A self-powered underwater glider using bidirectional swing-rotation hybrid nanogenerator

With the development of marine exploitation, ocean robots pose a great challenge to traditional battery power supply, scavenging green and sustainable energy from the ocean environment to improve duration time and operation range has become a feasible solution. Herein, a self-powered underwater glider using a bidirectional swing-rotation triboelectric-electromagnetic hybrid nanogenerator (BSR-HNG) has been fabricated to harvest energy from water waves. A mechanical rectification method using a novel gear escapement mechanism is introduced to rectify irregular low-frequency wave excitation into the stable high-frequency rotation, enabling the BSR-HNG to operate stably even at an excitation frequency of 0.1 Hz. Compared to traditional swing-rotation nanogenerators using one-way bearing, the BSR-HNG utilizes symmetrically arranged gear escapement mechanisms to convert bidirectional swing into unidirectional rotation. With the optimized design, the average output power generated in one cycle increases by 48%, and the peak power of the triboelectric nanogenerator (TENG) and electromagnetic nanogenerator (EMG) at 0.8 Hz reaches about 0.4 mW and 0.12 W, respectively. Furthermore, a commercial thermometer and a calculator are utilized to demonstrate the high performance of the BSR-HNG in a simulated wave environment. The BSR-HNG is also integrated into the underwater glider as a power source, and a depth-sensor in the underwater glider is successfully powered by BSR-HNG, which provides a new solution to improve the endurance of marine robots.