Triboelectric Nanogenerator Unit Research Articles

Structure-Foldable and Performance-Tailorable PI Paper-Based Triboelectric Nanogenerators Processed and Controlled by Laser-Induced Graphene.

Laser-induced graphene (LIG) technology has provided a new manufacturing strategy for the rapid and scalable assembling of triboelectric nanogenerators (TENG). However, current LIG-based TENG commonly rely on polymer films, e.g., polyimide (PI) as both friction material and carbon precursor of electrodes, which limit the structural diversity and performance escalation due to its incapability of folding and creasing. Using specialized PI paper composed of randomly distributed PI fibers to substantially enhance its foldability, this work creates a new type of TENG, which are structurally foldable and stackable, and performance tailorable. First, by systematically investigating the laser power-regulated performance of single-unit TENG, the open-circuit voltage can be effectively improved. By further exploiting the folding process, multiple TENG units can be assembled together to form multi-layered structures to continuously expand the open-circuit voltage from 5.3 to 34.4Vcm-2, as the increase of friction units from 1 to 16. Last, by fully utilizing the unique structure and performance, representative energy-harvesting and smart-sensing applications are demonstrated, including a smart shoe to recognize running motions and power LEDs, a smart leaf to power a thermometer by wind, a matrix sensor to recognize writing trajectories, as well as a smart glove to recognize different objects.

A triboelectric sensing array integrating material identification and self-healing enabled by a healable polyamide-based device unit

To develop skin-like tactile sensor systems with both self-healing ability of repairing mechanical damage and perception ability of identifying materials and objects is significantly valuable for smart and high-quality interaction with environment. It is noticed that the sensing array comprised of distinct triboelectric nanogenerator (TENG) units shows great advantages in material recognition. However, those attempts of integrating self-healing ability into above triboelectric sensing array are challenged by the lack of self-healing TENG constituent units with differentiated electron affinity. Herein, we exploit a self-healing polyamide (SPA) with high mechanical strength as the base material for constructing a novel self-healing TENG unit with distinctive electron affinity. The healing of the prepared SPA-based TENG (SPA-TENG) can be autonomously conducted at room temperature without external intervention required. Our results reveal that SPA-TENG possesses stronger electron affinity compared to existing self-healing TENGs, which enables it to be an ideal constituent unit to construct self-healing triboelectric sensing array for material identification. After combining SPA-TENG with other previously reported self-healing TENGs, we firstly demonstrate a fully self-healing triboelectric sensing array capable of distinguishing various commercial plastic products based on their fingerprint waveform combinations, which shows promising application in fields of intelligent robots, artificial prosthesis, and automatic production etc.

Triboelectric–Electromagnetic Hybrid Energy Nanogenerator with Variable‐Frequency Effect Inspired by Magnetic Gears for Efficient Use of Low‐Speed Flow Energy

In the macrocontext of a low‐carbon and energy‐efficient economy, the rise of new energy vehicles is expected to replace traditional fuel vehicles. However, with the increasing number of new energy vehicles, the source of electricity for charging facilities faces new challenges. This study proposes a triboelectric–electromagnetic energy hybrid nanogenerator (VF‐TEMG) with a variable‐frequency effect inspired by an axial magnetic gear. The unit consists of one triboelectric nanogenerator (TENG) unit and two electromagnetic generator (EMG) units. The TENG unit employs a ternary dielectric structure to achieve kilovoltage output and reduce torque. Moreover, charging efficiency is enhanced using a mixture of high voltage from the TENG and EMG high current. Using the magnetic field modulation principle, the magnetic poles, which are produced by the low‐speed rotor permanent magnets, are modulated by a pole‐modulating piece into a magnetic pole harmonic equal to the number of pairs of high‐speed rotor permanent magnets. Consequently, when the low‐speed rotor starts to rotate, it drives the high‐speed rotor to rotate at high speed, thereby achieving variable‐frequency motion. This work establishes the theoretical and experimental basis for harvesting and effectively utilizing green energy based on frequency conversion.

A wind-driven rotating micro-hybrid nanogenerator for powering environmental monitoring devices based on a brush-type triboelectric unit

Abstract The rapid rise of the IoT (Internet of Things) technology and microelectronics technology has promoted the development of sensors to ultra-low power consumption. However, for conventional wired power supply and chemical battery power supply, there are difficulties in wiring, inconvenient battery replacement and environmental pollution problems, so there is an urgent need for a green power supply. The low cost and simple structure of TENG (Triboelectric nanogenerator) have attracted much attention from researchers. However, for most of the existing TENG, there are some problems such as narrow operating frequency range, short life of TENG, insufficient traditional flexible friction contact, and serious wear of rigid friction contact. Herein, we propose a rotary brush-type triboelectric-electromagnetic hybrid nanogenerator. Through the experimental tests, the TENG part can output the maximum power of 0.88 mW under the external load of 8 MΩ at 400 rpm (wind speed of about 8.3 m/s). The EMG (Electromagnetic Generator) part can output the maximum power of 15.5 mW under external load of 360 Ω. The LED lighting test proves that the generator broadens the frequency of energy harvesting. In the capacitor charging test, the high voltage characteristics of tribological power generation play the advantages of continuous voltage boost, and the high current characteristics of electromagnetic power generation play the advantages of high power. The hybrid nanogenerator can realize the wind energy harvesting under the broadband wind speed of 3 m/s~14 m/s. At a wind speed of 5.6 m/s, the hybrid nanogenerator ran at about 225 rpm and successfully powered the anemometer after 21 s. After 80,000 cycles, the maximum open circuit voltage only drops by 5.6%, which proves that the rotary TENG unit has a long generation life, and can realize the harvesting of wind energy and the power supply of wind speed sensor.

Wearable All-Fabric Hybrid Energy Harvester to Simultaneously Harvest Radiofrequency and Triboelectric Energy.

Distributed micro-energy harvesting devices offer the flexibility, sustainability, and multi-scenario applicability that will be critical to wearable electronic products in the Internet of Things. The radiofrequency and triboelectric (RF-TE) hybrid energy harvester (HEH) concept and prototype is presented for the first time, to simultaneously capture the energy from ambient electromagnetic waves and biological motions. The proposed hybrid energy harvesting system consists of a wearable rectenna, a triboelectric nanogenerator (TENG), and a power management circuit (PMC). Among them, the all-fabric rectenna exhibits good impedance matching characteristics in the ISM frequency. The flexible TENG unit can generate a maximum power density of 0.024µWcm-2. The designed multifunctional fabric-based PMC can considerably enhance the controllability of harvested hybrid energy. Additionally, a normalizable fabric circuit board quasi surface mount technology (FCB-SMT) is proposed to integrate all modules on the same fabric substrate in one step, making the entire system superior mechanical robustness. The proposed wearable fabric-based RF-TE hybrid energy harvester is capable of successfully driving consumer electronics (such as sensors, watches, etc.). It provides a new energy solution strategy for self-powered wearable electronic devices and is anticipated to encourage the efficient utilization of renewable energy.

Boosting the Electrical Performance of PLA-Based Triboelectric Nanogenerators for Sustainable Power Sources and Self-Powered Sensing.

Triboelectric nanogenerators (TENGs) have emerged as a promising technology for harvesting mechanical energy from the ambient environment. However, developing tribopositive materials with strong piezoelectric effects and high electron-donating ability still remains a challenge. Herein, poly(ethylene glycol) monomethyl ether (mPEG) to soft poly(lactic acid) (PLA) is adopted, then PLA/mPEG nanofibers are fabricated under electrospinning and used as the tribopositive material for fabricating robust power density TENGs. The crystallinity and dynamic mechanical properties of PLA/mPEG nanofibers are investigated. The results revealed that the incorporation of mPEG provided an effective approach to elevate the electron-donating ability and charge transfer efficiency in PLA. The PLA/mPEG-based TENGs achieved a high open-circuit voltage of 342.8V, a short-circuit current of 38.5µA, and a maximum power density of 116.21Wm-2 over a 2cm2 contact area at an external load of 106Ω, respectively. Strikingly, excellent stability and durability are demonstrated after continuous cycles up to104 cycles.Noteworthy, the TENGs are explored for self-powered sensing applications, with seven TENG units integrated to act as self-powered sensors playing music through buzzers when pressed by fingers. Eventually, this work provides new insights into tuning the structures and properties of electrospun polymers to reinforce the TENG output and self-powered systems.

Tensegrity triboelectric nanogenerator for broadband blue energy harvesting in all-sea areas

The integration of high-density friction layer units is a promising approach for achieving high output in triboelectric nanogenerators (TENGs). Yet, the synchronization and sufficient contact separation of these high-density layer units are inherently challenging due to the cumulative impact of gravity. Herein, a tensegrity structure was applied and effectively organized the high-density stacked TENG units into an ordered whole, thereby proposing the T-TENG. Along with achieving orderly contact and separation of high-density friction layers, the T-TENG effectively reduced the device's height (up to 52%) and improved the friction layer surface area density (up to 1.07 cm−1). Significantly, the built-in prestress modulation not only enhances the device's load-bearing capacity but also enables ease in changing the T-TENG's response frequency by adjusting the prestress value. This is especially suitable for efficiently capturing omnidirectional wave energy in all-sea areas with frequency variations. The working mechanism and output influencing parameters of T-TENG were systematically expounded, and it demonstrated a maximum output voltage of up to 1020 V and output charge per unit time of 0.816 mC/min, sufficient to light up to 1512 LEDs directly. Moreover, customization of low-loss gas discharge tubes to amplify outputs allows T-TENG to harvest wave energy for power supply to small electronic devices such as water quality testing pens and Bluetooth modules when placed over water bodies. This work provides a foundational model to develop high-density friction layers and high-output TENGs.

Broadband and Multi-Cylinder-Based Triboelectric Nanogenerators for Mechanical Energy Harvesting with High Space Utilization.

The development and utilization of new energy sources is an effective means of addressing the limits of traditional fossil energy resources and the problem of environmental pollution. Triboelectric nanogenerators (TENG) show great potential for applications in harvesting low-frequency mechanical energy from the environment. Here, we propose a multi-cylinder-based triboelectric nanogenerator (MC-TENG) with broadband and high space utilization for harvesting mechanical energy from the environment. The structure consisted of two TENG units (TENG I and TENG II) assembled by a central shaft. Both an internal rotor and an external stator were included in each TENG unit, operating in oscillating and freestanding layer mode. On one hand, the resonant frequencies of the masses in the two TENG units were different at the maximum angle of oscillation, allowing for energy harvesting in a broadband range (2.25-4 Hz). On the other hand, the internal space of TENG II was fully utilized, and the maximum peak power of the two TENG units connected in parallel reached 23.55 mW. In contrast, the peak power density reached 31.23 Wm-3, significantly higher than that of a single TENG unit. In the demonstration, the MC-TENG could power 1000 LEDs, a thermometer/hygrometer, and a calculator continuously. Therefore, the MC-TENG will have excellent application in the field of blue energy harvesting in the future.

Triboelectric Nanogenerators for Ocean Wave Energy Harvesting: Unit Integration and Network Construction

As a clean and renewable energy source with huge reserves, the development of ocean wave energy has important strategic significance. Harvesting ocean wave energy through novel triboelectric nanogenerators (TENGs) has shown promising application prospects. For this technology, the integration of TENG units is the crucial step to realize large-scale network commercialization. All aspects of the TENG networking process are systematically summarized in this review, including the topology design and the circuit-connection scheme. Advancing the research on the large-scale TENG network is expected to make great contributions to achieve carbon neutrality.

Double-blade structured triboelectric–electromagnetic hybrid generator with aerodynamic enhancement for breeze energy harvesting

Wind energy is a form of renewable energy with excellent development prospects. However, low-speed wind energy has not been effectively explored and utilized. To this end, a double-blade structured triboelectric–electromagnetic hybrid generator (DB-TEHG) is designed in this paper, which can efficiently harvest breeze energy by using double-blade structured design to improve the aerodynamic performance of the device. The improved blade structures directly drive the triboelectric nanogenerator (TENG) and electromagnetic generator (EMG) without requiring additional transmission systems. The blade parameters are simulated and optimized using computational fluid dynamics to enhance the wind energy harvesting capability of the device. The minimum starting wind speed of DB-TEHG is found to be 2 m/s. The output performance of a single TENG unit is 910 V, 45 μA, 280 nC, and the peak power is 4 mW, and that of the EMG is 236 V, 24.2 mA, and a peak power of 0.5 W, when the wind speed is 5 m/s. It is also found that at this wind speed the DB-TEHG can convert wind energy into electricity output with an efficiency of 20.88%. The demonstration results prove that the proposed DB-TEHG can power a wireless thermometer by harvesting outdoor natural wind energy. This paper presents the application potential of DB-TEHG in the Internet of Things and also provides a novel solution to harvest breeze energy by combining TENGs and EMG.

Copper particles-PTFE tube based triboelectric nanogenerator for wave energy harvesting

Developing sustainable energy is essential to achieve carbon neutrality. The emergence of triboelectric nanogenerators (TENGs) makes it possible to efficiently harvest the abundant wave energy in nature for their excellent operational stability and electrical performance at low frequencies. Here, a simplified copper particles-PTFE tube structured TENG (CP-TENG) was fabricated by encasing copper particles into a polytetrafluoroethylene tube and the small copper particles move with nearly fluid-like characteristics, expanding the contact area to ensure high charge density. A single CP-TENG includes two parallel-connected TENG units and can reach a maximum current density of 41.4 mA m−3 at a frequency of 1 Hz. Meanwhile, several CP-TENG units can be flexibly assembled into various arrays to accomplish output increase. A sealed CP-TENG power box demonstrates an impressive capability to collect wave energy, lighting up at most 210 LEDs. The CP-TENG-based energy network may present a new technical approach for blue energy harvesting.

Interconnected array design for enhancing the performance of an enclosed flexible triboelectric nanogenerator

Triboelectric nanogenerators (TENGs) have been widely reported as a means of transforming mechanical energy into electricity to charge small devices in the environment. However, the effect of the working environment, such as high humidity, rain, snow, and dust or particulates, on the stability of TENG performance can hamper their practical application. Herein, a novel enclosed and flexible interconnected TENG array was designed to protect it from the external environment, allowing it to effectively operate in humid conditions and even function in water. Furthermore, the influences of surface morphology of the triboelectric layer and various structural factors of each TENG unit on the output performance were optimized and analyzed. The designed interconnected TENG array composed of multiple TENG units showed a higher output performance and sensitivity compared with more common independent TENG arrays because the air pressure inside each TENG unit was optimized. Consequently, the interconnected TENG array could be applied for gait monitoring, self-powered waterproof keyboards, and mechanical energy harvesting applications from a variety of sources, such as related to rain, wind, or impact vibration. The novel interconnected TENG array composed of multiple TENG units showed greater output performance and sensitivity compared with the more commonly used independent TENG because of optimization of the air pressure in each TENG unit. The interconnected TENG array was demonstrated in a smart shoe insole, a self-powered waterproof keyboard, and for a variety of mechanical energy harvesting. • The novel interconnected TENG array composed of multiple TENG units showed greater output performance and sensitivity. • The interconnected TENG array allowed to be effectively used in high humidity conditions or even in water. • It is proved that the triboelectric charges has nothing to do with the electrical properties of the external contact objects.

Advances of High-Performance Triboelectric Nanogenerators for Blue Energy Harvesting

The ocean is an enormous source of blue energy, whose exploitation is greatly beneficial for dealing with energy challenges for human beings. As a new approach for harvesting ocean blue energy, triboelectric nanogenerators (TENGs) show superiorities in many aspects over traditional technologies. Here, recent advances of TENGs for harvesting blue energy are reviewed, mainly focusing on advanced designs of TENG units for enhancing the performance, through which the response of the TENG unit to slow water agitations and the output power of the device are largely improved. Networking strategy and power management are also briefly discussed. As a promising clean energy technology, blue energy harvesting based on TENGs is expected to make great contributions for achieving carbon neutrality and developing self-powered marine systems.

Hybrid All‐in‐One Power Source Based on High‐Performance Spherical Triboelectric Nanogenerators for Harvesting Environmental Energy

AbstractWith the development of the Internet of Things (IoTs), widely distributed electronics in the environment require effective in situ energy harvesting technologies, which is made challenging by the unstable supply and severe conditions in some environments. In this work, a hybrid all‐in‐one power source (AoPS) is demonstrated for widely adaptive environmental energy harvesting. With a novel structure, the AoPS hybridizes high‐performance spherical triboelectric nanogenerators (TENGs) with solar cells, enabling the harvesting of most typical environmental energies from wind, rain drops, and sun light, for complementary supply. The spherical TENG units with a packaged structure can work robustly to collect energy from fluid. Nearly continuous direct current and a high average power of 5.63 mW can be obtained by four TENG units, which is further complemented by solar cells. Typical application scenarios are also demonstrated, achieving self‐powered soil moisture control, forest fire prevention and pipeline monitoring. The work realizes the concept of an environmental power source that can be deployed in the environment with high adaptability to make use of all kinds of surrounding energies for powering electronics in all‐weather conditions, providing a reliable foundation for the era of the IoTs.

Power cables for triboelectric nanogenerator networks for large-scale blue energy harvesting

Abstract Triboelectric nanogenerators (TENGs), a prospective technology for large-scale harvesting of blue energy from the ocean, have been extensively investigated recently. However, little attention has been paid to the cables linking the individual TENG units to form an energy harvesting network. Herein, several basic requirements for power cables suitable for effective TENG networks are outlined. The cables should avoid tangling among the TENG units, protect the transmission wires, and output electric power. Here, a TENG network based on plane-like power cables consisting of spring steel tapes and three polymer films is described. The steel tape inside the power cables has a dual role as both structural skeleton and an electrode. The tape guarantees the stability of the TENG network and eliminates the electrostatic induction from ions in seawater. The porous PTFE film on the outside is highly hydrophobic and generates electricity by liquid-solid interface contact while collaborating with the steel tapes. The working mechanism and output performance of the power cable were systematically studied. A maximum open-circuit voltage of 34 V and a transferred charge quantity of 25 nC were achieved using a single cable in a single period. An over-water test was also carried out to experimentally demonstrate the feasibility of the TENG networks. This work provides a possible strategy for network construction for large-scale blue energy harvesting.

Direct current contact-mode triboelectric nanogenerators via systematic phase shifting

The intermittency and discontinuous nature of power generation in Triboelectric Nanogenerators (TENGs) are arguably their most significant drawback, despite the promise demonstrated in low-power electronics. Herein, we introduce a novel technology to overcome this issue, in which, built-in systematic phase shifting of multiple poles is used to design a pseudo direct-current TENG. Unlike previous attempts of constructing near direct-current TENGs that base on the segmentation of electrodes of a sliding mode TENG, this technology introduces a new method that depends on planned excitation of constituent TENG units at different time intervals to obtain the necessary phase shifts, achieved by their structural design that contains an asymmetric spatial arrangement. Therefore, the direct current generation for TENG, which was previously limited to the sliding mode TENG units, are expanded to contact-mode TENGs. The technology allows for continuous and smooth operation of the driven loads and paves the way for a new dawn in energy scavenging from mechanical sources. We use the distance-dependent electric field (DDEF) platform to design the systematic phase shifting technology, which is experimentally demonstrated via a free-standing mode TENG (FSTENG) based design, to power a number of prototype devices. The resultant power output of the TENG indicates a crest factor close to 1.1 at relatively low frequencies, the best reported values for TENGs with contact-mode basic units, to date. This work provides a highly awaited solution to overcome the intermittency and sporadic nature of TENG outputs, thus, promoting the field towards powering next generation autonomous and mobile electronics.

An In‐Plane Sliding Triboelectric Nanogenerator with a Multielectrode Array for Self‐Powered Dynamic Addressing and Trajectory Tracking

The recognition and detection of micromotion, widely existant in modern microsystems, directly affects the sensing performance of advanced low‐dimensional electronics. Herein, a subtle in‐plane sliding triboelectric nanogenerator (TENG) composed of a polytetrafluoroethylene (PTFE) plate and an adjustable Al electrode array is reported. Each TENG unit can deliver an open‐circuit voltage of about 11.6 V, with a short‐circuit current close to 36 nA. An array of Al electrodes linearly aligned along the sliding direction enables dynamic addressing by recording and calculating sliding time without interference from sliding speed. In addition, two types of TENG‐based flexible self‐powered sensor matrices show an accurate mapping capability for stylus or finger movements, realizing real‐time trajectory tracking without using any external power sources. Herein, TENG‐based sensing applications are expanded, especially in active artificial intelligence and Internet of things.

Multi-functional wind barrier based on triboelectric nanogenerator for power generation, self-powered wind speed sensing and highly efficient windshield

Abstract The integration of traditional wind barriers and novel wind energy harvesters is highly desirable for the conversion of wind energy to electricity while protecting transportations from strong wind. In this work, a multi-functional wind barrier integrated by manifold triboelectric nanogenerator (TENG) units is proposed and investigated. The TENG unit consists of two copper electrodes and one strip of fluorinated ethylene propylene (FEP) membrane whose two ends are fixed on a 3D printed channel. Based on the optimized structure of each TENG unit, a wind barrier is presently constructed by 66 TENG units connecting in parallel. It is found that the wind barrier can generate the output current and power of up to 440 μ A and 26 mW at the wind speed of 10 m/s. It is also significant that the TENG-based wind barrier can harvest slipstream energy induced by passing vehicles. More importantly, the windshield efficiency of the TENG-based wind barrier is 35% higher than that of the traditional porous wind barrier, significantly improving the safety of transportations. In addition, each TENG unit of the wind barrier can work as a self-powered anemometer to monitor the condition of the wind barrier. Therefore, the present novel wind barrier has a great potential to apply for wind energy harvesting, self-powered wind speed sensing and highly efficient wind protection.

A Movable Electrode Triboelectric Nanogenerator Fabricated Using a Pencil Lead for Self‐Powered Locating Collision

The configurations of triboelectric nanogenerators (TENGs) are usually determined by their specific applications. The immobility of triboelectrodes limits the TENGs’ possible application in dynamic sensing. A subtle novel TENG composed of a movable pencil lead electrode is reported herein. The electricity can be extracted from the pencil lead, by touching an arch‐shaped unit, irrespective of whether the touched surface is the polymer layer or metal foil. It is found that the TENG device can deliver the maximal voltage of 2.37 V at the vibration frequency of 8 Hz. Moreover, due to the high sensitivity to collision/pressure, a sensor array system made of four TENG units is constructed to demonstrate the potential locating application. With the assistance of a self‐made testing program, the TENG array illustrates the capacity of self‐powered locating collisions that is independent of external power sources. Herein, not only TENG‐based devices’ diversity is promoted but also a new active locating route that greatly boosts the development of intelligent interaction is presented.

A high-efficient breeze energy harvester utilizing a full-packaged triboelectric nanogenerator based on flow-induced vibration

Wind energy is an important and promising renewable energy for the sustainable development of society. However, considering the limitations of device structures, collection of low-speed wind energy by triboelectric nanogenerators (TENGs) still faces some challenges such as huge energy loss, destructive friction wear and restrictions of onset wind speed. To solve these problems, we have developed a novel-designed TENG based on flow-induced vibration (FIV) effect (FIV-TENG). Distinguishing from previous wind-driven TENGs, the TENG components of this device are packaged in a bluff body and connected with a cantilever beam. This unique design not only separates the TENG units from the wind-driven part to free from environmental disruptions, but also avoids the great rotation resistance and friction wear in the ordinary designed TENG-based wind energy harvesters. Benefiting from the novel configuration, this FIV-TENG can be easily triggered by wind and delivers an excellent electrical output. The output performance of the as-fabricated device is systematically investigated under wind speeds ranging from light breeze to moderate gale, and a theoretical model is constructed to further understand the working mechanism and oscillating behaviors of the FIV-TENG. Additionally, structural parameters of the device have been optimized to achieve an optimal energy production, and the stability when working in harsh environment is also investigated. The creative device structure realizes the superior robustness and reliability, and also provides an efficient approach to realizing practical wind energy harvesting and applications.