- Simple method for making vertically aligned graphene-carbon fiber electrodes (VGCFs) for flexible supercapacitors
- Safely made with aqueous electrolytes (not flammable, toxic organic solvents)
- Enables 100 percent capacitance retention after 100,000 electrochemical cycles
Researchers at the University of Central Florida have developed a simple, low-cost method of creating electrodes for flexible, robust supercapacitors. The UCF invention resolves the performance and safety issues associated with producing supercapacitors for wearable electronic devices. It also offers a way to build commercially available supercapacitors with high specific capacitance and long cycle life. These capabilities are essential for applications such as microelectronics and hybrid electric vehicles.
Existing fabrication methods require tedious material processing and may use flammable and toxic solvents. Still, others result in electrodes with inferior cycle life or do not meet the bendability requirements of wearable devices. In contrast, the UCF method uses safer aqueous electrolytes to produce vertically aligned graphene-carbon fiber electrodes (VGCFs). Electrodes made with the hybrid material retain 100 percent capacitance after 100,000 electrochemical cycles and 100 percent high-specific capacitance retention after 1,000 bending cycles.
The UCF invention comprises a simple and facile method for fabricating highly efficient supercapacitor electrodes. It includes using pristine graphene sheets that are vertically stacked and electrically connected onto any electrically conducting substrate. The technique results in 3D mesoporous VGCF nanostructures. The graphene displays good adhesion and resists delamination during severe bending and twisting conditions. In an example process, graphene sheets are electrophoretically deposited onto a carbon fiber substrate using nickel ions as the charged elements in the deposition bath. The resulting 3D architecture enables faster and efficient electrolyte-ion diffusion with a specific capacitance of 333.3 F/g. Also, compared to a supercapacitor with metallic current collectors, the supercapacitor is substantially less weight.
The research team is looking for partners to develop the technology further for commercialization.
- Enables robust supercapacitors with high performance and high flexibility
- Safe and efficient
- Improves electrochemical performance without adopting strategies such as doping, surface functionalization and nanocomposites
- Automotive body parts that can store energy
- Wearable textiles