Sol-gel Capacitor Dielectric Offers Record-high Energy Storage
Using a hybrid silica sol-gel material and self-assembled monolayers of a common fatty acid, researchers have developed a new capacitor dielectric material that provides an electrical energy storage capacity rivaling certain batteries, with both a high energy density and high power density.
If the material can be scaled up from laboratory samples, devices made from it could surpass traditional electrolytic capacitors for applications in electromagnetic propulsion, electric vehicles and defibrillators. Capacitors often complement batteries in these applications because they can provide large amounts of current quickly.
The new material is composed of a silica sol-gel thin film containing polar groups linked to the silicon atoms and a nanoscale self-assembled monolayer of an octylphosphonic acid, which provides insulating properties. The bilayer structure blocks the injection of electrons into the sol-gel material, providing low leakage current, high breakdown strength and high energy extraction efficiency.
“Sol-gels with organic groups are well known and fatty acids such as phosphonic acids are well known,” noted a professor in the at the Georgia Institute of Technology. “But to the best of our knowledge, this is the first time these two types of materials have been combined into high-density energy storage devices.”
The research, supported by the Office of Naval Research and the Air Force Office of Scientific Research, was reported July 14 in the journal Advanced Energy Materials.
The need for efficient, high-performance materials for electrical energy storage has been growing along with the ever-increasing demand for electrical energy in mobile applicationsdefense
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