Lignin-Based Gel Polymer Electrolyte for Cationic Conductivity

Area of Science:

• Materials Science
• Polymer Chemistry
• Electrochemistry

Background:

• Lignin, a natural biopolymer from *Pinus sylvestris*, is an abundant and renewable resource.
• Developing sustainable electrolytes is crucial for next-generation energy storage devices.
• Existing electrolytes often face limitations in conductivity and ion transport.

Purpose of the Study:

• To prepare and characterize a gel-polymer electrolyte (GPE) using chemically modified lignin.
• To investigate the ionic conductivity and ion transport mechanisms within the lignin-based GPE.
• To evaluate the potential of this novel biopolymer electrolyte for electrochemical applications.

Main Methods:

• Sulfonation and chlorination of lignin to enable mono-ionic conductivity.
• Synthesis of a composite gel-polymer electrolyte with polyvinyl alcohol.
• Impedance spectroscopy to determine electronic characteristics and conductivity.
• Qualitative and quantitative analysis, including quantum-chemical calculations.

Main Results:

• Successfully synthesized a lignin-based GPE with predominantly cationic conductivity.
• Achieved a specific volume conductivity of 2.48 × 10^-4 S cm^-1.
• Attained a record lithium cation transference number (tLi+) of 0.89.
• Established correlations between chemical modification, GPE structure, and ionic conductivity.

Conclusions:

• Chemically modified lignin can serve as a viable matrix for high-performance gel-polymer electrolytes.
• The developed GPE exhibits competitive conductivity and superior lithium ion transport.
• This research offers insights into tailoring biopolymer electrolytes for enhanced electrochemical performance.