Can We Stop Lithium-Ion Batteries Burning?

From third degree burns to in-flight implosions, the fire risk of the Galaxy Note 7 made global headlines. Now banned from a string of international airlines, the controversial device has left engineers questioning whether it’s possible to stop lithium-ion batteries from burning.

After extensive research, scientists from Stanford University now believe that they’ve found a solution. It comes in the form of ‘smart’ fibers that actively release flame retardant when temperatures get dangerously hot. The tiny capsules are designed to curb fires before they start, with high temperatures melting the plastic shells. This releases the flame retardant encapsulated inside, and stops fires before they flare out of control.

“We have fabricated a novel “smart” nonwoven electrospun separator with thermal-triggered flame-retardant properties for lithium-ion batteries,” reads the Science Advances abstract co-authored by the team.  

The ‘cream éclair’ effect

So how does it work? Lithium-ion batteries are powered by ions that use liquid electrolyte to travel between positive and negative electrodes. As commonly used electrolytes are highly flammable, a short circuit can generate enough heat to create sparks, flames and eventually, out of control fires.

Unfortunately, simply injecting the electrolyte with flame retardant jeopardises efficiency. So, the team created miniscule capsules that can be inserted in-between a battery’s electrodes, and release flame retardant only when necessary. In normal conditions, the capsules simply lie dormant and prevent the flame retardant from infiltrating the electrolyte. Critics have compared the capsules to cream éclairs, though not quite as delicious.

“The encapsulation of a flame retardant 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,” explains the abstract. During thermal runaway of the lithium-ion battery, the protective polymer shell would melt, triggered by the increased temperature, and the flame retardant would be released, thus effectively suppressing the combustion of the highly flammable electrolytes.”

The next generation battery

The revolutionary new technique was published in the journal Science Advances, with laboratory tests already confirming positive results. When tested on electrolytes topping temperatures of over 160° Celsius, the flame retardant fibers were able to quash fires within 0.4 seconds.

For battery engineers, the findings represent an exciting new opportunity to develop high density, ultra-efficient batteries, without the safety issues associated with the use of highly flammable liquid organic electrolytes.

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