Researchers have built a more efficient, more reliable potassium-oxygen battery, a step toward a potential solution for energy storage on the nation’s power grid and longer-lasting batteries in cell phones and laptops.
In a study published Friday in the journal Batteries and Supercaps, researchers from The Ohio State University detailed their findings centering around the construction of the battery’s cathode, which stores the energy produced by a chemical reaction in a metal-oxygen or metal-air battery. The finding, the researchers say, could make renewable energy sources like solar and wind more viable options for the power grid through cheaper, more efficient energy storage.
“If you want to go to an all-renewable option for the power grid, you need economical energy storage devices that can store excess power and give that power back out when you don’t have the source ready or working,” said Vishnu-Baba Sundaresan, co-author of the study and professor of mechanical and aerospace engineering at Ohio State. “Technology like this is key, because it is cheap, it doesn’t use any exotic materials, and it can be made anywhere and promote the local economy.”
Renewable energy sources don’t emit carbon dioxide, so they don’t contribute to global warming — but they provide energy only when the sun is shining or the wind is blowing. In order for them to be reliable sources of power for a region’s energy grid, there needs to be a way to store excess energy gathered from sunshine and wind.
Companies, scientists and governments around the world are working on storage solutions, ranging from lithium-ion batteries — bigger versions of those in many electric vehicles — to giant batteries the size of a big-box store made using the metal vanadium.
Potassium-oxygen batteries have been a potential alternative for energy storage since they were invented in 2013. A team of researchers from Ohio State, led by chemistry professor Yiying Wu, showed that the batteries could be more efficient than lithium-oxygen batteries while simultaneously storing about twice the energy as existing lithium-ion batteries. But potassium-oxygen batteries have not been widely used for energy storage because, so far, they haven’t been able to recharge enough times to be cost-effective.
As teams tried to create a potassium-oxygen battery that could be a viable storage solution, they kept running into a roadblock: The battery degraded with each charge, never lasting longer than five or 10 charging cycles — far from enough to make the battery a cost-effective solution for storing power. That degradation happened because oxygen crept into the battery’s anode — the place that allows electrons to charge a device, be it a cell phone or a power grid. The oxygen caused the anode to break down, making it so the battery itself could no longer supply a charge.
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