A research team at the Chinese Academy of Sciences has demonstrated a sodium-ion battery that fully suppresses thermal runaway at the ampere-hour level, according to findings published April 6 in Nature Energy. Led by Hu Yongsheng at the Institute of Physics, the group developed a polymerizable non-flammable electrolyte (PNE) that forms an internal “firewall” to block heat propagation and prevent chain reactions inside the cell.
Instead of relying on traditional flame-retardant additives, the PNE system integrates thermal stability, interface robustness, and physical isolation into a multi-layer protection framework. Under normal conditions, the electrolyte remains liquid. When internal temperatures exceed 150 °C, it transitions into a solid barrier that separates reactive components and stops failure propagation rather than merely delaying ignition.
The technology was validated in a 3.5 Ah cylindrical sodium-ion cell subjected to nail penetration and external heating up to 300 °C. During these extreme tests, the cell produced no smoke, fire, or explosion, demonstrating complete interruption of thermal runaway pathways. Despite the added safety, performance metrics remain strong: the cell operates reliably from –40 °C to 60 °C, sustains voltages above 4.3 V, and achieves a cell-level energy density of 211 Wh/kg.
This research is linked to Zhongke Haina (HiNa), a sodium-ion battery developer spun out of the same institute. Early commercial heavy truck trials have reported roughly 15 percent lower energy consumption per kilometer and about a 20 percent increase in driving range under typical conditions. HiNa anticipates that sodium-ion battery costs will reach parity with lithium-ion systems by around 2027, with overlapping price ranges as production scales by 2028.
Parallel industry developments underscore the broader momentum behind sodium-ion technology. One major automaker has revealed a sodium-ion cell capable of full charging in approximately 11 minutes, along with stable operation across –40 °C to 60 °C and high-temperature abuse resistance.
Source: CarNewsChina
