Lithium-metal and lithium-ion batteries are known for their high energy density, but can be vulnerable to thermal runaway. This dangerous chain reaction, often caused by overheating or internal short circuits, produces flammable gases and extreme temperatures. Such events, though rare, can lead to prolonged fires that are difficult for emergency responders to extinguish.
Smart Gas Management Strategy: Chinese Researchers Created Lithium-Metal Cells Resistant to Fire and Explosion With Built-In Fire Suppression
Background
Several incidents of unexpected combustions related to lithium-based batteries have been reported and documented. These range from defective batteries in smartphones or battery failures in electric vehicles. Overheating or improper handling of the batteries or the associated devices can also cause unexpected fires. Fires from these batteries are hard to extinguish with water alone.
Thermal runaway is a result of self-sustaining chemical reactions that can occur without oxygen from the air. The reaction can keep going internally even if the flames are smothered. Damaged cells can also reignite hours or days later when residual heat triggers renewed decomposition. It also requires thousand liters of waters to cool a single EV or residential lithium battery.
Researchers from the Institute of Chemistry at the Chinese Academy of Sciences have designed a lithium-metal battery with built-in flame suppression. They integrated flame-retardant polymers directly into the cathode structure to form flame-retardant interfaces that release inhibitory radicals during overheating. This prevented ignition and explosion in laboratory abuse tests.
Details
The team calls their approach a smart gas management strategy. It aims to address both the amount and composition of gases produced during overheating. The flame-retardant interfaces suppress oxygen release from the cathode, limit oxidative electrolyte decomposition, and emit inhibiting radicals that diffuse to the anode to block further combustible gas generation.
Conventional lithium-metal cells reached approximately 1000 degrees Celsius and erupted into flames within minutes once exceeding 120 degrees Celsius under controlled thermal abuse test. The prototype equipped with flame-retardant interfaces peaked at only around 220 degrees Celsius and showed no signs of thermal runaway. This was true even when fully charged.
The analytical work of the research, including chemical surface mapping and gas composition analysis, confirmed that the new design reduced both the volume and flammability of gases inside the cell. This dual effect not only limits the likelihood of ignition but also reduces internal pressure buildup, thereby addressing multiple stages of the thermal runaway process.
Researchers also describe their design as compatible with current manufacturing processes. This compatibility may enable adoption without significant retooling of production lines. The proposed lithium metal battery design is an attractive option for manufacturers of electric vehicles, portable electronics, and energy storage systems seeking to address fire safety concerns.
Takeaways
Experts note that the lab results are promising, but further evaluation is required. Large-scale testing, mechanical abuse simulations, aging studies, and independent safety verification will be essential before commercial deployment. Assessment of any byproducts from the flame-retardant polymers will also be necessary to ensure they do not introduce toxic hazards.
The research does not replace other safety measures but complements existing approaches such as improved separators, better thermal management, and safer chemistries. Nevertheless, if proven reliable and feasible at commercial scale, this built-in flame suppression system could become a critical layer of defense against the rare but severe risks posed by battery fires.
A paper published on 14 July 2025 in the Proceedings of the National Academy of Sciences of the United States details the entire design, laboratory abuse testing process, and subsequent results. The first author is Jun-Chen Guo, who is also affiliated with Beijing National Laboratory for Molecular Sciences. The entire research undertaking was supervised by Chunli Bai.
FURTHER READING AND REFERENCE
- Guo, J.-C., Chai, C.-Z., Wang, Y.-H., Zhao, Y., Xin, S., Zhang, Y., Guo, Y.-G., and Bai, C. 2025. “A Fire-Safe Li Metal Battery via Smart Gas Management.” Proceedings of the National Academy of Sciences. 122(29). DOI: 1073/pnas.2501549122