High-performance graphene-based supercapacitors made by a scalable blade-coating approach

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Graphene oxide (GO) liquid crystals (LCs) offer unique viscous properties for film fabrication.
• Scalable production of graphene-based materials is crucial for energy storage applications.

Purpose of the Study:

• To develop a scalable method for fabricating graphene-based supercapacitors.
• To compare the electrochemical performance of reduced graphene oxide (rGO) films prepared using different reduction methods.

Main Methods:

• Aqueous GO dispersions were utilized to form viscous liquid crystals.
• Blade-coating technique was employed to fabricate GO films.
• Reduced GO (rGO) films were prepared using hydrazine (HZ) or hydroiodic acid (HI) wet chemical reduction.
• Solid-state supercapacitors were assembled using rGO electrodes and carbon nanotube current collectors.

Main Results:

• The hydrazine-reduced GO (HZ-rGO) films exhibited superior performance compared to hydroiodic acid-reduced GO (HI-rGO) films.
• The enhanced capacitance of HZ-rGO is attributed to its 3D graphene sheet structure.
• Utilizing a liquid sulfuric acid electrolyte further increased capacitance to 265 F/g (52 mF/cm²).

Conclusions:

• Scalable fabrication of high-performance graphene supercapacitors is achievable using LC-GO films and blade-coating.
• HZ-rGO films are promising electrode materials for supercapacitors due to their structural advantages.
• Liquid electrolytes significantly enhance the capacitive performance of these supercapacitors.