Energy

New energy cell can store up solar energy for release at night

New energy cell can store up s...
Researchers have, for the first time, found a way to store electrons generated by photoelectrochemical (PEC) cells for long periods of time
Researchers have, for the first time, found a way to store electrons generated by photoelectrochemical (PEC) cells for long periods of time
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Researchers have, for the first time, found a way to store electrons generated by photoelectrochemical (PEC) cells for long periods of time
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Researchers have, for the first time, found a way to store electrons generated by photoelectrochemical (PEC) cells for long periods of time
A photoelectrochemical cell can turn sunlight into either electricity or chemical energy in the form of hydrogen
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A photoelectrochemical cell can turn sunlight into either electricity or chemical energy in the form of hydrogen

A photoelectrochemical cell (PEC) is a special type of solar cell that gathers the Sun's energy and transforms it into either electricity or chemical energy used to split water and produce hydrogen for use in fuel cells. In an advance that could help this clean energy source play a stronger role within the smart grid, researchers at the University of Texas, Arlington have found a way to store the electricity generated by a PEC cell for extended periods of time and allow electricity to be delivered around the clock.

Currently, the electricity generated by a PEC cell could not be stored effectively, as the electrons would quickly "disappear" into a lower-energy state. This meant that these cells were not a viable solution for a clean-energy grid, as the electricity had to be used very shortly after being produced. That is, on sunny days, at a time when standard PV panels would already be producing energy at full tilt.

Now, researchers Fuqiang Liu and colleagues have created a PEC cell that includes a specially designed photoelectrode (the component that converts incoming photons into electrons). Unlike previous designs, their hybrid tungsten trioxide/titanium dioxide (WO3/TiO2) photoelectrode can store electrons effectively for long periods of time, paving the way for PEC cells to play a bigger role within a smart energy grid.

A photoelectrochemical cell can turn sunlight into either electricity or chemical energy in the form of hydrogen
A photoelectrochemical cell can turn sunlight into either electricity or chemical energy in the form of hydrogen

The system also includes a vanadium redox-flow battery (VRB). This is an already established type of energy storage cell that is very well-suited for the needs of the electrical grid as it can stay idle for very long times without losing charge, is much safer than a lithium-ion cell (though less energy-dense), is nearly immune to temperature extremes, and can be scaled up very easily, simply by increasing the size of its electrolyte tanks.

According to the researchers, the vanadium flow battery works especially well with their hybrid electrode, allowing them to boost the electric current, offering great reversibility (with 95 percent Faradaic efficiency) and allowing for high-capacity energy storage.

"We have demonstrated simultaneously reversible storage of both solar energy and electrons in the cell," says lead author of the paper Dong Liu. "Release of the stored electrons under dark conditions continues solar energy storage, thus allowing for continuous storage around the clock."

The team is now working on building a larger prototype, with the hope that this technology could be used to better integrate photoelectrochemical cells within the smart grid.

A paper describing the advance appears in the latest edition of the journal ACS Catalysis.

Source: UT Arlington via Kurzweil AI

5 comments
Don Duncan
How much less energy dense, compared to Li, is it? How much more expensive? Will the energy storage increase be cost effective?
Leithauser
Lots of details missing. How long can the PEC hold energy for? Of course, anything over 14 hours or so is good enough to power the house overnight. Even a few hours would help even out the power flow when a cloud passes over. Why does the PEC work especially well with the vanadium flow battery? Is there some good match of voltage or something? For that matter, why do you need the battery if the PEC stores energy itself? I assume it is a matter of how much energy it can hold, with the battery being charged once the PEC has reached capacity, but it would be nice to include these details. The fact that the vanadium flow battery is less energy dense than a lithium battery is not too important for a stationary applications like a home, assuming it is not ridiculously low energy density. The fact that it is nearly immune to temperature extremes means the batteries can be stored in wasted space in the attic.
Stephen N Russell
Mass produce & needed for these locales No Africa Hawaii Mexico India Vietnam Australia Brazil, Ecuador, Venezula, Peru, Chile US: CA NV HI AZ TX FL CO KS ID ND IL. Awesome idea
NickTedesco
It truly is amazing to read about potential solar power breakthroughs. Hopefully this will be taken to market real soon. In the mean time, homeowners can save thousands of dollars over the long term by switching to solar.
Scott in California
These articles uncritically never mention the cost of materials. I see vanadium and platinum in the drawing, which means that this is a very expensive proposition, per watt of power output. I think the readers of GizMag are all "grown up". We can take it, if the article said, "The cost of materials (Vanadium and Platinum) was $10 to output .01 watt-hour of energy. Researchers hope to improve it to one cent per watt-hour" or something like that...