Enhancing power generation with a SnSe2-MXene composite in a piezo-triboelectric hybrid nanogenerator for autonomous energy applications

Abstract

Advancements in 5 G and IoT technologies have led to increasing power demands, and energy harvesting technology has emerged as a sustainable, eco-friendly alternative. These technologies address the issue of global warming associated with conventional fossil fuels. Due to its simple structure and efficient mechanical energy conversion, the triboelectric nanogenerator (TENG) has attracted significant attention. However, the practical applications of TENG have been constrained by its electrical output. The electrical output from energy harvesting technologies can be enhanced by combining different energy conversion mechanisms, although this approach encounters challenges due to increased structural complexity and optimization difficulties. In this research, an integrated piezo-triboelectric hybrid generator (SM-HG) is fabricated using a simple method. This method involves embedding tin diselenide (SnSe2) and MXene as piezoelectric materials and conductive fillers, respectively, within polydimethylsiloxane (PDMS). SnSe2, an n-type semiconductor and piezoelectric, enhances charge separation and storage under mechanical pressure, boosting the dielectric constant and work function through its electron-donating nature and the electronegativity of tin (Sn) and selenium (Se). MXene, as a conductive filler, forms a conductive network and micro-capacitor, improving charge transfer and dielectric properties. MXene fabricated with LiF further raised the work function due to the highest electron attraction of fluorine (F). Moreover, these materials improve conductivity and electron mobility within the PDMS, facilitating charge separation and increased induced charge generation, significantly enhancing the electrical output of the nanogenerator. The expected piezoelectric properties of SnSe2 contribute to generating additional piezoelectric charges during the operation of the hybrid generator, thereby increasing the electrical output. The piezoelectric properties of SnSe2 are verified through the increased electrical output resulting from poling and the generation of electrical output by the sandwich-structured SM-HG, which minimized the triboelectric effect. Consequently, the SM-HG achieves an open-circuit voltage (VOC) of 202.31 V and a short-circuit current (ISC) of 108.55 μA, reaching a maximum power density of 19.77 W/m2 with a load resistance of 50 MΩ. The application of SM-HG is demonstrated in measuring vehicle speeds and detecting speeding. When vehicle speeds are measured using the SM-HG based system and a commercial radar module, the speeds detected by these two methods demonstrate very high accuracy, with an error of less than 10%. The power generated by the SM-HG during the passage of a car is stored via a power management integrated circuit and later used as an energy source to drive the alerting part when speeding is detected. These results highlight the potential of the proposed SM-HG for various self-powered applications.