'It doesn’t catch fire': Why China’s "fireproof" sodium battery could be the breakthrough that makes EVs safer than ICE cars
New polymer electrolyte stops dangerous battery reactions during overheating
by https://www.techradar.com/uk/author/wayne-williams · TechRadarNews By Wayne Williams published 8 April 2026
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- Internal battery firewall stops overheating before fires begin during failure conditions
- Ampere-hour sodium-ion cells demonstrate complete suppression of thermal runaway reactions
- Three-part safety system improves stability without reducing energy output performance
One of the biggest risks in modern batteries is overheating which can lead to fires, but scientists at the Chinese Academy of Sciences (CAS) claim to have developed a sodium-ion battery material that forms a solid internal barrier when temperatures rise, stopping fires before they begin.
The dangerous chain reaction it addresses is known as thermal runaway, and it happens when heat inside a battery builds faster than it can escape. Once it starts, temperatures rise quickly and can lead to gas release, fire, or explosions.
That failure mode remains one of the biggest safety concerns for electric vehicles and grid-scale storage systems. Preventing the reaction entirely, rather than trying to contain it afterward, has been a major goal for battery developers.
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A three-part structure
Electric vehicles are often compared with internal combustion engine (ICE) vehicles, which carry gasoline that can ignite if damaged. A battery that stops overheating before it spreads could reduce fire risk.
The Chinese research team built what it calls a polymerizable non-flammable electrolyte, or PNE. This liquid changes into a dense solid when temperatures exceed about 302°F (150°C).
That transformation creates an internal layer that blocks heat movement between battery components. In other words, the battery builds its own firewall at the moment overheating starts.
Researchers described the chemistry behind the system in their work published in Nature. “Here we propose a polymerizable and non-flammable electrolyte, which leverages the synergistic anion-cation solvation effect and undergoes thermally triggered polymerization,” they said.
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