophene monolayer shows enhanced metallic conductivity during the whole lithiation process. Compared to the buckled borophene (△), the extremely enhanced lithium adsorption energy of β12 and χ3 phase with vacancies weakens lithium ion diffusion. Therefore, it is important to control the generation of vacancy in the buckled borophene (△) anode for lithium ion batteries. Borophene is a promising candidate with high capacity and high rate capability for anode material in lithium ion batteries.