Amorphous Fe-Phytate Enables Fast Polysulfide Redox for High-Loading Lithium Sulfur Batteries |
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| Authors: | Guangfeng Zeng Dongjiang Chen Cheng Zhen Chao Feng Yashuai Pang Weidong He |
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| Affiliation: | 1. Collage of Chemistry and Food Science, Yulin Normal University, Yulin, 537000 P. R. China;2. State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 P. R. China;3. Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055 P. R. China;4. School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054 P. R. China;5. National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin, 150080 P. R. China |
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| Abstract: | Utilizing catalysts to accelerate polysulfides conversion are of paramount importance to eliminate the shuttling effect and improve the practical performance of lithium-sulfur (Li-S) batteries. The amorphism, attributes to the abundant unsaturated surface active sites, has recently been recognized as a contribution to increase the activity of catalysts. However, the investigation on amorphous catalysts has received limited interest in lithium-sulfur batteries due to lack of understanding of their composition structure activity. Herein, a amorphous Fe-Phytate structure is proposed to enhance polysulfide conversion and suppress polysulfide shuttling by modifying polypropylene separator (C-Fe-Phytate@PP). The polar Fe-Phytate with distorted VI coordination Fe active centers strongly intake polysulfide electron by forming Fe S bond to accelerate the polysulfide conversion. The surface mediated polysulfides redox gives rise to a higher exchange current in comparison with carbon. Furthermore, Fe-Phytate owns robust adsorption to polysulfide and effectively reduce the shuttling effect. With the C-Fe-Phytate@PP separator, the Li-S batteries exhibit an outstanding rate capability of 690 mAh g−1 at 5 C and an ultrahigh areal capacity of 7.8 mAh cm−2 even at a high sulfur loading of 7.3 mg cm−2. The work provides a novel separator for facilitating the actual applications of Li-S batteries. |
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| Keywords: | amorphous materials lithium-sulfur batteries polar Fe-O-P bond polysulfides conversion polysulfides trapping |
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