Triboelectric nanogenerator based on a moving bubble in liquid for mechanical energy harvesting and water level monitoring

Triboelectric nanogenerator (TENG) has attracted increasing attention for its superior properties in energy harvesting and self-powered systems. Herein we demonstrate a newly designed bubble-based TENG (B-TENG) by a moving air bubble in a liquid-filled polytetrafluoroethylene (PTFE) tube. The B-TENG can produce a stable voltage of ~ 17.5 V from a slow-moving air bubble in a PTFE tube filling with DI water. The dependence of output performance on the electrode width, electrode distance, bubble volume, and moving frequency were systematically studied. Besides, a three-electrode B-TENG was fabricated to demonstrate its ability in mechanical energy harvesting. Moreover, we demonstrate the application of the B-TENG by integrating it into a water level monitoring system to detect the water level height. These results may provide an effective approach for energy harvesting and self-powered systems.