N-doped Fe2(MoO4)3-decorated MoO3 nanorods via metal–organic framework-involved synthesis as a bifunctional nanoreactor for capturing and catalyzing polysulfides in lithium–sulfur batteries

Abstract

Shuttling behavior and sluggish redox kinetics of lithium polysulfides (LiPSs) are fundamental reasons hindering the application of lithium–sulfur batteries (LSBs). A functional interlayer, introduced between the electrode and separator, fabricated by materials with efficient polysulfide trapping-catalyzing capacity is an available method to alleviate the above problems. In this work, unique N-doped, Fe₂(MoO₄)₃-decorated MoO₃ nanorods (N-MoO₃@Fe₂(MoO₄)₃) are reported as interlayer materials. The MoO₃ component mainly contributes to adsorption and ensures conductivity, while the Fe₂(MoO₄)₃ component is used to further enhance the catalytic activity. In addition, nitrogen doping increases the polarization of the material and hence enhances the adsorption capacity. Combining these advantages of such a heterostructure material, cells with a N-MoO₃@Fe₂(MoO₄)₃ coated separator exhibit an ultrahigh initial capacity (1601.4 mA h g⁻¹ at 0.1C) and favorable cycling stability (642.5 mA h g⁻¹ at 1C for 600 cycles with a degradation rate of 0.049% per cycle), achieving effective adsorption and rapid kinetics of LiPSs.