Stanford researchers have found a way to extinguish a fire in a lithium-ion battery. The researchers put triphenyl phosphate (TPP) inside a shell which melts at a temperature of 150 °C (302 °F) releasing the flame retardant TPP which was observed to extinguish fires in under 0.4 seconds in tests.

‘We have fabricated a novel smart electrospun separator with thermal-triggered flame-retardant properties for lithium-ion batteries,” say the reasearchers, “the encapsulation of TPP inside a protective polymer shell has prevented direct dissolution of the retardant agent into the electrolyte, which would otherwise have negative effects on battery performance.”

In the research paper we read: “Thermally triggered melting of the PVDF-HFP polymer shell would release the flame retardant, thus effectively suppressing the combustion of the highly flammable electrolytes under thermal runaway conditions of the lithium-ion battery. It is anticipated that this type of smart separator can be used in other high-energy storage devices, which may encounter thermal runaway safety issues. In the future, mechanical (nail penetration test or crush test) or electrical abuse (overcharge or deep-discharge) tests involving large-format cells will be needed for further practical applications.”

We wonder, with the fire extinguisher active so quickly, will all this Stanford technology ensure the cellphone has time to dial 911?