Composite 2D film based on borophene and boron nanotube as anode material for lithium-ion batteries

In this study, using density functional theory, we were the first to obtain an atomistic model of a 2D composite film based on β12 borophene and a boron single-walled nanotube with the formation energy lower than that of a borophene monolayer. This composite material was evaluated for use as an anode material for lithium-ion batteries. It was found that the connection of boron nanotubes in a 2D film by a single borophene unit cell is energetically most favorable. The adsorption energy at full filling with lithium atoms exceeds the cohesive energy of lithium atoms by 0.9 eV / atom. Calculations of the electron transmission function revealed anisotropy of electrical conductivity during current transport along and perpendicular to the nanotube axis. The behavior of the open-circuit voltage curve suggests the presence of a discharge voltage plateau at 50 % or more filling of the composite 2D film with lithium atoms. The average open circuit voltage does not exceed one volt and is within the potential range for anode materials of lithium-ion batteries. The maximum theoretical capacity of the atomic model of the anode material was about 850 mAh∙g−1, which exceeds the theoretical capacity of the graphite anode by 2.28 times. The 2D film based on borophene and boron nanotube considered in this paper may be a promising anode material for lithium-ion batteries.

1. Russian Science Foundation - 24-79-00242