Facile and Scalable Synthesis Method for High-Quality Few-Layer Graphene through Solution-Based Exfoliation of...

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Graphene, a single layer of carbon atoms, possesses exceptional electronic properties but is challenging to produce defect-free.
• Traditional methods like Hummers' method for graphene oxide (GO) often introduce defects, limiting its performance.
• Stabilizing graphene in aqueous solutions is crucial for scalable applications.

Purpose of the Study:

• To develop a facile and scalable method for preparing defect-free graphene sheets.
• To stabilize exfoliated graphene in an aqueous solution using a novel polyelectrolyte precursor.
• To fabricate and characterize advanced electrode materials and supercapacitors utilizing the prepared graphene.

Main Methods:

• Exfoliation of graphite using poly(p-phenylenevinylene) (PPV-pre) as a stabilizer in aqueous solution, forming graphene/PPV-pre (GPPV-pre).
• Layer-by-layer fabrication of (GPPV-pre/GO)n film electrodes by alternating GPPV-pre and GO layers.
• Simultaneous conversion of PPV-pre and GO to conductive poly(p-phenylenevinylene) (PPV) and reduced graphene oxide (RGO) using hydroiodic acid vapor.

Main Results:

• GPPV-pre remained homogeneously dispersed in solution for over a year, with flake thicknesses of 1-10 nm and lateral dimensions of 1-2 μm.
• The GPPV-pre approach significantly reduced defects compared to graphene oxide (GO).
• Fabricated (GPPV/RGO)23 multilayer films exhibited superior electrical conductivity (483 S/cm) compared to (PPV/RGO)23 films (166 S/cm).
• Supercapacitor systems using GPPV/RGO demonstrated significantly enhanced volumetric capacitance (216 F/cm³ vs. 152 F/cm³), energy density (19 mWh/cm³ vs. 9 mWh/cm³), and power density (498 W/cm³ vs. 80 W/cm³).

Conclusions:

• The PPV-pre stabilization method offers a scalable route to high-quality, defect-free graphene.
• The resulting GPPV-pre material enables the fabrication of advanced electrodes with enhanced electrical conductivity.
• This approach significantly improves the performance of supercapacitor devices, paving the way for next-generation energy storage solutions.