Metallic bilayer Kagome borophene as a promising anode material for Li and post-Li ion batteries

For future breakthroughs in alkali metal ion batteries, it is essential to explore new anode materials with high storage capacity. Recently, a novel two-dimensional material, bilayer Kagome borophene (BK-borophene), consisting of lightweight elemental boron and having excellent metal conductivity, has been proposed. Thus, the structure, stability, electronic and electrochemical properties of BK-borophene are investigated using first-principles calculations to examine its feasibility as an anode material. Our results show that a single Li/Na/K can stably adsorb on the BK-borophene surface with adsorption energy values of −0.46/-0.25/-0.69 eV. Besides, the low diffusion barrier values (0.55/0.30/0.15 eV) ensure that Li/Na/K can migrate rapidly on its surface, and the low open circuit voltage values are favorable for increasing the operating voltage of the assembled battery. Most importantly, BK-borophene shows high theoretical storage capacities of 826 mA h g⁻¹ for Li, 1377 mA h g⁻¹ for Na, and 275 mA h g⁻¹ for K, which is much more favorable than other reported anode materials. Not only that, BK-borophene also exhibits good cycling stability. The above-mentioned findings suggest that BK-borophene can be a promising and convincing anode material for alkali metal ion batteries.