Amorphous Fe-Phytate Enables Fast Polysulfide Redox for High-Loading Lithium Sulfur Batteries

Guangfeng Zeng; Dongjiang Chen; Cheng Zhen; Chao Feng; Yashuai Pang; Weidong He

doi:10.1002/smll.202302548

Amorphous Fe-Phytate Enables Fast Polysulfide Redox for High-Loading Lithium Sulfur Batteries

Small. 2023 Oct;19(43):e2302548. doi: 10.1002/smll.202302548. Epub 2023 Jun 27.

Authors

Guangfeng Zeng¹, Dongjiang Chen², Cheng Zhen³, Chao Feng⁴, Yashuai Pang⁴, Weidong He⁵

Affiliations

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.

PMID: 37376835
DOI: 10.1002/smll.202302548

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.

Keywords: amorphous materials; lithium-sulfur batteries; polar Fe-O-P bond; polysulfides conversion; polysulfides trapping.

Abstract

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