Researchers at the University of Sydney just worked out how to solve one of the biggest problems standing in the way for zinc-air batteries to replace lithium-ion batteries as our go-to for modern electronics.
Zinc-air batteries are batteries powered by zinc metal and oxygen from the air. Becasue of how much zinc metal we have around the world (it's a lot), these batteries are much cheaper to produce than lithium-ion batteries, and they can also store more energy (theoretically five times more than that of lithium-ion batteries), are much safer and are more environmentally friendly.
Now, while zinc-air batteries are currently used as an energy source in hearing aids and some film cameras and railway signal devices, their widespread use has been hindered by the fact that, up until now, recharging them has proved difficult. This is because of the lack of electrocatalysts to reduce and generate oxygen during the discharging and charging of a battery.
The researchers developed a new three-stage method to overcome this problem.
According to lead researcher Professor Yuan Chen from the University of Sydneys Faculty of Engineering and Information Technologies, the new method can be used to create bifunctional oxygen electrocatalysts for building rechargeable zinc-air batteries - from scratch.
These new catalysts are produced through the simultaneous control of the composition, size and crystallinity of metal oxides of earth-abundant elements like iron, cobalt and nickel. They can then be applied to build rechargeable zinc-air batteries.
Researcher Dr Li Wei, also from the University's 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 percent 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," Professor Chen added.