Gel polymer electrolytes for room-temperature sodium sulfur batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-sulfur batteries offer low cost and high capacity but face challenges.
• Current electrolytes suffer from sodium dendrites, sulfur shuttling, and leakage.

Purpose of the Study:

• To develop a stable gel polymer electrolyte for room-temperature sodium-sulfur batteries.
• To overcome limitations of conventional liquid electrolytes.

Main Methods:

• Poly(vinylidene fluoride-co-hexafluoropropylene)-based gel polymer electrolytes were prepared using solution casting.
• Gel polymer membranes were activated by soaking in liquid electrolyte solution.

Main Results:

• The electrolyte demonstrated high ionic conductivity (1.37 mS cm⁻¹ at ambient temperature) and a wide electrochemical stability window (4.5 V vs Na⁺/Na).
• Stable sodium ion stripping/plating was observed for over 3000 hours in symmetric cells.
• Cells achieved high initial reversible capacity (398 mA h g⁻¹) and maintained 75 mA h g⁻¹ at cycle 200 with 99.9% coulombic efficiency.

Conclusions:

• The developed gel polymer electrolyte is a promising candidate for high-performance sodium-sulfur batteries.
• This material addresses critical issues hindering practical sodium-sulfur battery applications.