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

A low-cost hierarchical porous carbon (HPC) derived from pomegranate residues has been prepared via facile carbonization (at 600 degrees C, 700 degrees C and 800 degrees 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 m(2) g(-1) and pore volume of 1.12 cm(3) g(-1). When tested in Li-S 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. (C) 2019 Elsevier B.V. All rights reserved.