Monolayer boron‐arsenide as a perfect anode for alkali‐based batteries with large storage capacities and fast mobilities

Abstract We investigate, by means of first‐principles density functional theory (DFT) calculation, the possibility of using hexagonal boron‐arsenide (h‐BAs) as an anode material for alkali‐based batteries. We show that the adsorption strength of alkali atoms (Li, Na, and K) on h‐BAs in comparison with graphene and other related materials changes a little as a function of alkali atom concentration. When the separation between alkali atoms and h‐BAs is less than the critical distance of ~5 Å, the adsorption energy abruptly increases showing fast adsorption without an energy barrier. Furthermore, the low energy barriers of 0.322, 0.187, and 0.0.095 eV for Li, Na, and K, respectively, ensure the fast ionic diffusivities for all the three alkali atoms. Additionally, the addition of these alkali atoms transforms the electronic properties of h‐BAs from semiconducting to metallic, resulting in improved electronic conductivities. Most interestingly, the excellent storage capacities of h‐BAs (~626 mAh/g) for alkali atoms make it a material of similar caliber to that of other popular anode materials. Finally, the average open circuit voltages are calculated and found to be in the desired range. In short, h‐BAs possess every quality that is crucial for an anode material and thus it is interesting to see h‐BAs in alkali‐based battery technologies.