Zinc is a very useful battery material, especially when in combination with oxygen. Zinc-air batteries can be a powerful and safer alternative to lithium-ion, but until now, they’ve had one key fault. And it’s a big one.
“These have been in the market for years now, but they’re not chargeable. They’re just one time use,” says Dr Muhammad Rizwan Azhar, a researcher at Edith Cowan University (ECU) and co-author on a paper recently published in EcoMat.
But now Azhar and colleagues have developed a rechargeable zinc-air battery – and they have electric vehicles in their sights.
“We have tested it for 950 hours, it doesn’t lose any power, it can be continuously charged and discharged,” he says.
The difference between this battery and conventional disposable ones is the material in the battery cathode. The team has developed a cathode made from nickel, iron, carbon and a small amount of cobalt.
“The cathode material, which acts as a catalyst, gets oxygen from the air to get charging and discharging happening,” says Azhar.
“Once it’s been used, it gives back that oxygen.”
Batteries work by performing a chemical reaction that releases energy – in rechargeable batteries, it’s a reversible reaction.
In the case of a zinc-air battery, that reaction happens between zinc and oxygen – as Azhar says, “it’s breathing air”.
The battery they’ve developed can stay stable for a long time, and has a high peak power density, making it very efficient.
“We have tested these batteries for 3-4 years now, in individual cells. We are in the process of scaling it up as a larger cell and also a battery pack in different cells together, and then putting them for a real time application in a in an EV,” says Azhar.
The team hopes to test out the zinc-air battery in ECU’s motorsports discipline.
“Our students and staff there make a racing car. We are in the process putting [our battery] into our motorsports car.”
Azhar would eventually like to see onshore manufacturing of zinc-air batteries in Australia.
“If we have the interest and enthusiasm from industry and government as well, the research can be very quickly transformed into products,” he says.
“Australia has the largest reserves of zinc, which will be used for these types of batteries.”
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