Triboelectric Charging Research Articles

Recent Progress of Solid-Liquid Interface-Mediated Contact-Electro-Catalysis.

Contact electrification (CE) is a common physical process by which triboelectric charges are generated through the mutual contact between two objects. Despite the ongoing debates on CE's mechanism, recent advancements in technology have elucidated the primary role of electron transfer in most CE processes. This discovery leads to the spawning of an emerging field, known as contact-electro-catalysis (CEC), which utilizes the electron transfer phenomenon during CE to initiate CEC. In this work, we provide the first comprehensive review of the recent progress of the solid-liquid interface-mediated CEC process, including its working principles, relationship with surface science, recent breakthroughs in applications, and future challenges. We aim to provide fundamental guidance for researchers to understand the reaction mechanism of the CEC process and to propose potential pathways to enhance CEC efficiency from a surface and interfacial science perspective. Later, recent application scenarios using the novel CEC techniques are summarized, including wastewater treatment, efficient generation of hydrogen peroxide (H2O2), lithium-ion battery recycling, and CO2 reduction. In general, CEC technology has opened a new avenue for catalysis, effectively expanding the range of catalyst options and holding promise as a solution to a variety of complex catalytic challenges in the future.

A Fully Self-Powered Ocean Wave Observation System Empowered by Natural Light Modulated by a Friction-Driven Polymer Network Liquid Crystal.

Conventional ocean wave observation instruments are powered by batteries, limiting the continuous observation time. Besides, the waste of batteries brings environmental contaminations. Triboelectric nanogenerators (TENGs) can reveal ocean wave information through their electrical output, taking the triboelectric charge as the information carrier. However, charge amplification is necessary, consuming additional energy. Herein, taking the photons rather than electrons as the information carrier, we developed a fully self-powered natural light-enabled sensing system for ocean wave monitoring by coupling two rotary-freestanding sliding TENGs (RFS-TENGs) and a polymer network liquid crystal (PNLC)-triggered optical system. The natural light is modulated by the PNLC driven by ocean wave-induced friction. With the assistance of a one-way bearing, the rise and fall of the wave will trigger different RFS-TENGs to power the PNLC in different voltage drops, leading to different transmitted natural light intensities. The wave height information can be obtained through the number of pulse signals with the same trough light intensity, while the wave period can be obtained through the duration between the same two sets of pulse signals. The effectiveness of the developed sensing paradigm in practical applications was verified by flume-based experiments, with the highest accuracies of 90.7% in wave height and 99.8% in wave period.

Controllable Manipulation of Large-Volume Droplet on Non-Slippery Surfaces Based on Triboelectric Contactless Charge Injection.

Controllable droplet manipulation is crucial in diverse scientific and engineering fields. Traditional electric-based methods usually rely on commercial high-voltage (HV) power sources, which are typically bulky, expensive, and potentially hazardous. The triboelectric nanogenerator (TENG) is a highly studied device that can generate HV output with limited current, showing great potential in droplet manipulation applications. However, current TENG-based approaches usually utilize traditional free-standing TENGs that produce short-pulsed alternating-current signals. This limitation hinders continuous electrostatic forces necessary for precise droplet control, leading to complex circuitry and suboptimal droplet motion control in terms of volume, distance, direction, and momentum. Here, a triboelectric contactless charge injection (TCCI) method employing a novel dual-functional triboelectric nanogenerator (DF-TENG), is proposed. The DF-TENG can produce both high voltage and constant current during unidirectional motion, enabling continuous corona discharges for contactless charge injection into the droplets. Using this method, a large-volume droplet (3000 µL) can be controlled with momentum up to 115.2 g mm s-1, quintupling the highest value recorded by the traditional methods. Moreover, the TCCI method is adaptable for a variety of non-slippery substrates and droplets of different compositions and viscosities, which makes it an ideal manipulation strategy for droplet transport, chemical reactions, and even driving solids.

Dry Recycling of Lithium‐Containing Material by Forced Tribocharging and Electrostatic Separation

AbstractLithium‐containing components in batteries, electronics, and renewable energy pose material and waste challenges. Ongoing research focuses on eco‐friendly recycling, emphasizing electrostatic separation as a method to recover, for instance, lithium, especially in battery recycling. This study investigates forced dry triboelectric charging and electrostatic separation of powdered materials, with a focus on the charging behavior of lithium aluminate and talcum. The electrostatic separation efficiency for a blend of powders is also evaluated. Collected samples are analyzed via inductively coupled plasma‐mass spectrometry testing to assess component enrichment. Results show successful lithium enrichment from a talcum‐lithium aluminate mixture, highlighting significant separation success.

Unfolding the facts of structural parameters of needle punched nonwoven in influencing its triboelectrification phenomenon: a detailed experimental analysis

Triboelectrification has been a well-known phenomenon for a long time. Although there are numerous debates regarding the actual mechanism involved in this, there are few interesting works uncovering its unique signatures. In this work, triboelectrification of needle punched nonwoven structures has been explored from a few important perspectives. The effect of linear density of constituent fibre on the triboelectric charge generation ability of needle punched nonwoven structures has been investigated. Further, the influence of antistatic agent on the triboelectric charge generation has been enlightened. An attempt has also been made to correlate the structural parameters of nonwoven with its triboelectrification performance. This research work not only reveals the triboelectrification phenomenon of this fibrous structure but also it is a food for novel thoughts on triboelectric charge generation process.

Effect of atmospheric dielectric barrier discharge treatment on the triboelectric charging properties of brominated Polyethylene granules

This paper aims to investigate the effect of dielectric barrier discharge (DBD) plasma treatment on the triboelectric charging properties of granular materials containing brominated flame retardants (BFRs). This work focuses on the impact of treatment time and the applied voltage frequency. Experiments were carried out on Polyethylene (PE) particles containing 40000 ppm of bromine (PE 4.6 % of Hexabromobenzene) and BFR-free PE. The DBD treated particles were then charged by triboelectric effect in a multi-cylinder device. The triboelectric charge acquired by each sample was quantified using a Faraday cage connected to an electrometer. The humidity of the ambient air ranged between 51 % and 60 % and the temperature varied from 16.5 °C to 19 °C during the experiments. Results show the significant influence of DBD treatment time on the triboelectric charging of brominated and non-brominated PE granules. In case of brominated PE, the particles acquire less charge than the non-brominated ones. Furthermore, it was found that the charge of DBD-treated particles is influenced by the applied voltage frequency. The observed variation in triboelectric behavior may be attributed to the changes in the roughness and wettability of the polymer surface caused by DBD.

Create more and more triboelectric charges on polymer surface

Electrostatic potential induced by contact/tribo electrification on the polymer surface is often regarded as a hazard to be avoided, since it is usually the cause of electrical sparks and accidental fires. However, this electrification effect can also be an opportunity for energy harvesting and self-powered sensors through triboelectric nanogenerator (TENG) technology. More and more electrostatic charges on the surface of triboelectric polymers are the first challenge for improving the performance of TENGs and achieving various triboelectric applications. This perspective reviews strategies for increasing the charge density and the fundamental principles and conclusions related to the triboelectric properties of polymers.

Lab-based Martian analogue experiments investigating electric and magnetic fields of dust devils

Dust devils – rotating vortices of lofted particulates formed by convection from solar heating - are a prevalent aspect of Martian weather.Within a dust devil, particles become charged though triboelectrification, and observations of terrestrial dust devils have revealed electric and magnetic fields. Understanding the behaviour of these aeolian events is vital for mission planning and duration, for example, with the Insight lander as a prime example of a mission cut short due to obscuration of solar panels by lofted dust, which is highly likely to be charged. Charged dust devils on Mars strongly imply the existence of electric discharges due to the low breakdown field. The existence of discharges would in turn imply a global electric circuit on the planet – with implications for organic chemical formation and methane losses.This work presents a laboratory-based experimental set up for investigation into both electric and magnetic fields and the feasibility of using Martian analogue dust as alternative to in-situ measurements. In a dust devil, there are two main driving motions – a vertical separation of small and large particles, and the characteristic tight spiralling motion. The experimental set-up splits these components, allowing investigation into each. It is made up of a carefully designed cylindrical tank into which dusts or powders can be dropped to allow triboelectric charging as they fall under gravity. The base of the tank has a Faraday cup for charge measurement and there is also a field mill looking into the tank from the top. The rotational component is achieved using a paddle arrangement for samples placed in the base of the tank. Electric and magnetic fields have successfully been detected from charged dust with this system.

Effect of moisture content on the triboelectric charging of polymers

The triboelectrostatic separation allows the sorting of granular polymers according to their contact charging characteristics. It consists in the appropriate triboelectric charging of particles, followed by their selective sorting in an electrostatic field. Exposed to a humid atmosphere, the polymer granules adsorb water moisture onto their surfaces, which modifies their charging characteristics, by improving the contact between surfaces. The present work was aimed at studying the effect of storage environmental conditions on the triboelectric charging of granular polymers in vibratory-type devices. Four granular different plastic wastes were placed in a climatic chamber and kept for 96 hours under controlled humidity, RH = 82% ± 4%, at 19 °C ± 1 °C. The measurement of the water content of the polymer granules pointed out an increase of at least 10% after 96 h of exposure to high relative humidity ambient conditions. The granules were successively charged by triboelectric effect in a vibratory device equipped with recipients in two different materials, at ambient conditions. The tribocharging efficiency was analyzed by measuring the electric charge of the granules with a Faraday pail connected to an electrometer. The thin water layer formed at the surface of the particle can explain their modified triboelectric behavior. The difference between the triboelectric charging behavior of “humid” and “normal” polymer granules depended also on the nature of the recipient of the tribocharging device.

Influence of the Reynolds number from Reτ = 150 to 210 on size-dependent bipolar charging

We recently found wall-bounded turbulence to suppress and control bipolar triboelectric charging of particles of identical material. This control is due to fluid modifying the motion of light particles. Thus, the particles’ charge distribution depends on their Stokes number distribution. More specifically, fluid forces narrow the bandwidth of the charge distribution, and bipolar charging reduces dramatically. Consequently, not the smallest but mid-sized particles collect the most negative charge. However, the influence of the Reynolds number or particle concentration on bipolar charging of polydisperse particles is unknown. This paper presents the charging simulations of same-material particles the in different wall-bounded flows. In a comprehensive study, we vary the Reynolds number from Reτ = 150 to 210 and the particle number density from 4 × 109m-3 to 1 × 1010m-3 to further explore the influence of the carrier flow on bipolar charging. We model charge transfer based on the balance of transferable charge species. Such species can represent adsorbed ions transferred during collisions or free electrons captured into a lower energy state on the other surface. The turbulent flow is modeled via Direct Numerical Simulations (DNS) and is coupled to the particulate phase modeled via the Discrete Element Method (DEM). Overall, our multiphysics approach couples the fluid dynamics, electric field, triboelectric charging, and particle momentum into one complex simulation.

A fast electron-injection strategy for enhancing triboelectric surface charge density of polymers

Surface charge density regulation has been used for diverse range of applications. As a newly emerged high-efficiency energy converter, triboelectric nanogenerator (TENG) is sensitive to the surface charge density, making triboelectric polymers with high charge density crucial for expanding the range of TENG applications. Direct charge injection is an efficient strategy to boost output performance of TENG. However, it traditionally requires a high voltage (about 10 kV) and an injection period over minutes. The fast (<1 s) and low-voltage (< 3 kV) electron-injection process in this study for a contact-separate nanogenerator yields an output charge density of 252 μC·m−2, which is twice as large as that of the pristine device. The provided strategy can be applied to various polymers, providing opportunities for investigations in multi-science fields, not just limited to TENGs.

Recent Progress of Bioinspired Triboelectric Nanogenerators for Electronic Skins and Human–Machine Interaction

Advances in biomimetic triboelectric nanogenerators (TENGs) have significant implications for electronic skin (e-skin) and human–machine interaction (HMI). Emphasizing the need to mimic complex functionalities of natural systems, particularly human skin, TENGs leverage triboelectricity and electrostatic induction to bridge the gap in traditional electronic devices’ responsiveness and adaptability. The exploration begins with an overview of TENGs’ operational principles and modes, transitioning into structural and material biomimicry inspired by plant and animal models, proteins, fibers, and hydrogels. Key applications in tactile sensing, motion sensing, and intelligent control within e-skins and HMI systems are highlighted, showcasing TENGs’ potential in revolutionizing wearable technologies and robotic systems. This review also addresses the challenges in performance enhancement, scalability, and system integration of TENGs. It points to future research directions, including optimizing energy conversion efficiency, discovering new materials, and employing micro-nanostructuring techniques for enhanced triboelectric charges and energy conversion. The scalability and cost-effectiveness of TENG production, pivotal for mainstream application, are discussed along with the need for versatile integration with various electronic systems. The review underlines the significance of making bioinspired TENGs more accessible and applicable in everyday technology, focusing on compatibility, user comfort, and durability. Conclusively, it underscores the role of bioinspired TENGs in advancing wearable technology and interactive systems, indicating a bright future for these innovations in practical applications.

Hybrid Cellulose‐Based Systems for Triboelectrification in Aerosol Filtration, Ammonia Abatement and Respiration Monitoring

AbstractThe dissipation of charges by aging or under the effect of humid conditions considerably impedes a broader utilization of electrostatic fields in aerosol filtration. This study introduces a respiration‐driven air filter (RAF) that continuously generates triboelectric charges within a pair of tribolayers, which facilitates a sustained filtration performance. Such system is integrated in a multilayer unit that is inserted in personal protective equipment (RAFM) to efficiently capture, sense, and degrade airborne pollutants with no need for external power sources. The triboelectric nanogenerator‐based RAF continuously replenishes static charges and maintains an electrostatic field through breathing by the effect of contact‐electrification between two cellulose‐based tribolayers: a cellulose/metal organic framework cryogel (electron donor) and a cellulose–based electrospun membrane (electron acceptor). Notably, the triboelectric field of the RAF's tribolayer pair substantially enhances both the filtration efficiency (up to 93.8% for 0.3 µm particulate matter) and sensing/catalytic degradation (ammonia; degradation &gt;20%). When integrated in a circuit module, the RAFM effectively monitors respiration dynamics, acting as a breathing indicator/regulator. Overall, this study adds to the promise of tribogeneration through cellulose‐based materials and its application in exposure‐risk operations.

Revamping Triboelectric Output by Deep Trap Construction.

High output performance is critical for building triboelectric nanogenerators (TENGs) for future multifunctional applications. Unfortunately, the high triboelectric charge dissipation rate has a significant negativeimpact on its electrical output performance. Herein, a newtribolayer is designed through introducing self-assembled molecules with large energy gaps on commercial PET fibric toform carrier deep traps, which improve charge retention while decreasing dissipation rates. The deep trap density of the PET increases by two orders of magnitude, resulting in an 86% reduction in the rate of charge dissipation and a significant increase in the charge density that can be accumulated on tribolayer during physical contact. The key explanation is that increasing the density of deep traps improves the dielectric's ability to store charges, making it more difficult for the triboelectric charges trapped by the tribolayer to escape from the deep traps, lowering the rate of charge dissipation. This TENG has a 1300% increase in output power density as a result of altering the deep trap density, demonstrating a significant improvement. This work describes a simple yetefficient method for building TENGs withultra-high electrical output and promotes their practical implementation in the sphere of the Internet of Things.

Triboelectric charging and electrostatic separation of granular plastic wastes exposed to long-term action of high levels of ambient humidity

Triboelectric charging and electrostatic separation of granular plastic wastes exposed to long-term action of high levels of ambient humidity

Achieving Ultrahigh DC-Power Triboelectric Nanogenerators by Lightning Rod-Inspired Field Emission Modeling.

Direct current triboelectric nanogenerators (DC-TENGs) are a groundbreaking technology to capture micromechanical energy from the natural environment, which is crucial for directly powering sensor networks. However, the research bottleneck in enhancing the triboelectric electrification capability and charge storage capability of dielectrics has hindered the overall performance breakthroughs of the DC-TENG. Here, a field emission model-based DC-TENG (FEM-TENG) is proposed, inspired by lightning rods. The enhanced local electric field between dielectric materials and electrodes induces strong electron tunneling, which improves charge neutralization on the surface of materials and their internal charge storage space, thereby utilizing the dielectric volume effect effectively and strengthening triboelectricity. Guided by the field emission model, the FEM-TENG with a historic crest factor of 1.00375 achieves a groundbreaking record of an average power density of 16.061 W m-2 Hz-1 (1,591 W m-3 Hz-1), which is 5.36-fold of the latest DC-TENG. In particular, the FEM-TENG with high durability (100%) truly realizes the collection of breeze energy and continuously drives 50 thermohygrometers. Four additional applications exemplify the FEM-TENG, enabling comprehensive sensing of land, water, and air. This work proposes a paradigm strategy for the in-depth utilization of dielectric films, aiming to enhance the output power of DC-TENGs.

Controlling the magnitude and polarity of surface charges in PEBA polymers by adding UIO-66 MOFs

In the present work, we demonstrate that incorporating UiO-66 and UiO-66-NH2 MOF particles into the PEBA polymer increases the triboelectric surface charge density and enables control of charge polarity by using MOFs with modified linkers.

A review of material design for high performance triboelectric nanogenerators: performance improvement based on charge generation and charge loss.

As a type of innovative device, triboelectric nanogenerators (TENGs) are capable of converting mechanical energy into electrical energy through the triboelectric effect. Based on the working mechanism, the output performance of TENGs heavily relies on the triboelectric materials used. The modification of triboelectric materials is the most efficient way to improve the output performance of TENGs. Herein, this review focuses on the recent progress in triboelectric material design for high-performance TENGs. First, the basic theory of TENGs is introduced. Second, the relationship between the triboelectric materials and the output performance of TENGs is summarized in detail based on a theoretical model of the triboelectric charge dynamic equilibrium. Furthermore, the relevant strategies are analyzed in detail. Finally, challenges and shortcomings of the triboelectric materials for high-performance TENGs are discussed. This review provides a basis for the research status and future development of triboelectric materials.

High efficiency triboelectric charge capture for high output direct current electricity

A novel strategy is proposed for capturing energy lost within the tribo-layer by rationally arranging charge-collecting electrodes, achieving the highest output charge density (10.06 mC m−2) among various types of TENGs.

Surface-grafting modification of attapulgite nanorods with polysiloxane coupling agents for highly-efficient mechanical and triboelectric performance enhancement of silicone rubbers

The quest for polymeric materials that combine mechanical robustness with high triboelectric charge density is paramount in a novel kind of triboelectric nanogenerators (TENGs) that can directly convert mechanical energy into electricity in a clean and green way. Silicone rubbers (SRs) are one of the most frequently-used triboelectric materials owing to their excellent processability and high tendency of being negatively charged via contact electrification (CE), but their potential can be further maximized by strategic doping with nanomaterials. Herein, we introduced a novel kind of naturally occurring clay mineral attapulgite nanorods with surfaces modified by elaborately-synthesized polysiloxane coupling agents (PCA@ATP) to elevate the mechanical and triboelectric performance of silicone rubbers (SRs) efficiently. The modified SRs not only amplified the tensile strength by over 21 % with the addition of only 4 phr PCA@ATP, but also possessed a significant increase by 40.11 % in triboelectric charge density (ρ(Q)). Moreover, the ρ(Q) of modified SR films showed a continuously increasing trend with a further increase of PCA@ATP content. Particularly, SR films doped with 8 phr PCA@ATP showcased a ρ(Q) enhancement by 59 %, rendering them as exceptional candidates for TENGs. Through rigorous experimentation, we observed that increasing the impact frequency and PCA@ATP content consistently enhanced both the output voltage and current of the SR-based TENGs. In comparison to undoped SR films, doping with 4 phr and 8 phr PCA@ATP resulted in an impressive 122 % and 146.68 % boost in voltage and a 393 % and 508.53 % surge in power, respectively. This highly-efficient mechanical and triboelectric performance enhancement of SRs can be ascribed to the homogeneous incorporation of 1D inorganic nanomaterials PCA@ATPs with high Young's modulus, dielectric constant, and topologically-reinforced interface, leading to a comprehensive improvement of mechanical energy transfer, conversion, storage, and dissipation efficiency. This study presents a pioneering strategy for crafting robust triboelectric materials with superior CE performance, paving the way for more effective mechanical energy harvesting.