The LiTFSI/COFs Fiber as Separator Coating with Bifunction of Inhibition of Lithium Dendrite and Shuttle Effect for Li-SeS2 Battery

Abstract

The safety problem caused by lithium dendrite of lithium metal anode and the rapid capacity decay problem caused by the shuttle effect of polysulfide and polyselenide during the charge and discharge of selenium disulfide cathode limit the application of lithium selenium disulfide batteries significantly. Here, a fibrous ATFG-COF, containing rich carbonyl and amino functional groups, was applied as the separator coating layer. Density Functional Theory (DFT) theoretical calculations and experimental results showed that the abundant carbonyl group in ATFG-COF had a positive effect on lithium ions, and the amino group formed hydrogen bonds with bis ((trifluoromethyl) sulfonyl) azanide anionics (TFSI−), which fixed TFSI− in the channel, so as to improve the transfer number of lithium ions and narrow the channels. Therefore, ATFG-COF fiber coating can not only form a rapid and uniform lithium-ion flow on the lithium anode to inhibit the growth of lithium dendrites, but also effectively screen polysulfide and polyselenide ions to suppress the shuttle effect. The Li-SeS2 cell with ATFG-COF/polypropylene (ATFG-COF/PP) separator exhibited good cycle stability at 0.5 C and maintained a specific capacity of 509 mAh/g after 200 cycles. Our work provides insights into the design of dual-function separators with high-performance batteries.

Covalent Organic Framework-Based Materials for Advanced Lithium Metal Batteries

“…Consequently, this leads to a decrease in the concentration gradient resulting from the diffusion rate, ultimately mitigating the formation of lithium dendrites. Wang et al 153 synthesized carbonyl-rich ATFG-COF, which contains numerous groups and exhibits a favorable influence on lithium ions. Consequently, the ATFG-COF/PP composite material not only facilitates the rapid and homogeneous formation of lithium-ion channels on the lithium electrode, thereby impeding the growth of lithium dendrites, but also effectively hinders the shuttle effect by effectively screening polysulfide/polyselenium ions (Figure 9a).…”

Application of Covalent Organic Frameworks in Sulfur‐Based Battery Separators

“…In addition, Ke et al have synthesized a kind of ATFG‐COF fiber (synthesized from 2,4,6‐trihydroxy‐1,3,5‐benzenetrialdehyde and hydrazine) and modified it onto PP that can serve as a coating layer in Li–SeS 2 battery. [ 93 ] Experimental results and DFT theoretical calculations show that the ATFG‐COF with abundant carbonyl group could facilitate Li + transport, and trap bis[(trifluoromethyl)sulfonyl]azide anionics (TFSI − ) through the hydrogen bond generated between TFSI − and the amino group in the channel, thus narrowing the channels and promoting the Li + ‐transfer number. Hence, ATFG‐COF fiber coating can not only reduce the appearance of Li dendrites by constructing a quick and consistent Li + diffusing layer on the Li anode, but also conquer the shuttling effect by screening polysulfide and polyselenides ions.…”

Multi-sulfonated functionalized hydrophilic covalent organic framework for highly efficient dye removal from real samples

“…The lower specific surface area might be explained by the large sulfonic acid groups occupying the partial volume of the pores reducing the specific surface area of the materials. [35][36][37] Moreover, the total pore volume was calculated to be 0.97 cm 3 g À1 at P/P 0 = 0.99. Pore size distribution (PSD) analysis revealed a relatively uniform distribution of pore apertures at ca.…”