Synergistic catalytic conversion and chemisorption of polysulfides from Fe/Fe3C/FeN0.0324 nanocubes modified separator for advanced Li-S batteries

Lithium sulfur batteries (LSBs) have been considered as one of the most promising options for next generation high-performance batteries. However, the heavy shuttle effect and inferior redox conversion during the charge/discharge processes of the batteries have greatly hindered their further applications. In this study, to address these disadvantages of LSBs, Fe/Fe 3 C/FeN 0.0324 heterostructured nanocubes were designed and prepared through high temperature carbonization process using Prussian blue precursor. Then the Fe/Fe 3 C/FeN 0.0324 nanocubes were used to modify the commercial polypropylene (PP) separator, which can greatly catalyze the redox transformation of polysulfides and provide sufficient active sites for chemisorption . As result, the modified separator endowed LSBs with excellent rate capacity and cycle stability, delivering a high-capacity of 1025 mAh/g at 0.5 C with nearly 100% coulombic efficiency. It also displayed a superb cycling performance with a per-cycle capacity attenuation rate of 0.09% after 300 cycles. When the current density increased to 1 C with the S loading of 1.73 mg cm −2 , Fe/Fe 3 C/FeN 0.0324 -PP separator presented a satisfactory capacity decay rate of 0.05% per cycle after 1000 cycles. Besides, it also presented outstanding electrochemical performance even at high sulfur loading of 4.5 mg cm −2 . This work has provided a new avenue for the design of nanomaterials with synergistic effect of catalytic conversion and chemisorption of polysulfides for the promotion of high-performance Li-S batteries.