A New Single-Electrode Generator for Water Droplet Energy Harvesting with A 3 mA Current Output

Triboelectric nanogenerators (TENGs) based on water droplets can harvest water kinetic energy using triboelectrification and electrostatic induction mechanisms. However, the development of traditional liquid-solid TENGs (L-S TENGs) is severely limited due to their low-performance output and high device encapsulation requirements for preparation technology. In this work, a single-electrode mode droplet-based TENG (D-TENG) is devised to effectively harvest water kinetic energy by optimizing the interface contact behavior of droplets, increasing the short-circuit current (ISC) of one drop of water from microamperes to milliamperes levels. In the D-TENG configuration, the electrode is positioned above the dielectric rather than at the bottom, allowing efficient utilization of generated friction charges and reducing the dissipation of these charges, thereby enhancing the output performance of the TENG. The influencing factors and operational mechanisms of D-TENG are studied to obtain optimized working conditions to improve its output performance. Under optimal conditions, the D-TENG can saturate the charge of the PTFE surface with only 8 droplets, achieving an ISC of up to 3.51 mA and an output voltage (VO) of 298.27 V. This work provides a convenient method for efficiently harvesting water kinetic energy based on interfacial behavior control. A single-electrode mode droplet-based triboelectric nanogenerator (D-TENG) is devised through direct contact between the electrode and water, which can obtain a short-circuit current greater than 3 mA without prolonged charge accumulation. The influence of the motion state of droplets on the change of electrical signals is expounded from the perspective of fluid dynamics.image