Supercapacitor Using Reduced Graphene Oxide and Polymer Sponge

High-Capacity RGO Supercapacitor Electrode Based on Freeze-Dried Cellulose Sponge

This technology is a method for manufacturing supercapacitor electrodes by creating RGO/sponge composite electrodes through the capillary absorption of a reduced graphene oxide (RGO) aqueous solution into a cellulose polymer sponge, followed by freeze-drying. The resulting 3D structure, with RGO distributed throughout the porous sponge framework, ensures both a high specific surface area and effective conductive pathways for the electrode.

While supercapacitors offer the advantages of rapid charge/discharge and long cycle life, they have historically been limited by low specific energy density. Activated carbon used as an electrode material has limitations in increasing operating voltage, while metal oxides are restricted by the need for transition metals and the requirement to remain stable in strong acid electrolytes.

This technology utilizes an eco-friendly, natural pulp-based cellulose sponge as a supporting framework for RGO, enabling the implementation of composite electrodes that function in acidic, alkaline, and neutral electrolytes. It achieves an exceptionally high specific capacitance of 1200–1250 F/g and stable charge/discharge cycle performance. Applicable to auxiliary power for electric vehicles, solar energy storage, and portable electronic power modules, it paves the way for low-cost mass production of high-capacity storage electrodes through simple immersion and freeze-drying processes.

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Key Features:

• Immersing a rigid cellulose polymer sponge in a reduced graphene oxide aqueous solution to allow the solution to be absorbed into the internal pores of the sponge via capillary action
• Freeze-drying the cellulose polymer sponge that has absorbed the reduced graphene oxide aqueous solution to obtain a composite electrode for a supercapacitor
• Using an aqueous solution containing 0.3 to 0.7 mg of reduced graphene oxide per 1 ml of water and performing freeze-drying for 5 to 7 hours
• Impregnating the manufactured electrode in one of H2SO4 (acidic), KOH (alkaline), or Na2SO4 (neutral) electrolytes to obtain a supercapacitor with a specific capacitance of 1200 to 1250 F/g

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This invention was developed with support from the Ministry of Education, Science and Technology for the development of graphene-based biosensors.

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