Sodium-ion batteries are the future of safe energy storage

New research from Deakin's Battery Technology Research and Innovation Hub (BatTRI-Hub) has proven the viability of sodium-ion batteries, which can be cheaper and safer than their lithium-ion counterparts.

Sodium-ion batteries aren't affected by the explosive problems plaguing lithium-ion, which caused massive recalls and bans of certain model phones on some airlines in 2016. Sodium-ion batteries are also capable of charging and discharging at higher rates.

BatTRI-Hub Director Professor Maria Forsyth said sodium-ion batteries could be made using readily-available materials without costly, environmentally-harmful and ethically-dubious mining for rare materials such as cobalt.

"Unlike lithium-ion batteries, the key components of sodium-ion batteries are synthesised from low-cost, abundant materials with secure supply chains," Professor Forsyth said.

"There's a lot of opportunity here because of the cost benefits and availability, and it can also be a drop-in technology for manufacturers currently using lithium-ion, without the need for a complete re-tooling of their manufacturing process."

Sodium-ion battery technology has been investigated since the 1970s, but it's never before been optimised for mainstream use due to the discovery and unprecedented expansion of lithium-ion technology.

That's now changing, as Professor Forsyth, BatTRI-Hub co-director Associate Professor Patrick Howlett and their team have demonstrated through advances using high-stability electrolyte formulations to improve the technology.

Their latest findings are being presented as part of a specially-curated edition of the renowned Advanced Energy Materials journal, co-edited by Professor Forsyth with international experts Professors Teofilo Rojo, Yong-Sheng Hu and Xiaolin Li.

Professor Forsyth and her group used non-conventional electrolytes composed entirely of salt, similar to table salt, but retaining a liquid state. The new generation electrolytes, known as ionic liquids, have shown enhanced sodium battery performance during testing at the BatTRI-Hub.

Professor Forsyth said there was considerable interest in sodium-ion battery research and development for mainstream commercial use, which was the next step in order to take the technology to consumers.

"Given the significance of reliable and sustainable energy to the modern world, the development of energy storage solutions is critical – batteries are an inseparable part of this, and as society continues to grow and evolve, so too must battery technologies," she said.

"Sodium-ion batteries are proving to be an emergent technology with very attractive properties, particularly in future smart energy grids.

"The first generation versions are already on route for commercial use, so the future of sodium-ion battery research is very promising."

Associate Professor Howlett said the team's breakthrough research showed how sodium secondary cells could also be used in conjunction with lithium-based devices.

"We need to look beyond lithium, and a global focus on alternative energy storage technologies has seen this area of research drastically expand in recent years," he said.

"As sodium and lithium share similarities in their electrochemistry, there is rationale for renewed interest in the area of sodium batteries."

The special edition of Advanced Energy Materials is set to be released in June, featuring 16 individual perspectives on different aspects of sodium-ion battery research.