Researchers at the University of Sydney has figured out how to solve one of the biggest problems standing in the way for zinc-air batteries to replace lithium-ion batteries. The reason zinc batteries are so sought after is because they're powered by zinc metal -- the 24th most abundant element in Earth's crust. Not only are they cheaper to produce than lithium-ion batteries, they can theoretically store five times more energy, are much safer and environmentally friendly. The problem with zinc batteries stems around them being difficult to charge because of the lack of electrocatalysts needed to reduce and generate oxygen during the discharging and charging of a battery. labnet shares a report from Gizmodo: "Up until now, rechargeable zinc-air batteries have been made with expensive precious metal catalysts, such as platinum and iridium oxide. In contrast, our method produces a family of new high-performance and low-cost catalysts." 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. The research was published in the journal Advanced Materials.