Sugar is the key to creating longer lasting lithium-sulfur batteries

sugar

The Monash Energy Institute team (L-R): Mahdokht Shaibani, Mainak Majumder, Matthew Hill, Yingyi Huang. Image: Monash.

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 essential for aviation, electric vehicles and submarines. 

Assisted by the CSIRO, the Monash team reported in Nature Communications that they have stabilised lithium-sulfur battery technology using a glucose-based additive on the positive electrode. This could be 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,” Monash Energy Institute associate director and lead author professor Mainak Majumder said. 

“It could also enable innovation in delivery and agricultural drones where light weight is paramount.” 

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 the electrodes deteriorate rapidly and the batteries break down in use. This is because 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 stabilised 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 1,000 cycles, while still holding far more capacity than equivalent lithium-ion batteries.  

“So each charge lasts longer, extending the battery’s life,” first author and PhD student Yingyi Huang said. 

“And manufacturing the batteries doesn’t require exotic, toxic and expensive materials.” 

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

“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,” Monash researcher and second author Dr Mahdokht Shaibani said. 

The process was developed by the Monash team with significant contribution from Dr Matthew Hill’s research group in CSIRO Manufacturing. 

The Lithium-sulfur Battery Research Program at Monash University has been supported by the government through the Australian Research Council and the Department of Industry, Innovation and Science. The work has also been supported by Cleanfuture Energy, Australia, an Australian subsidiary of the Enserv Group of Thailand. 

Enserv is an energy research and innovation company that comprises two core businesses: Clean Energy Innovation and Clean Energy Generation. 

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,” Enserv Australia managing director Mark Gustowski said.  

“We plan to make the first lithium-sulfur batteries in Australia using Australian lithium within about five years.”