Synthesis of Lightweight and High-Strength Polyimide/Gelatin Composite Aerogels: A Thermal Insulation Material for Preventing the Thermal Runaway of Lithium Batteries

Gelatin (GA) was used as a reinforced material in the study to enhance the thermal-mechanical properties of the polyimide (PI) aerogel. The effects of the content and the freezing rate on the thermal-mechanical properties of the composite aerogels were investigated. The internal structure and chemical composition of the composite aerogels were analyzed by using characterization methods. Finally, the mechanism of enhancement of thermal-mechanical of the composite aerogels is further discussed. The results show that GA can effectively enhance the thermal-mechanical properties of PI aerogel, and the appropriate freezing rate can form a dense pore structure inside the composite aerogel to reduce the thermal conductivity and improve the mechanical property. Moreover, the thermal runaway protection result demonstrated that the composite aerogel significantly delayed the time of thermal runaway of the lithium battery.