Engineers hope finding could solve key bottleneck in zinc-air battery design

Two engineers from Melbourne’s Monash University have unveiled a catalyst they say could help create batteries that offer more power, with a longer life and lower costs.

Saeed Askari and Parama Banerjee from the university’s Department of Chemical and Biological Engineering are lead authors of an article detailing the catalyst, which they say supported high performance in zinc–air batteries.

Using a heat treatment, the researchers turned a 3D material into ultra-thin carbon sheets and added individual cobalt and iron atoms, creating a catalyst they say makes the battery’s oxygen reactions much faster and more efficient.

An article published in Chemical Engineering Journal shows the catalyst “exhibited exceptional cycling ability, maintaining consistent performance over 74 days with 3552 charging cycles”.

Powered by the oxidisation of zinc with oxygen from the air, zinc-air batteries are currently widely used in small devices such as hearing aids and watch batteries.

With zinc typically more affordable than lithium or sodium, there has been keen interest in scaling up the battery for use in rechargeable, high-power applications, and in moving the technology closer to real-world, grid-scale and transport uses.

Askari and Banerjee say the catalyst their team worked on outperformed standard commercial catalysts made from expensive metals like platinum and ruthenium.

“By engineering cobalt and iron as individual atoms on a carbon framework, we achieved record-breaking performance in zinc-air batteries, showing what is possible when catalysts are designed with atomic precision,” Askari says.

“Our advanced simulations revealed that the cobalt-iron atom pairs, combined with nitrogen dopants, enhance charge transfer and optimise reaction kinetics, solving one of the biggest bottlenecks for rechargeable zinc-air batteries.”

Banerjee said the principles behind this design could also be applied to other clean energy technologies including fuel cells, water splitting and CO₂ conversion.

“Running a rechargeable zinc-air battery continuously for more than two months is a milestone for the field. It demonstrates that this technology is ready to move beyond the laboratory and into practical applications,” Banerjee says.

“These catalysts not only solve a key bottleneck for zinc-air batteries, but their design principles can be applied across the energy landscape – from fuel cells to water splitting – offering broad impact for clean energy.”

CAPTION: Dr Parama Banerjee, left, and Saeed Askari of Monash University.