Three-dimensional carbon framework as high-proportion sulfur host for high-performance lithium-sulfur batteries

Abstract

Lithium-sulfur (Li-S) batteries are anticipated as one of the most promising candidates for the high-energy-density storage systems. However, the insulating nature and shuttling effect of sulfur severely limits their performance. The incorporation of sulfur with carbon materials has been deemed as one of the most powerful strategies to improve electrical conductivity and suppress soluble polysulfide shuttling. Herein, a novel three-dimensional carbon framework (3DCF) is prepared and employed as a sulfur host (3DCF@S) for Li-S batteries. The 3DCF not only supplies abundant paths for lithium ion diffusion and electron transport, but also strengthens polysulfide immobilization during the lithium/sulfur conversion reactions. As a result, the 3DCF@S with high sulfur content of 90% exhibits a high capacity of 1366 mA h/g at 0.1 C and excellent cycling stability with a satisfactory capacity of 601 mA h/g after 600 cycles at 2.0 C. The resultant Li-S button battery based 3DCF@S electrode could power a light-emitting diode for 2 h. The acquired 3DCF@S is expected to be widely used in Li-S batteries and this study will promote developments of carbon/sulfur composites for Li-S batteries.