Science Education News (SEN) Journal 2017 Volume 66 Number 4 December 2017 | Page 49

GENERAL ARTICLES University of Sydney charges ahead on zinc-air batteries By Jennifer Peterson-Ward 15th August 2017; Republished from “Three-stage method could revolutionise rechargeability: http://sydney.edu.au/news-opinion/ news/2017/08/15/university-of-sydney-charges-ahead-on-zinc- air-batteries.html?cid=em_mdr-jpw, by permission from the University of Sydney and Nanyang Technological University outlines a new three-stage method to overcome this problem. According to lead author Professor Yuan Chen , from the University of Sydney's Faculty of Engineering and Information Technologies , a new method can be used to create bifunctional oxygen electro-catalysts for building rechargeable zinc-air batteries from scratch. “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,” he said. “These new catalysts are produced through the simultaneous control of the: 1) composition, 2) size and 3) crystallinity of metal oxides of earth-abundant elements such as iron, cobalt and nickel. They can then be applied to build rechargeable zinc-air batteries.” The paper’s co-author, Dr Li Wei , also from the University's Faculty of Engineering and Information Technologies , said that 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. A University of Sydney researcher holds up a rechargeable zinc-air battery University of Sydney researchers have found a solution for one of the biggest stumbling-blocks preventing zinc-air batteries from overtaking conventional lithium-ion batteries as the power source of choice in electronic devices. “We are solving fundamental technological challenges to realise more sustainable metal-air batteries for our society,” Professor Chen added. Zinc-air batteries are batteries powered by zinc metal and oxygen from the air. Due to the global abundance of zinc metal, 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 more environmentally friendly. Media enquiries and interview requests: Jennifer Peterson-Ward - [phone], 0434 561 056, jennifer.peterson-ward@sydney. edu.au While zinc-air batteries are currently often 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 due to the lack of electro-catalysts that successfully reduce and generate oxygen during the discharging and charging of a battery. A typical pack of six hearing-aid air-zinc batteries. These are not rechargeable However, in a paper recently published in Advanced Materials: , a paper authored by chemical engineering researchers 49 SCIENCE EDUCATIONAL NEWS VOL 66 NO 4