New sodium-ion battery withstood heating up to 300 °C

New sodium-ion battery withstood heating up to 300 °C

Chinese researchers have reported a major step forward in sodium-ion battery development: a team led by Professor Hu Yongsheng at the Institute of Physics, Chinese Academy of Sciences, has built a battery design in which thermal runaway has been completely eliminated. The scientists say this is the first result of its kind worldwide. At the heart of the breakthrough is a new polymerisable non-flammable electrolyte (PNE) that includes a self-protection mechanism.

How the polymerisable non-flammable electrolyte (PNE) stops thermal runaway

The new approach is based on triethyl phosphate and remains non-flammable in normal conditions, while at elevated temperatures it can rapidly polymerise. This process forms a protective barrier inside the battery, separating the electrodes and preventing mechanical and chemical interaction between them. According to the researchers, that is what fully halts the chain reaction that drives thermal runaway.

Safety testing of a 3.5 Ah sodium-ion cell

The technology was validated experimentally using a 3.5 Ah sodium-ion cell in a steel casing. The cell stayed operational even when heated to 300 °C, and it also passed a nail-penetration test-one of the most severe safety испытаний for batteries. During the test, there was no smoke, no fire and no explosion.

Performance and operating temperature range

The researchers also state that the revised design does not compromise practical performance. They report a wide operating temperature window from -40 to +60 °C and a high energy density (211 Wh/kg).

Finally, the team stresses that all materials used in the new battery are already mature industrial products. This suggests the work is not merely a laboratory demonstration, but a potentially viable basis for further industrialisation of sodium-ion batteries.