Dawson-type polyoxometalate modified separator for anchoring/catalyzing polysulfides in high-performance lithium-sulfur batteries. (1st October 2022)

• Record Type: Journal Article
• Authors: Zhang, Hangyu; Ma, Zhiyuan; Duan, Suqin; Liu, Yi; Jiang, Xinyuan; Zhou, Qiuping; Chen, Ming; Ni, Lubin; Diao, Guowang
• Is Part Of: Electrochimica acta. Volume 428(2022)
• Publication Date: 2022-10-01
• Subjects: Lithium-sulfur batteries -- Shuttle effect -- Dawson-type polyoxometalate -- Modified separator -- Electrospinning; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2022.140868
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Dawson-type POM modified polypropylene separator for Li-S batteries was prepared through the electrospinning method. The P2 W18 /PVDF/PP separator shows a high specific capacity and a low capacity decay rate. The P2 W18 /PVDF nanofiber demonstrated efficient adsorption and catalytic effect towards LiPSs. Abstract: 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 polysulfides (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 polyoxometalate (K6 P2 W18 O62, P2 W18 ) modified polypropylene membrane (P2 W18 /PVDF/PP) with multiple functions 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 P2 W18 can effectively adsorb LiPSs and accelerate LiPSs conversion kinetics to improve the electrochemical performance of LSBs. As a result, LSBs with P2 W18 /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. Graphical abstract: The P2 W18 /PVDF nanofiber acts as interlayer to trap and catalyze conversion from soluble LiPSs to insoluble Li2 S during discharge-charge process, which effectively suppresses the shuttle effect and protects the lithium anode for stable cycling life in the lithium-sulfur batteries. Image, graphical abstract