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Salt Baths Boost Electric Car Batteries

Pre-treating a battery’s lithium metal electrodes with an electrolyte salt solution extends the battery’s life and increases performance and safety, according to research published in Nature Communications.

The technology has the potential to improve driving range and battery charge to a point where electric vehicles will soon be competitive with traditional petrol vehicles.

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,” he 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 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,” Best said. Batteries that have undergone the process can also spend up to a year on the shelf without loss of performance.

CSIRO holds patents over the electrolyte salt solutions, which come in a range of chemical compositions.