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 3s, 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.