Enhancing capacitive storage of carbonaceous anode by surface doping and structural modulation for high-performance sodium-ion battery

Carbon-based composites are the most promising anode materials for sodium-ion batteries (SIBs), due to the sustainability and high electronic conductivity. However, the poor dynamics of SIBs limit the practical application of carbon materials. Herein, the nitrogen doped three-dimensional porous carbons (NPC) with expanded graphitic interlayer space (0.37 nm) was prepared by a hard MgO template assisted method through using zero-cost asphalt powder as precursors and low-cost urea as an additional nitrogen source. The unique structure of NPC is not only conducive to the increase of reversible capacity, but also to accelerate the diffusion of Na+, enabling the NPC anode with rapid capacitive sodium storage. The NPC-based electrode delivers a high reversible capacity (352.7 mAh g−1 at 0.2 A g−1), cycle life (with 99% at 5.0 A g−1 for 900 cycles) and diffusion rate of Na+ (1.66 × 10−9 and 3.78 × 10−9 cm2 s−1 for anodic and cathodic, respectively). Furthermore, the NPC is prepared via a one-step low-cost process, suggesting a prospective development of carbon-based anode materials for SIBs.