Sustainable and robust oxalate-crosslinked quasi-solid chitosan hydrogel membrane electrolyte for durable solid-state...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid-state electrolytes are crucial for safe, high-performance electrochemical double-layer capacitors (EDLCs).
• Current synthetic polymer electrolytes face limitations in ionic conductivity and environmental compatibility.
• Bio-derived electrolytes offer a sustainable alternative for energy storage.

Purpose of the Study:

• To develop a green, scalable, and high-performance chitosan-based hydrogel electrolyte.
• To investigate the potential of potassium oxalate as an ionic crosslinker for chitosan.
• To evaluate the electrochemical properties and performance of the developed electrolyte in EDLCs.

Main Methods:

• Chitosan hydrogel membrane electrolyte (OCCME) preparation using potassium oxalate as an ionic crosslinker.
• Systematic investigation of crosslinking mechanism, structure, and properties via spectroscopic, morphological, and electrochemical analyses.
• Fabrication and testing of EDLC devices utilizing the OCCME.

Main Results:

• Optimized OCCME exhibited high ionic conductivity (4.84 mS cm⁻¹), a wide electrochemical stability window (2.10 V), and high ionic transference number (0.92).
• The electrolyte demonstrated excellent areal capacitance (300.8 mF cm⁻²), energy density (42.1 μWh cm⁻²), and cycling stability (>46,000 cycles).
• A prototype EDLC powered a red LED, confirming practical applicability.

Conclusions:

• Oxalate-based ionic crosslinking is an effective green strategy for developing advanced biopolymer electrolytes.
• The developed chitosan hydrogel electrolyte shows significant promise for sustainable energy storage applications.
• This work paves the way for next-generation, environmentally friendly energy storage devices.