Abstract
A low-cost hierarchical porous carbon (HPC) derived from pomegranate residues has been prepared via facile carbonization (at 600 °C, 700 °C and 800 °C) and activation, and applied as a sulfur host for lithium‑sulfur batteries. The rich protein in pomegranate residues provides nitrogen sources for the N-doped HPC. The influence of carbonization temperatures on the microstructure and performance of HPC has been investigated. In comparison to the HPC-700 and HPC-800, the HPC-600 sample has the highest BET surface area of 2064.32 m2 g−1 and pore volume of 1.12 cm3 g−1. When tested in LiS batteries, the as-prepared HPC/S-600 cathode with loading sulfur content of 71.54 wt% shows a high initial discharge capacity of 1010 mAh g−1 at 0.1C，and the reversible capacity retains 550 mAh g−1 after 500 cycles. The high cycling stability of HPC/S electrode is attributed to the synergistic effect of hierarchical porous structure and N-doping, which can provide strong physical and chemical confinement to sulfur and the soluble lithium polysulphides.
•A simple strategy to prepare nitrogen-doped hierarchical porous carbon (HPC) from low-cost biomass pomegranate residues.•HPC shows high specific surface area (2064m2 g−1) and high pore volume (1.12 cm3 g−1).•The HPC derived from pomegranate residues is first applied in a cathode for LiS battery.•The initial discharge capacity of HPC/S-600 composite achieves a value of 1010 mAh g−1 at 0.1C.•HPC/S composites show good prospects in the application of LiS batteries.