One-pot fabrication of pitch-derived soft carbon with hierarchical porous structure and rich sp2 carbon for sodium-ion battery

Soft carbons with porous structure have attracted increasing attention as attracting anode active materials for sodium-ion battery. However, the reported anode active materials are plagued by limited capacity and unsatisfying rate performance. Besides, the improvement of electrical conductivity is often performed by post treatment, which is time-consuming and high cost. Herein we report an one-pot fabrication of pitch-derived soft carbon using zinc acetate as hard templates. Zinc acetate can not only play a vital role in constructing hierarchical porous structure but also providing additional sp2 carbon during carbonization, resulting in significantly enhanced sodium-ion storage capacity and improved rate performance. As anode active materials for sodium-ion battery, the as-prepared soft carbon with hierarchical porous structure, rich sp2 carbon and doped N, O heteroatoms, exhibits an impressively high reversible capacity of 293 mAh g−1 at 0.05 A g−1 in sodium-ion half cells, good rate capability of 53 mAh g−1 at 5 A g−1, and high capacity retention of 92.2% after 1000 cycles at 1 A g−1. Our strategy affords a facile way to prepare high-quality soft carbon materials as anode active materials for sodium-ion batteries.