High temperature supercapacitors using water-in-salt electrolytes: stability above 100 °C

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• High-temperature operation is a critical challenge for energy storage devices.
• Water-in-salt electrolytes offer potential for enhanced electrochemical stability.

Purpose of the Study:

• To investigate the high-temperature performance of water-in-salt electrolytes in supercapacitors.
• To evaluate the operational stability and capacitance of supercapacitors at elevated temperatures.

Main Methods:

• Utilized carbon-based electrodes and commercial cell components.
• Tested supercapacitors with 21 m Li bis(trifluoromethylsulphonyl)imide (TFSI) and 21 m LiTFSI + 7 m Li trifluoromethanesulphonyl electrolytes.
• Operated devices at temperatures up to 120 °C.

Main Results:

• Supercapacitors achieved stable 2V operation at 100 °C and 120 °C.
• Gravimetric capacitances exceeded 100 F g-1 under high-temperature conditions.
• Demonstrated the viability of water-in-salt electrolytes for high-temperature energy storage.

Conclusions:

• Water-in-salt electrolytes are suitable for high-temperature supercapacitor applications.
• The investigated electrolytes provide excellent performance and stability at elevated temperatures.
• This work paves the way for advanced energy storage solutions in demanding environments.