The intrinsic impact of dielectric constant on output generation of triboelectric nanogenerators

Abstract

Triboelectric Nanogenerators (TENG), which convert mechanical energy into electrical pulses, are envisioned to lead future energy harvesting and self-powered sensing applications in wearable and IoT sectors. While optimisation of most parameters related to TENG is well understood, the impact of dielectric constant, which is fundamental to their output generation, is still a highly debated topic. The intrinsic impact of dielectric constant on TENG performance is extremely difficult to assess experimentally, as it closely associates with other parameters like surface charge density that can alter TENG outputs. Herein, for the first time, we present a study to fully characterise the intrinsic impact of dielectric constant on TENG outputs. First, theoretical methods are used to investigate TENG outputs against increasing dielectric constant. A novel experimental technique is introduced using an array of liquid filler materials, providing a unique pathway to systematically tune the dielectric constant without impacting other TENG parameters. This study, for the first time, unveils the load-dependent behaviour of TENG output generation against increasing dielectric constant, along with several other previously unreported output trends. By tuning the dielectric constant, we demonstrate up to 122% (theoretical) and 28% (experimental) increments in TENG power output, paving the way for enhanced TENG optimisation.