Ultra small, flexible micro-supercapacitors unveiled

The team, from the Leibniz Institute for Solid State and Materials Research in Dresden, began by examining the use of manganese dioxide as a more environmentally friendly and less expensive alternative electrode material. While manganese dioxide is not a natural choice for an electrode material (it isn't very electrically conductive, nor is it naturally flexible or strong), the scientists overcame this by vapourising it using an electron beam and then allowing the gaseous atoms to precipitate into thin, bendy films. They also incorporated very thin layers of gold into the films to improve its electrical conductivity. Tests on the new device showed that it achieved a maximum energy density and a maximum power density much higher than other solid state supercapacitors currently available. Project leader Dr Chenglin Yan commented: "The device could be applied to many miniaturised technologies, including implantable medical devices and RFID tags for self powered, miniaturised devices. "The major challenge we had to overcome in developing this technology was to obtain really high energy density on the micro scale, at a low cost. The inclusion of gold in our micro-supercapacitor makes it more expensive, so we are now looking at replacing gold with cheaper metals, such as manganese, to make the device more practical for the market."