CSIRO prescribes salt baths for batteries

Salt baths are the solution for stabilising the lithium-ion batteries of the future, says the CSIRO (Commonwealth Scientific and Industrial Research Organisation).

An R&D team comprising staff from the CSIRO, the RMIT and QUT has successfully demonstrated their procedure, which is affordable and easily integrated in a commercial production scenario. According to the CSIRO, this treatment process will hasten the introduction of newer technology in lithium-based batteries for electric vehicles (such as lithium air).

The new batteries will be safer in an automotive operating environment, since the salt-bath treatment for the lithium metal electrodes reduces the propensity for fire and explosion while recharging. In addition, says the CSIRO, the ionic liquids – AKA room temperature molten salts – will extend battery life, reduce recharging time and improve battery range.

"Our research has shown by pre-treating lithium metal electrodes, we can create batteries with charge efficiency that greatly exceeds standard lithium batteries," said CSIRO battery researcher Dr Adam Best.

During the proposed production process, lithium metal electrodes would be dipped in an electrolyte bath containing a mixture of the ionic liquids and lithium salts. The ionic liquids, which are colourless, odourless and non-flammable, leave a protective film on the surface of the electrode for a more stable performance 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.

Range anxiety is set to be a thing of the past, with the new battery technology promising to deliver range in EVs comparable to that of internal-combustion vehicles – and for around the same purchase price.

An added bonus that has broader implications for batteries beyond the automotive sector is shelf life. Batteries that have been subjected to the salt-bath treatment prior to assembly can last up to 12 months uncharged, without loss of performance.

And it won't cost the earth for manufacturers to incorporate in a production process.

"The pre-treatment process is readily transferrable to existing manufacturing processes," says QUT researcher, Associate Professor Anthony O'Mullane.

The electrolyte salt solutions, to which CSIRO holds patents, come in a range of chemical compositions, and the organisation is seeking partners to aid in the process of commercialising the materials for the market.