Researchers have designed a lithium-ion battery that contains a fire-extinguishing material, which is released if the battery gets too hot.

研究人员设计出一款自带灭火材料的锂离子电池，在电池过热时就会释放灭火材料。

Flame retardant triphenyl phosphate (TPP) sits inside a shell within the electrolyte fluid. The shell melts when the temperature reaches 150C (302F), releasing the chemical compound.

In tests, battery fires were extinguished in 0.4 seconds.

Lithium-ion batteries power many devices but are a known fire hazard.

The Stanford University research team's peer-reviewed paper has been published by the journal Science Advances.

Previous attempts to incorporate TPP inside batteries without the shell have hampered their performance.

If a lithium-ion battery cell charges too quickly or a tiny manufacturing error slips through the net it can result in a short circuit - which can lead to fire.

In February 2016, the US National Transportation Safety Board issued a warning about lithium batteries in aeroplane cargo, describing them as "a fire and explosion ignition source".