Sponge-like hierarchical porous carbon decorated by Fe atoms for high-efficiency sodium storage and diffusion.

Hierarchical pores with accessible active sites in carbon are highly desired for enhancing sodium storage in sodium ion batteries (SIBs). However, it is still challenging to construct such materials with tunable architectures. Herein, a sponge-like 3D hierarchical porous Fe-doped carbon (Fe@NCS) was successfully assembled from an energetic framework. The continuous distribution of micro/meso/macro-pores in the range of 5 nm-2 μm and homogenously decorated Fe atoms were achieved, which greatly enhanced the storage and diffusion of Na + ions and displayed brilliant high-rate capability and cycling stability.