New sodium-ion battery withstands heating to 300 °C

New sodium-ion battery withstands heating to 300 °C

Chinese researchers have reported a significant advance in sodium-ion batteries. A team led by Professor Hu Yongsheng at the Institute of Physics, Chinese Academy of Sciences, has developed a battery in which thermal runaway has been completely eliminated. According to the scientists, this is the first result of its kind worldwide. The central component is a new polymerisable non-flammable electrolyte (PNE) with a self-protection mechanism.

Self-protecting non-flammable electrolyte

The new system uses triethyl phosphate and remains non-flammable. As the temperature rises, however, it can polymerise rapidly. This creates a protective barrier inside the battery, separating the electrodes and preventing mechanical and chemical interaction between them. The researchers say this mechanism completely halts the chain reaction responsible for thermal runaway.

Sodium-ion battery tests at 300 °C

The technology was tested experimentally in a 3.5 Ah sodium-ion cell housed in a steel casing. It remained operational even at 300 °C and also passed a nail-penetration test, one of the harshest battery safety scenarios. No smoke, fire or explosion was recorded during testing.

The revised design did not compromise operating performance. Its developers report a broad operating temperature range of -40 to +60 °C and a high energy density of 211 Wh/kg.

All materials used in the new battery are already established industrial products. This means the development appears to be more than a laboratory result and could provide a potentially viable basis for the further industrialisation of sodium-ion batteries.