Discovery sweetens the opportunity for lithium-sulfur commercialisation
Scientists at an Australian university have stabilised lithium-sulfur batteries by using sugar on its positive electrode.
A team from the Monash Energy Institute— a cross faculty initiative at the the Monash University— used a glucose-based additive on the positive electrode to create a sustainable rival to lithium-ion batteries.
Test coin-cell prototypes constructed by the team retained 60% capacity after 1,000 cycles.
The team's pouch-cell prototypes reported in their manuscript were 3cm x 5cm, with an overall capacity of ~ 04-0.5Ah. Its recent pouches exceed the ones reported in the article and are ~ 1Ah.
The research by the Monash team, assisted by Australian government agency The Commonwealth Scientific and Industrial Research Organisation, was published in the scientific journal Nature Communications.
Professor Mainak Majumder, associate director of the Monash Energy Institute, said that in less than a decade the technology could lead to vehicles travelling more than 800km without recharging.
In theory, lithium-sulfur batteries can store up to five times more specific energy than lithium-ion batteries— but the electrodes deteriorate rapidly because the positive sulfur electrode weakens due to substantial expansion and contraction causing the negative lithium electrode to become contaminated by sulfur compounds.
Last year, the Monash team opened 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.
First author and PhD student Yingyi Huang and her colleagues were inspired by a 1988 geochemistry report that described how sugar-based substances resist degradations in geological sediments by forming strong bonds with sulfides.
Dr Mahdokht Shaibani, second author and Monash researcher, said: “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.”
The process was developed by the Monash team with significant contribution from Dr Matthew Hill’s research group in CSIRO Manufacturing.
Energy research and innovation company Enserv Australia hopes to develop and manufacture the batteries in Australia.
A spokesmn for Monash told BEST: "Certain aspects have been licensed to Enserv Australia. Whilst it has been an absolute delight to work with Enserv group, currently, our engagement with Enserv on this battery technology has been completed. We are looking forward to working with new venture partners to take the technology forward. It is our expectation that advanced prototypes will supercede the current technology at our disposal
Mark Gustowski, managing director of Enserv Australia, said his firm would look to use the technology to enter the electric vehicles and electronic devices market.
He said: “We plan to make the first lithium-sulfur batteries in Australia using Australian lithium within about five years.”
New salts for lithium-ion
Scientists at the Monash University School of Chemistry in Australia have developed an alternative to hexafluorophosphate salt for lithium-ion battery electrolytes.
The electrolyte was developed under the leadership of professor Doug MacFarlane and Dr Mega Kar alongside battery developer Calix.
The synthesised battery grade fluoroborate salt, made using a recrystallisation process, was found to be stable even when exposed to air.
When used in a battery with lithium-manganese-oxide cathodes, the cell achieved more than 1,000 cycles, even after atmospheric exposure, reported the team.
