Interpenetrating silicene networks: A topological nodal-line semimetal with potential as an anode material for sodium ion batteries

Motivated by the novel properties of topological nodal-line semimetal and its compatibility with the well-developed Si-based semiconductor technology, we propose a three-dimensional all-silicon topological nodal-line semimetal composed of interpenetrating silicene networks (ISN). Using state-of-the-art first-principles calculations and the cluster expansion method, we find the ISN structure to be dynamically, thermally, and mechanically stable. In addition, it exhibits linearly dispersive band crossings along two perpendicular high-symmetry directions due to the band inversion and shows two nontrivial nodal lines, traversing in the Brillouin zone near the Fermi level. Furthermore, ISN has the potential as an anode material for sodium-ion batteries with an extremely low diffusion energy barrier and a small volume change during the charging/discharging process, which would lead to a high rate and stable cycling performance.