Progress in Triboelectric Materials: Toward High Performance and Widespread Applications

Abstract

Triboelectric phenomena can be observed everywhere; however, they are consistently omitted from applications. Although almost all substances exhibit a triboelectrification effect in daily life, chemists as well as materials scientists have performed extensive investigations in both the aspects of basic science and practical applications to promote the development of triboelectric nanogenerators (TENGs). Here, a detailed survey of materials engineering for high triboelectric performance and multifunctional materials toward specific applications is summarized, including constructing micro/ nanostructures, chemically modifying the frication surface, modulating bulk friction materials, the mechanism for improved performance, and preparing materials for implantable medical devices, bionic skin, and wearable electronic devices. Moreover, an in depth discussion of the current challenges and future efforts for strengthening the performance of TENGs is elaborated in detail, which will better guide new researchers toward a deeper understanding of and explorations about TENGs.urgently needed to alleviate a more severe energy crisis, which has diverted extensive attention toward renewable energy (solar energy, geothermal energy, etc.) by virtue of its large quantity and ubiquitous existence in our environment. [1][2][3][4][5][6][7][8][9] In addition, the rapid development of science and technology has also suggested higher requirements for energy delivery. In the past few decades, large numbers of mobile communication electronics, smart wearable devices, and internet of things (IoT) devices based on tens of thousands of sensors have appeared in every corner of the globe. These electronic devices are usually characterized by requiring a small amount of power, only on the microwatt or even the milliwatt level, whereas they hold a relatively large shape to facilitate frequent charging or battery replacement for embedded traditional solid-state power sources. It is, therefore, desirable to integrate an energy harvester together with a battery to form a self-powered system that could be recharged by absorbing and transferring external fragmental energy. Furthermore, considering that a majority of these electronic devices are closely contacting the human body, the individualization of the energy-supply mode related to the person itself remains to be studied in depth.To tackle energy shortages and content-specific power supply requirements, researchers have designed a diversity of energyconversion devices derived from assorted working principles to collect energy, such as solar cells, electromagnetic generators, thermoelectric generators, piezoelectric nanogenerators, and triboelectric nanogenerators (TENGs). [10][11][12][13][14][15][16][17][18][19][20][21] Primarily benefiting from their light weight, low cost, multiple structures, extensive material selection, and even great efficiency at low operating frequencies, the novel TENGs have been proven as up-and-coming candidates to complementarily solve the energy-deficiency issue. T...

Smart Soft Actuators and Grippers Enabled by Self‐Powered Tribo‐Skins

“…Since the two strips have different boundary conditions, Strip‐B will deform together with the soft actuator following an equal bending degree. The contact area will increase with further bending of the actuator, making the Strip‐A with copper positively charged and Strip‐B with PTFE negatively charged according to the triboelectric theory . When the soft finger returns to its original shape, the contacted surfaces separate apart with electrons flowing from Strip‐A to Strip‐B to neutralize the positive charges triggered by triboelectricity.…”

Bioinspired Triboelectric Nanogenerators as Self‐Powered Electronic Skin for Robotic Tactile Sensing

“…[23,24] In addition to the self-powered features, the sensitivity and measurement range of TENG based sensors can be enhanced or modulated through modifications of surface conditions, device mode or structures, etc. [29] Indeed, TENG as an effective approach to realize e-skin sensors has been verified by a number of studies. [29] Indeed, TENG as an effective approach to realize e-skin sensors has been verified by a number of studies.…”

“…Specifically, we fabricate the interlocking structures in the triboelectric layers through the facile replication of the cone-like array microstructures of the Calathea zebrine leaf. Meanwhile, since PTFE has been known as an effective tribo-negative material, [29] PTFE tiny burrs in the size of micron or submicron were generated on top of microstructured PDMS surface through evaporation and reactive ion etching (RIE) to enhance triboelectric effect, as shown in Figure 1e. Due to the flexibility, the self-powered TENG e-skin sensor can be easily attached onto a bionic hand to verify its applications in robotics.…”

Liquid‐Filling Polydimethylsiloxane Composites with Enhanced Triboelectric Performance for Flexible Nanogenerators

“…The facility of easy‐processing and simple procedure is also an very important and attractive point which makes PDMS popular in fabrication of different kinds of TENGs. [ 17 ] In addition, the transparency, stretchability, and adaptability of PDMS also make it a promising material for flexible TENGs which are prepared for the upcoming wearable electronics era. [ 17,18 ] The comprehensive advantages endowed PDMS a key role in TENGs.…”

“…This method included doping nanomaterials and inserting sublayers, which is proposed to reduce the thickness of PDMS and increase the dielectric constant of PDMS, or filling electron capture materials. [ 17 ] The method was a facile way by mixing with other materials in PDMS solution, and the adaptability was thereby kept. Traditionally, the modulating bulk friction materials method required the introduction of other materials which usually were solids and opaque.…”