Nitrogen-doped hierarchical porous carbon derived from low-cost biomass pomegranate residues for high performance lithium‑sulfur batteries

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.