Superbases-templated carbons doped with electrochemically active oxygen as advanced supercapacitor electrodes

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Templating is key for porous carbon synthesis, yet template surface effects on derived carbon functionality remain underexplored.
• Oxygen-doped porous carbon nanosheets (O-PCNs) are promising for energy storage but require optimized synthesis.
• The influence of template basicity on O-PCN surface chemistry and electrochemical performance needs detailed investigation.

Purpose of the Study:

• To investigate the impact of template basicity on the surface functionality of derived O-PCNs.
• To correlate template basicity with the supercapacitor performance of synthesized O-PCNs.
• To optimize O-PCN synthesis for enhanced energy storage applications.

Main Methods:

• Fabrication of nanocarbon materials using laboratory-made K/Mg(OH)2 superbases with varying K/Mg ratios as templates.
• Characterization of surface functionalities, including electrochemically active oxygen species (conjugated carbonyl and hydroxyl groups).
• Evaluation of supercapacitor performance metrics such as specific capacitance, rate capability, energy density, and cycling stability.

Main Results:

• Increasing template basicity initially enhanced active oxygen species content from 8.4 to 11.4 atom%, then decreased it.
• Microporosity of O-PCNs increased with KOH loading due to etching effects, with O-PCN-20 showing a surface area of 930 m²/g.
• O-PCN-20 exhibited excellent supercapacitor performance: 375 F/g at 1.0 A/g, 81.1% rate capability up to 20 A/g, and stable cycling over 20,000 cycles.

Conclusions:

• Template basicity significantly influences the surface chemistry and porosity of O-PCNs.
• O-PCN-20, derived from a 20% K/Mg(OH)2 template, demonstrates superior electrochemical properties due to high porosity and active oxygen content.
• These findings highlight the potential of O-PCN-20 as an advanced electrode material for high-performance energy storage devices.