A facile respiration-driven triboelectric nanogenerator for multifunctional respiratory monitoring

Respiration is an important physiological process of human body that can not only act as vital signs for physical health management or "biomarkers" of some diseases, but also as a kind of energy that can be utilized to drive triboelectric nanogenerator (TENG). It is particularly desirable to develop a facile TENG that can be driven by human respiration itself for multifunctional human respiratory monitoring. In this work, a respiration-driven TENG based on Ce-doped ZnO-PANI nanocomposite film that can convert respiratory airflow energy into electric signals was developed for the detection of multiple respiratory parameters including trace-level NH3 concentration, human respiratory flow and respiratory frequency. It was found that the as-designed TENG exhibited excellent ability for respiratory flow monitoring (2-6 L/min), identification of human breathing frequency and recognition of different breathing patterns. Furthermore, output voltage of the self-powered NH3 sensor monotonously decreases with the increase of NH3 concentrations from 0.1 to 25 ppm. Especially, a good NH3-sensing performance was exhibited when exposed to a trace-level NH3 atmosphere ranging from 0.1 to 1 ppm, implying a promising potential in self-powered disease screening related to the detection of exhaled NH3 in human breathing. This research offers a facile method to establish a multifunctional respiratory monitoring system driven by respiration itself, which is of significant importance in self-powered human health monitoring through non-implantable respiratory diagnosis.