Single-use lithium metal batteries use lithium metal as their anode. This distinguishes their chemistry from rechargeable lithium-ion batteries, which use lithiated metal oxides in their cathodes. Both designs can discharge very high currents if they short circuit, and release high heat. Scientists at Beijing National Laboratory for Molecular Sciences have conceived a fire safe lithium metal battery, which sounds like a great step forward.
Fire Safe Principles of Modified Lithium Metal Batteries
A lithium metal battery that overheats in the manner that we described, can enter thermal runaway if the temperature increases uncontrollably. The battery can explode, and release flames that spread beyond the affected cell.
The scientists at Beijing National Laboratory for Molecular Sciences, incorporated flame-retarding interfaces in a lithium metal battery cathode. However, they do not mention the specific cathode material in their research overview, that we link to below.
But the scientists do confirm that their modified, fire safe lithium metal battery “enabled a smart response to thermal abuse, and significantly suppressed gas generation while altering gas composition”.
How the Modified Battery Discouraged Fire
The scientists explain how the flame-retarding interfaces reduced oxygen release at the cathode, that might otherwise have encouraged a fire. But the interfaces also helped reduce flammability, and prevent the case bursting open as follows:
- The self-heating rate of the modified cells was four times lower than standard lithium metal cells.
- This ‘smart gas’ strategy therefore enhanced both electrochemical stability, and thermal safety too.
The scientists from Beijing National Laboratory for Molecular Sciences, appear to justifiably claim to offer a “transformative pathway”. We take that to mean a direction to follow, that should deliver fire safe lithium metal batteries suitable for energy storage.
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