Proton Hydrogel-Based Supercapacitors with Rapid Low-Temperature Self-Healing Properties

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Hydrogel-based supercapacitors offer potential for safe, portable energy storage.
• Cryogenic temperatures limit hydrogel electrolyte conductivity and self-healing due to restricted polymer chain movement and bond reconstruction.

Purpose of the Study:

• To develop a highly conductive, self-healing hydrogel electrolyte for supercapacitors that functions effectively across a wide temperature range, including subzero conditions.
• To address the limitations of current hydrogel electrolytes in terms of low-temperature performance and durability.

Main Methods:

• Synthesis of a polyacrylamide-phytic acid (PAAm-PA) hydrogel electrolyte.
• Characterization of ionic conductivity, self-healing efficiency, and adhesion properties.
• Fabrication and testing of integrated hydrogel-based supercapacitors at various temperatures.

Main Results:

• The PAAm-PA hydrogel exhibited high ionic conductivity (102.0 mS cm^-1) via the Grotthuss mechanism.
• The hydrogel demonstrated rapid self-healing (79.4% efficiency at -20 °C) and excellent adhesion.
• Supercapacitors achieved a specific capacitance of 139.5 mF cm^-2 at 25 °C and retained 92.1% capacitance after self-healing cycles at -20 °C.
• The devices showed remarkable stability with only 6.4% capacitance degradation after 5000 cycles at -20 °C.

Conclusions:

• The developed PAAm-PA hydrogel electrolyte enables high-performance, self-healing supercapacitors functional at subzero temperatures.
• This research provides a viable pathway for creating robust, flexible energy storage solutions for extreme environments.
• The study highlights the potential of phytic acid in designing advanced hydrogel electrolytes for energy applications.