Non-flammable electrolyte developed for sodium batteries

Australian and US researchers have created a non-flammable electrolyte material for use in sodium batteries, providing a safer and cheaper alternative to lithium-ion batteries. Their breakthrough has been published in the journal Nature Materials.

Led by Dr Xiaoen Wang and Professor Maria Forsyth from Deakin University’s Institute for Frontier Materials, the research team developed a solid polymer electrolyte material that can replace the flammable liquid solvents currently used in sodium batteries. Known as a fluorine-containing polymer and originally used for biological application, this is the first time this class of polymer has been used in solid-state sodium batteries.

“Most industries that develop sodium batteries generally use carbon-based electrode and liquid electrolyte, which has low capacity and also can fuel a fire if the battery overheats,” Wang said.

“We are taking a different approach, using reactive sodium metal as an anode to increase battery capacity, and in the process are developing safer electrolytes to ensure the safety of sodium batteries.”

A key component in the electrolyte was developed by Dr Cheng Zhang and Professor Andrew K Whittaker, from The University of Queensland’s Australian Institute for Bioengineering and Nanotechnology. Researchers from the University of Illinois Chicago and the University of California, Santa Barbara also contributed to the research.

According to Wang, one of the main benefits of using sodium as an alternative source to lithium in battery production is its low production cost, as sodium resources are more abundant. That said, one drawback of current sodium batteries is that they do not last as long as lithium batteries and have a lower energy density.

In pairing sodium batteries with the new polymer electrolytes, they offer close to 1000 cycles — comparable to the current well-developed lithium batteries. Small-scale testing of the batteries has been successful, with upscaling and prototyping coming soon; with further research, opportunities could be on the horizon for use in stationary energy storage such as solar or even in electric cars.

To continue and extend Deakin’s extensive research into sodium and lithium batteries, the university is currently establishing a new $9.5 million facility at its Melbourne Burwood campus, due for completion in August this year. The expansion project involves upgrading the current Battery Technology Research and Innovation Hub (BatTRI-Hub) facility to include a testing lab and pilot production line to research and manufacture advanced lithium and sodium batteries.

Image credit: ©stock.adobe.com/au/dolphfyn

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