Electrically Conductive, Optically Responsive, and Highly Orientated Ti3C2Tx MXene Aerogel Fibers

Abstract Aerogel fibers, which combine the lightweight and multimesoporous properties of aerogel with the flexible and slender characteristics of the fiber, have received growing attention in the fields of smart fabrics, flexible electronic devices, and transparency‐determined optics. Herein a pure Ti 3 C 2 T x MXene aerogel fiber, showing an intriguing oriented mesoporous structure, ultrahigh electrical conductivity, and electrothermal/photothermal dual‐responsiveness, is fabricated via a simple dynamic sol–gel spinning and subsequent supercritical CO 2 drying. MXene aerogel fibers exhibit tunable porosity (96.5–99.3%), high specific surface area (up to 142 m 2 g −1 ), and low density (down to 0.035 g cm −3 ). Benefiting from the metal‐like conductive MXene nanosheets and their high orientation induced by dynamic sol–gel wet spinning, the resultant Ti 3 C 2 T x MXene aerogel fibers display ultrahigh conductivity up to 10 4 S m −1 , which far surpasses the known aerogel materials (including aerogel monoliths, aerogel fibers, and aerogel films) reported in the literature. In addition, MXene aerogel fibers also have excellent electrothermal/photothermal dual‐responsiveness due to high electrical conductivity and remarkable light absorption ability. The combination of these characteristics makes MXene aerogel fibers with encouraging potential in flexible wearable devices, smart fabrics, and portable equipment applications.