New flow battery could revolutionize energy storage

MIT researchers have developed a new flow battery that has the potential to revolutionize how renewable energy is storage. It can store electricity for very long durations for about a fifth the cost of current technologies.

The “air-breathing” battery developed by the MIT researchers uses sulphur dissolved in water for its anode – a cheap and abundant by-product of industrial processes. For the battery’s cathode, the researchers made an unexpected discovery with a compound called potassium permanganate: the battery was recharging due to an unexpected oxygen reaction in the cathode, which was running entirely on air.

“This battery literally inhales and exhales air, but it doesn’t exhale carbon dioxide, like humans – it exhales oxygen,” Yet-Ming Chiang, a professor of Materials Science and Engineering at MIT, said in a statement. The research was published in the latest edition of the journal Joule.

The battery’s total chemical cost is about 1/30th the cost of competing batteries, such as lithium-ion batteries. The researchers believe that scaled-up versions of the flow battery could be used to store electricity from wind or solar power for longer durations of time –entire seasons even – for just $20 to $30 per kilowatt hour.

According to MIT, this could be the first technology in terms of cost and energy density to compete with pumped hydroelectric storage systems. These currently provide most of the energy storage for renewables around the world but are very restricted by location.

“The energy density of a flow battery like this is more than 500 times higher than pumped hydroelectric storage. It’s also so much more compact, so that you can imagine putting it anywhere you have renewable generation,” Chiang said.

 

Image: Courtesy of the researchers. Left photo: Felice Frankel.

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