A Flexible Capacitive Humidity Sensor Enabled by LIG-Anchored Synergistic GO-PEDOT:PSS-MXene Composite

Indispensable roles in personalized health monitoring and human–machine interaction are played by flexible humidity sensors. However, high costs and complex vacuum processes are often involved in current fabrication methods, thereby restricting their broader applications. In this work, a high-performance flexible capacitive humidity sensor is presented, wherein a ternary composite of graphene oxide, PEDOT:PSS, and MXene (GO-PEDOT:PSS-MXene) is loaded onto a laser-induced graphene (LIG) interdigitated electrode. A pronounced synergistic effect among the three components is systematically exploited by this multidimensional architecture to significantly optimize the overall sensing performance. Within a relative humidity range extending from 11% to 97%, a remarkable measurement sensitivity of 18,643.02 μF/%RH is recorded. Furthermore, a characteristic negative capacitive response is consistently induced by moisture-driven microstructural swelling, by which the internal interlayer spacing is increased. The continuous monitoring of human respiratory rhythms and precise non-contact spatial sensing is successfully enabled by rapid response and recovery times of 31.7 s and 11.2 s, respectively. Uniquely, a vacuum-free, synergistic multidimensional architecture is successfully utilized to achieve an ultrahigh sensitivity. Practically, a highly scalable and low-cost paradigm is established by this research for the mass deployment of future wearable electronic systems across diverse monitoring scenarios.