Batteries enhanced with polymeric materials that emit chemicals to suppress flames at elevated temperatures are considerably less prone to catching fire. This innovation can markedly improve the safety of battery-operated devices, including electric vehicles and medical equipment.

“Our method enhances safety in conventional liquid lithium batteries,” says Ying Chan from the Chemistry Institute of the Chinese Academy of Sciences. “It functions like a safety valve. These chemicals help to stifle flammable gases before they ignite, thus preventing fires.”

Zhang and her team developed and examined polymeric materials that extinguished flames in prototype lithium metal batteries. These batteries are presently being utilized, but upcoming versions are expected to potentially replace current batteries in electric vehicles and portable electronic gadgets. Lithium metals can store ten times more energy than widely used lithium-ion batteries by utilizing pure lithium in place of graphite for the negative electrodes.

The researchers incrementally raised the temperature of the prototype battery along with standard lithium metal batteries to 50°C. When the temperature exceeded 100°C, both batteries began to overheat, yet the special polymeric material in the prototype began to break down autonomously, releasing chemicals that functioned as “microscopic fire extinguishers.”

At temperatures surpassing 120°C, the standard battery without safety mechanisms overheated to 1000°C within 13 minutes and ignited. In contrast, under similar circumstances, the prototype battery’s peak temperature reached 220°C without any fire or explosion.

This “innovative material science strategy” suggests that it’s not only lithium metal batteries that can benefit, but also specific lithium-ion and lithium-sulfur batteries which may lower the risk of battery fires and overheating. Jaggit Nanda at the SLAC National Accelerator Laboratory, California, expresses that this could lead to safer batteries, especially for electric vehicles and aircraft.

Fire control technology has been incorporated into current battery manufacturing as a “short-term safety enhancement,” and the industry is actively seeking a long-term solution that encompasses alternative battery designs and materials, according to Zhang. However, she notes that integrating polymeric materials into the battery necessitates a re-manufacturing process.