High-sensitivity RGO-TiO2 humidity sensor driven by triboelectric nanogenerators for non-contact monitoring of human respiration

Respiratory monitoring is an effective method to assess human health and provides valuable information for early warning and diagnosis of respiratory diseases. However, respiratory monitoring equipment relies on traditional power supply model, which limits real-time monitoring of breathing in fields of outdoor adventure, nomadism and long-distance running. As a solution, a triboelectric nanogenerator (TENG)-driven self-powered humidity sensor for human breath monitoring was prepared. A flexible TENG composed of Ti3C2Tx: PDMS composite film and Ni/Cu polyurethane foam sponge was used as self-powered part of the device, RGO-TiO2 humidity sensor was used as the respiratory sensing part of the device. Compared with the traditional humidity sensor, TENG-driven self-powered RGO-TiO2 (TENG-RGTO) shows high response (359.2), fast response/recovery time (1/5.2 s), good reversibility, small humidity hysteresis (0.54%) in the range from 0% RH to 95% RH. Furthermore, TENG-RGTO humidity sensor can realize recognition of breathing states at different frequencies and intensities in real time. Meanwhile, a breathing alarm device driven by humans is designed. This research not only broadens the application range of TENG but also provides a new design idea for self-powered breathing monitoring sensor.