Gabriel Veith
Exploding lithium-ion batteries can wreak havoc on airline flights or in waste services after folks toss their previous electronics into the trash. Now, scientists at Oak Ridge Nationwide Laboratory (ORNL) have provide you with a brand new chemical recipe that might fight the issue.
A lithium battery has two electrodes, separated by a skinny plastic sheet and submerged in a liquid electrolyte—that is a chemical medium (normally a flammable lithium-ion fluid) that enables cost to stream between a lithium-ion cathode to a carbon anode. When that skinny plastic sheet breaks (resulting from an excessive amount of jostling within the cargo maintain of an airplane, as an example), the electrodes can come collectively, shorting out the battery. This produces warmth, which may ignite the liquid electrolyte, and increase! You could have a small hearth within the cargo maintain.
That is why the FAA prohibits something containing lithium-ion batteries in checked baggage. In 2017 alone, the company reported 46 incidents of exploding batteries on airplanes.
Non-flammable strong electrolytes might clear up the issue, however ORNL physicist Gabriel Veith says this might require a big overhaul of the manufacturing course of for lithium-ion batteries, a substantial capital funding that producers may not want to make. That is why he and his cohorts are researching methods to tweak the traditional electrolyte recipe.
Talking at this week’s assembly of the American Chemical Society in Boston, Veith stated he discovered inspiration for a tweak whereas introducing his children to a cornstarch and water combination popularly generally known as “oobleck.”
The nickname is a nod to Dr. Seuss’ youngsters’s story, Bartholomew and the Oobleck, through which a magic spell gone awry causes sticky inexperienced stuff to rain down from the sky. The true-world oobleck is an instance of a non-Newtonian fluid. Isaac Newton’s definition of a super liquid is one through which the viscosity (how a lot friction or resistance there may be to stream) is primarily depending on temperature and stress. That’s, water flows the identical even when you apply a shearing drive by stirring or mixing.
American Chemical Society Press Convention.
For non-Newtonian fluids like oobleck, nonetheless, the viscosity modifications in response to a shearing drive. Initially, the particles within the substance (on this case a colloid, the place cornstarch grains are suspended in water) are loosely bonded, however any sharp influence causes the bonds to strengthen so the particles lock into place. Punch a bowl of oobleck, and it hardens right into a strong, softening once more because the vitality dissipates.
Technically, it is a shear-thickening fluid of the kind utilized in prototype bullet-proof vests or the “sensible armor” first worn by Canadian skiers within the 2006 Winter Olympics. Veith realized that this property might be invaluable in an electrolyte resolution, which might solidify in response to influence and stop the 2 electrodes from touching.
The recipe is straightforward: simply droop sphere-shaped silica nanoparticles within the standard liquid electrolytes used for lithium-ion batteries, and your work is completed. The difficult half is guaranteeing all of the nanoparticles are the identical dimension (200 nanometers in diameter); in any other case, it has the alternative impact and the liquid turns into much less viscous upon influence (a shear-thinning fluid). “And that is unhealthy,” stated Veith. (Once more, ka-boom.) There is a slight tradeoff when it comes to lowered battery capability and slower charging, however in any other case efficiency is akin to the present crop of lithium-ion batteries. And it’ll solely require a small modification to the manufacturing course of.
