Heteroatom‐doped nanoporous carbon with high rate performance as anode for sodium-ion batteries

Heteroatom doping was considered as an effective strategy to improve the electrochemical performance of carbon anode material for sodium-ion batteries (SIBs). In this work, heteroatom (N, P and O)-doped nanoporous carbon (HDNPC) was obtained through a simple pyrolysis process using ionic liquid as a source of heteroatoms. The synergistic effect of nanoporous structure and the heteroatom doping in the carbon framework provides the HDNPC with abundant defects and active sites, enlarged interlay space and short ion diffusion distance, which favor Na+ intercalation/deintercalation and thus improve the specific capacity and rate performance of the HDNPC. As a result, when used as anode material for SIBs, the HDNPC exhibits reversible capacities of 226.6, 200.2, 173.9, 155.6, 137.4 and 126.8 mAh g− 1 at 0.1, 0.2, 0.5, 1, 2 and 3A g− 1, respectively, and delivers a capacity of 114.3 mAh g− 1 at a current density of 5.0 A g− 1 after 500 cycles.