Ammonium phosphate-based dry powder and Na2HPO4·12H2O composite powder for suppressing the thermal runaway of lithium-ion batteries

In response to the deficiencies of existing fire extinguishing agents, such as insufficient cooling performance, electrical conductivity, and the generation of toxic gases when dealing with lithium battery fires, this study has developed a composite powder fire extinguishing agent that combines commercial ABC dry powder (the main component is ammonium phosphate.) with disodium hydrogen phosphate dodecahydrate (DHPD) to address lithium-ion battery fires. Experiments have shown that 35 %DHPD@ABC can reduce the fire temperature by 297 °C within 20 s in a oil pool fire experiment, representing a 34 % improvement in cooling performance. In thermal runaway (TR) suppression tests, it rapidly lowers the battery temperature to 162 °C, with an 80 % increase in cooling efficiency and effective prevention of TR propagation. Differential scanning calorimetry (DSC) and thermogravimetric infrared (TG-IR) analyses reveal that the fire-extinguishing mechanism integrates chemical inhibition with physical cooling and isolation. This composite powder fire extinguishing agent offers an innovative strategy for the prevention of lithium-ion battery fires.