Recent advances in stretchable, wearable and bio-compatible triboelectric nanogenerators

Triboelectric Nanogenerators (TENGs) can convert mechanical energy into electricity and harvest this energy. It is critical to highlight and study the material selection, structure, and fabrication technique to further improve their shortcomings, such as limited comfortability, stretchability, and low current density. Thus, the recent progress of TENGs was reviewed from the aspects of stretchable materials, and fabrication methods to develop wearable TENGs, bio-based TENGs, and TENG-based hybrid devices. Moreover, for a deep understanding of TENG performance, which is helpful for optimization, the influence of critical parameters such as the contact area, mechanical tension, internal resistance, and conditioning circuit on the performance of TENGs was systematically evaluated. Furthermore, self-powered sensing devices based on TENGs have been developed for wearable and flexible electronics due to their merits over conventional power supplies. Therefore, the latest development of TENGs as smart sensors and the power supply of sensing systems was summarized in three main fields: environmental monitoring, human-machine interface (HMI), and human health monitoring. Finally, based on the challenges and limitations, we presented suggestions and prospects as future research trends for the development of TENGs.