Raindrop energy-powered autonomous wireless hyetometer based on liquid–solid contact electrification

Abstract

Triboelectric nanogenerators (TENGs) can directly harvest energy via solid–liquid interface contact electrification, making them very suitable for harvesting raindrop energy and as active rainfall sensors. This technology is promising for realizing a fully self-powered system for autonomous rainfall monitoring combined with energy harvesting/sensing. Here, we report a raindrop energy-powered autonomous rainfall monitoring and wireless transmission system (R-RMS), in which a raindrop-TENG (R-TENG) array simultaneously serves as a raindrop energy harvester and rainfall sensor. At a rainfall intensity of 71 mm/min, the R-TENG array can generate an average short-circuit current, open-circuit voltage, and maximum output power of 15 μA, 1800 V, and 325 μW, respectively. The collected energy can be adjusted to act as a stable 2.5 V direct-current source for the whole system by a power management circuit. Meanwhile, the R-TENG array acts as a rainfall sensor, in which the output signal can be monitored and the measured data are wirelessly transmitted. Under a rainfall intensity of 71 mm/min, the R-RMS can be continuously powered and autonomously transmit rainfall data once every 4 min. This work has paved the way for raindrop energy-powered wireless hyetometers, which have exhibited broad prospects in unattended weather monitoring, field surveys, and the Internet of Things.

A Multifunction Freestanding Liquid–Solid Triboelectric Nanogenerator Based on Low-Frequency Mechanical Sloshing

“…It can be seen from Figures c,d that as the concentration of KCl increased from 0 to 1 mol/L, the values of V oc and I sc decreased from <40 V to 2.5 V and 1 μA to 0.12 μA, respectively, and a similar trend also appears in NaCl solution. Previous studies have shown that the introduction of ions can reduce the electron transfer between liquid and solid surfaces, suggesting that salt solutions will lead to a significant reduction in electrical output performance. ,− …”

Recent Progress in Self-Powered Wireless Sensors and Systems Based on TENG

“…Traditional rain gauges have some disadvantages, such as complex mechanical structures, high maintenance costs, and environmental pollution [ 55 ]. Xu et al reported a new rain gauge system, which was powered by raindrops (shown in Figure 3 d) [ 56 ]. The system can harvest the raindrop energy and serve as a rainfall sensor.…”

“…( d ) A raindrop energy-powered autonomous rainfall monitoring and wireless transmission system. Reproduced with permission [ 56 ]. Copyright 2022, Springer Nature.…”

Droplet energy harvesting panel

“…Due to the alternating current output of the transistor-inspired structure, full-wave rectification is commonly required to achieve effective energy harvesting. In conventional array designs, every droplet energy harvester cell is equipped with a full-wave rectifier, 32 causing high cost and inconvenience in fabrication and maintenance. Furthermore, for array/panel integration, we cannot take it for granted that the total power output is the product of the number and power output of each droplet energy harvester cell.…”