Lithium-ion batteries are a hot commodity for the renewable energy industry. Their high energy density allows them to store huge amounts of power relative to their size, making them a go-to choice for electric vehicles, smartphones, and other rechargeable devices. Unfortunately, the heat from those same hot commodities occasionally becomes literal. Rechargeable batteries need two components for a chemical reaction to occur: a lithium metal anode that oxidizes and releases electrons and a nickel-rich oxide cathode that charges those electrons. But another byproduct is flammable gas. If ignited, the intense flames can blaze for hours while releasing smoke plumes laden with toxic chemicals. In some cases, a single lithium battery car fire requires as much as 30,000 gallons of water to fully extinguish.
With this threat in mind, automotive engineers are continually working to improve battery designs and casings. Some researchers argue that another layer of protection may also boost battery safety. According to a study published July 14 in Proceedings of the National Academy of Sciences, integrating better fire extinguisher systems into lithium-ion batteries could offer an effective, additional failsafe for drivers and passengers.
A team led by molecular chemist Ying Zhang from the Chinese Academy of Sciences Institute of Chemistry recently developed a prototype battery with cathodes infused with a flame-retardant polymer. They then tested it against a standard industry lithium battery by gradually raising their internal temperatures.
The devices both began overheating after surpassing 212 degrees Fahrenheit, but that’s where the prototype’s secret weapon came into play. At that temperature, the specialized polymers inside the cathodes started breaking down, releasing flame-inhibiting radicals to suppress the inevitable buildup of flammable gases. After passing 248 degrees, the standard battery’s runaway chain reaction caused it to explode within 13 minutes, with flames eventually reaching 1,832 degrees. In contrast, the new prototype battery topped out at 428 degrees without ever catching fire.
“This smart gas management strategy enhances both thermal safety and electrochemical stability, offering a transformative pathway to fire-safe Li metal batteries for advanced energy storage applications,” the study’s authors explained.
If scalable, the team’s design could help prevent countless battery fires by staving off even the initial flames—but it’s that detail that will be key to its success.
While some battery manufacturers already line their products with flame retardant chemicals, past studies indicate they do little to actually prevent fires. What’s more, those same chemicals may release even more toxins into the air when heated. For this latest design to work, engineers will need to make sure their invention not only prevents fires, but also does not generate any of the hazardous fumes that may come with the flames. At least so far, that seems to be the case.
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