Recent Progress on Flexible Triboelectric Nanogenerators for SelfPowered Electronics

Recently, smart systems have met with large success. At the origin of the internet of things, they are a key driving force for the development of wireless, sustainable, and independent autonomous smart systems. In this context, autonomy is critical, and despite all the progress that has been made in low-power electronics and batteries, energy harvesters are becoming increasingly important. Thus, harvesting mechanical energy is essential, as it is widespread and abundant in our daily life environment. Among harvesters, flexible triboelectric nanogenerators (TENGs) exhibit good performance, and they are easy to integrate, which makes them perfect candidates for many applications and, therefore, crucial to develop. In this review paper, we first introduce the fundamentals of TENGs, including their four basic operation modes. Then, we discuss the different improvement parameters. We review some progress made in terms of performance and integration that have been possible through the understanding of each operation mode and the development of innovative structures. Finally, we present the latest trends, structures, and materials in view of future improvements and applications. Electrifying progress: Mechanical energy harvesters are becoming a valuable energy source for autonomous systems. Specifically, flexible triboelectric nanogenerators are quickly evolving. They are now easy to integrate and exhibit good performance, both of which make them perfect candidates for many applications. This review introduces this new technology and presents its recent progress and some of the latest trends.