In this paper, we develop a cylindrical triboelectric nanogenerator (TENG) for omnidirectional wind energy harvesting, by designing a slanted slit structure along the outer surface of the cylinder. The TENG consists of an inner cylinder based on Al film and a 3D printed outer structure. Wind blowing through the slits of the outer structure causes the inner cylinder to rotate in the slanted direction, and the contact-separation between the Al cylinder and polytetrafluoroethylene attached to the inner surface of the outer structure generates an output voltage. The performance of the harvester with different inner cylinder diameters under various wind speeds is experimentally studied. The results indicate that the TENG with a smaller Al cylinder is suitable for a self-powered wind speed sensor while that with a larger cylinder is optimal for efficient energy harvesting. In addition, the TENG is capable of harvesting wind energy in all directions. Its potential utility to be used as a supplementary power source for small electronic devices is verified through various experiments. Based on its compact size, simple design, and ease of manufacturing, the proposed TENG can be used as a low-cost, portable harvester.

In this study, we demonstrated a triboelectric nanogenerator composed of a vertical column, and a cylindrical shell, for omnidirectional wind energy harvesting. With a simple structure using a metal wire, the height between the two triboelectric materials can be maintained, and the Al coated shell can also be electrically connected to the electrode. When the shell is deformed by wind, its Al layer and Polytetrafluoroethylene (PTFE) on the outside of the column can be triboelectrically charged. Thus, wind energy can be harvested through a triboelectric energy conversion mechanism. In particular, due to the high flexibility of the shell, the nanogenerator operates even at wind speeds as low as 1 m/s. Although the output voltage is asymmetrical depending on the wind direction due to the metal wire, it was experimentally confirmed that the device can harvest wind energy from all directions. The measured output RMS power was approximately 15 μW at a wind speed of 6 m/s.