Sunday, August 2, 2015

Sol-gel Capacitor Dielectric Offers Record-high Energy Storage

Here are new wonderful results on a sol gel capacitor technology that could beat batteries in the future aiming at both high power and energy density. Thanks Heiko for helping me to find this one.  Georgia Tech reports : 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.

Samples of the new hybrid sol-gel material are shown placed on a clear plastic substrate for testing. (Credit: John Toon, Georgia Tech)

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.

“This is the first time I’ve seen a capacitor beat a battery on energy density,” said Perry. “The combination of high energy density and high power density is uncommon in the capacitor world.”

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.

Publication: Yunsang Kim, et al., “Bilayer Structure with Ultra-high Energy/Power Density Using Hybrid Sol-Gel Dielectric and Charge Blocking Monolayer, (Advanced Energy Materials, 2015).

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