The theoretical capacity of zinc-air batteries is five times higher than that of lithium-ion batteries. At the same time they are much cheaper, environmentally friendly and much safer. However, zinc-air batteries are not used as widely – and there is a reason. The fact is that the electricity in them is produced by the reaction of zinc and oxygen, and to extract the latter from the air, expensive catalysts are needed.
Zinc-air batteries are now used in hearing aids, premium film cameras, in electronics on the railroad. Technological obstacles for their use in other areas are not, the problem is purely economic. For their work, expensive catalysts based on platinum or iridium are required. However, researchers from the University of Sydney have managed to develop a three-step process of replacing them with waste.
Bifunctional oxygen catalysts for zinc-air batteries can be made from crystals of nickel, cobalt or iron oxides, carefully controlling their size, shape and composition. That is, instead of the usual, natural substance, create man-made granules with given parameters. The tests conducted by Professor Yuan Cheng showed that batteries with such a “substitute” are capable of multiple recharging.
With cobalt there may be some problems, due to its relevance in the components of electric vehicles, but nickel and iron are extremely common and very cheap. True, they do not work as well – after 60 cycles of recharge, the battery with the new catalyst showed a 10% reduction in efficiency. However, even such a result allows us to hope that the key problem of prospective zinc-air batteries will find its solution.