Low-Cost Synthetic Honeycomb-like Carbon Derived from Cotton as a Sulfur Host for the Enhanced Electrochemical Performances of Lithium–Sulfur Batteries

Abstract

Lithium–sulfur batteries with high-energy density are witnessed to be the most prospective next-generation advanced batteries. Nonetheless, the existing issues of the serious shuttle effect and insulating property restrict their further applications. Herein, a honeycomb-like porous carbon derived from cotton is designed and prepared as a sulfur host to overcome the abovementioned problems. The cotton carbon carbonized at 700 °C acquires plentiful mesopores/macropores and displays a high surface area (458.85 m2 g–1). The C/S composite shows a relatively high capacity of 1271 mAh g–1 for the first cycle at 100 mA g–1. The carbon treated at 600 °C possesses abundant carbon–oxygen groups, which is beneficial for chemical adsorption of soluble polysulfides. The high-sulfur-loading (74 wt %) C/S electrode exhibits long-span cycling stability over 200 cycles. Benefiting from the excellent conductivity of cross-linked carbon fibers and the unique porous structure for trapping sulfur as well as the polysulfides, the cotton C/S composites exhibit superior properties for advanced lithium–sulfur batteries.