Effects of electrical properties on vibrations via electromechanical coupling in triboelectric energy harvesting

Abstract

Vibration energy harvesting has been a popular research topic in recent years and is a promising technology in the development of the Internet of Things. Triboelectric energy harvesting, as a relatively new energy harvesting technique, is drawing attention. However, relevant studies from the perspective of structural dynamics are rare, and a study on how the electrical properties of triboelectric energy harvesters (TEHs) affect their vibration is still missing. In this paper, we perform such a study for TEHs that use the two most common working modes—namely the lateral sliding mode and the vertical contact-separation mode. In the first part of the paper, the coupled electromechanical model of a sliding mode TEH—based on a cantilever beam system involving friction—is established. The effects of the tribo-charge surface density and the load resistance on the vibration of the harvester are investigated. It is found that the effects of the tribo-charge surface density on vibrations are similar to those of mechanical damping, while the load resistance can result in an interesting resistive shunt damping phenomenon which is distinct from the one found in piezoelectric energy harvesters. In the second part, the modelling of a vertical contact-separation mode TEH is established based on a single-degree-of-freedom vibro-impact oscillator, and the effects of the same electrical properties on vibrations are studied. The variation of the tribo-charge surface density can result in both vibration amplitude attenuation and resonance frequency shifting, while the change of the load resistance can influence vibrations only in the case of large tribo-charge surface densities. This study further unveils the electromechanical coupling mechanisms in TEHs and sheds some light on achieving desirable dynamic responses of TEHs via tuning their electrical properties.

Structural and Electrical Dynamics of a Grating-Patterned Triboelectric Energy Harvester with Stick-Slip Oscillation and Magnetic Bistability

“…The QZS spring could produce quite low stiffness in a fairly large displacement region, which enhanced harvesting efficiency under ultra-low frequency vibration. Based on a sliding-mode triboelectric energy harvester consisting of a cantilever beam, a tip mass and three magnets, multistable dynamics [23] and the effect of electrical properties for triboelectric films on vibrations [24] were investigated numerically. Tan et al [25] also proposed a cantilever-beam-based harvester with magnetic multistability, and the friction was analysed from the perspective of structural dynamics and electric output.…”

“…For triboelectric energy harvesting with sliding mode, friction is an essential factor, which exists at the interface between two distinct materials involving contact and relative sliding. In some publications [23,25,49] about sliding-mode triboelectric energy harvesters, the friction is usually modelled by Coulomb's friction law, which depends on two significant parameters, namely the coefficient of static friction 𝜇 s and the coefficient of kinetic friction 𝜇 k . It is well known that the coefficient of static friction is larger than the coefficient of kinetic friction for most materials.…”

Multifunctional Metamaterials for Energy Harvesting and Vibration Control

“…In comparison with the other three methods, a triboelectric nanogenerator (TENG) has a simpler structure but higher efficiency. It is based on the conjunction of triboelectrification effect and electrostatic induction and can efficiently harvest mechanical energy with different kinds of working modes: vertical contact mode, [ 27 ] lateral sliding mode, [ 28 ] freestanding mode, [ 29 ] and single‐electrode mode. [ 30 ] Since its invention, researchers have proposed various approaches and novel designs to improve energy harvesting efficiency.…”

“…Metamaterials are engineered materials that have unique material characteristics such as negative refractive index or negative effective properties that cannot be observed in nature. [1,2] They have periodic or non-periodic architectured structures mechanical energy with different kinds of working modes: vertical contact mode, [27] lateral sliding mode, [28] freestanding mode, [29] and single-electrode mode. [30] Since its invention, researchers have proposed various approaches and novel designs to improve energy harvesting efficiency.…”

Power Backpack for Energy Harvesting and Reduced Load Impact

“…The triboelectric nanogenerator (TENG), − as a method of harvesting ambient energy, has been created and exploited. It is based on the coupling of the electrostatic induction effect and the triboelectrification effect. − Since being created in 2012 by Wang et al ., it has witnessed rapid developments and great achievements in the self-powered sensors, − micronano energies, ,− blue-ocean energies, − and high voltage applications. − The TENG has shown many advantages in converting mechanical energy into electrical energy under a low-frequency environment, such as high output power, high energy conversion efficiency, low cost, and easy fabrication. ,, In the literature, there are a few applications of TENG to harvest the mechanical energy in a backpack. Yang et al .…”