Researchers at the University of California, Riverside found that supercapacitors, an energy storage device like batteries and fuel cells, based on transition metal oxide modified nanocarbon graphene foam electrode could work safely in aqueous electrolyte and deliver two times more energy and power compared to those commercially available today.
The foam electrode was successfully cycled over 8,000 times with no fading in performance.
Supercapacitors (also known as ultracapacitors) have garnered substantial attention in recent years because of their ultra-high charge and discharge rate, excellent stability, long cycle life and very high power density.
These characteristics are desirable for many applications including electric vehicles and portable electronics.
However, supercapacitors may only serve as standalone power sources in systems that require power delivery for less than 10 seconds because of their relatively low specific energy.
A team led by Cengiz S Ozkan and Mihri Ozkan at UC Riverside are working to develop and commercialise nanostructured materials for high energy density supercapacitors.
High capacitance, or the ability to store an electrical charge, is critical to achieve higher energy density, researchers said.
To achieve a higher power density it is critical to have a large electrochemically accessible surface area, high electrical conductivity, short ion diffusion pathways and excellent interfacial integrity. Nanostructured active materials provide a mean to these ends, researchers said.
"Besides high energy and power density, the designed graphene foam electrode system also demonstrates a facile and scalable binder-free technique for preparing high energy supercapacitor electrodes," said graduate student Wei Wang, author of the research paper.
"These promising properties mean that this design could be ideal for future energy storage applications," said Wang.
The finding was published in the journal Nature Scientific Reports.