A Strain-Resistant Flexible Thermistor Sensor Array Based on CNT/MXene Hybrid Materials for Lithium-Ion Battery and Human Temperature Monitoring

Flexible thermistor sensors (FTSs) are well-suited for myriad applications involving strain and dynamic temperature monitoring due to the outstanding thermosensitive performance and flexibility but still challenging. In this study, a novel FTS is proposed based on the hybrid materials of carbon nanotubes (CNTs) and MXene, integrated with an innovative flexible substrate (paper/polydimethylsiloxane (PDMS)/Si3N4 nanoparticles), which achieves low cost, stain resistance and results in a wide temperature detection range (-20 to 220 °C) with superior thermosensitivity (-0.52% °C⁻¹), exceptional temperature resolution (~ 0.3°C), rapid response and recovery times (~300ms and 3 s, respectively), and excellent mechanical durability (withstanding 2000 bending fatigue cycles). And the sensors excel in diverse conditions like compression, underwater, and curved surfaces. Additionally, the optimal thermosensitive performance is achieved with a 1:2 ratio of CNT and MXene. Mechanistic analysis reveals that the addition of CNT can effectively adjust the interlayer spacing of MXene, enhancing its electrical and thermosensitive properties. Furthermore, a 2×2 FTS array is successfully applied for comprehensive temperature monitoring in lithium-ion batteries (LiBs), as well as for monitoring human body and environmental temperatures as wearable devices. This technology offers high sensitivity and real-time temperature recognition, providing the possibilities for FTS applications in environmental monitoring, medical electronics, and electric vehicles.