The team led by Zhang Ying from the Institute of Chemistry, Chinese Academy of Sciences, has designed a lithium metal battery prototype equipped with a built-in "fire extinguisher," providing an innovative solution to address safety hazards in lithium metal batteries. The related research findings have been published in the Proceedings of the National Academy of Sciences.

Lithium metal batteries have an energy storage capacity ten times that of lithium-ion batteries, making their high energy density ideal for high-energy-consuming devices such as electric vehicles and portable electronics. However, their structure—using lightweight lithium metal anodes and high-voltage nickel-rich oxide cathodes—easily generates flammable gases, which can accumulate and lead to fires or explosions, greatly limiting their applications.

To overcome this challenge, Zhang Ying's team incorporated a flame-retardant polymer into the cathode of the prototype lithium metal battery. In experiments, both the prototype battery and a standard lithium metal battery were placed in an environment gradually heating from 50°C. When the temperature exceeded 100°C, both batteries began to overheat. At this point, the special polymer in the prototype battery started to decompose, releasing chemical substances that suppress flame radicals, inhibiting the reduction reactions producing flammable gases on the anode—functioning like a miniature fire extinguisher. When the temperature exceeded 120°C, the standard battery overheated to 1000°C and caught fire within 13 minutes, while the prototype battery reached a peak temperature of only 220°C without igniting or exploding.

The researchers stated that this intelligent gas management strategy enhances the thermal safety and electrochemical stability of the battery, providing a transformative approach for fire-safe lithium metal batteries in advanced energy storage applications. If this fire-extinguishing technology is applied on a large scale, it will fundamentally change the battery safety landscape in fields such as portable electronics, medical devices, grid energy storage, and electric vehicles, reducing fire risks and encouraging more people to choose electric vehicles. Additionally, the flame-retardant material requires only minor modifications to be incorporated using existing battery production methods, facilitating faster promotion and acceptance of the batteries.