Gelatin-Based Freeze-Resistant Hydrogel Supercapacitors with Oriented Porous Structure

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-in-one hydrogel-based supercapacitors require high capacity, mechanical flexibility, and anti-freezing properties.
• Existing designs often compromise these critical characteristics.

Purpose of the Study:

• To develop a mechanically flexible, freeze-resistant, all-in-one hydrogel-based supercapacitor with enhanced areal capacity.
• To investigate the role of an oriented porous structure in improving supercapacitor performance.

Main Methods:

• Fabrication of a gelatin-based hydrogel electrolyte using a facile gelation-directional-freezing process.
• In situ polymerization of polypyrrole (PPy) onto the hydrogel electrolyte to create the all-in-one supercapacitor.
• Incorporation of a glycerol/water binary solvent for anti-freezing properties.

Main Results:

• The oriented porous structure significantly improved ionic conductivity and electrode-electrolyte interaction, leading to 3.5 times higher areal capacitance compared to non-oriented structures.
• The supercapacitor demonstrated excellent capacitance retention (77.2%) at -23 °C.
• The device maintained performance after 100 cycles of mechanical stress (stretching, compression, bending).

Conclusions:

• The oriented porous structure in gelatin hydrogels is a highly effective strategy for enhancing supercapacitor performance.
• The developed supercapacitor exhibits promising anti-freezing properties, mechanical flexibility, and structural stability for practical applications.
• This work paves the way for advanced flexible and wearable energy storage devices.