Batteries of the Future Set to be Cheaper and Better – Thanks to Sugar

The Monash team, assisted by CSIRO, report that using a glucose-based additive on the positive electrode they have managed to stabilize lithium-sulfur battery technology, long touted as the basis for the next generation of batteries.

“In less than a decade, this technology could lead to vehicles including electric buses and trucks that can travel from Melbourne to Sydney without recharging. It could also enable innovation in delivery and agricultural drones where light weight is paramount,” says lead author Professor Mainak Majumder, from the Department of Mechanical and Aerospace Engineering and Associate Director of the Monash Energy Institute.

In theory, lithium-sulfur batteries could store two to five times more energy than lithium-ion batteries of the same weight. The problem has been that, in use the electrodes deteriorated rapidly, and the batteries broke down.

There were two reasons for this—the positive sulfur electrode suffered from substantial expansion and contraction weakening it and making it inaccessible to lithium, and the negative lithium electrode became contaminated by sulfur compounds.

Last year the Monash team demonstrated they could open the structure of the sulfur electrode to accommodate expansion and make it more accessible to lithium.

Now, by incorporating sugar into the web-like architecture of the electrode they have stabilized the sulfur, preventing it from moving and blanketing the lithium electrode.

Test-cell prototypes constructed by the team have been shown to have a charge-discharge life of at least 1000 cycles, while still holding far more capacity than equivalent lithium-ion batteries.

“So each charge lasts longer, extending the battery’s life,” says first author and PhD student Yingyi Huang. “And manufacturing the batteries doesn’t require exotic, toxic, and expensive materials.”

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Yingyi and her colleagues were inspired by a 1988 geochemistry report that describes how sugar-based substances resist degradations in geological sediments by forming strong bonds with sulfides.

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Dr Mahdokht Shaibani, second author of the paper, published in Nature Communications, and Monash researcher, says, “While many of the challenges on the cathode side of the battery has been solved by our team, there is still need for further innovation into the protection of the lithium metal anode to enable large-scale uptake of this promising technology—innovations that may be right around the corner.”