Self-Powered Flow Rate Sensing via a Single-Electrode Flowing Liquid Based Triboelectric Nanogenerator

Recently, triboelectric nanogenerators (TENGs) have emerged as having an important role in the next wave of technology due to their large potential applications in energy harvesting and smart sensing. Recognizing this, a device based on TENGs, which can solve some of the problems in the liquid flow measurement process, was considered. In this paper, a new method to measure the liquid flow rate through a pipe which is based on the triboelectric effect is reported. A single-electrode flowing liquid-based TENG (FL-TENG) was developed, comprising a silicon pipe and an electrode coated with a polyvinylidene fluoride (PVDF) membrane. The measured electrical responses show that the FL-TENG can generate a peak open-circuit voltage and peak short-circuit current of 2.6 V and 0.3 µA when DI water is passed through an 8 mm cell FL-TENG at a flow rate of 130 mL/min and reach their maximum values of 17.8 V-1.57 µA at a flow rate of 1170 mL/min, respectively. Importantly, the FL-TENG demonstrates a robust linear correlation between its electrical output and the flow rate, with the correlation coefficient R² ranging from 0.943 to 0.996. Additionally, this study explores the potential of the FL-TENG to serve as a self-powered sensor power supply in future applications, emphasizing its adaptability as both a flow rate sensor and an energy harvesting device.