Supercapacitors – key to renewable energy
Researchers at the University of Canterbury are investigating energy storage devices so they can provide greater renewable energy options.
Professor Alison Downard and Dr Paula Brooksby have received a $739,000 Marsden fund grant to research supercapacitors energy storage devices.
They will lay the groundwork for enhanced supercapacitor devices. Supercapacitors are used in situations where bursts of energy are required, such as hybrid vehicle braking systems and defibrillators.
“Renewable energy sources are playing an increasing role in meeting the global energy demand,” Professor Downard says.
“To fully exploit renewable energy sources such as wind and solar, efficient and costeffective energy storage is essential because renewable energy is not necessarily generated at the place and time when we need it, so storage is required.
“Current energy storage capabilities have to be improved to match the advance in renewable energy generation. Supercapacitors can be part of the energy storage solution. Compared with batteries, existing supercapacitors have low energy density, but they can be rapidly recharged and have long charge-recharge lifetimes.
“The energy density of a super-capacitor is directly dependent on the area of its electrodes. The key to increasing the storage capability of supercapacitors is maximising the area of electrodes.
“Graphene, a super-thin single layer of graphite, has the highest theoretical capacitance of any material and so is ideal for constructing supercapacitors.”
However, the problem with graphene is that the sheets clump together and so most of its surface area is lost. The challenge faced by scientists is to arrange them in a way that maximises the capacitance (electrical charge storage).
“We have designed novel strategies for stacking carefully spaced graphene sheets upright on electrode surfaces. We can tune the spacing between sheets so we can maximise the capacitance,” Professor Downard says.
Their research will be carried out over the next three years and by 2017 UC will have its new $212 million Regional Science and Innovation Centre where the chemistry department will be based.