New graphene based electrode to boost solar power

Melbourne: Inspired by an American fern, scientists have developed a new graphene based electrode that could boost the capacity of existing solar integrable storage technologies by 3,000 per cent.

The "groundbreaking" prototype created by researchers from RMIT University in Australia could be the answer to the storage challenge still holding solar back as a total energy solution.

The prototype also opens a new path for the development of flexible thin film all-in-one solar capture and storage, bringing us one step closer to self-powering smart phones, laptops, cars and buildings, researchers said.

The new electrode is designed to work with supercapacitors, which can charge and discharge power much faster than conventional batteries.

Supercapacitors have been combined with solar, but their wider use as a storage solution is restricted because of their limited capacity.

According to RMIT's Professor Min Gu, the new design drew on nature's own genius solution to the challenge of filling a space in the most efficient way possible - through intricate self-repeating patterns known as "fractals".

"The leaves of the western swordfern are densely crammed with veins, making them extremely efficient for storing energy and transporting water around the plant," said Gu.

"Our electrode is based on these fractal shapes - which are self-replicating, like the mini structures within snowflakes - and we have used this naturally-efficient design to improve solar energy storage at a nano level.

"The immediate application is combining this electrode with supercapacitors, as our experiments have shown our prototype can radically increase their storage capacity - 30 times more than current capacity limits," Gu added.

"Capacity-boosted supercapacitors would offer both long-term reliability and quick-burst energy release - for when someone wants to use solar energy on a cloudy day for example - making them ideal alternatives for solar power storage," he said.

Combined with supercapacitors, the fractal-enabled laser-reduced graphene electrodes can hold the stored charge for longer, with minimal leakage.

The fractal design reflected the self-repeating shape of the veins of the western swordfern, Polystichum munitum, native to western North America.

Lead author, Litty Thekkekara, said because the prototype was based on flexible thin film technology, its potential applications were countless.

"The most exciting possibility is using this electrode with a solar cell, to provide a total on-chip energy harvesting and storage solution," Thekkekara said.