Traditional Chinese medicine residue-derived micropore-rich porous carbon frameworks as efficient sulfur hosts for high-performance lithium-sulfur batteries.

Biomass-derived carbon-based energy materials are receiving extensive attention nowadays. As the widespread use of traditional Chinese medicine in disease treatment and health care, a great deal of herb residue is thrown away after the unique decoction process. Here, through hydrothermal carbonization combined with KOH activation, a micropore-riched and Nitrogen-doped porous carbon frameworks (MRNCFs) are prepared from the waste roots of a kind of well-known and widely used traditional Chinese medicine—acanthopanax senticosus. Compared with ordinary carbon-based sulfur host materials, the MRNCFs can effectively hinder he shuttle effect and dissolution of polysulfides through the synergistic action of physical confinement to micropores and chemical anchoring to Nitrogen-doping, and the Lithium-sulfur batteries using MRNCFs as host presents superior electrochemical performance. In a high sulfur content over 75 %, the as-prepared electrodes exhibit a high reversible specific capacity of 540.4 mAh g-1 at a current density of 0.5 C after 150 cycles and excellent rate capability at different current density.