Published online 20 April 2015
Scientists make new hybrid supercapacitors that offer fast, high-charge storage and can be fitted inside thin electronic devices.
Researchers from University of California and Cairo University have created a new kind of hybrid supercapacitor and microsupercapacitor that can fit inside paper-thin electronics1.
These supercapacitors and microsupercapacitors have faster and much higher charge storage efficiencies than existing commercial supercapacitors.
The team first created three-dimensional graphene electrodes by focusing laser beams on a DVD coated with a graphite oxide film. They then electrochemically deposited manganese dioxide nanoparticles on the laser-carved graphene electrodes, forming hybrid graphene electrodes.
To make the supercapacitors, they placed two electrolyte-soaked hybrid electrodes face-to-face separated by a porous membrane. For the microsupercapacitors, they placed the hybrid electrodes side by side like interwoven fingers.
The supercapacitors retained 96% of their original charge storage efficiencies after 10,000 cycles of charging and discharging and exhibited six times the energy density of commercial carbon-based supercapacitors. The microsupercapacitors showed double the charge storage capacity of a lithium thin-film microbattery.
“These supercapacitors can be merged with solar cells to power off-grid street lighting and are potentially useful for hybrid electric vehicles, or as backup power sources for buildings, military and space applications," says Maher EI-Kady, the lead author of the study. The microsupercapacitors can also be fitted to a drug-loaded rechargeable adhesive bandage to supply current for the continuous release of drugs.
EI-Kady, M. F. et al. Engineering three-dimensional hybrid supercapacitors and microsupercapacitors for high-performance integrated energy storage. Proc. Natl Acad. Sci. USAhttp://dx.doi.org/10.1073/pnas.1420398112 (2015).