Single Sodium-Ion Conducting Sulfonated Polytriazole and Composite Electrolyte Membranes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium metal batteries (LMBs) face supply and cost challenges due to lithium scarcity.
• Sodium metal batteries (SMBs) are a promising alternative due to sodium's abundance and lower cost.
• Reactivity of conventional electrolytes with sodium anodes in SMBs necessitates safer electrolyte designs.

Purpose of the Study:

• To design and evaluate novel single-ion conducting polymer electrolytes (SICPEs) for sodium metal batteries.
• To investigate the performance of sulfonated graphene oxide (Na-SGO) fillers and blend composites.
• To enhance the thermal, mechanical, and dimensional stability of electrolytes for SMBs.

Main Methods:

• Development of SICPEs incorporating Na-SGO fillers and sulfonated polytriazole (PTSICPE-90).
• Evaluation of blend composites and comparison with commercial Celgard 2400.
• Measurement of Na-ion conductivity, solvent absorption, wettability, and porosity.

Main Results:

• Na-SGO filler achieved a Na-ion conductivity of 11.91 × 10⁻² Scm⁻¹ at 90 °C (solvated).
• SICPEs exhibited high solvent absorption (70 wt.%), good wettability (22.2°), and porosity (58%).
• Notable Na-ion conductivities of 0.23 × 10⁻⁵ Scm⁻¹ (nonsolvated, 30 °C) and 1.17 × 10⁻⁵ Scm⁻¹ (solvated, 40 °C) were recorded.

Conclusions:

• The developed SICPEs demonstrate superior thermal, mechanical, and dimensional stability compared to Celgard 2400.
• The unique properties of SICPEs, including high conductivity and solvent uptake, make them suitable for SMB electrolytes.
• These findings pave the way for safer and more efficient sodium metal battery technologies.