A sodium alginate based composite aerogel for effective thermal runaway blockage and flame retardancy in lithium-ion batteries

Thermal runaway is often accompanied by fire and explosion, causing great harm. Therefore, effective thermal protection materials are currently needed to suppress the occurrence of TRP in power batteries. However, many existing thermal insulation materials have problems such as weak thermal insulation capacity, poor flame retardancy and heavy weight, making them difficult to apply. Therefore, This study synthesized a novel composite material by introducing ammonium polyphosphate (APP) and kaolin (Al₂Si₂O₅(OH)₄) into the sodium alginate (SA) matrix through freeze-drying method. This material has low thermal conductivity as 0.0472 W/m·K and excellent flame retardancy with the 68% limiting oxygen index (LOI) as V-0 level Underwriters Laboratories(UL-94, American combustion test standards) by adding flame retardants. The aerogel sheet used for battery thermal runaway had a thickness of 2 mm. This composite material also effectively suppresses thermal runaway propagation in Lithium-ion batteries, achieving a TRP suppression time of up to 30 min while lowering the peak TR temperature by as much as 400 °C., thereby providing a robust basis for the safe deployment of LIBs.