Metal-Organic-Framework-Mediated Fast Self-Assembly 3D Interconnected Lignin-Based Cryogels in Deep Eutectic Solvent...

Area of Science:

• Materials Science
• Sustainable Chemistry
• Energy Storage

Background:

• Lignin, a sustainable biopolymer, is abundant but underutilized.
• Developing robust and functional materials from lignin is crucial for a circular economy.
• Existing methods for lignin-based materials often lack mechanical integrity or scalability.

Purpose of the Study:

• To develop a cost-effective and sustainable method for producing mechanically robust lignin-based cryogels.
• To investigate the use of deep eutectic solvents (DES) and metal-organic frameworks (MOFs) in lignin gel synthesis.
• To evaluate the energy storage performance of the resulting lignin-based carbon cryogels.

Main Methods:

• Synthesis of lignin-resorcinol-formaldehyde (LRF) gels using a choline chloride-lactic acid (ChCl-LA) DES.
• Incorporation of metal-organic frameworks (MOFs) to accelerate gelation.
• Production of copper-doped LRF carbon cryogels.
• Characterization of cryogel structure and electrochemical performance.

Main Results:

• A robust 3D interconnected string-bead-like framework was achieved.
• DES molar ratio and MOF doping significantly influenced gelation time and properties.
• LRF carbon cryogels with 1.2 nm micropores were produced in just 4 hours.
• Copper-doped cryogels exhibited a specific capacitance of 185 F g⁻¹ at 0.5 A g⁻¹ with excellent cycling stability.

Conclusions:

• A novel, rapid, and sustainable method for synthesizing high-lignin-content carbon cryogels was established.
• The developed cryogels demonstrate significant potential for use in high-performance energy storage devices.
• This approach offers a viable pathway for valorizing lignin into advanced functional materials.