标题：Manipulating Polysulfide Conversion with Strongly Coupled Fe3O4 and Nitrogen Doped Carbon for Stable and High Capacity Lithium–Sulfur Batteries
作者：Lu, Ke ;Zhang, Hong ;Gao, Siyuan ;Ma, Houyi ;Chen, Junzheng ;Cheng, Yingwen
作者机构：[Lu, Ke ;Gao, Siyuan ;Cheng, Yingwen ] Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb; IL; 60115, United States;[Chen, 更多
来源：Advanced Functional Materials
摘要：Li–S batteries are among the most promising energy storage technologies but their commercialization faces substantial challenges, largely due to difficulties in controlling their reaction pathways under practical conditions. Here, the synthesis of strongly coupled Fe3O4 and N-doped carbon directly in flexible carbon cloth is demonstrated, as well as their novel use for hosting sulfur with outstanding performance for Li–S batteries. It is discovered that the synergistic effects of Fe3O4 and N-carbon bring strong adsorption toward lithium polysulfide, and ensure nearly complete conversion of short-chain polysulfide to Li2S during discharge. The Li2S solids generated on these novel hosts are extremely reactive and can be readily charged back to S without a noticeable overpotential. The critical roles of Fe3O4 and N-doped carbon are studied and direct correlations are established between their surface concentration/crystallinity and the Li2S4 to Li2S conversion capacity. This novel manipulation of polysulfide conversion allows to fabricate freestanding and flexible sulfur cathodes that deliver a specific capacity of 1316 mAh g−1 at 0.1C and stable cycling for 1000 cycles at 0.2C under a high sulfur loading of ≈4.7 mg cm−2.
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