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 H 3 PW 10 Mo 2 O 40 (PW 10 Mo 2 ) evenly decorated on the MWCNTs conductive framework by electrostatic attraction as the functional interlayer materials. W and Mo atoms in PW 10 Mo 2 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 PW 10 Mo 2 , 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.