Researchers have successfully tested a fire-retardant substance that could be used to make lithium batteries much safer and longer-lasting.

The safety of lithium-ion batteries have been an issue of concern in recent years, particularly since incidents of the devices catching fire on a plane and in Samsung phones.

The pictures above show ignition tests of glass fibres saturated with a conventional electrolyte (on the left) and the new  fire-retardant electrolyte (on the right).

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“Rechargeable lithium metal batteries are regarded as the ‘holy grail’ of energy storage systems, but their practical applications have long been hindered by poor cyclability and severe safety concerns,” said researchers from the US Department of Energy’s Pacific Northwest National Laboratory in Washington.

The researchers tested a high-concentration, fire-retardant electrolyte that “dramatically overcomes its disadvantages” and “greatly enhances the cycling stability of Li-NMC622 batteries for more than 600 cycles” according to the research which was published by sustainable energy journal Joule.

Li-NMC622 refers to a type of lithium-ion battery that uses six parts nickel, three parts manganese and two parts cobalt.

NMC (also called NCM) batteries are the dominant technology used by electric car makers — although Elon Musk’s Tesla is more focused on NCA (nickel-cobalt-aluminium) batteries.

“These findings open up a new avenue for developing highly stable and safe electrolyte systems for high-energy-density lithium metal batteries for practical applications,” the researchers said.

“This new electrolyte can enable safe operation of high-energy lithium metal batteries for practical applications.”

An electrolyte is a compound that can conduct electricity when its ions are dissolved in a solution such as water.

You can read the full research report here.