Dielectric Capacitors Have Increased Energy Storage Ability, Nanotechnology Breakthrough
A team of researchers recently developed an advanced technique which will enable dielectric capacitors to store significantly high levels of energy using 3D features, according to a recent study.
"With our approach, we achieved an energy density of about two watts per kilogram, which is significantly higher than that of other dielectric capacitor structures reported in the literature," said Bingqing Wei, the study's researcher, professor of mechanical engineering at the University of Delaware.
Capacitors are key elements of many portable electronic devices, computing systems and electric vehicles; in some aspects they are like batteries. Even though capacitors and batteries work in different ways, they both store electrical energy. Batteries have high storage capacities, but they slowly release energy, while capacitors provides fast delivery but poor storage capacity.
In their new study, the researchers use nanotechnology to improve the energy density of dielectric capacitors, which involves an insulating material sandwiched between two conducting metal plates.
"To our knowledge, this is the first time that 3D nanoscale interdigital electrodes have been realized in practice," Wei said. "With their high surface area relative to their size, carbon nanotubes embedded in uniquely designed and structured 3D architectures have enabled us to address the low ability of dielectric capacitors to store energy."
In order for their new capacitor to work, the researchers used an interdigitated design, which is similar to interwoven fingers between two hands with "gloves," which significantly decreases the distance between opposing electrodes (conductors of electricity) and increases the ability of the capacitor to store an electrical charge.
In addition, the capacitor's new feature, a three-dimensional nanoscale electrode, has a high voltage breakdown. Therefore the integrated dielectric material (alumina, Al2O3) does not easily fail in its intended function as an insulator, according to the researchers.
"In contrast to previous versions, we expect our newly structured dielectric capacitors to be more suitable for field applications that require high energy density storage, such as accessory power supply and hybrid power systems," Wei said.
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