N/O dual-doped hierarchical porous carbon boosting cathode performance of lithium—sulfur batteries

Abstract

A combination of NaOH activation and continuous pyrolysis of biomass is used to prepare N and O dual-doped hierarchical porous carbon as the carrier of Li—S batteries from egg, yolk and albumen respectively. Among the three sources, the biomass porous carbon derived from albumen has the most abundant hierarchical pore morphology. Its specific surface area, average pore diameter, and sulfur loading are 693.0 m2 · g−1, 3.1 nm and 62.0 wt.%, respectively. The albumen-derived porous carbon/sulfur (AC/S) electrode exhibits excellent reversibility and electrochemical performance (1115 mAh · g−1 at 0.05 C) due to the synergistic effect of hierarchical pore structure and element doping. The rate capacity of AC/S is 15% and 25% higher than that of egg-derived porous carbon/sulfur (EC/S) and yolk-derived carbon/sulfur (YC/S) at 2 C. And the capacity retention rate of AC/S after 50 cycles is 77%, which is 15% and 11% higher than those of EC/S and YC/S, respectively.