Free-standing interconnected carbon nanofiber electrodes: new structural designs for supercapacitor application.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Supercapacitors require advanced electrode materials for higher energy and power densities.
• Carbon nanofibers (CNFs) offer promising properties but often need structural enhancement for optimal performance.

Purpose of the Study:

• To develop and characterize novel free-standing interconnected carbon nanofiber electrodes.
• To investigate the impact of multi-walled carbon nanotubes (MWCNTs) and polyvinylalcohol (PVA) on carbonized polyacrylonitrile (PAN) nanofibers for supercapacitor applications.

Main Methods:

• Electrospinning of ternary nanofiber mats comprising PAN, PVA, and varying wt% of MWCNTs.
• Carbonization of the electrospun mats to form interconnected CNF electrodes.
• Characterization of surface area, electrical conductivity, and electrochemical performance (capacitance, energy/power density, cyclic stability).

Main Results:

• Ternary composite carbonization yielded CNFs with doubled surface area and tenfold higher electrical conductivity compared to binary or neat PAN fibers.
• The optimal composition (PAN-PVA-0.3 wt% MWCNT) demonstrated the highest surface area, electrical conductivity, and capacitive performance.
• Achieved energy density of 27.8 Wh kg⁻¹, power density of 110.59 kW kg⁻¹, and 95% cyclic stability over 2000 cycles.

Conclusions:

• The interconnected CNF design significantly enhances electrical conductivity, surface area, and capacitive performance.
• Nanotube alignment, interconnected morphology, and altered graphitization contribute to improved electrochemical properties.
• This new design presents a viable free-standing electrode for electrochemical double layer capacitor (EDLC) fabrication.