Balance Internal and Surficial Structures of Electrochemically Exfoliated Graphene for Optimal Capacitance...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Graphene is a promising electrode material for supercapacitors.
• Electrochemical exfoliation is a cost-effective and eco-friendly method for graphene production.
• Electrolyte composition critically influences graphene properties and supercapacitor performance.

Purpose of the Study:

• To investigate the effect of different anions in the electrolyte on the structural properties of electrochemically exfoliated graphene.
• To correlate graphene structure with its electrochemical capacitance performance in supercapacitors.

Main Methods:

• Electrochemical exfoliation of graphite using electrolytes with varying anions (SO₄^2-, ClO₄^-, CO₃^2-).
• Characterization of synthesized graphene's internal and surficial structures.
• Fabrication and testing of symmetric supercapacitors using the synthesized graphene electrodes.

Main Results:

• Sulfate (SO₄^2-) anions facilitated the production of graphene with the highest specific surface area and moderate oxygen groups.
• Graphene synthesized using SO₄^2- exhibited optimal double-layer capacitance and pseudocapacitance.
• Supercapacitors made with SO₄^2- derived graphene achieved an energy density of 20.47 μWh cm^-2 at 0.25 mW cm^-2.
• Perchlorate (ClO₄^-) and carbonate (CO₃^2-) anions were less effective in controlling graphene thickness and oxygen content.

Conclusions:

• The selection of anions in electrochemical exfoliation is crucial for tailoring graphene structure and enhancing supercapacitor performance.
• Sulfate anions are optimal for producing high-performance graphene electrodes for supercapacitors.
• This study offers valuable insights for optimizing graphene synthesis for advanced energy storage devices.