This technology involves separating large-area graphene oxide sheets with an average lateral size of approximately 47㎛ from graphite without fragmentation, then mixing them with VO2 nanobelts to create a porous electrode film. The key is to sort the sheets by size using only thermal expansion and stepwise centrifugation, eliminating the need for ultrasonication.
Graphene oxide obtained via the conventional Hummers' method typically fragments into pieces smaller than 1㎛ during exfoliation, resulting in high contact resistance between sheets. This has historically limited the ability to sufficiently enhance the electrical conductivity and specific capacitance of graphene electrodes.
By increasing the sheet size to reduce tunneling barriers, this technology lowers the film's sheet resistance by approximately 100 times and doubles the specific capacitance (from 385 to 769 F/g) compared to small-area graphene. Applicable to hybrid supercapacitors, next-generation batteries, transparent electrodes, and touchscreens, it enhances both the charge-discharge performance and cycle stability of high-power energy storage devices.
This invention was developed with support from the Ministry of Education, Science and Technology for research on the manufacturing and properties of self-assembled graphene nanocomposite films.
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