Water wave energy harvesting and self-powered liquid-surface fluctuation sensing based on bionic-jellyfish triboelectric nanogenerator

Due to the natural working mechanism of triboelectric nanogenerators (TENGs), potential energy stored by elastic materials may not be effectively converted into electric power, post mechanical triggering. Here, we report a practical bionic-jellyfish triboelectric nanogenerator (bjTENG) with polymeric thin film as the triboelectric material, which is shape-adaptive, with a hermetic package and a unique elastic resilience structure, similar to the behavior of a jellyfish. The charge separation in the elastic resilience of this bionic-structure is based on the liquid pressure-induced contact-separation of the triboelectric layers. On the basis of the conjunction of the triboelectrification and the electrostatic induction, a sustainable and enhanced output performance of 143 V, 11.8 mA/m² and 22.1 μC/m² under a low frequency of 0.75 Hz and at a water depth of 60 cm is produced, which can be used to supply power for dozens of green LEDs or a temperature sensor directly. More significantly, bjTENG is believed to be a priority technology which is attributable to its highly sensitivity, portability, and suitability for continuous detection of water level and fluctuation. Furthermore, a wireless self-powered fluctuation sensor early-warning system, which provides exact and wireless monitoring of fluctuation of a liquid surface, is also successfully developed.