Capacitors--one of the most common methods of short-term energy storage--store energy by accumulating electrostatic charges on two parallel metal plates. Thin film technology is important in the development of high energy density capacitors, because capacitors typically have low specific energy and hence require massive systems for delivery of large total energy.
The ability to tailor material structures at the molecular level with thin film and other micro- and nanotechnologies will increase not only capacitor energy storage capabilities, but the ability to integrate microsize power systems with sensors and actuators to produce very small systems for such applications as surveillance, and detection and warning of hazardous agents; centimeter size devices with limited mobility could be dispersed by the thousands to cover an area with a detector net.
In commercial markets, capacitors are an important contender for power source of clean vehicles. They are an environmentally friendly technology which may enable zero- emission vehicles, which is important to improving environmental quality, as well as to improving competitiveness of U.S. automobile manufacturers in U.S. and world markets if environmental regulation becomes stricter and more prevalent. They also contribute to a reduction in dependence on imported oil supplies. In addition, capacitor energy storage systems are being developed for systems requiring high peak power from burst mode operation, such as pulsed weapons.
The United States is the world leader in high-power capacitors, especially those suited for military applications. While few other countries offer any competition, Japan and Europe (France, Germany, and the United Kingdom) are doing some promising work in dielectric materials. Japan is behind the United States and is losing ground.