River Flow-Driven Hybrid Triboelectric–Electromagnetic Generator for Self-Powered Monitoring of Aquatic Environmental Parameters

Herein, we report a river flow-driven hybrid triboelectric–electromagnetic generator (TENG-EMG) for self-powered monitoring of aquatic environmental parameters. The device integrates a zigzag triboelectric nanogenerator (ZZ-TENG), consisting of two contact–separation TENG units, with an electromagnetic generator (EMG) to effectively harvest low-frequency river flow energy. The friction surfaces of the ZZ-TENG are oppositely charged aluminum and PDMS layers, and the EMG component consists of neodymium magnets and copper coil winding. All independent components are integrated into a cylindrical acrylic casing. The ZZ-TENG component generates a maximum output with an open-circuit voltage of ≈35 V, a short circuit current of 13 μA, and a maximum power of 32 μW at a 50 MΩ load resistance. Under the movement of the magnet inside the cylindrical acrylic casing, which produces electric flux in the coil, the EMG component generates a maximum output with an open-circuit voltage of 0.4 V, a short circuit current of 22 mA, and a maximum power of 0.4 mW at an 80 Ω load resistance. The hybrid device charged a 0.3 μF capacitor to 15 V within 40 s, and the cyclic charging-discharging performance of a 0.1 μF capacitor completed 9 cycles within 500 s. The real-time application was developed by integrating the hybrid generator with a power management circuit, a microcontroller unit, and aquatic sensors. The system enables cloud-based transmission of pH, air temperature, water temperature, and humidity data at 10 s intervals, demonstrating its potential for autonomous river environmental monitoring.