Self-Adaptive Gyroscope-Structured Hybrid Triboelectric-Electromagnetic Buoy System for Real-Time Ocean Currents Monitoring.

With the rapid development of Internet of Things (IoT) technology, sensors have become the most important nodes for information exchange in the IoT. However, ensuring stable power supply and network communication of a plethora of distributed sensing nodes has become the key technical bottleneck that restricts the development of marine IoT. Herein, a self-adaptive gyroscope-structured hybrid triboelectric-electromagnetic nanogenerator (SAG-HTENG) is designed for omnidirectional wave energy harvesting. Through seamlessly integrating an electromagnetic generator (EMG) and triboelectric nanogenerator (TENG) modules into one device, the wave energy conversion efficiency can be significantly enhanced. Furthermore, through incorporating ferromagnetic electrode, remarkable peak power density of 29.92 W m-3 Hz-1 of the TENG module and 402.08 W m-3 Hz-1 of the EMG module can be achieved, respectively. Meanwhile, the TENG module exhibited superior working stability and applicability for harvesting low-frequency wave energy in a water tank field test compared to the EMG module. Leveraging the IoT platform, a self-powered real-time ocean currents monitoring buoy system (OCMBS) is constructed of determining the wave direction and current type. This work offers a novel energy solution for the distributed sensing nodes toward future smart marine IoT.