Thermal runaway has long been a challenge in battery technology, especially in lithium-ion batteries, which typically use flammable electrolytes. This self-accelerating chain reaction occurs when a battery enters an uncontrollable heating state. A preventive solution based on sodium-ion batteries and a new electrolyte formulation has been advanced by researchers from the Chinese Academy of Sciences and Jilin University, China.
The polymerizable, nonflammable electrolyte for sodium-ion batteries works by forming a solid protective polymer barrier when temperatures increase, blocking dangerous reactions between the electrodes. This structure serves as an internal firewall, physically blocking heat from spreading and cutting off the chain reactions that typically lead to explosions. The process also impedes side reactions and the generation of reductive gases.
Testing described in Nature Energy confirmed that the battery survived external heating up to 300° C (572° F) without triggering thermal runaway. The cell also passed nail penetration tests, simulating an internal short circuit, with complete structural integrity. The device maintained a competitive energy density of 211 Wh/kg and operated reliably in temperatures ranging from -40° C to 60° C (-40° F to 140° F).
According to the researchers, “The electrolyte system uses only commercially available, conventional raw materials, making it cost-effective, easy to scale up and highly valuable for industrial application. In the future, this technology will provide a novel solution for high-energy-density, high-safety batteries.”
