A paper published in the Advanced Materials journal this week by the team, in co-operation with Singapore's Nanyang Technological University, outlined a three-stage method to overcome the problems.
A statement from the University of Sydney said that zinc-air batteries were much cheaper to produce that their lithium-ion counterparts. They could also store much more energy — theoretically five times more — and were safer and also more environmentally friendly.
But recharging zinc-air batteries had proved difficult. This was because of the lack of electrocatalysts that successfully reduced and generated oxygen during the process of discharging and charging.
“Up until now, rechargeable zinc-air batteries have been made with expensive precious metal catalysts, such as platinum and iridium oxide," Prof Chen said. "In contrast, our method produces a family of new high-performance and low-cost catalysts.”
He said these new catalysts were produced through simultaneous control of the composition, size and crystallinity of metal oxides of elements like iron, cobalt and nickel which were available in abundant quantities. Theses could then be applied to build rechargeable zinc-air batteries.
Paper co-author Dr Li Wei, also from the Faculty of Engineering and Information Technologies, said trials of zinc-air batteries developed with the new catalysts had demonstrated excellent rechargeability – including less than a 10% battery efficacy drop over 60 discharging/charging cycles of 120 hours.
“We are solving fundamental technological challenges to realise more sustainable metal-air batteries for our society,” Prof Chen said.
Earlier this year, researchers at the University of Texas said they had created the first all-solid-state battery cells that could lead to safer, faster-charging, longer-lasting rechargeable batteries for mobiles, electric cars and stationary storage.
Photos: courtesy University of Sydney