High performance supercapacitors using lignin based electrospun carbon nanofiber electrodes in ionic liquid...

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Developing sustainable and high-performance electrode materials is crucial for advanced energy storage.
• Lignin, a biomass-derived polymer, presents a promising renewable resource for carbon materials.
• Polyvinyl alcohol (PVA) can aid in processing lignin into desired nanostructures.

Purpose of the Study:

• To fabricate flexible, binder-free carbon nanofibers (ACNF) from lignin:PVA blends.
• To investigate the electrochemical performance of these ACNFs in supercapacitors.
• To optimize electrode composition and electrolyte for enhanced energy density.

Main Methods:

• Electrospinning of lignin:PVA blends followed by heat treatment.
• Stabilization, carbonization, and CO2 activation to produce ACNFs.
• Preparation and characterization of ionic liquid electrolytes.
• Fabrication and testing of coin cell supercapacitors.

Main Results:

• ACNFs derived from lignin:PVA 80:20 blend exhibited a high surface area (2170 m² g⁻¹) and mesopore volume (0.365 cm³ g⁻¹).
• All ACNFs showed high graphitization degrees, confirmed by Raman analysis.
• Modified ionic liquid electrolyte demonstrated a four-fold increase in ionic conductivity.
• Supercapacitors achieved 87 F g⁻¹ specific capacitance and a record 38 Wh kg⁻¹ energy density for lignin:PVA blends.

Conclusions:

• Flexible, binder-free ACNF electrodes can be successfully fabricated from lignin:PVA blends.
• The lignin:PVA 80:20 composition yields superior ACNFs for supercapacitor applications.
• Optimized ionic liquid electrolytes significantly enhance supercapacitor performance, achieving high energy density.