Natural Okra Shells Derived Nitrogen‐Doped Porous Carbon to Regulate Polysulfides for High‐Performance Lithium–Sulfur Batteries

Abstract

Low conductivity of elemental sulfur, the “shuttle effect” of polysulfides, and structural change hamper lithium–sulfur batteries that have poor electrochemical performance. Herein, a facile and scalable approach to fabricate porous carbon is derived from common okra wastes, okra shells, as a matrix for sulfur active materials. Especially, the material calcined under NH 3 (N‐doped biomass‐derived porous carbon [N‐OSC]) with a high specific surface area of 2702 m 2 g −1 and large pore volume (0.17 cm 3 g −1 ) provides necessary physical adsorption, resulting in the 69.71 wt% loading of sulfur and excellent trapping capacity for polysulfides during the redox process. Furthermore, N element can act as catalytic active sites to facilitate redox conversion from polysulfides to Li 2 S. Benefiting from the aforementioned advantages, the cell of the N‐OSC/S electrode manifests superior electrochemical performance. The initial capacity is found up to be 1387 mA h g −1 at a current density of 0.1 C and 750 mA h g −1 after 200 cycles at 0.5 C rate (where 1 C = 1672 mA h g −1 ). For durability evaluations, the capacity is maintained at 416 mA h g −1 at 2 C after 1000 cycles with a mere decay of 0.05% per cycle.