Triboelectric nanogenerators for wind energy harvesting

Researchers in different disciplines from all around the world are constantly working on the development of new technologies for harvesting energy from sustainable sources. Among the various alternatives, wind is one of the most abundant resources. Traditionally, wind energy has been harvested to produce electrical energy using various types of wind turbines, including onshore or offshore wind turbines, horizontal or vertical axis wind turbines and micro-wind turbines; or, less traditionally, using wind pumps, or windmills, on sailing boats, and through some sports activities (such as kiteboarding, windsurfing and kitesurfing). In this context, wind energy harvesting using triboelectric nanogenerators (TENGs) has unique characteristics able to challenge the existing wind energy harvesting technologies. Wind-driven TENGs are in fact characterized by simple structures, reduced size and weight, easy installation, flexibility and low-cost operation. Here, starting from a detailed comparison with conventional wind turbine systems, we introduce the technological advancement of wind-driven TENGs. Device structures, materials, fabrication processes and performance characteristics in terms of costs and applications are outlined. Open issues and challenges to be addressed towards the development and industrialization of commercial products are also presented.