In Situ Armoring: A Robust, High-Wettability, and Fire-Resistant Hybrid Separator for Advanced and Safe Batteries

Development of nonflammable separators with excellent properties is in urgent need by next-generation advanced and safe energy storage devices. However, it has been extremely challenging to simultaneously achieve fire resistance, high mechanical strength, good thermomechanical stability, and low ion-transport resistance for polymeric separators. Herein, to address all these needs, we report an in situ formed silica@silica-imbedded polyimide (in situ SiO2@(PI/SiO2)) nanofabric as a new high-performance inorganic–organic hybrid separator. Different from conventional ceramics-modified separators, this in situ SiO2@(PI/SiO2) hybrid separator is realized for the first time via an inverse in situ hydrolysis process. Benefiting from the in situ formed silica nanoshell, the in situ SiO2@(PI/SiO2) hybrid separator shows the highest tensile strength of 42 MPa among all reported nanofiber-based separators, excellent wettability to the electrolyte, good thermomechanical stability at 300 °C, and fire resistance. The L...