Coaxial fiber supercapacitor using all-carbon material electrodes.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Supercapacitors are crucial for energy storage.
• Developing flexible and high-performance supercapacitors is essential for wearable electronics.
• Existing fiber supercapacitors face limitations in energy density and power delivery.

Purpose of the Study:

• To design and fabricate a novel coaxial fiber supercapacitor.
• To evaluate the electrochemical performance, including capacitance, energy density, and power density.
• To assess the mechanical stability and cycling performance for practical applications.

Main Methods:

• Fabrication of a coaxial fiber supercapacitor with carbon microfiber bundles coated with multiwalled carbon nanotubes (core) and carbon nanofiber paper (outer electrode).
• Optimization of electrode volume ratio using half-cell tests.
• Electrochemical characterization using cyclic voltammetry and galvanostatic charge-discharge measurements.
• Evaluation of performance under mechanical bending stress.

Main Results:

• Achieved a capacitance of 6.3 mF cm⁻¹ (86.8 mF cm⁻²) at a core electrode diameter of 230 μm.
• Demonstrated an energy density of 0.7 μWh cm⁻¹ (9.8 μWh cm⁻²) at a power density of 13.7 μW cm⁻¹ (189.4 μW cm⁻²).
• Exhibited negligible changes in cyclic voltammetry characteristics at 180° bending and excellent cycling stability.

Conclusions:

• The coaxial fiber supercapacitor demonstrates superior performance compared to previous reports.
• The high performance is attributed to the coaxial structure, high effective surface area, and high conductivity of all-carbon electrodes.
• This technology holds significant potential for advancing textile electronics and wearable energy storage solutions.