Researchers from RMIT University in Melbourne, Australia have developed a revolutionary model that might have broken the impasse in storage technologies. The device, a new type of electrode, was inspired by an American fern and could put solar firmly on the map as a total energy solution. Existing storage technologies’ capacity could be boosted by up to 30 times with the new device.

The prototype, based on graphene, could also pave the way for the improvement of flexible thin film “all in one” solar capture and storage. This would bring scientists a step closer to developing laptops, smart phones, buildings and cars that are completely self- powered.

The new device works with supercapacitors. These supercapacitors charge and discharge power much faster than traditional batteries do. Solar has been combined with supercapacitors in the past, but their wider use as a storage solution has until now been restricted because of their limited capacity.

Min Gu, a professor at RMIT noted that their new design draws on nature’s own brilliant solution to the challenge of filling a space in a way that is most efficient. This is done through complex self-repeating patterns known as “fractals”.

Gu is the Associate Deputy Vice-Chancellor for Research Innovation and Entrepreneurship at RMIT and the leader of the Laboratory of Artificial Intelligence Nanophotonics. He explained that the leaves of the western sword fern are very efficient for transporting water around the plant and storing energy, as they are densely packed with veins.

The research team’s prototype is based on the fractal shapes, which are self-replicating, similar to the mini structures within snowflakes. This design, which is naturally efficient, was used at a nano level to improve solar energy storage.









The first application the team attempted was combining the electrode with supercapacitors. Their experiments demonstrated that the prototype could drastically increase their storage capacity by 3000 percent up from current capacity limits.

Supercapacitors with their capacity boosted would boost both quick burst energy release and reliability in the long term. This would make them ideal alternatives for solar power storage, as they could be used when someone wants to for example, use solar energy on a cloudy day.

When the laser-reduced fractal-enabled graphene electrodes are joined with supercapacitors, they have minimal leakage and can hold the stored charge for longer. The fractal design was based on the self-repeating shape of the veins of the western sword fern, Polystichum munitum, which is native to western North America.

Litty Thekkekara, a PhD researcher and lead author of the paper noted that the prototype’s potential applications were numerous as it was based on flexible thin film technology.

Thekkekara found that using the prototype with a solar cell to provide a total on-chip energy storage and harvesting solution was the most exciting possibility of the technology.

She added that although that can already be done with existing solar cells, the current solution is rigid and bulky. The real potential of the electrode lies in integrating the prototype with flexible thin film solar. This technology is however still in its infancy.

Flexible thin film solar could be used anywhere that can be imagined, from car panels to building windows, smart watches to smart phones. Charging stations would no longer be required for hybrid cars, nor would batteries be used to charge phones.

The storage part of the challenge has been solved with the flexible electrode prototype. The team has also demonstrated that they can work with solar cells without performance being affected negatively. The focus now needs to shift to flexible solar energy. This would allow the team to work towards achieving their vision of solar reliant electronics that is self-powered.

The study was published in the journal Scientific Reports.

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