Interfacial self-healing engineered bifunctional quasi-solid electrolyte for high-performance lithium-sulfur...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur batteries (LSBs) offer high energy density but suffer from polysulfide shuttle and lithium dendrite issues.
• Existing quasi-solid-state electrolytes face challenges in mechanical strength and ion transport.
• Developing stable and efficient electrolytes is crucial for practical LSB applications.

Purpose of the Study:

• To develop a bifunctional quasi-solid-state electrolyte with interfacial self-healing properties for LSBs.
• To enhance the electrochemical performance and stability of LSBs by addressing key limitations.
• To investigate the mechanisms behind the improved performance using computational methods.

Main Methods:

• Fabrication of a Polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP)/Graphene oxide (GO)/Copper benzene-1,3,5-tricarboxylate (HKUST-1)/Borate bond Quasi-Solid-State Electrolyte (PHGKB QSSE).
• Synergistic interaction design between borate bonds, GO, and HKUST-1 within the PVDF-HFP matrix.
• Electrochemical performance testing, including cycling stability, capacity retention, and dendrite suppression.
• Density functional theory (DFT) calculations to elucidate interfacial mechanisms.

Main Results:

• The PHGKB QSSE demonstrated excellent mechanical properties with 312% elongation at break.
• Achieved high areal capacity of 3.65 mAh cm⁻² and excellent thermal stability up to 200 °C.
• Exhibited superior cycling stability with a low capacity decay rate of 0.052% per cycle over 500 cycles.
• DFT calculations confirmed enhanced polysulfide anchoring and Li⁺ transport kinetics.

Conclusions:

• The developed interfacial self-healing strategy effectively suppresses polysulfide shuttle and lithium dendrites.
• The PHGKB QSSE significantly improves the electrochemical performance and stability of LSBs.
• This molecular-level design approach offers a promising pathway for high-performance quasi-solid-state LSBs.