Surface morphology effects in a vibration based triboelectric energy harvester

Abstract

Despite the abundance of ambient mechanical energy in our environment, it is often neglected and left unused. However, recent studies have demonstrated that mechanical vibrations can be harvested and used to power small wireless electronic devices, such as micro electromechanical sensors (MEMS) and actuators. Most commonly, these energy harvesters convert vibration into electrical energy by utilizing piezoelectric, electromagnetic or electrostatic effects. Recently, triboelectric based energy harvesters have shown to be among the simplest and most costeffective techniques for scavenging mechanical energy. The basis of triboelectric energy harvesters is the periodic contact and separation of two surfaces with opposite triboelectric properties which results in induced charge flow through an external load. Here, a vibration driven triboelectric nanogenerator (TENG) is fabricated and the effect of micro/nano scale surface modification is studied. The TENG produces electrical energy on the basis of periodic out-of-plane charge separation between gold and polydimethylsiloxane (PDMS) with opposite triboelectric charge polarities. By introducing micro/nano scale surface modifications to the PDMS and gold, the TENG's power output is further enhanced. This work demonstrates that the morphology of the surfaces in a TENG device is important and by increasing the effective surface area through micro/nano scale modification, the power output of the device can increase by 118%. Moreover, it is shown that unlike many TENGs proposed in the literature, the fabricated device has a high RMS open circuit voltage and short circuit current and can perform for an extended period of time.

Theories for triboelectric nanogenerators: A comprehensive review

“…Property modification is realized primarily through physical and chemical means. The former is to change the surface morphology of materials to increase the output performance, according to which various micro-/nano-textured patterns of the surface are designed for tribo-pairs, and their influence on the output of TENGs was studied experimentally [24][25][26][27]. In chemical means, Liu et al produced a two-step anodization method of Ti sheets to increase triboelectrically generated surface charge and thereby realized significant increment of output voltage and current [28].…”

Increased Interfacial Area between Dielectric Layer and Electrode of Triboelectric Nanogenerator toward Robustness and Boosted Energy Output

“…Introducing surface topography onto a dielectric layer is a common strategy to boost the energy output of the TENG [37,38,39,40]. Given the fact that the TENG is operated under numerous physical contact and separation conditions, the reliable electrical performance for long-lasting operation is hard to be expected from the surface topography-based strategy because mechanical wear of the surface structure is inevitable.…”

High-Performance Triboelectric Devices via Dielectric Polarization: A Review

“…Previously, the surface modification of triboelectric materials or the introduction of highly dielectric materials has been reported to increase the surface charge density. Surface modification, such as the control of surface morphology [14][15][16][17] or the introduction of charged ions [18][19][20][21], increases surface charge density by enlarging the surface area or triboelectric polarity between the triboelectric pair layers. In addition to tuning the surface property, an increase in the dielectric constant can enhance the capacitance of the dielectric (1)…”