Dawson-type polyoxometalate modified separator for anchoring/catalyzing polysulfides in high-performance lithium-sulfur batteries

Considering ultrahigh energy density as well as the cost-effectiveness of lithium-sulfur batteries (Li-S, LSBs), it is considered the most outstanding battery. However, the shuttling behavior and sluggish conversion of poly -sulfides (LiPSs), and the dendrite formation seriously impede the practical applications of LSBs. The modified separator is an effective method to solve the above problems. Herein, we propose a Dawson-type poly-oxometalate (K6P2W18O62, P2W18) modified polypropylene membrane (P2W18/PVDF/PP) with multiple func-tions for inhibiting the diffusion of LiPSs, promoting the redox kinetics of LiPSs conversion, avoiding the dendrite formation, and promoting Li+ rapid transfer. Based on spectroscopic techniques as well as electrochemical dates, it was confirmed that P2W18 can effectively adsorb LiPSs and accelerate LiPSs conversion kinetics to improve the electrochemical performance of LSBs. As a result, LSBs with P2W18/PVDF/PP separator show an initial specific capacity of 724 mAh g-1 at 3.0 C with excellent cycling stability over 400 cycles. The result offers a new perspective for exploring the role of Dawson-type polyoxometalate in extending cycling life and increasing specific capacity in LSBs.