A phase-synchronized triboelectric-assisted electromagnetic energy harvesting system for omnidirectional low-frequency wave energy

Wave energy is an essential component of clean energy and an excellent choice for powering ocean sensors. However, the inherent challenges posed by the low-frequency and multi-directional characteristics of waves limit the effective collection and utilization of wave energy. In this study, we propose a novel solution: a multi-directional, triboelectric-assisted electromagnetic generator driven by an eccentric rod rotation. A motion equation of the eccentric rod rotation under regular wave action was established using an ideal wave model as input. The employed eccentric pendulum is highly sensitive to multi-directional, low-frequency external wave excitations. The gear-driven mechanism ensures synchronized output in both frequency and phase domains. This synchronized characteristic is strategically leveraged to incorporate triboelectric energy as an auxiliary power source, thereby enhancing the system's overall electromagnetic energy conversion efficiency. The experimental results demonstrate that under excitation frequencies within 1 Hz, this multi-source collaborative harvesting device achieves up to 50 % higher output power compared to single electromagnetic energy rectification systems. At the same time, the device can output a maximum of 195 mW DC energy at 1Hz excitation frequency. In addition, the study validated the robust performance of the device in simulated wave environments using a commercial module. This new idea provides a new energy harvesting strategy for ocean sensors.