Triboelectric Nanogenerator Technology Research Articles

Enhancing the filtration efficiency and wearing time of disposable surgical masks using TENG technology.

The COVID-19 pandemic has caused an unprecedented human and health crisis. And the shortage of protective equipment, especially the personal protective disposable surgical masks, has been a great challenge. Here, we developed an effective and simple scheme to prolong the lifetime of disposable surgical masks without changing their current structure, which is beneficial to solve the shortage of personal masks. After electrifying the meltblown PP filter by the new-developed single-electrode-based sliding triboelectric nanogenerator (TENG) charge replenishment (NGCR) technology, the processed filter is bipolar charged and has a filtration efficiency beyond 95% for the particulate matter (PM) ranging from PM0.3 to PM10.0. Further, we demonstrate the 80 °C dry heating is an effective decontamination method. This method is compatible with single-electrode-based sliding TENG charge replenishment technology. The 80 °C dry heating and the NGCR technology can make up an effective regeneration procedure for the mask. Even after ten cycles of simulated 4 h wearing process and such regeneration procedure, the filtration efficiency of the disposable surgical masks PM0.3 is still higher than 95%.

Recent advances in ocean wave energy harvesting by triboelectric nanogenerator: An overview

Abstract A sustainable power source is more and more important in modern society. Ocean wave energy is a very promising renewable energy source, and it is widely distributed worldwide. But, it is difficult to develop efficiently due to various limitations of the traditional electromagnetic generator. In recent years, the newly developed triboelectric nanogenerator (TENG) provides an excellent way to convert water wave energy into electrical energy, which is mainly based on the coupling between triboelectrification and electrostatic induction. In this paper, a review is given for recent advances in using the TENG technology harvesting water wave energy. We first introduce the four most fundamental modes of TENG, based on which a range of wave energy harvesting devices have been demonstrated. Then, these applications’ structure and performance optimizations are discussed. Besides, the connection methods between TENG units are also summarized. Finally, it also outlines the development prospects and challenges of technology.

Energy Harvesting from Breeze Wind (0.7–6 m s−1) Using Ultra‐Stretchable Triboelectric Nanogenerator

AbstractWind is one of the most important sources of green energy, but the current technology for harvesting wind energy is only effective when the wind speed is beyond 3.5–4.0 m s−1. This is mainly due to the limitation that the electromagnetic generator works best at high frequency. This means that light breezes cannot reach the wind velocity threshold of current wind turbines. Here, a high‐performance triboelectric nanogenerator (TENG) for efficiently harvesting energy from an ambient gentle wind, especially for speeds below 3 m s−1 is reported, by taking advantage of the relative high efficiency of TENGs at low‐frequency. Attributed to the multiplied‐frequency vibration of ultra‐stretchable and perforated electrodes, an average output of 20 mW m−3 can be achieved with inlet wind speed of 0.7 m s−1, while an average energy conversion efficiency of 7.8% at wind speed of 2.5 m s−1 is reached. A self‐charging power package is developed and the applicability of the TENG in various light breezes is demonstrated. This work demonstrates the advantages of TENG technology for breeze energy exploitation and proposes an effective supplementary approach for current employed wind turbines and micro energy structure.

Respiration-driven triboelectric nanogenerators for biomedical applications.

As a fundamental and ubiquitous body motion, respiration offers a large amount of biomechanical energy with an average power up to the Watt level through movements of multiple muscles. The energy from respiration featured with excellent stability, accessibility and continuality inspires the design and engineering of biomechanical energy harvesting devices, such as triboelectric nanogenerators (TENGs), to realize human‐powered electronics. This review article is thus dedicated to the emerging respiration‐driven TENG technology, covering fundamentals, applications, and perspectives. Specifically, the human breathing mechanics are first introduced serving as the base for the developments of TENG devices with different configurations. Biomedical applications including electrical energy generation, healthcare monitoring, air filtration, gas sensing, electrostimulation, and powering implantable medical devices are then analyzed focusing on the design‐application relationships. At last, current developments are summarized and critical challenges for driving these intriguing developments toward practical applications are discussed together with promising solutions.

Towards Truly Wearable Systems: Optimizing and Scaling Up Wearable Triboelectric Nanogenerators.

SummaryTriboelectric nanogenerator (TENG) is an upcoming technology to harvest energy from ambient movements. A major focus herein is harvesting energy from human movements through wearable TENGs, which are constructed by integrating nanogenerators into clothing or accessories. Textile-based TENGs, which include fiber, yarn, and fabric-based TENG structures, account for the majority of wearable TENGs, with many designs and applications demonstrated recently. This calls for a comprehensive analysis of textile-based TENG technology, and how the state-of-the-art device optimization concepts can be deployed to construct them efficiently. Concurrently, how advanced engineering concepts and industrial manufacturing techniques, which are bound with fiber, yarn, and fabric-related developments, can be applied into the TENG context for their output enhancement is still under investigation. Herein, we fill this vital gap by analyzing the state-of-the-art developments, upcoming trends, output optimization strategies, scalability, and prospects of the textile-based TENG technology, presenting a textile engineering perspective.

Electrode selection rules for enhancing the performance of triboelectric nanogenerators and the role of few-layers graphene

The development of portable and wearable electronics requiring only few tens of microwatts to operate fosters the search for low power energy sources. Moreover, the fast-growing demand for new sustainable energy has raised the interest in energy harvesters able to convert mechanical energy into electrical power. Triboelectric nanogenerators (TENGs) can provide such green power supply. Recent developments in TENGs technology show that they can be used in different applications ranging from wearable self-powered sensors to wind and sea wave energy harvesting. In spite of the wide number of TENGs developed so far, an in depth understanding of their working principle is still missing. In this work, we highlight the fundamental role played by the interface between the triboelectric material and the electrode collector in contributing to the TENG's power generation. We show that by simply replacing the 'standard' gold electrodes with flexible few layer graphene electrodes in TENGs operating in vertical contact mode, a 26-fold increase in power density is achieved. Here, we elucidate the main mechanism at the base of such boost in power output, describing guidelines for the combination of electrode and triboelectric materials to optimize the mechanical energy conversion efficiency in TENGs.

Polymer Materials for High-Performance Triboelectric Nanogenerators.

As an emerging branch of energy conversion technologies, the triboelectric nanogenerator (TENG) pioneers a brand‐new path to effectively harness varieties of mechanical energies for the purpose of powering and/or sensing. Since its invention in 2012, the TENG has experienced a booming and revolutionary development in every respect, ranging from materials synthesis and modification, architecture design to performance optimization, power management, and application exploration. In comparison to the organic solar cell and organic light‐emitting diodes, TENG is a unique technique that opens the venue of using polymer materials (PMs) for harvesting mechanical energy. So far, by virtue of superior charge transfer and capturing capabilities during friction, various kinds of PMs have been developed and used as triboelectric materials in order to achieve high‐performance TENGs. Here, this work focuses on the utilization and development of PMs for the TENGs technology and first gives a summary of main PMs that are frequently adopted in currently reported energy‐harvesting TENGs. Second, several kinds of PMs used lately in a few novel TENGs for special or specific energy‐harvesting circumstances are introduced and highlighted. Finally, the perspectives on and challenges in developing high‐performance PMs toward TENGs technology are conceived and expected to be instructive to future research.

Actuation and sensor integrated self-powered cantilever system based on TENG technology

Actuation and sensors for driving and monitoring of cantilever beam system are of most significant in the field of micro-electro-mechanical systems (MEMS). However, the AC voltage driving module and piezoelectric materials used in cantilever highly raise the system complexity and costs. Here, we propose a motion-triggered cantilever beam (MC) accompanied by an integrated real-time oscillation-monitoring sensor (ROS) designed based on the principle of triboelectric nanogenerator (TENG). Utilizing the periodically built and neutralized high DC voltage during the operation of the freestanding mode TENG, the low-frequency mechanical motion (down to 5 up to 200 mm/s) can be converted into high-frequency oscillation up to 100 Hz. Different from AC trigger method that requires excitation frequency matching the intrinsic frequency of the cantilever, DC actuation strategy is universal to all kinds of cantilever systems. Additionally, based on the single electrode mode TENG, the integrated self-powered ROS shows ultra-high sensitivity (223 mV/mm compared with 72 mV/mm for laser micro-motion meter). Finally, a self-powered micro-weighing system based on MC and ROS is demonstrated. This work exhibits notable advantages of using TENG technology for both power supply and sensing in MEMS applications.

High-voltage applications of the triboelectric nanogenerator—Opportunities brought by the unique energy technology

ABSTRACT

(Invited) Standardization of Triboelectric Nanogenerators: Progress and Perspectives

The rapid development of the Internet of Things (IoT) and the increasing energy crisis call for a new type of energy sources. Triboelectric nanogenerators (TENGs), which can convert mechanical energies to be electricity, develop quickly in recent years and catch more and more people’s eyes in the world. Meanwhile the importance of the standardization for TENG has been emphasized, and developing the standardized theoretical models and experimental methods to evaluate the performance quantitatively becomes more and more important for the commercialization and industrialization of the TENG technology. This presentation will systematically review the origin of the V-Q plot based standardized characterization methods and the figure-of-merits (FOM) based the standard for quantitatively charactering the energy output. This presentation will also discuss several essential factors, including the input energy, environmental factors, and life-time assessment, to be potentially involved in standards for TENGs in future. The standardization of TENG will be great helpful to understand and improve this emerging energy harvester towards further applications. We believe the standardization of TENG will greatly facilitate the commercialization and industrialization of TENGs in future.

Standardization of triboelectric nanogenerators: Progress and perspectives

The rapid development of the Internet of Things (IoT) and the increasing energy crisis call for a new type of energy sources. Triboelectric nanogenerators (TENGs), which can convert mechanical energies to electricity, develop quickly in recent years and catch more and more people's attention all over the world. Meanwhile the importance of the standardization for TENG has been emphasized, thus developing standardized theoretical models and experimental methods to quantitatively evaluate the performance becomes more and more important for the commercialization and industrialization of the TENG technology. This paper systematically reviews the origin of the V-Q plot (the standardized characterization tool) and the figure-of-merits (FOM, the standard for quantitatively charactering the energy output per cycle for TENG). Several essential factors which are going to be potentially involved in the standardization for TENGs will also be discussed in this paper, including the input energy, environmental factors, and life-time assessment. The standardization of TENG will be extremely helpful to understand and improve further applications of this emerging energy harvester. We believe that the standardization of TENG will greatly facilitate the commercialization and industrialization of TENGs in the future.

Harvest of ocean energy by triboelectric generator technology

Water wave energy widely distributed in the globe is one of the most promising renewable energy sources. However, it has not been effectively exploited by current energy harvesting technologies which primarily rely on electromagnetic generator (EMG). EMG's have various limitations, especially when operating in environment with irregular and/or low frequencies ( < 5 Hz) wave motions. Triboelectric nanogenerators (TENGs) exhibit obvious advantages over EMG in harvesting energy from low-frequency water wave motions. The networking of TENGs has been regarded as a potential method towards large-scale blue energy harvesting. In this review, recent progress of the TENG technology for blue energy harvesting is presented, including a comparison between TENG and EMG in physics and engineering design, and the fundamental mechanism of nanogenerator based on Maxwell's displacement currents is systematically introduced. The review of hydrodynamic TENG, liquid-solid contact electrification TENG, hybrid (dual-modes) TENG, fully enclosed TENG, and TENG network for blue energy harvesting is discussed. The TENG networks are expected to harvest large-scale blue energy from the ocean, which will be a feasible approach for realizing the blue energy dream. Moreover, the energy harvested by TENG from various sources, such as human motion and vibration, is not only new energy, but more importantly, energy using for the new era-the era of internet of things.At the request of the authors, this article is being retracted effective 15 May 2019.

Development, applications, and future directions of triboelectric nanogenerators

Since the invention of the triboelectric nanogenerator (TENG) in 2012, it has become one of the most vital innovations in energy harvesting technologies. The TENG has seen enormous progress to date, particularly in applications for energy harvesting and self-powered sensing. It starts with the simple working principles of the triboelectric effect and electrostatic induction, but can scavenge almost any kind of ambient mechanical energy in our daily life into electricity. Extraordinary output performance optimization of the TENG has been achieved, with high area power density and energy conversion efficiency. Moreover, TENGs can also be utilized as self-powered active sensors to monitor many environmental parameters. This review describes the recent progress in mainstream energy harvesting and self-powered sensing research based on TENG technology. The birth and development of the TENG are introduced, following which structural designs and performance optimizations for output performance enhancement of the TENG are discussed. The major applications of the TENG as a sustainable power source or a self-powered sensor are presented. The TENG, with rationally designed structures, can convert irregular and mostly low-frequency mechanical energies from the environment, such as human motion, mechanical vibration, moving automobiles, wind, raindrops, and ocean waves. In addition, the development of self-powered active sensors for a variety of environmental simulations based on the TENG is presented. The TENG plays a great role in promoting the development of emerging Internet of Things, which can make everyday objects connect more smartly and energy-efficiently in the coming years. Finally,the future directions and perspectives of the TENG are outlined. The TENG is not only a sustainable micro-power source for small devices, but also serves as a potential macro-scale generator of power from water waves in the future.

Battery-Free Electronic Smart Toys: A Step toward the Commercialization of Sustainable Triboelectric Nanogenerators

Next-generation toys are designed to entertain and interact with children. Such toys need a power source, generally a battery that must be replaced frequently, leading to increased maintenance costs. Recently, an innovative biomechanical energy harvester called a triboelectric nanogenerator (TENG) was introduced as an eco-friendly generator that scavenges waste energy. Here, in a step toward the commercialization of TENG devices, we present a novel approach that uses TENG technology to develop battery-free electronic smart toys. This robust, eco-friendly, and cost-effective approach for harnessing biomechanical energy can transform a traditional toy into a smart toy. With this innovative idea, we developed a smart clapping toy (SCT-TENG) and a smart duck toy (SDT-TENG) using biocompatible materials. We employed a simple inbuilt circuit with light-emitting diodes that are powered using biomechanical energy. The SCT-TENG and SDT-TENG exhibited output voltages of 65 Vp-p and 260 Vp-p, respectively. We believ...

Self-powered Real-time Movement Monitoring Sensor Using Triboelectric Nanogenerator Technology

The triboelectric nanogenerator (TENG) has great potential in the field of self-powered sensor fabrication. Recently, smart electronic devices and movement monitoring sensors have attracted the attention of scientists because of their application in the field of artificial intelligence. In this article, a TENG finger movement monitoring, self-powered sensor has been designed and analysed. Under finger movements, the TENG realizes the contact and separation to convert the mechanical energy into electrical signal. A pulse output current of 7.8 μA is generated by the bending and straightening motions of the artificial finger. The optimal output power can be realized when the external resistance is approximately 30 MΩ. The random motions of the finger are detected by the system with multiple TENG sensors in series. This type of flexible and self-powered sensor has potential applications in artificial intelligence and robot manufacturing.

Maximized Effective Energy Output of Contact‐Separation‐Triggered Triboelectric Nanogenerators as Limited by Air Breakdown

Recent progress in triboelectric nanogenerators (TENGs) has demonstrated their promising potential as a high‐efficiency mechanical energy harvesting technology, and plenty of effort has been devoted to improving the power output by maximizing the triboelectric surface charge density. However, due to high‐voltage air breakdown, most of the enhanced surface charge density brought by material/surface optimization or external ion injection is not retainable or usable for electricity generation during the operation of contact‐separation‐triggered TENGs. Here, the existence of the air breakdown effect in a contact‐separation mode TENG with a low threshold surface charge density of ≈40–50 µC m−2 is first validated under the high impedance external load, and then followed by the theoretical study of the maximized effective energy output as limited by air breakdown for contact‐separation‐triggered TENGs. The effects of air pressure and gas composition are also studied and propose promising solutions for reducing the air breakdown effect. This research provides a crucial fundamental study for TENG technology and its further development and applications.

A size-unlimited surface microstructure modification method for achieving high performance triboelectric nanogenerator

Triboelectric nanogenerator (TENG) is a promising mechanical energy harvesting device, which has many advantages such as low cost, high efficiency and easy fabrication. Surface modification on tribo-surface has been proved to be an efficient way to improve the output performance of TENG. However, the existing methods are time-consuming, high-cost and difficult for large-area processing, which, to some extent, limited the industrial production of TENG technology. In this work, we demonstrated a simple, fast and low-cost method, in which the tribo-surfaces of TENG were processed without size limitations to improve its output performance. Through this method, a large-scale treated TENG can be easily achieved and its output voltage and power can be increased by a factor of 3 and 5, respectively, providing us a size-unlimited, low-cost and time-saving surface micro-structure modification method for improving the output of TENG. This work showed great chance for industrial fabrication of TENG, which was crucial for sustainable power supply in the future.

Triboelectric Nanogenerators for Blue Energy Harvesting.

Blue energy in the form of ocean waves offers an enormous energy resource. However, it has yet to be fully exploited in order to make it available for the use of mankind. Blue energy harvesting is a challenging task as the kinetic energy from ocean waves is irregular in amplitude and is at low frequencies. Though electromagnetic generators (EMGs) are well-known for harvesting mechanical kinetic energies, they have a crucial limitation for blue energy conversion. Indeed, the output voltage of EMGs can be impractically low at the low frequencies of ocean waves. In contrast, triboelectric nanogenerators (TENGs) are highly suitable for blue energy harvesting as they can effectively harvest mechanical energies from low frequencies (<1 Hz) to relatively high frequencies (∼kHz) and are also low-cost, lightweight, and easy to fabricate. Several important steps have been taken by Wang's group to develop TENG technology for blue energy harvesting. In this Perspective, we describe some of the recent progress and also address concerns related to durable packaging of TENGs in consideration of harsh marine environments and power management for an efficient power transfer and distribution for commercial applications.

Hybrid nanogenerators based on triboelectrification of a dielectric composite made of lead-free ZnSnO3 nanocubes

Based on mixed piezoelectric and ferroelectric nanostructures with polymers in various architectural forms, the flexible triboelectric nanogenerators (TENGs) have been extensively investigated. In this study, we design and fabricate lead-free ZnSnO3 nanocubes @ polydimethylsiloxane (PDMS) based TENG by dispersing ZnSnO3 nanocubes into PDMS elastomer at different ratios. Finally, the TENG can attain a maximum electrical output signal up to 400V and 28μA at a current density of 7μAcm−2, and an effective power to 3mW at 6wt% mass ZnSnO3 mixed into PDMS. The harvested energy is utilized to drive 106 blue LEDs. In addition, this TENG generates stable electric power, even in the compressing-and-releasing process for over 500 cycles. Further investigation by electrostatic force microscopy shows clearly the maximum surface charge density appears at the optimal mixing ratio of ZnSnO3 piezoelectric nanostructures into PDMS. This demonstrates that the optimization of the mixing ration between ZnSnO3 piezoelectric nanostructures and PDMS is an effective method to increase the surface charges on the composite thin film and then improve the performance of the TENG. This TENG technology reveals a great candidate to be applied in large-scale device fabrications, flexible sensors and biological devices because of its easy fabrication process, high output power and biocompatibility.

Theory of freestanding triboelectric-layer-based nanogenerators

Triboelectric nanogenerator technology is emerging as a promising candidate for mechanical energy harvesting from ambient environment. Freestanding triboelectric-layer-based nanogenerators (FTENGs) are one of the fundamental operation modes with many advantages. In this paper, the first theoretical model of FTENGs is proposed with thorough analysis of their operation principle. Both contact-mode and sliding-mode FTENGs are discussed to fully uncover their unique characteristics. Contact-mode FTENGs have superior linearity, which is highly beneficial for both energy-harvesting and self-powered sensing applications. Sliding-mode FTENGs have two subcategories based on the material of their freestanding layer. For both of the two subcategories, the coupling effect of the height of the freestanding layer and the electrode gap on their output characteristics are discussed in detail to obtain the strategy for their structural optimization.