A rotational pendulum based electromagnetic/triboelectric hybrid-generator for ultra-low-frequency vibrations aiming at human motion and blue energy applications

Abstract

Abstract There is abundance of low-frequency biomechanical and blue energy that can be harvested from our ambient environment. Utilization of these energy plays a significant role for the sustainability of the wearable devices and environmental monitoring devices. Here, we presented a rotational pendulum triboelectric-electromagnetic hybrid generator (RPHG) which is able to scavenge low-frequency ( 2 and 79.9\u202fW/m 2 are obtained at a driving frequency of 2\u202fHz and amplitude of 14\u202fcm by the TENG and EMG, respectively, which can charge a capacitor of 22μF to 7\u202fV rapidly in 30\u202fs. The RPHG can light up about more than hundreds of commercial lights emitting diodes (LEDs). Then, the RPHG was placed on human body and tested by running on treadmill and rope skipping. The open-circuit voltage of the EMG can be about 9\u202fV and that of TENG can reach 150\u202fV. Finally, the RPHG was tested on a homemade buoy in Tai Lake. When the wave frequency is about 1\u202fHz and the wave height is 20\u202fcm, the open-circuit voltage of EMG can reach over 3\u202fV and that of TENG can reach 80\u202fV regardless of whether the RPHG is placed vertically or horizontally. Generally, the proposed device demonstrates the effectiveness towards energy harvesting from ambient environment of multidirectional and wide frequency range, i.e., human motion and blue energy, showing the great potential of being a sustainable power source for those wearable devices and monitoring devices in blue ocean.