Green preparation of flake nano porous carbon: For sulfur scaffolds in high-performance lithium sulfur batteries

Abstract

In this report, we describe the creation of 2D porous nitrogen-doped carbon nanosheets using carbon precursors derived from silkworm cocoon biomass and CaCl2, a non-toxic and environmentally friendly material. The resulting carbon material exhibits a unique structure of nitrogen-doped nanosheets, extensive pore structure, and a significant specific surface area of 675 m2 g−1, which is attributed to the effect of Ca2+ on the structural conformation of silk glue protein. The high nitrogen doping, thin carbon sheets, and dense pore structure of the electrode material contribute to its excellent electrochemical performance. When used in a lithium‑sulfur composite electrode, it demonstrates exceptional electrochemical properties, including a very high initial capacity of 1403 mAh g−1, good multiplicity performance, and excellent cycling performance (700 mAh g−1 after 100 cycles at 0.1 C, 319 mAh g−1 after 1000 cycles at 1 C, and a capacity decay rate of 0.07 % per cycle). Importantly, the preparation strategy avoids the use of strong acid and alkaline structural restructuring agents, and provides an effective and green way to prepare advanced porous carbon electrode materials for lithium‑sulfur batteries.