Raman Spectroscopy Measurements Support Disorder-Driven Capacitance in Nanoporous Carbons

Area of Science:

• Materials Science
• Electrochemistry
• Spectroscopy

Background:

• Nanoporous activated carbons are crucial for electrochemical double-layer capacitors.
• Local carbon structure significantly impacts capacitive performance.
• Previous studies suggested a correlation between structural disorder and capacitance.

Purpose of the Study:

• To validate the disorder-driven capacitance theory in nanoporous carbons.
• To investigate the utility of Raman spectroscopy for assessing carbon structure and predicting capacitance.
• To correlate structural disorder metrics with electrochemical performance.

Main Methods:

• Raman spectroscopy was employed to analyze the structural disorder of nanoporous carbons.
• Analysis focused on the D and G bands, and the I_D/I_G intensity ratio.
• Results were correlated with existing NMR data and capacitance measurements.

Main Results:

• Broader D bands in Raman spectra correlated with higher capacitance.
• Smaller I_D/I_G intensity ratios, indicative of smaller graphene-like domains, were associated with increased capacitance.
• Raman spectroscopy effectively probed domain sizes, supporting NMR findings.

Conclusions:

• Structural disorder is a key factor for achieving high capacitance in nanoporous carbons.
• Raman spectroscopy is a rapid and effective tool for screening materials for supercapacitor applications.
• The findings support the use of disorder metrics for optimizing nanoporous carbon performance.