An effective implantation strategy of Mo atom in polyoxometalate to boost high-performance lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) present wide range of market and tremendous application potential. Nevertheless, the “shuttle effect” of lithium polysulfides (LiPSs) and the sluggish redox kinetics restrict their large-scale application. We report herein the Mo-substituted Keggin type H3PW10Mo2O40 (PW10Mo2) evenly decorated on the MWCNTs conductive framework by electrostatic attraction as the functional interlayer materials. W and Mo atoms in PW10Mo2 provide chemical adsorption sites for polysulfides, and density functional theory (DFT) calculations further confirm that Mo sites possess stronger capture ability to LiPSs than that of W sites. Meanwhile, the Mo implantation can effectively expedite the redox reaction of LiPSs. Furthermore, MWCNTs afford the plentiful attachment points for PW10Mo2, thus exposing abundant active sites to adsorb and catalyze polysulfides. The resulting cells demonstrate superior discharge capacity of 1064.9 mAh g−1 under 0.2C up to 100 cycles as well as excellent long-life cycling stability with low recession rate of 0.051 % under 3C up to 1000 cycles. Our work illustrates the effect of Mo atom substitution of polyoxotungstates as interlayer materials and thereby provides a new strategy for developing LSBs with superior reversible capacity and long cycling performance.