Advanced Li-S Batteries Enabled by a Biomimetic Polysulfide-Engulfing Net

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Lithium-sulfur (Li-S) batteries offer high energy density but suffer from polysulfide dissolution and shuttling.
• These issues limit the practical application and cycle life of Li-S batteries.

Purpose of the Study:

• To develop a novel separator modification strategy for advanced Li-S batteries.
• To mitigate polysulfide shuttling and enhance electrochemical performance.

Main Methods:

• Grafting hydroxylated multiwalled carbon nanotubes (MWCNT-OH) with a supramolecular polymer (heptakis(6-amino-6-deoxy)-β-cyclodextrin).
• Coating the modified material onto a battery separator to create a polysulfide-engulfing net.
• Characterizing the material's structure and its effect on polysulfide adsorption and electron transfer.

Main Results:

• The modified separator demonstrated excellent rate capacities (945.5 and 625.4 mA h g⁻¹ at 2 C and 4 C).
• High areal capacities (5.86 and 7.2 mA h cm⁻²) were achieved at significant sulfur loadings (4.5 and 6.0 mg cm⁻²).
• Good cycling stability was observed with 200 cycles at 0.1 C.

Conclusions:

• Supramolecular polymer-grafted carbon provides a dynamic polysulfide adsorption mechanism.
• This strategy effectively addresses polysulfide issues, paving the way for advanced Li-S batteries.
• The biomimetic approach offers a promising direction for next-generation energy storage devices.