Sulfur-doped porous carbon as high-capacity anodes for lithium and sodium ions batteries

S-doped porous carbon (S/C) has been successfully fabricated from biomass waste (drug residue). The S/C not only has a unique porous structure and channel, but porous structures are interconnected to form a sponge-like structures. The unique structure not only increases the specific surface area and energy storage sites, but also shortens the path of ion transmission and charge transfer. When S/C-1 is used as lithium ion batteries (LIBs) anode, the capacity of 710 mAh g−1 can be achieved after 50 cycles at 0.1 A g−1. The capacity still has 364 mAh g−1 at 5 A g−1 for long-life-cycle. For sodium ion batteries (SIBs), a capacity of 518 mAh g−1 can be delivered at 0.1 A g−1 for 50 cycles, and a capacity of long-life-cycle at 5 A g−1 still maintains 230 mAh g−1. The improving rate capacities of S/C-1 can be attributed to the short diffusion lengths of Li+ and Na+ ions for uniform sponge-like structure, large specific surface area (SSA) and additional active sites. This work has an important opportunity to change the current energy situation.