Triboelectric Nanogenerator Based on Fully Enclosed Rolling Spherical Structure for Harvesting Low‐Frequency Water Wave Energy

TLDR

Water waves are increasingly viewed as a promising source for large‑scale energy, and triboelectric nanogenerators (TENGs) are recognized as a leading approach for harvesting wave energy. The study investigates a freestanding, fully enclosed triboelectric nanogenerator that houses a rolling ball within a rocking spherical shell. The device uses a rolling ball inside a fully enclosed spherical shell with a multielectrode arrangement to enhance output under random wave motions from all directions. Optimized material and structural parameters enable the 6 cm spherical TENG to deliver up to 1 μA peak current and 10 mW instantaneous power, drive multiple LEDs, charge supercapacitors, power a thermometer for 20 min, and its lightweight, simple design allows it to rock on or in water, offering an effective large‑scale blue‑energy harvesting solution.

Abstract

Water waves are increasingly regarded as a promising source for large‐scale energy applications. Triboelectric nanogenerators (TENGs) have been recognized as one of the most promising approaches for harvesting wave energy. This work examines a freestanding, fully enclosed TENG that encloses a rolling ball inside a rocking spherical shell. Through the optimization of materials and structural parameters, a spherical TENG of 6 cm in diameter actuated by water waves can provide a peak current of 1 μA over a wide load range from a short‐circuit condition to 10 GΩ, with an instantaneous output power of up to 10 mW. A multielectrode arrangement is also studied to improve the output of the TENG under random wave motions from all directions. Moreover, at a frequency of 1.43 Hz, the wave‐driven TENG can directly drive tens of LEDs and charge a series of supercapacitors to rated voltage within several hours. The stored energy can power an electronic thermometer for 20 min. This rolling‐structured TENG is extremely lightweight, has a simple structure, and is capable of rocking on or in water to harvest wave energy; it provides an innovative and effective approach toward large‐scale blue energy harvesting of oceans and lakes.