Energy harvesting devices and smart sensors based on porous sponge-type triboelectric nanogenerators

Abstract

Currently, the application of triboelectric nanogenerators (TENGs) in energy harvesting and self-powered sensors has garnered widespread attention. Developing TENGs with excellent electrical performance, good resilience, and durability remains a challenging task. In this study, we proposed a porous graphene–Ecoflex triboelectric nanogenerator (PGE-TENG). Using a sacrificial sugar templating method, few-layer graphene (FLG) was thoroughly mixed with Ecoflex to prepare a flexible porous sponge. By combining the conductive sponge with conductive silver fiber fabric, a TENG with mechanical, conductive, energy harvesting, and pressure-sensitive properties was fabricated. To improve the output performance, the optimized PGE-TENG, achieved by systematically controlling the mass ratio of FLG to Ecoflex, exhibited a 220% enhancement in frictional–electrical performance compared to the non-optimized TENG. Furthermore, the instantaneous power density of the PGE-TENG reached 174 mW m⁻². Thus, it can power small electronic devices and serve as a pressure sensor to respond to pressure signals. Importantly, the PGE-TENG exhibited over 19 times higher resilience and over 5 times higher pressure resistance compared to the non-optimized TENG, with good stability during continuous pressing and long-term use. This study demonstrated a low-cost and simple method for preparing high-performance TENGs; through the use of Internet of Things (IoT) technology, the single-electrode mode PGE-TENGs can be integrated into real-time control switch systems for smart homes, enabling the identification of trigger signals for smart home modules (e.g., lamps, doors, fans, and humidifiers) and controlling their operating status. This advancement provided valuable insights into the development of TENG devices in smart sensing applications.