Triboelectric Nanogenerator: Structure, Mechanism, and Applications

Abstract

With the rapid development of the Internet of Things (IoT), the number of sensors utilized for the IoT is expected to exceed 200 billion by 2025. Thus, sustainable energy supplies without the recharging and replacement of the charge storage device have become increasingly important. Among various energy harvesters, the triboelectric nanogenerator (TENG) has attracted considerable attention due to its high instantaneous output power, broad selection of available materials, eco-friendly and inexpensive fabrication process, and various working modes customized for target applications. The TENG harvests electrical energy from wasted mechanical energy in the ambient environment. Three types of operational modes based on contact-separation, sliding, and freestanding are reviewed for two different configurations with a double-electrode and a single-electrode structure in the TENGs. Various charge transfer mechanisms to explain the operational principles of TENGs during triboelectrification are also reviewed for electron, ion, and material transfers. Thereafter, diverse methodologies to enhance the output power considering the energy harvesting efficiency and energy transferring efficiency are surveyed. Moreover, approaches involving not only energy harvesting by a TENG but also energy storage by a charge storage device are also reviewed. Finally, a variety of applications with TENGs are introduced. This review can help to advance TENGs for use in self-powered sensors, energy harvesters, and other systems. It can also contribute to assisting with more comprehensive and rational designs of TENGs for various applications.

Multifunctional and Physically Transient Supercapacitors, Triboelectric Nanogenerators, and Capacitive Sensors

“…In this single electrode device, triboelectrification was obtained between this insulating PSG layer and hand, which simply enabled the conversion of mechanical energy into electrical energy. [73,74] The related mechanism is schematically illustrated in Figure 3a. Initially, surfaces of the nitrile glove and PCA/PSG layer had zero charges.…”

Temperature Field-Assisted Ultraviolet Nanosecond Pulse Laser Processing of Polyethylene Terephthalate (PET) Film

“…During the laser processing of polymers, laser ablation is a combination of photothermal and photochemical processes [26,29]. Between these two mechanisms, the photothermal mechanism plays an important role in laser processing, especially for transparent polymers with poor absorption.…”

“…Firstly, the PET film was almost transparent at the laser excitation wavelength (355 nm), and the absorbed single photon energy (3.49 eV at 355 nm) was insufficient to break the polymer backbone bonds directly (3.69 eV for C-C). The photothermal mechanism dominated the laser processing or ablation process of the PET film, and the decomposition of the PET polymer chains was mainly pyrolysis [13,26,[33][34][35]. Secondly, regarding the laser irradiation and photothermal conversion, the PET polymer chains either decomposed into small molecules or short-chain polymers, or recomposed [13,26,36].…”

“…The photothermal mechanism dominated the laser processing or ablation process of the PET film, and the decomposition of the PET polymer chains was mainly pyrolysis [13,26,[33][34][35]. Secondly, regarding the laser irradiation and photothermal conversion, the PET polymer chains either decomposed into small molecules or short-chain polymers, or recomposed [13,26,36]. At the same time, ambient gases such as oxygen and nitrogen also participated in this process.…”

Patch-Type Vibration Visualization (PVV) Sensor System Based on Triboelectric Effect

“…Static electricity is generated on its own only by physical contact, and thus no additional energy supply is required. In addition, triboelectric sensor probes offer a wide material choice window, light weight, high robustness, low cost, and high structural variability [25,26]. For vibration sensing on arbitrary surfaces in a nuclear power plant, the structure must be thin and flexible so that it can be applied to various geometries.…”