Whirling-Folded Triboelectric Nanogenerator with High Average Power for Water Wave Energy Harvesting

Ocean wave energy, as one of the most abundant resources on the earth, is a promising energy source for large-scale applications. Triboelectric nanogenerators (TENGs) provide a new strategy for water wave energy harvesting; however, its average performance in realistic water wave conditions is still not high. In this work, a whirling-folded TENG (WF-TENG) with maximized space utilization and minimized electrostatic shielding is constructed by 3D printing and printed circuit board technologies. The flexible vortex structure responds easily to multiform wave excitation with improved oscillation frequency. A standard water wave tank is established to generate controllable water waves to characterize the device performance. It is found to be determined by wave conditions and internal structure, which is also revealed by a theoretical dynamical analysis. The WF-TENG can produce a maximum peak power of 6.5 mW and average power of 0.28 mW, which can power a digital thermometer to operate constantly and realize self-powered monitoring on the TENG network to prevent possible damage in severe environments. Moreover, a self-charge-supplement WF-TENG network is proposed to improve the output performance and stability. This study provides an effective strategy for improving the average power and characterizing the performance of spherical TENG towards large-scale blue energy.