Researchers from Saudi Arabia’s King Abdullah University of Science and Technology (KAUST) and the U.S. University of Wisconsin-Madison have created what they call a “solar flow battery” designed to act as both a solar cell and a storage system.
The scientists have harnessed the abilities of both a solar cell and a battery into the "solar flow battery", a single device that soaks up sunlight and efficiently stores it as chemical energy for later on-demand use.
The research group said its new device can act like a standard solar cell, which produces electricity from solar radiation and also to absorb solar energy during daylight hours and store it as chemical energy to deliver later as electricity, when night falls or the sky grows cloudy.
The solar flow battery can also act like just a storage device, which can be charged by electrical energy if needed.
“Compared with separated solar energy conversion and electrochemical energy storage devices, combining the functions of separated devices into a single, integrated device could be a more efficient, scalable, compact, and cost-effective approach to utilising solar energy,” the research group said in a statement released.
The scientists said that these kinds of devices may become particularly suitable in the future for off-grid solar applications in remote locations.
They admitted that the device in its current configuration is too expensive for commercial and mass production.
However, they do believe with further design improvements, the use of so-called “emerging solar materials”, and new electrochemistry, the device may eventually reach efficiencies of up to 25%.
The team's most recent solar flow battery model is able to store and deliver electricity from solar energy more efficiently than any other integrated device currently in existence.
In their research, they presented the design principles for, and the demonstration of, a highly efficient integrated solar flow battery (SFB) device, with a record solar-to-output electricity efficiency of 14.1%.
“Some of the current device’s voltage is still going to waste – meaning the scientists may need to tweak the redox species and photoelectrode materials that work in tandem to convert solar energy input into electrical output,” the researchers asserted.
Song Jin, a professor of chemistry at the University of Wisconsin-Madison believes the solar flow battery could help transcend the limitations of the electrical grid by making electricity more readily available to people living in rural areas and providing an alternative source of energy when traditional electrical systems fail.
Jin and his team developed the device in collaboration with Jr-Hau He, a professor of electrical engineering at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia.
"These integrated solar flow batteries will be especially suitable as distributed and stand-alone solar energy conversion and storage systems in remote locations and enable practical off-grid electrification," says Jin.
Jin believes that, with further research, solar flow batteries may soon be practical. He also believes simpler designs, cheaper solar cell materials, and technological advances could help cut costs in the future.
"We believe we could eventually get to 25% efficiency using emerging solar materials and new electrochemistry," says Jin. "At this efficiency range, without using the expensive solar cells, it should be quite competitive with other renewable energy technologies. Then I think commercialization could be possible."
And while the current model is comparatively quite efficient, the team has plans to further improve its design.
In September, scientists at Germany‘s Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) also revealed plans to develop an energy-storing solar cell through two different research projects.