High-Performance Borophene/Graphene Heterostructure Anode of Lithium-Ion Batteries Achieved via Controlled Interlayer Spacing

Borophene has been predicted to be a potential anode material of lithium-ion batteries because of its high specific capacity, high mechanical strength, and low diffusion barrier. However, borophene cannot be stable without metal substrates, impeding the industrial applications. Hence, using first-principles calculations, we proposed to form van der Waals heterostructures to improve the stability of monocomponent borophene and found graphene to be an alternative substrate for stabilizing borophene as a borophene/graphene (B/G) heterostructure. We find that B/G has a high adsorption energy of Li (−2.959 eV) and a high theoretical specific capacity (1469.35 mA h/g). Also, systematic climbing-image nudged elastic band calculations show that B/G has a low diffusion barrier (0.613 eV), and these properties change with the interlayer distance of B/G, theoretical specific capacity increasing to 1763.22 mA h/g, and diffusion barrier decreasing to 0.353 eV. Our results demonstrate that B/G is a promising anode material and that the electrochemical performance can be changed by adjusting the interlayer spacing.