High-Capacity and Stable Sodium-Sulfur Battery Enabled by Confined Electrocatalytic Polysulfides Full Conversion |
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| Authors: | Zhanpeng Huang Bin Song Hong Zhang Fan Feng Wenli Zhang Ke Lu Qianwang Chen |
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| Affiliation: | 1. Institutes of Physical Science and Information Technology, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Anhui University, Hefei, 230601 China;2. Laboratory of Nanoscale Biochemical Analysis, Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology (NANO-CIC), Soochow University, Suzhou, 215123 China;3. School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 China;4. Guangzhou Key Laboratory of Clean Transportation Energy Chemistry, School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 China;5. Institutes of Physical Science and Information Technology, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Anhui University, Hefei, 230601 China Hefei National Laboratory for Physical Science at Microscale and Department of Materials Science & Engineering, University of Science and Technology of China, Hefei, 230026 China |
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| Abstract: | The efficient polysulfide capture and reversible sulfur recovery during reverse charging process are critical to exploiting the full potential of room temperature Na S batteries. Here, based on a core-shell design strategy, the structural and chemical synergistic manipulation of sodium polysulfides quasi-solid-state reversible conversion is proposed. The sulfur is encapsulated in the multi-pores of 3D interconnected carbon fiber as the core structure. The Fe(CN)64−-doped polypyrrole film serves as a redox-active polar shell to lock up polysulfides and promote complete polysulfide conversion. Importantly, the short-chain Na2S4 polysulfides are reduced to Na2S directly leaving with a small fraction of soluble intermediates as the cation-transfer medium at the core/shell interface, and freeing up formation of solid Na2S2 incomplete product. Further, the redox mediator with open Fe species electrocatalytically lowers the Na2S oxidation energy barrier and renders the high reversibility of electrodeposited Na2S. The tunable quasi-solid-state reversible sulfur conversion under versatile polymer sheath greatly enhances sulfur utilization, affording a remarkable capacity of 1071 mAh g−1 and a stable high capacity of 700 mAh g−1 at 200 mA g−1 after 200 cycles. The confined electrocatalytic effect provides a strategy for tuning electrochemical pathway of sulfur species and guarantees high-efficiency sulfur electrochemistry. |
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| Keywords: | confined electrocatalysis core-shell structures Na?S batteries polysulfide manipulation reaction kinetics |
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