While lithium-ion batteries have emerged as a key component in the energy transition, their availability is hindered by restricted lithium reserves, potentially polluting extraction processes and the anticipated steep escalation of mineral prices due to rising demand. In this context, researchers propose zinc-air batteries (ZAB) as a greener and more cost-effective solution. However, more research is needed.
According to Edith Cowan Univerisity’s (ECU) Researcher, Muhammad Rizwan Azhar, ZABs are becoming more appealing because of their low cost, lower environmental impact, high theoretical energy density and inherent safety. If developed properly, ZABs are posed to meet and surpass the capabilities of lithium-ion batteries.
Azhar explains that ZABs consist of a zinc-negative electrode and an air-positive electrode. ZABs operate based on a process involving oxygen reactions. When these batteries are being charged, they generate oxygen. During discharge, they consume oxygen. However, the challenge lies in difficulties in efficiently managing these oxygen reactions, which result in significant energy losses as batteries go through their charging and discharging cycles. To enhance the overall efficiency of ZABs, it is crucial to develop specialized materials that excel in both generating and consuming oxygen. This improvement in oxygen reactions will have a positive impact on the batteries' efficiency and their ability to store and release energy effectively, as reported in Azhar’s paper.
Azhar suggests that creating efficient air electrodes for ZABs is a complex task. The challenge is in the two main processes involved: making and using oxygen. These processes typically occur at different places within the electrode and follow separate paths. This makes it tough to make a single material that is good at both. Instead, a smarter way to boost ZAB performance is to create some composite electrocatalysts with different spots that work well for each of the two oxygen-related processes. This helps the battery work better overall by having the right materials in the right places for each job.
According to Yahoo! Finance, ECU’s breakthrough has enabled engineers to use a combination of new materials, such as carbon, cheaper iron and cobalt-based minerals to redesign ZABs. However, technology has not been completely developed and further study is required, as ZABs’ efficiency has been proven only in theory. However, the development of this new storage method could change the way OEMs and countries transition to cleaner sources, as minerals like zinc, cobalt and iron are easier to extract.
In 2019, China produced around 13.2Mt of zinc, which was over 33% of the world’s production. The country was followed by Peru with 10.7%, Australia with 10.2%, Mexico with 6.5% and the US with 5.7%. According to BBVA, zinc is one of the minerals that can be recycled more easily and unlimited times as it does not lose its properties during the process. It is estimated that over 30% of the world’s zinc is recycled, which adds more value to ZABs in terms of sustainability.