Electrochemical Exfoliation of Large Antioxidative MXene Flakes for Polymeric Fire Safety

Large-size MXene flakes have drawn growing attention due to their fascinating properties, which inevitably suffer from the low yield and weak oxidation resistance. Herein, an electrochemical exfoliation approach is proposed to achieve a high recording yield of 87% for preparing large antioxidative MXene flakes with an average lateral size of 8.3 µm, which combines the etching, electrolyte intercalation, interlay expansion, and short-time sonication. Moreover, the MXene flakes can keep stable for over three months in the presence of water and oxygen, and even have good stability over 500 °C under an air atmosphere, ascribed to the protection of the surface electrolyte layer. Combined with bacterial cellulose, the MXene can serve as an intelligent resistance-type sensor for contact/non-contact fire alarm, and further integrate with IoT for remote fire detection and warning within 1 s. In addition, the MXene significantly improves the flame-retardant properties of indoor textiles and household materials, owing to the large thermostable 2D barriers to restrain heat and mass transfer. This work establishes an innovative and efficient method to prepare the large antioxidative MXene flakes in high yield for practical usage and extends its application to polymeric fire safety.