Aqueous Supramolecular Binder for High-Performance Lithium-Sulfur Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but face challenges like electrode deformation and polysulfide shuttling.
• Current electrode preparation methods can also lead to environmental pollution, hindering practical application.

Purpose of the Study:

• To develop a water-soluble, green, and environmentally friendly binder for Li-S batteries.
• To improve the long cycle life and stability of Li-S cells by mitigating electrode degradation and polysulfide issues.

Main Methods:

• Synthesis of a supramolecular binder (HUG) by modifying guar gum (GG) with HDI-UPy, incorporating cyanate and pyrimidine groups.
• Characterization of HUG's nanonet-structure formed by covalent and hydrogen bonds, and its polysulfide adsorption capabilities.
• Fabrication and electrochemical testing of Li-S cells utilizing the HUG binder.

Main Results:

• The HUG binder effectively resists electrode bulk deformation due to its 3D nanonet-structure.
• HUG demonstrates strong adsorption of polysulfides, significantly inhibiting the shuttle effect.
• Li-S cells with HUG achieved a high reversible capacity of 640 mAh g⁻¹ after 200 cycles at 1C with 99% Coulombic efficiency.

Conclusions:

• The synthesized HUG binder is a promising, sustainable solution for advanced Li-S battery electrode design.
• HUG contributes to enhanced electrochemical performance and cycle stability in Li-S batteries.
• This work paves the way for greener and more efficient Li-S battery technologies.