Ultra-sensitive and robust MXene/Ag-Ag nanocomposite-based conformal temperature sensor for broad-range thermal monitoring

Temperature sensors play a vital role in fields such as food safety, medical diagnostics, and aerospace. However, the development of conformal temperature sensors with high sensitivity, low cost, broad detection range, and reliable performance under extreme conditions remains a significant challenge due to limitations in materials and fabrication technologies. In this study, we synthesized titanium carbide/silver (MXene/Ag) nanocomposites through electrostatic adsorption and in-situ self-reduction, and formulated a hybrid ink suitable for aerosol jet printing (AJP). The MXene/Ag-Ag-0.28 % ink, prepared with the optimal MXene/Ag and Ag mass ratio, demonstrated outstanding printability with a resolution of up to 10 μm, along with excellent electrical conductivity and mechanical durability. The printed traces achieved a conductivity as high as 2.32 × 10⁷S/m, representing a 56 % improvement over traces printed with Ag ink. Furthermore, the resistance of the printed traces changed by only 2.8 % after 1000 bending cycles, which is 3.22 times more stable than Ag traces. In addition, the printed sensors exhibited a wide temperature detection range from −50 °C to 270 °C, with a response delay as short as 90 ms and a temperature coefficient of resistance (TCR) as high as 3.03 × 10⁻³/°C at 30 °C, which is 24 % higher than that of pure Ag ink. The sensor also demonstrated reliable responsiveness under extreme conditions such as open flame and exposure to liquid nitrogen. Moreover, high-quality conformal temperature sensors were successfully fabricated on a variety of complex curved surfaces, highlighting the advanced manufacturing capabilities of AJP. Notably, conformal sensors were also integrated onto the surface of a turning tool for real-time temperature monitoring during the machining of carbon fiber reinforced polymer (CFRP). These results offer valuable insights into the potential of AJP technology for fabricating high-performance, conformal electronic sensors.