A droplet-based multi-position and multi-layered triboelectric nanogenerator for large-scale raindrop energy harvesting

The triboelectric nanogenerator (TENG) is an emerging technology proven to have great potential in rainwater energy harvesting. However, most studies have focused only on single-position droplets, and there needs to be more research on multi-position, large-scale rainwater energy. In this work, we develop a multi-position and multi-layered triboelectric nanogenerator (MM-TENG) for large-scale raindrop energy harvesting. The multi-position structure can harvest multiple droplets in the horizontal direction. The water reservoir with multiple holes can convert a large amount of water into droplets, ensuring the output performance of the TENG. The multi-layered structure improves the efficiency of space utilization, as demonstrated by the current integration calculation, where a double-layered structure increases the output by 15.27% and a three-layered structure increases the output by 38.2% at the same height. Finally, we successfully lit up 50 LEDs and drove a commercial calculator with the power generated by the MM-TENG. This work provides a practical guide for collecting large-scale raindrop energy and self-driven sensing of the rainwater environment.