High performance aqueous supercapacitor based on nitrogen-doped coal-based activated carbon electrode materials

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Supercapacitors (SCs) are crucial energy storage devices.
• Coal-based activated carbon is a potential material for SCs.
• Improving the performance of activated carbon-based SCs is an active research area.

Purpose of the Study:

• To develop a low-cost, modified nitrogen-doped coal-based activated carbon (MACN) for supercapacitors.
• To investigate the effect of nitrogen doping on the electrochemical performance of coal-based activated carbon.
• To evaluate the specific capacitance, life cycle, and rate performance of the fabricated supercapacitors.

Main Methods:

• KOH/H2O co-activation of lignite to produce modified nitrogen-doped coal-based activated carbon (MACN).
• Density functional theory (DFT) calculations to understand structural and chemical changes.
• Fabrication of supercapacitors using MACN and evaluation of their electrochemical performance (specific capacitance, cycle life, rate capability).

Main Results:

• Nitrogen doping increased the internal disorder (ID/IG up to 0.99) and structural stability of the activated carbon.
• MACN exhibited a high specific surface area (2129 m²/g), abundant micropores, and significant N-doping (9.59 wt%).
• The MACN-based supercapacitor achieved a high specific capacitance of 323 F/g at 0.5 A/g, a 64.8% improvement over undoped carbon, and an energy density of 10 Wh/kg at 250 W/kg.

Conclusions:

• Nitrogen doping is an effective strategy to enhance the electrochemical performance of coal-based activated carbon for supercapacitors.
• The developed MACN material offers a promising low-cost solution for high-performance energy storage.
• The study demonstrates the potential of modified coal-based activated carbon in advancing supercapacitor technology.