Preoxidation Assisted Alkali Activation Constructs Polyacrylonitrile-Based Porous Carbon for Supercapacitors

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Tailoring porous structures in polyacrylonitrile-based carbon materials is crucial for enhancing capacitive performance.
• Developing advanced carbon materials with high specific surface area and controlled porosity is essential for energy storage applications.

Purpose of the Study:

• To synthesize hierarchical porous carbons (HPCs) using a novel preoxidation-assisted alkali activation strategy.
• To investigate the effect of preoxidation temperature on the porous structure and electrochemical properties of HPCs.
• To evaluate the supercapacitor performance of the optimized HPC material.

Main Methods:

• Polyacrylonitrile (PAN) was used as a precursor for synthesizing HPCs via a preoxidation and alkali activation strategy.
• Varying preoxidation temperatures were employed to control the specific surface area and pore volume.
• Electrochemical tests were conducted to assess specific capacitance, energy density, power density, and cycle life in supercapacitor devices.

Main Results:

• The optimized HPC-300 material achieved a high BET specific surface area of 3161 m² g⁻¹ and a micropore volume of 1.45 cm³ g⁻¹.
• Electrochemical tests revealed specific capacitances of 314.1 F g⁻¹ at 1 A g⁻¹ and 213.0 F g⁻¹ at 10 A g⁻¹ in KOH electrolyte.
• Supercapacitors demonstrated high energy densities (up to 21.1 Wh kg⁻¹) and excellent capacitance retention (98.1% over 20,000 cycles).

Conclusions:

• The preoxidation coupled with alkali activation method is effective for preparing high-performance PAN-based porous carbons.
• The synthesized HPCs possess desirable properties for advanced supercapacitor applications.
• This strategy offers a promising route for developing next-generation energy storage materials.