Candle flame generated Co and Fe single atoms supported in soot as novel host for lithium-sulfur batteries with excellent electrochemical performance

• Published in: Journal of alloys and compounds 2025-01, Vol.1010, p.177776, Article 177776
• Main Authors: Ren, Wurong, Wang, Danqin, Guo, Jiajun, Lian, Yicheng, Yao, Honglin, Liu, Wanchao, Du, Xin
• Format: Article
• Language: English
• Subjects: Electrochemical performance; Host; Lithium-sulfur batteries; Single atoms
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2024.177776

By simply introducing metal salts into paraffin, Co and Fe single atoms dispersed in candle soot (CS) can be directly collected from the flame of home-made candles without any byproducts. STEM, XRD and XANES analysis demonstrate that Co and Fe exist in single atom state. The prepared Co-CS and Fe-CS, with high specific area and excellent sulfur loading capability, can be used as innovative host for cathode to assemble Li-S pouch cells, and exhibit excellent electrochemical performance with higher specific capacities (approximately 1250 mAh/g at 0.1 C with 7.5 mg/cm² sulfur loading) and improved cycling stability (retaining about 63 % of capacity after 50 cycles) than bare CS host. Meanwhile, density functional theory (DFT) calculations demonstrate that Fe-CS/Co-CS decrease the energy barriers of conversion reactions from Li2S8 to Li2S due to the increased binding energy between Co-CS/Fe-CS and LiPSs, therefore effectively mitigating the polysulfides shuttle effect. Such a strategy holds promise for practical cell-level designs in Li-S batteries. •Candle flame generated Fe and Co single atoms supported in soot (Fe-CS and Co-CS).•Porous Fe-CS and Co-CS as novel host with high sulfur loading.•Fe-CS and Co-CS facilitate reaction kinetics and mitigate shuttle effect.•Assembled Li-S pouch cell with improved electrochemical performance.