Designing of zwitterionic proline hydrogel electrolytes for anti-freezing supercapacitors

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Hydrogel electrolytes face performance limitations at subzero temperatures due to water freezing, which drastically reduces ionic conductivity.
• This freezing issue hinders the practical application of hydrogel electrolytes in cold environments.

Purpose of the Study:

• To develop a novel anti-freezing hydrogel electrolyte with high ionic conductivity at subzero temperatures.
• To investigate the role of zwitterionic proline as an additive for enhancing low-temperature performance.

Main Methods:

• Incorporation of zwitterionic proline into hydrogel electrolyte formulations.
• Measurement of ionic conductivity at various subzero temperatures.
• Electrochemical performance testing of supercapacitors using the developed hydrogel electrolytes, including specific capacitance and cycling stability at low temperatures.

Main Results:

• Proline-based hydrogel electrolytes exhibited high ionic conductivity (4.2 mS cm⁻¹) even at -40 °C.
• Supercapacitors demonstrated high specific capacitances of 145.8 F g⁻¹ at 25 °C and 116.1 F g⁻¹ at -30 °C.
• The supercapacitors maintained 71% capacitance retention after 12,000 cycles at -30 °C, indicating excellent low-temperature stability.

Conclusions:

• Zwitterionic proline effectively prevents hydrogel electrolyte freezing and maintains high ionic conductivity at subzero temperatures.
• The developed anti-freezing hydrogel electrolytes show significant promise for low-temperature energy storage applications.
• This research opens new possibilities for reliable energy storage devices operating in extreme cold conditions.