(Image: ecu.edu.au)

Zinc-air batteries have emerged as a better alternative to lithium in a recent Edith Cowan University (ECU) study into the advancement of sustainable battery systems, led by ECU’s Dr. Muhammad Rizwan Azhar. Lithium-ion (Li-ion) batteries, although a popular choice for EVs around the world, face limitations related to cost, finite resources, and safety concerns.

“Rechargeable zinc-air batteries (ZABs) are becoming more appealing because of their low cost, environmental friendliness, high theoretical energy density, and inherent safety,” Azhar said. “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 Li-ion batteries.”

A ZAB consists of a zinc negative electrode and an air positive electrode. Their major disadvantage has been the limited power output, due to poor performance of air electrodes and short lifespan — until now.

The team’s breakthrough has enabled engineers to use a combination of new materials, such as carbon, cheaper iron, and cobalt-based minerals to redesign zinc-air batteries.

“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,” Azhar said. “In addition to revolutionizing the energy storage industry, this breakthrough contributes significantly to building a sustainable society, reducing our reliance on fossil fuels, and mitigating environmental impacts.

“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.”

Here is an exclusive Tech Briefs interview — edited for length and clarity — with Azhar.

Tech Briefs: What was the biggest technical challenge you faced while advancing this ZAB?

Azhar: Because we have been working with these type of batteries for four years now, the main challenge is to avoid corrosion issues, which can be on the anode side. And the second challenge is getting the cathode side, we’ll call it electrode, so that it can get the oxygen diffused through it. Because that will be the reaction. So, these are the two challenges: The corrosion of zinc and also the diffusion of oxygen from air into the battery so that it can get charged.

Tech Briefs: How much safer, more cost effective, and better performing are the new ZABs compared to Li-ion batteries?

Azhar: It is way cheaper, and the safety is at a higher level compared to a Li-ion, because it doesn’t catch fire. Hopefully, the recycling is much easier once we reach that level. So, it’s cost effective, definitely much safer than Li-ion, and also has more availability — as the raw materials are there because zinc is much easier to process compared to lithium.

Tech Briefs: How much better performing and cheaper are the ZABs compared to prior technologies?

Azhar: The first thing is about the cost. For the existing ones, the materials being used are precious metals. The one we have developed, the material for cathode is totally based on transition metal — cobalt, nickel, iron, etc. All cheaper. So, it’ll be much cheaper than the existing ones in the market.

Tech Briefs: How soon could we see ZABs commercialized?

Azhar: That will be very soon because in the test phase, one U.S. company has tested for 20,000 hours. So, it'll be soon — hopefully in the next two to three years we will see ZABs at a commercial scale.

Tech Briefs: What are your next steps? Do you have any other future research work, etc., on the horizon?

Azhar: What we are trying to do now is we are in the process of developing battery packs of the zinc air. We know about the lithium battery packs and we have them in our EVs. So, we are in the process of manufacturing. That means developing battery packs and then putting them together for the larger applications including EVs, because we have at our university a motorsports department where students work on developing their own EV — a racing car. So, we are planning to have our battery developed in-house at ECU and then put into the car we develop.

Tech Briefs: Do you have any advice for engineers aiming to bring their ideas to fruition?

Azhar: My advice is to keep up with one type of research and then take it to the next levels instead of just doing research for publishing papers. It should be a holistic approach so that it’ll be a transforming thing for sustainability, what we need — energy storage and Net Zero by 2050. That’s my advice: Not focusing on covering papers but really developing the technology.

Tech Briefs: Is there anything else you'd like to add that we didn’t touch upon?

Azhar: My message for the industry is to come forward and then have conversations and collaborations with the universities across the globe and not just focus on one part of the world but all over the world. We have the responsibility to come up with solutions and projects for renewables and reduction in emission of greenhouse gases.