The team have already fielded calls from companies around the world, including electric vehicle manufacturers keen to harness the technology.
“This technology is the heir-apparent to current batteries,” said Dr Mahdokht Shaibani, the Monash University engineer who led the team. “We have proven prototypes, and that makes us and the whole industry very excited.”
What’s old is new again
Lithium-ion batteries, like the one in your phone, have made modern life possible. But the technology has advanced at a frustratingly slow pace. Over the past decade, your phone’s software and camera have become much more powerful but the battery still only lasts a day or less.
Lithium-ion batteries also come with inherent problems: they are expensive, can explode and die after a certain number of uses. Scientists have improved their efficiency, but they’re starting to reach their limits.
And cobalt, a key ingredient, is mined mostly in the Congo, often by child labourers.
But they remain state of the art because there is nothing better available.
Labs and companies around the world are working on several alternatives, including lithium-sulphur batteries. Sulphur is cheap, abundant and can theoretically hold six times more power at the same weight.
“That’s the irony,” said Dr Shaibani. Lithium-sulphur batteries can hold so much power the sulphur swells up to almost twice its original size and breaks. Despite keen interest, that’s prevented commercialisation so far.
The team believe they may have solved the swelling problem with a simple tweak to how the electrode, the end of the battery that holds the charge, is made.
Factories make electrodes by mixing carbon and sulphur together into a wet paste, which then dries. Dr Shaibani’s team found that slowly mixing the ingredients with only a tiny bit of water produced a thick slurry – a bit like mixing detergent powder with a drop of water.
Under the microscope, the team discovered the slurry was filled with microscopic holes, like Swiss cheese. That meant the sulphur particles could swell up without breaking as they fill with charge.
“It gives the sulphur particles some room to breathe,” said Dr Shaibani.
Most research on sulphur batteries tries to solve problems using exotic materials or impractical techniques. That’s why industry is not picking it up, said Dr Shaibani.
“There have been over 8000 papers published in this field since 2010. Most of them are claiming breakthrough after breakthrough,” she noted.
“I tried to use a solution that industry would accept: cheap materials, similar design.”
A lab in Germany has been manufacturing prototype cells using the new technology. Dr Shaibani’s team has now received $1.1 million from the federal government to test the cells in electric cars this year. They hope to have a commercial product within two to four years.
Dr Shaibani’s research is partially funded by Cleanfuture Energy, a renewable energy company that hopes to use the technology to develop better storage batteries.
Liam is The Age and Sydney Morning Herald’s science reporter