Enhanced cycling performance of a high-energy and low-cost lithium–sulfur battery with a sulfur/hardwood charcoal composite cathode material

Abstract

Lithium–sulfur battery is an attractive candidate for advanced energy storage devices due to its high specific energy of 2600 Wh kg⁻¹ arising from the high theoretical specific capacity (1675 mAh g⁻¹) of the sulfur cathode. However, short cycle life and low cycling efficiency are still the main obstacles preventing the practical development of this promising battery system. In this work, we show that a low-cost Li/S cell employing an activated hardwood charcoal–sulfur (S–AHC) nanocomposite cathode can be operated for more than 300 cycles while still maintaining high specific capacity (600 mAh g⁻¹) and coulombic efficiency of 97 %, achieved by a new formulation of liquid electrolyte containing a fluorinated solvent. Such an improved capacity retention and cycle life, as compared to its conventional counterparts, prove that active mass lost via polysulfide dissolution can be effectively inhibited by utilization of this liquid electrolyte solution. Considering these results, we believe that the Li/S battery consisted of this composite cathode and the liquid electrolyte may be proposed as a promising candidate for low-cost energy storage applications.