Three-Dimensional Carbon-Honeycomb as Nano-Porous Lithium and Sodium Deposition Scaffold

Using the density functional theory method, we demonstrate that the recently synthesized three-dimensional carbon-honeycomb (C-honeycomb) can serve as a promising nanoporous scaffold for both lithium and sodium deposition with good electronic conductivity. Lithium/sodium can insert into the channels of C-honeycomb with low migration energy barriers along the walls of one-dimensional pores (<0.5 eV for lithium and <0.25 eV for sodium) and exist in the form of metal nanorods. A high theoretical capacity (711 mAh/g, almost twice that of graphite) can be achieved when the one-dimensional pores are filled with lithium/sodium atoms. The volume expansion of the C-honeycomb after metal insertion is less than 5 and 15% for lithium and sodium, respectively. Further introduction of defects such as pyridinic-N doping or single vacancy can provide initial nucleation sites for the metal nanorods and increase the open-circuit voltage.