Highly stretchable conductors reveal the effect of dielectric layer thickness on triboelectric nanogenerator output

Triboelectric nanogenerators (TENGs) have been extensively studied as harvesting devices for high-entropy energy in the internet of things (IoT) era. However, the mechanism by which the dielectric layer affects the TENG output remains controversial. In this paper, through studying the TENG based on liquid metal (LM) thermoplastic polyurethane (TPU) composite film (LM-TENG), a clear understanding of how the thickness of the dielectric layer affects the output of the TENG is obtained. The resistance-invariant property of the highly stretchable elastic conductor TPU@LM under large strain enables the LM-TENG to work under continuous changes in the thickness of the dielectric layer. The existence of the most suitable thickness of the TENG dielectric layer is demonstrated. The optimum equivalent thickness increased the output power of the LM-TENG by a factor of nine. This result provides important guidance for the structural design of TENGs. Finally, an anti-peeping smart door lock password system based on LM-TENG was successfully designed, demonstrating the great application potential of TENG in the field of smart home.