Zinc-air batteries offer lithium alternative

Lithium-ion batteries proliferate the battery storage market, but their shortcomings in terms of cost, resource demands and safety are well known. In a new study, led by engineers at Edith Cowan University (ECU) in Perth, it was shown that batteries with electrodes composed of zinc and air could deliver better performance than lithium-ion across a range of metrics. The work is published in Ecomat.

"Rechargeable zinc-air batteries (ZABs) are becoming more appealing because of their low cost, environmental friendliness, high theoretical energy density, and inherent safety," said Dr Muhammad Rizwan Azhar, a chemical and materials engineer at ECU.

"With the emergence of next-generation long-range vehicles and electric aircraft in the market, there is an increasing need for safer, more cost-effective, and high-performance battery systems that can surpass the capabilities of lithium-ion batteries."

ZABs use a zinc negative electrode and an air positive electrode. Until now, they have exhibited both limited power output and a short lifespan. According to Dr Azhar, the ECU team has been able to enhance ZAB performance through the incorporation of new materials into the battery design, such as carbon, iron and cobalt-based minerals. This produced ZABs that delivered a high peak power density of 228 mW cm⁻² and a low voltage gap of 0.77 V, as well as an ultra-long lifespan of 950 hours. 

"The new design has been so efficient it suppressed the internal resistance of batteries, and their voltage was close to the theoretical voltage which resulted in a high peak power density and ultra-long stability," Dr Azhar said.

What’s more, the resources required to make the ZABs should result in reduced cost and environmental impact compared with current supply chains.

"By using natural resources, such as zinc from Australia and air, this further enhances the cost-effectiveness and viability of these innovative zinc-air batteries for the future,” said Dr Azhar.

"Due to the abundance of zinc available in countries such as Australia, and the ubiquity of air, this becomes a highly viable and reliable energy storage solution."