TiCT MXene Composite with Much Improved Stability for Superior Humidity Sensors.

MXenes have attracted tremendous attention in electromagnetic interference shielding, energy storage, and gas and humidity detections because of their ultralarge surface area and abundant functional groups. However, their poor stability against hydration and oxidation makes them challenging for long-term storage and applications. Herein, we proposed and demonstrated a TiCT MXene composite-based humidity sensor, of which the stability is pronouncedly enhanced by introducing an O adsorption competitor of extracted bentonite (EB). All the results of TEM, XPS, and Raman spectroscopy show that the oxidation of the TiCT MXene is significantly suppressed by the introduction of EB. Its excellent performance in humidity detection further confirms the effectiveness of EB in improving the stability. An ultrahigh response value of 6400% and an ultrafast response time of 1 s at 85% RH are observed, suggesting promising prospects for superior humidity detection of the TiCT MXene composite. Furthermore, its feasibility for flexible humidity detection was also examined on a PET substrate, which exhibited high flexibility and excellent discrimination in speaking words.