Hoverboards and certain cell phones powered by lithium-ion batteries occasionally go up in flames. Scientists now have a new plan for squelching these fires before they flare out of control: incorporating a flame retardant in the battery that’s released if temperatures get too toasty.
Within lithium-ion batteries, ions travel between positive and negative electrodes through a liquid called an electrolyte. But commonly used electrolytes are highly flammable. And if a short circuit in the battery produces enough heat, the electrolyte can ignite.