Sodium battery 'significant breakthrough'

New battery technology using a type of molten salt processed from sea water has been successfully tested in Australia by an international team of researchers.

Led by Shenlong Zhao from the University of Sydney's School of Chemical and Biomolecular Engineering, the battery is made using sodium-sulphur and could be a cheaper alternative to lithium. 

Industrial use of clean energy sources is accelerating, as is household energy storage, but cost remains a barrier for many.

"Our sodium battery has the potential to dramatically reduce costs while providing four times as much storage capacity," Dr Zhao said.

"This is a significant breakthrough for renewable energy development."

The team of researchers, who have had their research published in the journal Advanced Materials, say the new, low-cost battery could significantly reduce the cost of transitioning to a decarbonised economy.

"When the sun isn't shining and the breeze isn't blowing, we need high-quality storage solutions that don't cost the earth and are easily accessible on a local or regional level," Dr Zhao said.

"We hope that by providing a technology that reduces costs we can sooner reach a clean energy horizon ... the faster we can decarbonise, the better chances we have of capping warming."

He said energy storage manufactured using plentiful resources like sodium, which can be processed from sea water, could also allow more countries to join the shift to net zero emissions.

Although sodium-sulphur (Na-S) batteries have existed for more than half a century, they have been viewed as an inferior alternative because of a low-energy capacity and short life cycles.

Using a simple pyrolysis process and carbon-based electrodes, the battery took on super-high capacity and ultra-long life at room temperature.

The researchers say the Na-S battery is also a more energy dense and less toxic alternative to lithium-ion batteries, which, while used extensively in electronic devices and for energy storage, are expensive to manufacture and recycle.

The battery has been specifically designed for large renewable energy storage systems, such as electrical grids.

The lab-scale batteries have been fabricated and tested in the University of Sydney's chemical engineering facility, and there are plans to improve and commercialise the cells.