A salt bath could boost next gen batteries for electric cars

Posted on 16 Jun 2016 by Tim Brown
CSIRO, RMIT and Queensland University of Technology are currently working on developing a “salt bath” that stabilise lithium metal foils and increase battery life and performance for electric cars - image courtesy of CSIRO.
CSIRO, RMIT and Queensland University of Technology are currently working on developing a “salt bath” that stabilise lithium metal foils and increase battery life and performance - image courtesy of CSIRO.

Scientists from the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO), in collaboration with Melbourne's RMIT University and the Queensland University of Technology, have demonstrated that pre-treating a battery’s lithium metal electrodes with an electrolyte salt solution extends the battery life and increases performance and safety.

The simple method is set to accelerate the development of next-gen energy storage solutions and overcome the issue of ‘battery range anxiety’ that is currently a barrier for widespread adoption of electric cars. The technology reportedly has the potential to improve drive range and battery charge of electric cars to a point where electric vehicles will soon be competitive with traditional petrol vehicles.

The research was published this week in Nature Communications.

CSIRO battery researcher Dr Adam Best said the pre-treated lithium metal electrodes could potentially outperform other batteries currently on the market.

“Our research has shown by pre-treating lithium metal electrodes, we can create batteries with charge efficiency that greatly exceeds standard lithium batteries,” Dr Best said.

The pre-treatment process involves the immersion of lithium metal electrodes in an electrolyte bath containing a mixture of ionic liquids and lithium salts, prior to a battery being assembled. Ionic liquids or room temperature molten salts, are a unique class of material that are clear, colourless, odourless solutions and are non-flammable.

When used in batteries these materials can prevent the risk of fire and explosion, a known rechargeable battery issue. The salt bath pre-treatment adds a protective film onto the surface of the electrode that helps stabilise the battery when in operation.

“The pre-treatment reduces the breakdown of electrolytes during operation, which is what determines the battery’s increased performance and lifetime,” Dr Best said.

A strange bedfellow for the electric car

Batteries that have undergone the process can also spend up to one year on the shelf without loss of performance. QUT researcher Assoc. Prof. Anthony O’Mullane said the method can be easily adopted by manufacturers.

“The pre-treatment process is readily transferrable to existing manufacturing processes,” Assoc. Prof. O’Mullane said.

The electrolyte salt solutions, to which CSIRO holds patents, come in a range of chemical compositions. The research formed part of Dr Andrew Basile’s doctoral thesis with RMIT University, working closely with CSIRO scientist Dr Anand Bhatt to investigate battery processes occurring at lithium metal.

The team of scientists is currently developing batteries based on this technology, and are looking for partners to help bring these materials and devices to market.

You can read complete the Nature Communication paper Stabilizing lithium metal using ionic liquids for long-lived batteries online.