Answer to renewable energy lies in the art of croissant making

Sustainability is today's demand and there is no doubt in that. In a new study, researchers took inspiration from the art of croissant-making to find a possible solution for the sustainable energy problem.

A kind of bread, the croissant is made by pressing and folding the dough to create a layered pastry.

And researchers applied this same technique to a dialectic capacitor, a device that stores energy like a battery.

By pressing and folding a polymer film capacitor - a capacitor with an insulating plastic film - they were able to store 30 times more energy than the best-performing commercially available dielectric capacitor, biaxially oriented polypropylene (BOPP).

The findings were published in the journal Nature Communications and showed that this is the highest energy density ever reported in a polymer film capacitor.

Renewable and sustainable energy sources like solar and wind are intermittent by nature and to make them of wider practical use it is necessary to develop efficient, low-cost and environmentally-friendly electric energy storage systems.

"With this technique, we can store large amounts of renewable energy to be used when the sun is not shining and it is not windy," said lead researcher Dr Emiliano Bilotti, from Queen Mary University of London.

Currently, there are three main energy storage options: batteries, electrochemical capacitors and dielectric capacitors.

Dielectric capacitors typically have ultrahigh power density, which makes them suitable for high power and pulse power technologies that require accumulating energy over a period of time and then releasing it very quickly. Examples include motor drives, mobile power systems, space, vehicle power systems and electrochemical guns.

However, dielectric capacitors are limited by the low amounts of energy they can currently store. This research study tackles this limitation.

Co-author Professor Mike Reece explained, "This finding promises to have a significant impact on the field of pulse power applications and could produce a step-change in the field of dielectric capacitors, so far limited by their low energy storage density."

Expensive and complex synthesis and processing routes are normally necessary to achieve high energy density in polymer film capacitors but this newly developed processing, pressing and folding, is unique for its simplicity, record high energy density and potential to be adopted by industry.