Mover Electrode/Stater with Double Electrodes Triboelectric Nanogenerator with High Instantaneous Current Triggered by a Surficial Contact Electrode

The conventional vertical contact-separation triboelectric nanogenerator (CS-TENG) and single-electrode triboelectric nanogenerator (SE-TENG) has attracted much attention due to practicality. In applications, although CS-TENG is always preferred than SE-TENG owing to the unique double-sided power generation layers, the top mover part and the bottom stator part should be connected by conductive wires, which lead to inconvenient control and unstable performance. On the contrary, in case of SE-TENG, the mover part is free to contact and separate with the stator part without connecting any conductive wires. However, the output is much lower than CS-TENG. Remarkably, a droplet-based electricity generator (DEG), which converts water-droplet energy into electrical energy, was invented in 2020. The DEG demonstrated several orders of magnitude higher instantaneous output than its counterparts. The DEG typically consists of tiny piece of top electrode and full coverage of bottom electrode, and a dielectric material between them. The core novelty lies in introducing a new bulk effect characterized by the formation of a closed loop between droplet, electrodes, and dielectric material. Charges flow directionally from a bottom electrode into the water contacted to the top electrode. In this study, inspired from the DEG, we introduce the mover electrode to DEG and call the device mover electrode/stater with double electrodes TENG (MESD-TENG). The MESD-TENG can achieve the same bulk effect in the case of solid-solid contact. The MESD-TENG was designed to meet the merits of CS-TENG, SE-TENG and DEG at the same time.<br/>The MESD-TENG and CS-TENG were fabricated. In the case of the MESD-TENG, a fluorine-doped tin oxide (FTO)-coated glass (500 mm× 500 mm) was used as the top mover part. For a bottom stator part, the f(FEP) film (500 mm× 500 mm) was pasted on the another FTO-coated glass covered by FEP film. In this system, the top FTO acts as the tribo-positive layer and electrode simultaneously, the FEP film acts the tribo-negative layer, and the bottom FTO acts an electrode. The tiny piece of Al electrode was pasted on the FEP film. The size of the Al electrode is 10 mm × 5 mm. The Al electrode was connected to the bottom FTO electrode through external circuit. The bottom stater part was fixed and the top mover part was made moved iteratively by a step motor at 0.5 Hz. In the case of CS-TENG, FTO-coated glass (500 mm× 500 mm) was used as the top mover part. For a bottom stator part, the f(FEP) film (500 mm× 500 mm) was pasted on the another FTO-coated glass covered by FEP film. FTO in the top mover part was connected to the bottom FTO electrode through external circuit. The bottom stater part was fixed and the top mover part was made moved iteratively by a step motor at 0.5 Hz. The electrical output of them was measured by the electrometer (Keithley 6517b).<br/>As a result, the MESD-TENG achieved a 15-fold enhancement of current and voltage of almost the same order of magnitude compared to the CS-TENG. For a more intuitive verification, we compared brightness when the same numbers of LED arrays (50 LEDs) are driven by the two devices of MESD-TENG and conventional CS-TENG under the same 0.5 Hz, and the results shows the LED arrays driven by MESD-TENG are lighted up much brighter than the other one. Therefore, this work provides an effective method to develop high-performance nanogenerators for further practical application.