Heteroatom co-doped green pea peel-derived biochar for high-performance energy storage applications

Area of Science:

• Materials Science
• Electrochemistry
• Waste Valorization

Background:

• Green pea peel (GPP) is an abundant agricultural waste suitable for biochar synthesis.
• GPP-derived biochar (GP) shows promise in wastewater treatment and supercapacitor applications.
• Heteroatom doping can enhance biochar properties, but uncontrolled doping can impede performance by clogging pores.

Purpose of the Study:

• To present the controlled synthesis of undoped, nitrogen-doped (NGP), and nitrogen-sulfur co-doped (NSGP) green pea peel biochar.
• To investigate the electrochemical performance of these biochars as electrode materials for supercapacitors.

Main Methods:

• Controlled synthesis of GP, NGP, and NSGP via carbonization and chemical activation.
• Characterization using techniques to analyze structure and properties.
• Electrochemical characterization to determine specific capacitance, energy density, and power density of electrode materials and supercapacitor devices.

Main Results:

• Synthesized GP, NGP, and NSGP exhibited nanosheet morphology with amorphous and defective structures.
• NSGP-based electrodes achieved a specific capacitance of 257.01 F g⁻¹, outperforming NGP (230.22 F g⁻¹) and GP (208.78 F g⁻¹).
• An assembled NSGP//NSGP supercapacitor device demonstrated 80.25 F g⁻¹ specific capacitance, 13.87 Wh kg⁻¹ energy density, 500 W kg⁻¹ power density, and 99.46% capacity retention over 5000 cycles.

Conclusions:

• Controlled N and S co-doping significantly enhances the electrochemical performance of green pea peel biochar.
• The improved performance is attributed to enhanced active sites and conductivity in NSGP.
• NSGP is a promising material for high-performance supercapacitor applications.