Batteries in frequently used smartphones, laptops and digital cameras need to be recharged often and can take hours to do so, and as they age, their energy storage potential diminishes. Powerful and flexible power-storage systems are a current weakness of mobile electronics and backup for the grid.
Moreover, the uses of renewable energy face a similar obstacle. Most wind, biogas and solar-power systems do not have storage capability and feed power directly into the grid, regardless of weather. Sometimes, however, the power feeds must be turned off because, otherwise, the grid would be overburdened. During such periods, valuable, clean power is lost due to the lack of storage capability.
But now, Super-Kon, an interdisciplinary research project at Martin-Luther University Halle-Wittenberg (MLU) in Germany is working to develop a so-called “Super Capacitor” to provide a solution. This long-life energy-storage system would be able to store power within seconds and keep it available without losses for long periods of time.
“Super capacitors are hardly subject to wear, do not heat up and only require a few seconds to accept or discharge energy, a fraction of the battery-charging time currently required,” said Hartmut Leipner, Super-Kon’s project manager and a lecturer and a scientific manager at the Interdisciplinary Centre for materials sciences at MLU.
The reasons for this are the operation of the energy-storage system. Conventional batteries must convert electrical energy to chemical energy to store it, whereas the energy in super capacitors is stored purely electrostatically. Therefore, super capacitors cannot have a so-called “memory effect,” like batteries that diminish over time.
To date, super capacitors are hardly used because they only have a very small storage density. This means, to date, only small amounts of energy can be stored efficiently.
“In the first two phases of the Super-Kon, we combined materials in new ways in extensive materials tests. In this manner, we were able to produce a flexible, nonconductive composite material, which is able to store more energy,” Leipner said. “After this ‘proof of concept,’ we are now testing this material in the industrial environment to further improve its properties and to test durability under environmental influences.”
To date, the scientists at MLU are already able to supply power to small devices that consume little energy, using the super capacitors.
“We are approaching higher energy densities step by step,” Leipner said. “Although the small storage devices to date work in the milliwatt region, I am confident that the first mature models can be seen in stores within the next three to five years. Small electronic devices may then already be supplied by super capacitors.”
In the parallel founders’ lab, supported by the state of Saxony-Anhalt and the EU, some doctoral candidates are already working on economically using the knowledge gained here by establishing their own companies.
“In about 10 years, we want to complete the project,” Leipner said. “By then, the development of storage modules will likely have advanced to the megawatt region so that the fast super capacitors may also be a fixed part of the energy transition.”