Highly Flexible and Self-Healing Supercapacitor Enabled by Physically Crosslinking Polymer Hydrogel Electrolyte

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Flexible supercapacitors require advanced materials for enhanced mechanical and self-healing properties.
• Current fabrication methods often face challenges in achieving both flexibility and durability.

Purpose of the Study:

• To fabricate a self-healable conductive hydrogel for flexible supercapacitors.
• To investigate the mechanical, electrical, and self-healing properties of the hydrogel.
• To develop a non-laminated, self-healing supercapacitor with improved performance.

Main Methods:

• Fabrication of a poly N-hydroxyethyl acrylamide (PHEAA) based conductive hydrogel with a dual-network structure.
• In-situ growth of an electrode film onto the hydrogel.
• Characterization of hydrogel properties including stretchability, ionic conductivity, and self-healing capability.
• Testing of the supercapacitor's performance under various mechanical stresses (bending, punching) and after repeated cutting-healing cycles.

Main Results:

• The PHEAA hydrogel demonstrated excellent stretchability (723%) and high ionic conductivity (21.8 mS/cm).
• A non-laminated, flexible, and self-healing supercapacitor was successfully fabricated using the hydrogel.
• The supercapacitor maintained stable operation under bending and punching, with an areal capacitance of 253.1 mF/cm².
• Capacitance retention reached 80% after five cutting-healing cycles, with the device powering a clock post-healing.

Conclusions:

• The developed self-healable hydrogel is a promising electrolyte for advanced flexible supercapacitors.
• The non-laminated structure and intrinsic self-healing ability enhance device durability and reliability.
• This work paves the way for robust and repairable energy storage devices.