A Gyroscope Nanogenerator with Frequency Up-Conversion Effect for Fitness and Energy Harvesting.

Converting the mechanical energy of human motion into electricity is considered an ideal energy supply solution for portable electronics. However, low-frequency human movement limits conversion efficiency of conventional energy harvesting devices, which is difficult to provide sustainable power for portable electronic devices. Herein, a fitness gyroscope nanogenerator (fg-NG) based on a triboelectric nanogenerator (TENG) and electromagnetic generator (EMG) is developed that can convert low-frequency wrist motion into high-frequency rotation by using the frequency up-conversion effect of the gyroscope. Remarkably, the fg-NG can reach a rotational speed of over 8000 rpm by hand, increasing the frequency by more than 280 times. The fg-NG can continuously and stably output a current of 17 mA and a voltage of 70 V at frequency of 220-230 Hz. The fg-NG is demonstrated to consistently power a hygrothermograph, smart bracelet, and mobile phone. Also, it can be applicated to a self-powered intelligent training system, showing its immense application potential in portable electronics and wireless Internet of Things devices.