A hybrid electromagnetic-triboelectric nanogenerator via rotational energy harvesting: towards agricultural irrigation systems

Abstract Powering electronics in agricultural irrigation systems relies highly on conventional batteries, which often suffers from the issues of bulkiness, low reliance, wiring complexity and poor environmental adaptability. In such settings, as a new form of sustainable power sources, the hybrid electromagnetic-triboelectric nanogenerators (EM-TENGs) have the potential to become a superior alternative compared with conventional batteries. Here, to address the need to durably harvest and utilize rotational mechanical energy of water pumps in agricultural irrigation systems, we design and develop a compact hybrid EM-TENG with a coaxial configuration of dual integrated rotors. Device performance is separately characterized and optimized for the components of the electromagnetic generator (EMG) and the triboelectric nanogenerator (TENG), with the maximum output powers of 95.10 mW and 2.94 mW achieved under the rotation speed of 700 rpm, respectively. Meanwhile, rotation speeds can be accurately sensed by the TENG module through the parameter of characteristic frequency with errors below 2%. Moreover, our EM-TENG is able to charge a 100 μ F capacitor to 5 V in 25 s under the rotation speed of 600 rpm and power some indispensable electronic devices in agricultural environments such as timers and thermohygrometers. Our EM-TENG offers a new solution to supply power to small electronics in a compact and sustainable manner in the context of agricultural irrigation systems, circumventing the inherent disadvantages of traditional batteries and power grids in such systems.