Sodium battery breakthrough could power safer, longer-lasting energy storage

A new battery material developed at UQ’s Australian Institute for Bioengineering and Nanotechnology (AIBN) could help bring sodium metal batteries (SMBs) closer to commercial use - and closer to powering a renewable future.

SMBs, or sodium metal batteries, have long been considered a promising candidate for grid-scale energy storage, thanks to their use of the inexpensive and widely available element – salt.

But AIBN Group Leader Dr Cheng Zhang explains that although SMBs offer an eco-friendlier alternative to lithium-ion batteries, their persistent safety and performance issues are a barrier to real-world use.

“One of the major roadblocks is the battery’s electrolyte – the key component that allows sodium ions to travel between the charging and discharging points,” Dr Zhang said.

“Most batteries use a liquid electrolyte, but these liquids are flammable and can overheat, causing fires like we’ve seen in electric vehicles and e-scooter batteries.”

He said these fires often stem from dendrite growth which are tiny metal spikes that form inside the battery and pierce through internal layers, triggering short circuits.

“This kind of growth usually happens when the electrolyte becomes unstable after repeated charge cycles, which makes the battery both unsafe and unreliable,” Dr Zhang said.

To solve this problem, Dr Zhang and first-year PhD student Zhou Chen developed a new fluorinated block copolymer called P(Na₃-EO₇)-PFPE – a plastic-like solid electrolyte that naturally forms internal tunnels wide enough to let sodium ions flow smoothly and efficiently.

Zhou, a joint PhD student under Dr Zhang and computational scientist Professor Debra Bernhardt, said the material breakthrough came after re-engineering its internal architecture.

“We tested a range of internal structures to find the one that would give us the best battery performance,” Zhou said.

“By adjusting the layout to form what’s known as a body-centered cubic structure, we were able to enhance the material’s naturally forming tunnels.

“This allowed sodium ions to move just as smoothly and efficiently as they do in lithium batteries, while also reducing the risk of harmful build-up like dendrites.”

During testing at 80°C, the AIBN-developed battery lasted more than 5,000 hours and retained over 91% of its original capacity after 1,000 charge cycles – a strong result for long-duration renewable energy applications.

“This kind of long-term performance is essential for grid-level energy storage and brings us closer to a more renewable-powered future, but we’re not there yet” Dr Zhang said.

 

“Our next challenge now is to optimise its efficiency at room temperature which is the critical step toward making it commercially viable.”

Dr Zhang said the success of the project reflects the power of combining academic research with real-world industry experience, and Zhou is a great example of that in action.

“As a joint PhD student with a background in both computational modelling and hands-on engineering from his time at battery manufacturer BYD, Zhou brought a unique perspective to this challenge,” Dr Zhang said.

“He’s shown how bridging industry and research can lead to extraordinary results, even in the first year of a PhD.”

The paper was published in Journal of the American Chemical Society and co-authored by Zhou Chen, Zhuojing Yang, Xiao Tan, Yiqing Wang, Associate Professor Bin Luo, Xiaoen Wang, Maria Forsyth, Craig J. Hawker, Debra J. Searles and Cheng Zhang.

Collaborative partners include the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, the Institute for Frontier Materials (IFM), ARC Industry Training Transformation Centre for Future Energy Storage, Deakin University, Department of Chemistry and Biochemistry, University of California, Santa Barbara, School of Chemistry and Molecular Biosciences (SCMB), The University of Queensland and the ARC Centre of Excellence for Green Electrochemical Transformation of Carbon Dioxide.