First-principles calculations of stability of graphene-like BC₃ monolayer and its high-performance potassium storage

With increasing demand for renewable energy, graphene-like BC monolayer as high performance electrode materials for lithium and sodium batteries are drawing more attention recently. However, its structural stability, potassium storage properties and strain effect on adsorption properties of alkali metal ions have not been reported yet. In this work, phonon spectra, AIMD simulations and elastic constants of graphene-like BC monolayer are investigated. Our results show that graphene-like BC monolayer possesses excellent structural stability and the maximum theoretical potassium storage capacity can reach up to 1653 mAh/g with the corresponding open circuit voltages 0.66 V. Due to potassium atom can be effectively adsorbed at the most energetically favorable h−CC site with obvious charge transfer, making adsorbed graphene-like BC monolayer change from semiconductor to metal which is really good for electrode utilization. Moreover, the migrations potassium atom on the graphene-like BC monolayer is rather fast with the diffusion barriers as low as 0.12 eV, comparing lithium atom with a relatively large diffusion barrier of 0.46 eV. Additionally, the tensile strains applied on the graphene-like BC monolayer have marginal effect on the adsorption and diffusion performances of lithium, sodium and potassium atoms. 3 3 3 3 3 3