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

Abstract

AbstractUtilizing 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.