Tetragonal C24: a topological nodal-surface semimetal with potential as an anode material for sodium ion batteries

Abstract

Na-ion batteries, as an alternative to Li-ion batteries, have gained increasing attention due to the abundance of sodium and its low cost. In the present work, we prepare a 3D porous carbon material by inserting hexagonal carbon rings into sp³ C–C bonds in a previously established 3D-(4,4) lattice, termed tC₂₄. Ab initio calculations uncover that not only is tC₂₄ thermally, dynamically and mechanically stable, but it also exhibits a unique electronic band structure with two topological nodal surfaces traversing through the whole Brillouin zone. More importantly, tC₂₄ is the first all carbon topological nodal-surface semimetal for Na-ion batteries, exhibiting a high theoretical capacity of 232.65 mA h g⁻¹, a low diffusion energy barrier for Na ions, an appropriate average voltage of 0.54 V and a negligible volume change (∼0.94%) during charging/discharging operation. These properties provide tC₂₄ with a potentially long cycling life when used as an anode material for Na-ion batteries.