B2C9 as a high-performance Li-ion battery anode: effects of boron-incorporation and strain-engineering on the adsorption and diffusion of lithium

Abstract

Two-dimensional (2D) materials have garnered significant attention due to their unique structural features and outstanding physicochemical properties, particularly in the context of anode materials for lithium-ion batteries (LIBs). Inspired by the 2D Janus carbon allotrope, we theoretically predict a novel 2D material, B₂C₉, which exhibits semiconducting behavior along with excellent dynamic, mechanical, and thermal stability. B₂C₉ demonstrates a high theoretical storage capacity (2743.94 mAh g⁻¹), a low diffusion energy barrier (0.34 eV), and a low operating voltage (0.29 V). To reveal the influence of B incorporation, the properties of TQ-graphene as the anode material of LIBs are explored, which show a much lower theoretical storage capacity of 812.3 mAh g⁻¹, a lower diffusion energy barrier (0.16 eV), and a relatively higher operating voltage (0.60 V). The adsorption strength of Li increases with higher strain levels, regardless of whether the strain is tensile or compressive. The diffusion energy barriers decrease with the tensile strain, while they increase with the compressive strain. Such synergistic features highlight B₂C₉ as a breakthrough anode contender in next-generation LIB anodes.