Stretchable conductive-ink-based wrinkled triboelectric nanogenerators for mechanical energy harvesting and self-powered signal sensing

The rapid development of flexible electronics and the corresponding fabrication technologies have increased the use of portable and wearable self-powered devices. In this work, a shape-adaptive flexible triboelectric nanogenerator (TENG) based on a conductive ink material is demonstrated. The conductive ink-based bottom electrode with wrinkled structure ensures that the TENG exhibits outstanding stretchability and output performance such that it can adapt to complex and varying environmental factors. An output voltage of 128 V and power density of 0.286 mW/cm2 were generated under contact mode with applied vertical compressive stress of 20 N. Furthermore, because of the intrinsic mechanical ductility of the wrinkled structure, the proposed TENG can maintain excellent output performance when deformed under a certain range of strains, and active motion monitoring and energy harvesting functions can also be stably achieved on the irregular surface. The device was combined with a wireless transmission system to form a wearable mechanical signal detection patch for real-time monitoring of human joint activity, which provides a new treatment option in the field of sports rehabilitation. These advantages demonstrate that the proposed cost-effective and portable TENG is a promising candidate for the development of a self-powered strain sensing device in future practical applications.