Highly stable performance of supercapacitors from phosphorus-enriched carbons

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Supercapacitors are crucial for energy storage.
• Enhancing energy density and operational voltage is a key challenge.
• Water electrolysis limits conventional supercapacitor voltage.

Purpose of the Study:

• To develop phosphorus-rich microporous carbons (P-carbons) for enhanced supercapacitor performance.
• To investigate the impact of phosphorus doping and micropore structure on electrochemical properties.
• To achieve stable supercapacitor operation at potentials exceeding water's decomposition potential.

Main Methods:

• Preparation of P-carbons via phosphoric acid (H3PO4) activation of carbon precursors.
• Electrochemical characterization in 1 M H2SO4 electrolyte.
• Analysis using intercept-free multiple linear regression to correlate structure and performance.

Main Results:

• P-carbons exhibit significantly enhanced supercapacitive performance.
• Stable operation achieved at potentials > 1.23 V (water decomposition potential).
• Energy density increased to 16 Wh/kg from 5 Wh/kg for commercial carbon.
• Phosphorus content and specific micropore sizes (0.65-0.83 nm) strongly correlate with capacitance.

Conclusions:

• P-carbons offer a viable route to high-energy-density supercapacitors.
• Optimized micropore structure and phosphorus doping are critical for performance.
• P-carbons enable supercapacitors to operate at higher voltages, expanding their application potential.