Self-adaptive and soft-contact ellipsoidal pendulum-structured triboelectric nanogenerator for harvesting water wave energy

The global increasing energy shortage has prompted extensive research into exploiting environmentally friendly clean energy. As one of the most promising new energy candidates, water wave energy has been regarded as a prominent clean energy. Therefore, it is imperative to develop highly efficient techniques for harvesting water wave energy. The advent of triboelectric nanogenerators (TENGs), aiming to capture low-frequency, large-scale, and random energy, aroused significant attention. However, traditional TENGs for wave energy harvesting are always limited by the small contact area and incomplete separation. In this paper, a soft-contact and self-adaptive ellipsoidal-pendular-structured TENG (SSEP-TENG) is designed for harvesting water wave energy. Compared to traditional spherical TENGs, the unique spring-actuated soft contact not only effectively increases the contact area and reduces the wear to the TENG, but creates a quick and complete contact-separation process, which effectively improves the SSEP-TENG's output performance. Moreover, the synergy of the two solid–solid contact-separations enhances the SSEP-TENG's output performance. Finally, the maritime IoT application, a self-powered Global Positioning System (GPS) wireless positioning and tracking, was successfully realized by the SSEP-TENG, including the tracked target's longitude, latitude, altitude, and other location information. This work demonstrates the advantage of the SSEP-TENG in harvesting wave energy.