Abstract
FeNC material comprising single-iron-atom sites was evaluated as a sulfur host in a positive electrode for Li–S batteries application. The FeNC belongs to the broad class of Metal-N-C materials, with good electronic conductivity, high surface polarity, and demonstrated activity toward O2 and CO2 reduction reactions. The FeNC catalyst shows significantly higher kinetics on lithium polysulfide conversion reaction compared to high surface area Ketjenblack. After impregnation of the FeNC catalyst-based carbon host structure by sulfur, the electrochemical performance of the FeNC@S electrode was studied in Li-S cell under severe conditions of electrolyte amount and sulfur loading. Additionally, the negative affect of the high electrolyte amount and subsequently less viscous lithium polysulfides on lithium dendrite growth is demonstrated. Finally, the FeNC@S electrode with the sulfur loading of 4.0 mg cm-2 under lean electrolyte condition (6 mL g-1) showed a discharge capacity of 1200 mAh g-1 at C/20. The stability of the above-mentioned electrode during repeated charge/discharge cycling performed at C/10 shows a promising retention of ~86% over more than 90 cycles.