Constructing the quinonyl groups and structural defects in carbon for supercapacitor and capacitive deionization...

Area of Science:

• Materials Science
• Electrochemistry
• Environmental Science

Background:

• Structural defects and oxygen-containing functional groups in carbon materials are crucial for supercapacitor and capacitive deionization performance.
• Tuning these properties during pyrolysis is key for high-performance ion storage.

Purpose of the Study:

• To prepare quinonyl-dominant defective porous carbon using a sustainable precursor.
• To investigate the material's suitability for electrochemical energy storage and capacitive deionization.
• To elucidate the synergistic effects of surface groups and defects on ion adsorption.

Main Methods:

• Pyrolysis and cross-linking of lavender stem and potassium acetate.
• Electrochemical testing for supercapacitors (specific capacitance, capacitance retention).
• Capacitive deionization performance evaluation (adsorption capacity).
• Density functional theory (DFT) calculations.

Main Results:

• Prepared defective porous carbon exhibits an ultra-high specific capacitance of 401 F g^-1 at 1 A g^-1.
• Achieved high capacitance retention of 63% at 100 A g^-1 in a KOH solution.
• Demonstrated a high adsorption capacity of 25.5 mg g^-1 for NaCl in capacitive deionization.
• DFT calculations confirmed synergistic facilitation of K⁺ and Na⁺ adsorption by quinonyl groups and defects.

Conclusions:

• Quinolyl-dominant defective porous carbon derived from lavender stem is a promising electrode material for energy storage and desalination.
• Surface quinonyl groups and carbon defects synergistically enhance ion adsorption and electrochemical performance.
• This study offers insights into designing advanced porous carbon materials for electrochemical applications.