A large-volume stable bubble-sliding triboelectric nanogenerator for high-efficiency low-frequency mechanical energy harvesting

Abstract

The efficient harvesting of low-frequency mechanical energy remains a pivotal challenge in the field of renewable energy. Although droplet sliding-based liquid–solid triboelectric nanogenerators (LS-TENGs) show potential, their practical application is limited by high triggering thresholds, three-phase contact line pinning, and trail residue. Existing bubble-driven LS-TENGs are mostly focused on sensing, with modest energy-harvesting performance (most outputs are <100 V and <1 µA), and pre-existing problems must be solved, such as the splitting of large bubbles and high trigger angles. Inspired by the ultra-low inclination sensitivity of bubble levels (0.1°), we created a large-volume stable bubble-sliding TENG (BS-TENG). Bubbles sliding on the lower FEP film exhibit the advantages of a low sliding trigger angle (1.5°), larger effective contact area, and superior structural integrity during motion. Through systematic optimization of four key parameters—bubble volume, device inclination angle, maximum linear motor speed, and FEP dielectric thickness—the BS-TENG achieves transferred charge of 1155 nC, an open-circuit voltage of 670 V, a short-circuit current of 40 µA, and energy output of 184 µJ per cycle. These metrics indicate that there are 1–2 orders of magnitude improvement with this nanogenerator over previously reported bubble-based TENGs, and it is capable of outperforming most reported droplet-based TENGs. Furthermore, the BS-TENG demonstrates excellent capacitor charging, multi-device collaboration, and practical power supply capability, providing a new strategy for high-performance LS-TENGs.