Non-Flammable Sodium Asymmetric Imide Salt-Based Deep Eutectic Solvent for Supercapacitor Applications.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Supercapacitors (SCs) require stable, high-performance electrolytes.
• Conventional electrolytes face challenges with flammability and safety.
• Deep eutectic solvents (DESs) present a promising alternative for energy storage applications.

Purpose of the Study:

• To develop and characterize novel deep eutectic solvents (DESs) for supercapacitor (SC) applications.
• To investigate the properties of DESs based on alkaline imide salts and ethylene carbonate.
• To evaluate the performance of SCs utilizing these new electrolytes.

Main Methods:

• Synthesis of two DESs using sodium (fluorosulfonyl) (trifluoromethanesulfonyl) imide (NaFTFSI) or sodium cyano-trifluoromethanesulfonyl imide (NaTFSICN) with ethylene carbonate (EC).
• Characterization of DES properties including volumetric, transport, and thermal stability.
• Fabrication and testing of symmetric SCs with activated carbon electrodes.

Main Results:

• The developed DESs are non-flammable, stable liquids with optimal compositions identified.
• Volumetric properties indicate strong anion-coordination without cation solvation.
• Supercapacitors achieved specific capacities of 150 F/g at 0.5 A/g and maintained 80% capacity over 100 hours at 2.4 V.

Conclusions:

• The novel DESs exhibit high organization and transport properties comparable to ionic liquids.
• These DESs provide a safe, simple, and effective electrolyte solution for advanced supercapacitors.
• The findings pave the way for next-generation energy storage devices.