Single-electrode-based rotationary triboelectric nanogenerator and its applications as self-powered contact area and eccentric angle sensors

We introduce a single-electrode-based rotationary triboelectric nanogenerator (SR-TENG) formed by two wheels and a belt for harvesting mechanical energy. The fundamental working principle is studied by conjunction of experimental results with finite element calculation. The continuous discharging (CD) mode and the instantaneous discharging (ID) mode have been demonstrated for the SR-TENG. The systematical experiments indicate that the short-circuit current increases with the rotating speed for SR-TENG with CD mode, but the open-circuit voltage maintains constant. The short-circuit current and open-circuit voltage decrease nearly linearly with the friction contact area, which provides an application as a self-powered surface area sensor of transmission wheel and gear. For SR-TENG with ID mode, the electric outputs are greatly enhances. The current peak is about 20 μA at variation rotating speeds even if the external load is 10 MΩ, which is 33 times higher than that of the SR-TENG with CD mode without external load. The SR-TENG with ID mode has also been demonstrated as a self-powered misalignment sensor.