Ellen Phiddian
What might it take to get zinc batteries offsetting some of the demand on lithium-ion?
According to a review in Nano Research Energy, a few avenues of research look set to make rechargeable zinc batteries efficient and long-lasting enough to be competitive.
If you want to store electricity, lithium-ion batteries are generally the most powerful and energy dense option.
But lithium isn’t a super-abundant metal, and it’s very reactive: lithium-ion batteries need elaborate safety systems to lower the risk of fires.
As battery demand soars, to shore up the transition to renewable energy, researchers are looking for alternatives to lithium.
“Zinc has a strong battery track record, having been used as anode material as early as 1799!” says co-author Dapeng Liu, a battery researcher with the Key Laboratory of Bio-inspired Smart Interfacial Science and Technology at Beihang University, China.
“Zinc-based battery technology already accounts for one-third of the world battery market.”
Zinc can be used in a range of different types of battery – including zinc-air batteries, which are currently available as small disposables, rechargeable flow batteries, or rechargeable non-flow zinc-bromide batteries.
Zinc-based batteries are typically cheaper than lithium-ion, and carry a much lower fire risk.
But while their performance has much improved over the past decade, they’re still not good for commercial rechargeable batteries yet. They’re not very energy-dense, and they have shorter life cycles.
Read more: How do batteries work?
According to the researchers, there are a few areas of chemistry that should be focused on to improve this.
First, say the reviewers, the anodes and cathodes of zinc batteries need to be developed so that they don’t deplete as much over time. They think that changing the surface of the anodes (interface modification), and alloying the zinc with other materials and additives, will yield the best results.
Next, better catalysts are needed to speed up zinc-air batteries’ reactions, making them more efficient.
Finally, the researchers suggest that new electrolyte mixtures can improve battery performance.
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“Rechargeable zinc-based batteries have a long way to go before large-scale application in the mobile, power, and other electronic equipment markets,” conclude the researchers in their paper.
A zinc-bromide battery factory opened in Australia in late September. Operated by Gelion, a renewable energy company that spun out from research at the University of Sydney, the facility is currently capable of making two megawatt hours of batteries per year.
Batty about batteries? Keep your eyes peeled for the next edition of Cosmos Weekly on Friday, where we’ll be exploring the mechanics – and potential – of flow batteries, and where they fit in the energy transition.