Sugar could extend endurance of lithium sulphur batteries

Simply by adding sugar, researchers from the Monash Energy Institute have created a longer-lasting, lighter, more sustainable rival to the lithium-ion batteries that are becoming essential for aviation, electric vehicles and, soon, submarines.

The Monash University team, assisted by CSIRO, report in the journal Nature Communications that by using a glucose-based additive on the positive electrode they have managed to stabilise lithium-sulphur battery technology.

“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-sulphur 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 can deteriorate rapidly and the batteries break down. There are two reasons for this – the positive electrode, made from sulphur, undergoes substantial expansion and contraction, weakening it and making it inaccessible to lithium; and the negative lithium electrode becomes contaminated by sulphur compounds.

Last year the Monash team demonstrated they could open the structure of the sulphur 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 stabilised the sulphur, 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.”

The Lithium-sulphur Battery Research Program at Monash University has been supported by the Commonwealth Government through the Australian Research Council and the Department of Industry, Science, Energy and Resources In addition, the work has also been supported by Cleanfuture Energy, Australia, an Australian subsidiary of the Enserv Group of Thailand.

Enserv Australia hopes to develop and manufacture the batteries in Australia, the world’s largest producer of lithium.  “We would be looking to use the technology to enter the growing market for electric vehicles and electronic devices,” says Mark Gustowski, Managing Director of Enserv Australia. “We plan to make the first lithium-sulphur batteries in Australia using Australian lithium within about five years.”