An amorphous carbon nitride/NiO/CoN-based composite: a highly efficient nonprecious electrode for supercapacitors and...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Transition metal oxides/nitrides are promising for energy storage due to low cost and good corrosion resistance.
• Graphitic carbon nitride is a non-metallic polymer used in energy and environmental fields.
• Developing efficient and economical electrode materials is crucial for electrochemical energy storage and conversion.

Purpose of the Study:

• To synthesize a novel amorphous carbon nitride/NiO/CoN-based composite (Ni-Co-CN).
• To evaluate the capacitive performance and electrocatalytic activity of the Ni-Co-CN composite for the oxygen evolution reaction (OER).
• To investigate the underlying mechanisms contributing to the material's enhanced electrochemical properties.

Main Methods:

• In situ fabrication of Ni-Co-CN composite via one-step pyrolysis.
• Electrochemical characterization including cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) tests.
• Electrocatalytic testing for OER, including overpotential and durability measurements.
• Density functional theoretical (DFT) calculations to understand performance enhancement.

Main Results:

• The optimized Ni-Co-CN electrode exhibited an ultra-high areal specific capacitance of 18.8 F cm-2 at 2 mA cm-2.
• The electrode retained 91.4% of its capacitance after 10,000 CV cycles, demonstrating excellent stability.
• As an OER electrocatalyst, Ni-Co-CN achieved an overpotential of 195 mV at 10 mA cm-2 with less than 1% potential loss over 60 hours.
• DFT calculations indicated that fast redox reactions, surface defects, and porous structures contribute to the performance.

Conclusions:

• The Ni-Co-CN composite is a highly efficient and stable electrode material for electrochemical energy storage.
• The material demonstrates excellent electrocatalytic activity for the oxygen evolution reaction (OER).
• This work presents a cost-effective strategy for developing advanced electrode materials by combining transition metals with carbon-based structures.