Triboelectric nanogenerator based on a water droplet spring with a concave spherical surface for harvesting wave energy and detecting pressure

Abstract

Abstract Triboelectric nanogenerator (TENG) has strong application potential in collecting nano energy and detecting micro motion. In this study, a TENG based on a water droplet spring with a concave spherical surface was proposed. The dispersive-aggregative triboelectric nanogenerator (DA-TENG) added the water droplet to the concave spherical surface which was covered with circular copper foil electrode and polytetrafluoroethylene. External loading/unloading caused water droplet dispersion/aggregation. Therefore, the solid and liquid electrodes could generate voltage by contacting and separating. Meanwhile, DA-TENG design parameters were optimized to find optimal output conditions, including the water droplet volume, the cross-sectional radius of the concave spherical surface, the force area of the elastic membrane, and the excitation frequency of the shaker. In addition, the voltage signal generated by volunteers pressing DA-TENG could show the keyboard usage habits of different people and thus serve as a basis for personnel identification, which suggested DA-TENG could be used as a self-powered pressure detector. Finally, DA-TENG was designed as a harvesting wave energy device. Under a 6 MΩ load, a unit of work could produce a peak current of 1.7 μA and an effective power of 8.82 μW; three units could produce a peak current of 5.3 μA.