A research team from the Chinese Academy of Sciences has developed a sodium-ion battery that eliminates thermal runaway at the ampere-hour level, according to findings published on April 6 in Nature Energy.
The study highlights a new safety-focused battery design aimed at addressing one of the most critical risks in energy storage systems.
The team, led by Hu Yongsheng at the Institute of Physics, introduced a polymerisable non-flammable electrolyte (PNE).
Unlike conventional solutions that rely on flame-retardant additives, the system integrates thermal stability, interface stability, and physical isolation into a multi-layer protection structure.
The electrolyte changes state when internal temperatures exceed 150°C, shifting from liquid to a solid barrier.
This transformation creates an internal separation layer that blocks heat transfer and prevents chain reactions inside the battery cell.
The design focuses on stopping failure propagation rather than delaying ignition, addressing a key limitation in traditional battery safety approaches.
The technology was tested in a 3.5Ah cylindrical sodium-ion cell.
During testing, the battery showed no smoke, fire, or explosion under nail penetration. It also avoided thermal runaway even at temperatures reaching 300°C.
These results indicate that thermal runaway pathways were fully interrupted under extreme conditions.
The improved safety does not appear to compromise performance.
The battery operates over a temperature range of -40°C to 60°C and remains stable at voltages above 4.3V.
Reported data shows an energy density of 211 Wh/kg at the cell level.
The research is linked to Zhongke Haina, a sodium-ion battery developer originating from the same institute.
Industry disclosures suggest sodium-ion batteries are moving closer to commercial deployment. Testing in heavy trucks showed around 15% lower energy consumption per kilometre and approximately 20% longer range under typical conditions, with early-stage commercial use already underway.