A research team from the Institute of Physics, Chinese Academy of Sciences has developed a self-protecting, non-flammable electrolyte that physically blocks "thermal runaway" in sodium-ion batteries – the first time this level of safety has been achieved in high-capacity cells. 

This "smart firewall" technology, which automatically solidifies when temperatures exceed 150°C, was detailed in a study published in Nature Energy on Monday.

For years, the industry has equated "flame-retardant electrolytes" with safety. Led by Hu Yongsheng, the team has developed Polymerizable Non-flammable Electrolyte (PNE) that acts as a multi-layered defense system.

Instead of a single line of defense, the liquid PNE can undergo a rapid phase change and solidify into a dense, physical barrier, effectively cut off the propagation of heat, and prevent the catastrophic fires or explosions typically associated with battery failure.

This breakthrough is expected to fast-track the adoption of sodium-ion batteries in sectors where safety is non-negotiable, such as Electric Vehicles (EVs), heavy-duty trucking, and massive grid-scale energy storage that are rapidly developing in China.