Triboelectric Nanogenerator Array Research Articles

Electrospun Cellulose Nanocrystals Reinforced Flexible Sensing Paper for Triboelectric Energy Harvesting and Dynamic Self-Powered Tactile Perception.

The technical synergy between flexible sensing paper and triboelectric nanogenerator (TENG) in the next stage of artificial intelligence Internet of Things engineering makes the development of intelligent sensing paper with triboelectric function very attractive. Therefore, it is extremely urgent to explore functional papers that are more suitable for triboelectric sensing. Here, a cellulose nanocrystals (CNCs) reinforced PVDF hybrid paper (CPHP) is developed by electrospinning technology. Benefitting from the unique effects of CNCs, CPHP forms a solid cross-linked network among fibers and obtains a high-strength (25MPa) paper-like state and high surface roughness. Meanwhile, CNCs also improve the triboelectrification effect of CPHP by assisting the PVDF matrix to form more electroactive phases (96% share) and a higher relative permittivity (17.9). The CPHP-based TENG with single electrode configuration demonstrates good output performance (open-circuit voltage of 116V, short-circuit current of 2.2µA and power density of 91mWm-2) and ultrahigh pressure-sensitivity response (3.95mVPa-1), which endows CPHP with reliable power supply and sensing capability. More importantly, the CPHP-based flexible self-powered tactile sensor with TENG array exhibits multifunctional applications in imitation Morse code compilation, tactile track recognition, and game character control, showing great prospects in the intelligent inductive device and human-machine interaction.

Versatile Ion‐Gel Fibrous Membrane for Energy‐Harvesting Iontronic Skin

AbstractDeveloping versatile and high sensitivity sensors is beneficial for promoting flexible electronic devices and human‐machine interactive systems. Researchers are working on the exploration of various active sensing materials toward broad detection, multifunction, and low‐power consumption. Here, a versatile ion‐gel fibrous membrane is presented by electrospinning technology and utilized to construct capacitive sensors and triboelectric nanogenerator (TENG). The iontronic capacitive sensor exhibits inherently favorable sensitivity and repeatability, which retains long‐term stability after 5000 cycles. The capacitive sensor can also detect a clear pulse waveform at the human wrist and enable the mapping of pressure distribution by a capacitive sensory matrix. For the iontronic TENG, the maximum peak power is 54.56 µW and can be used to power commercial electronics. In addition, the prepared iontronic TENG array can achieve interactive, rapidly responsive, and accurate dynamic monitoring, which broadens the exploration to direct and effective sensory devices. The versatile ion‐gel fibrous membrane is promising to provide an outstanding approach for physiological detection, biomechanical energy harvesting, human‐machine interaction, and self‐powered monitoring systems.

Ultrastretchable Triboelectric Nanogenerators Based on Ecoflex/Porous Carbon for Self‐Powered Gesture Recognition (Adv. Mater. Technol. 9/2023)

Triboelectric Nanogenerators In article number 2201769, Huamin Chen and co-workers present an ecoflex/porous carbon-based triboelectric nanogenerator (TENG) that exhibits ultrahigh stretchability and high performance due to the appropriate conductive networks and strong trapping effect. Its performance just degrades about 30% at a stretching strain of 177%. The stretchable TENG array can recognize gesture signal of the finger to control mechanical hand, which demonstrates a promising potential in human-machine interaction.

An Integrated Solar Panel with a Triboelectric Nanogenerator Array for Synergistic Harvesting of Raindropand Solar Energy.

The triboelectric nanogenerator (TENG) is regarded as an effective strategy for harvesting energy from raindrops, and is a complementary solution with solar cells to achieve all-weather energy harvesting and sustainable energy supply. However, due to the irregularity of natural rainfalls in the volume, frequency, density, and location, designing high-efficiency raindrop TENG (R-TENG) arrays faces great challenges. In this work, a highly transparent, large-area, and high-efficiency R-TENG array with rational material choice, electrode structure, and array distribution is developed for efficiently harvesting irregular raindrop energy. The problem of electrical signal cancellation among adjacent raindrops can be fully avoided, as viewed from the high-resolution space-time analyses of high-speed camera and electrical signal characteristics. With the rationally designed electrode instead of multiple complex electrodes, all charges can be exported by the R-TENG array in a simulated irregular raindrop scenario. Moreover, it is demonstrated that the R-TENG possesses higher average power density (40.80mW m-2 ) than that of the solar cell (37.03mW m-2 ) in rainy condition. Additionally, a self-powered wireless light-intensity-monitoring system is demonstrated for real-time and all-day weather monitoring. This work provides useful guidance for designing high-efficiency TENG arrays integrated with solar panels for harvesting irregular raindrop energy and solar energy.

Triboelectric Nanogenerator Array as a Probe for In Situ Dynamic Mapping of Interface Charge Transfer at a Liquid-Solid Contacting.

Contact between water droplets with hydrophobic surfaces is a common phenomenon at functional interfaces, and it has been extensively studied. However, quantifying the charge transfer between the liquid-solid interfacial contacting, especially for the charge density distribution throughout the movement of liquid droplet on a dielectric surface, remains to be investigated. Here, we developed a pixeled droplet triboelectric nanogenerator (pixeled droplet-TENG) array with high-density electrode array as a probe for measuring the charge transfer at a liquid-solid interface when a water drop moves on the hydrophobic surface. To intuitively observe the charge transfer between the liquid-solid interface, we "imaged" the transferred charges along movement trajectory of a water droplet as it slides along a tilted solid surface at a spatial resolution of 0.4 mm and time sensitivity of 0.02 s. Our study shows that the transferred charges are not uniformly distributed along the path, which is possibly due to the two-step model of electron transfer and ion adsorbed on the solid surface, and thus the formation of an electric double layer will inevitably shield the net surface on the solid surface. Our study presents a probe technology with potential applications in surface chemistry, physics, material science, and cell biology.

O-ring-modularized triboelectric nanogenerator for robust blue energy harvesting in all-sea areas

Triboelectric nanogenerator (TENG) has recently emerged as one of the most promising technologies for capturing low-frequency ocean energy. However, TENG has some disadvantages, such as low volumetric energy density, poor versatility, and poor anti-storm ability, limiting its commercialization. In this study, an O-ring-like TENG (O-TENG) for blue energy harvesting is introduced. This generator can be prepared by flexible splicing of fan-ring-shaped TENG blocks with different angles. The modular design of the O-TENG not only realizes omnidirectional wave energy harvesting but also regulates its response frequency spectrum based on the surroundings, thereby enhancing the energy capture efficiency of the TENG array. The effect of the configuration parameters of the oscillation frequency and swing amplitude was systematically investigated to optimize the output performance of the O-TENG, and a maximum transfer charge of 29.90 μC was obtained. Furthermore, the O-TENG exhibited almost the same charging efficiency even when placed upside-down, demonstrating its anti-storm ability against strong winds and wave interferences. Experimentally, O-TENG can efficiently capture wave energy on the wave pool and drive commercial RF modules to realize wireless signal transmission successfully. This work demonstrates that O-TENGs can capture wave energy and are a potential energy source for ocean monitoring systems, promoting the construction of the IoTs.

Rationally Structured Triboelectric Nanogenerator Arrays for Harvesting Water-Current Energy and Self-Powered Sensing.

Water-current energy is an enormous and widely distributed clean energy in nature, with different scales from large ocean flow to small local turbulence. However, few effective technologies have been proposed to make use of different forms of water currents as a power source. Here, high-performance paired triboelectric nanogenerators (P-TENGs) capable of integrating massively into a thin flexible layer as a structured triboelectric surface (STS) are demonstrated for harvesting water-current energy. Novel gas packet exchange structure and rigid-flexible coupling deformation mechanism are introduced to ensure that the device can work very effectively even in deep water under high water pressure. The rationally designed TENG array in the STS enables highly efficient power take-off from the flow. Typically, the STS demonstrates a high-frequency output up to 57Hz, largely superior to current TENG devices, and the power density is improved by over 100 times for triboelectric devices harvesting current energy. The flexible STS is capable of attaching to various surfaces or applying independently for self-powered sensing and underwater power supply, showing great potential for water-current energy utilization. Moreover, the work also initiates universal strategies to fabricate high-frequency devices under large environment pressure, which may profoundly enrich the design of TENGs.

Smart Pillow Based on Flexible and Breathable Triboelectric Nanogenerator Arrays for Head Movement Monitoring during Sleep.

Sleep quality plays an essential role in human health and has become an index for assessing physical health. Self-powered, sensitive, noninvasive, comfortable, and low-cost sleep monitoring sensors for monitoring sleep behavior are still in high demand. Here, a pressure-sensitive, noninvasive, and comfortable smart pillow is developed based on a flexible and breathable triboelectric nanogenerator (FB-TENG) sensor array, which can monitor head movement in real time during sleep. The FB-TENG is based on flexible and breathable porous poly(dimethylsiloxane) (PDMS) with a fluorinated ethylene propylene (FEP) powder and exhibits pressure sensitivity and durability. The electrical output of the FB-TENG is further optimized by modifying the porous structure and the FEP powder. Combining the FB-TENG and the flexible printed circuit (FPC), a self-powered pressure sensor array is fabricated to realize touch sensing and motion track monitoring. The smart pillow is formed by laying the self-powered pressure sensor array on an ordinary pillow to realize real-time monitoring of the head position in a static state and head movement trajectory in a dynamic state during sleep. Additionally, the smart pillow also has an early warning function for falling out of bed. This work not only provides a viable sensing device for sleep monitoring but also could be extended to real-time monitoring of some diseases, such as brain diseases and cervical spondylosis, in the future. It is expected to introduce a practical strategy in the real-time mobile healthcare field for disease management.

A Triboelectric Nanogenerator Array for a Self-Powered Boxing Sensor System

A Triboelectric Nanogenerator Array for a Self-Powered Boxing Sensor System

Ferromagnetic-assisted Maxwell’s displacement current based on iron/polymer composite for improving the triboelectric nanogenerator output

Triboelectric nanogenerator (TENG) based on Maxwell’s displacement current as the driving force has broad applications in energy harvesting and self-powered sensors. However, the effect of doped ferromagnetic materials with bearing an external magnetic field on TENG’s displacement current has not been clearly revealed. Herein, a ferromagnetic-assisted Maxwell’s displacement current is proposed for improving TENG output based on polymer/iron composite film (PICF). Based on Maxwell’s equations, the magnetizing current of the ferromagnetic medium coupled with the displacement current is investigated theoretically for boosting TENG output and verified simulationally and experimentally. Comparing TENG output with the magnetization method of PICF, the initial magnetization significantly determines the coupling mechanism between magnetizing current and displacement current. Moreover, the strength and direction of an external magnetic field further reveal the mechanism impacting the initial magnetization on TENG’s displacement current. A short-circuit current density of 27 mA/m2 and instantaneous power density of 2 W/m2 are achieved by the champion TENG, which are 800% and 8200% higher than those of pristine polymer. Finally, a distributed TENG array is developed for efficiently harvesting distributed energy to demonstrate the application potential of the improved TENG in self-powered systems. This work elaborates the coupling mechanism of the magnetizing current with TENG’s displacement current, which provides general guidance for investigating efficient energy harvester toward self-powered sensors, wearable electronics and flexible electromagnetic shielding devices.

Self-Rebound Cambered Triboelectric Nanogenerator Array for Self-Powered Sensing in Kinematic Analytics.

In challenging and dangerous equestrian sports, kinematic analysis and injury prevention based on distributed, portable, and real-time sensing technology is particularly important. Here, we report a flexible self-rebound cambered triboelectric nanogenerator that addresses the concerns and shows its applications for self-powered sensing in kinematic analysis. Benefiting from simple and effective design, ordinary materials by means of self-rebound cambered structure evolved into a micro-biomechanical energy harvester with mechanical properties including over 3000 cycles durability and superior resiliency and stability. At a size of 4.52 cm2, it could deliver a power density of 1.25 mW/m2 under an external load resistance of 60 MΩ. A self-powered riding characteristic sensing system has been developed with fast response time of 16 ms, to provide real-time statistics data and fall prediction for both horsemen and coaches, to take traditional equestrian sports to a advanced state. This work not only can promote the development of triboelectric nanogenerators in micro-biomechanical energy harvesting, but also could expand the application range of the self-powered system to intelligent sport monitoring and assisting.

High-Electrification Performance and Mechanism of a Water-Solid Mode Triboelectric Nanogenerator.

With the advantages of superior wear resistance, mechanical durability, and stability, the liquid-solid mode triboelectric nanogenerator (TENG) has been attracting much attention in the field of energy harvesting and self-powered sensors. However, most reports are primarily observational, and there still lacks a universal model of this kind of TENG. Here, an equivalent circuit model and corresponding governing equations of a water-solid mode TENG are developed, which could easily be extended to other types of liquid-solid mode TENGs. Based on the first-order lumped circuit theory, the full equivalent circuit model of water-solid mode TENG is modeled as a series connection of two capacitors and a water resistor. Accordingly, its output characteristics and critical influences are examined, to investigate the relevant physical mechanism behind them. Afterward, a three-dimensional water-solid TENG array constructed from many single-wire TENGs is fabricated, which can not only harvest tiny amounts of energy from any movement of water, but also can verify our theoretical predictions. The fundamentals of the water-solid mode TENG presented in this work could contribute to solving the problem of electrical phenomena on a liquid-solid interface, and may establish a sound basis for a thorough understanding of the liquid-solid mode TENG.

Designing Rules and Optimization of Triboelectric Nanogenerator Arrays

AbstractA triboelectric nanogenerator (TENG) is an effective means for the conversion of mechanical energy into electricity. Although Maxwell's displacement current is the underline mechanism of TENGs, the spatial and temporal variations of the electric field and electric displacement remain elusive, which prohibits an effective optimization of the energy conversion process. Here, the electric field distribution and energy dynamics of TENGs is determined using 3D mathematical modeling. The electrical energies stored in TENGs and extracted into the external circuit are calculated quantitatively whereby the ratio of the two, defined as the output efficiency, is obtained. Then, the power density and energy density of TENGs are defined. Utilizing the principle of virtual work, the minimum required external force–time relationship is evaluated. The influence of device parameters, geometry, and optimum conditions are discussed systematically so as to determine general optimization guidelines for TENGs. In addition, although the fringing electric field is practically inevitable, adjustments of the gap distance between neighboring TENG devices to assure that an optimized fringing electric field is “leaked”, is demonstrated to lead to improvement in a TENG array. Then, for the first time, this work presents universal design rules and holistic optimization strategies for the network structure of TENGs.

Liquid-solid triboelectric nanogenerators array and its applications for wave energy harvesting and self-powered cathodic protection

A new type of array combination for liquid-solid triboelectric nanogenerators is constructed by using polytetrafluoroethylene ultrafiltration membrane as the friction layer with water to collect wave energy to self-power the cathodic protection system in marine environment. The dual liquid-solid triboelectric nanogenerator array shows the output performance with a short current circuit of 2.68 μA and output voltage of 105 V. Meanwhile, a self-powered corrosion protection system with liquid-solid triboelectric nanogenerators array as the power supply is achieved for A3 carbon steel in 3.5 wt% NaCl solution. The electrochemical measurements results show that compared with the bare carbon steel, the open circuit potential drop of the carbon steel coupled with the liquid-solid triboelectric nanogenerators is about 330 mV. Compared with photocathodic protection and other new energy-based methods, the solid-liquid triboelectric nanogenerator could realize all-weather protection of metals by utilizing natural energy and through parallel or series circuit design, it could be used to achieve more efficient cathodic protection for metal materials. The intelligent self-powered system possesses great potential in the area of all-weather cathodic protection and power supply by utilizing liquid-solid friction energy for the ships, buoys, and marine equipments in ocean conditions.

Self-powered transparent and flexible touchpad based on triboelectricity towards artificial intelligence

Abstract Combining with an artificial intelligence and 5G technologies, the new era of Internet of Things (IoT) has been emerging. Hence, a human-machine interface (HMI) is becoming indispensable in IoT. However, conventional HMIs are suffering from limitations like, the requirement of power sources and structure-complexity. As a solution, triboelectric nanogenerator (TENG) based HMI can be considered as an attractive alternative due to the self-powered operation of TENG. Herein, we suggest the self-powered triboelectricity-based touchpad (TTP) which combines with artificial intelligence consisting of TENG array (49 pixels) constructed on thin, transparent, and flexible substrate, as well as this TTP works based on two major kinds of TENG mechanisms in tapping and sliding modes. The tracing ability of the TTP is demonstrated with high accuracy. Furthermore, the TTP recognizes the digit patterns from ‘0’ to ‘9’ with classification accuracy of 93.6%, 92.2%, and 91.8% at the bending angles of 0°, 119°, and 165° through the pre-trained neural network. With the remarkable applicability of the next-generation HMI in IoT, the TTP is implemented as the smart calculator by using graphical user interface modeling. Considering its good compatibility, it can be expected to be a promising HMI in near future with practical IoT towards artificial intelligence.

All-printed soft triboelectric nanogenerator for energy harvesting and tactile sensing

Rapid advancements in flexible and multifunctional electronics bring challenges to the corresponding power suppliers. Soft triboelectric nanogenerator (TENG), as a promising route to satisfy the demands of various self-powered sources and energy harvesting devices, has been developed in this study via facile all-printing method. The nanogenerator features a thin film with micro patterned friction silicone layers, which is fabricated through direct ink writing technology. Wrinkled silver electrode is sandwiched and protected by silicone layers, and constructed through prestrain, release, and buckling process based on inkjet printing technology. As an experimental result, TENG with 100% prestrain produces the maximum output voltage of 44.16 V at the frequency of 5 Hz and external force of 10 N, higher than the pristine nanogenerator. The output voltage of these TENGs could be enhanced slightly when it is stretched to a certain degree. The as-prepared TENG can work for biomechanical energy harvesting driven by human motions and instantaneously power 20 commercial Light Emitting Diodes (LEDs). Moreover, the all-printed soft TENG arrays show potential applications in tactile sensor for touch perception. Our work opens a new idea for fabrication of flexible and wearable TENG based on printing technology to shorten fabrication cycle, simplify individual design and make it more accessible for practical application. In this work, we present an all-printed soft triboelectric nanogenerator that is designed to harvest small mechanical energy. Based on the direct ink writing technology, the friction layer can be fabricated with regular micro structures to enlarge the surface area, and to protect the sandwiched electrode inside as well. The wrinkled silver electrode is constructed on the prestretched friction layer according to the inkjet printing process. The assembled TENG with an activation area of 10 × 10 mm 2 , operating in the contact-separation mode, can achieve an output voltage of 44.16 V at the prestrain 100% with the applied force of 10 N and frequency of 5 Hz. A power density of 1.03 W/m 2 could be produced correspondingly to drive 10 commercial LEDs connected in series. In addition, TENG can also be applied to monitor the movements of waist, foot and elbow for biomechanical energy harvesting, and the printed arrays have the potential application in mapping the touch location as tactile sensor. This simple, low-cost, controllable and reliable approach to TENG device based on all-printing technology provides new dimensions for rapid manufacturing of energy harvesters and wearable self-powered sensors. • Flexible and stretchable triboelectric nanogenerator was proposed based on all-printing method. • Micropatterned friction surface was constructed via direct ink writing. • Wrinkled silver electrode was fabricated through inkjet printing. • The powerful TENG is a promising candidate for portable and wearable biosensors.

A multifunctional and highly flexible triboelectric nanogenerator based on MXene-enabled porous film integrated with laser-induced graphene electrode

The ambient dissipated energy such as the vast scale of mechanical energy in the agricultural system (e.g., leaf swing energy) and the writing motion existing extensively in our daily life are underutilized. Herein, to address these issues and overcome the limitations of conventional batteries, we fabricated a highly flexible and effective triboelectric nanogenerator (TENG) based on MXene and polydimethylsiloxane (PDMS) composite (PDMS/MXene) film and laser-induced graphene (LIG) electrode. The introduction of conductive and electronegative MXene into PDMS to fabricate porous film, not only enhances the electrical conductivity but also increases the triboelectronegativity. As a result, the output performance is significantly improved, 7-fold greater than the pure flat PDMS-based TENG. The developed TENG with excellent performance, considerable adhesion, and outstanding flexibility was successfully applied for harvesting leaf swing energy and being used as a writing board to collect writing energy. Furthermore, we developed a MXene-based TENG array acting as a self-powered sensor for handwriting recognition. In this regard, MXene-enabled TENG possesses a great promising in harvesting mechanical energy from the agricultural field (e.g., leaf swing energy) and human activities (e.g., writing), moreover, it can further be applied in writing or tactile sensing for pad, robotics, and man-machine interaction field.

Spherical Triboelectric Nanogenerators Based on Spring‐Assisted Multilayered Structure for Efficient Water Wave Energy Harvesting

AbstractMaking use of water wave energy at large is one of the most attractive, low‐carbon, and renewable ways to generate electric power. The emergence of triboelectric nanogenerator (TENG) provides a new approach for effectively harvesting such low‐frequency, irregular, and “random” energy. In this work, a TENG array consisting of spherical TENG units based on spring‐assisted multilayered structure is devised to scavenge water wave energy. The introduction of spring structure enhances the output performance of the spherical TENG by transforming low‐frequency water wave motions into high‐frequency vibrations, while the multilayered structure increases the space utilization, leading to a higher output of a spherical unit. Owing to its unique structure, the output current of one spherical TENG unit could reach 120 µA, which is two orders of magnitude larger than that of previous rolling spherical TENG, and a maximum output power up to 7.96 mW is realized as triggered by the water waves. The TENG array fabricated by integrating four units is demonstrated to successfully drive dozens of light‐emitting diodes and power an electronic thermometer. This study provides a new type of TENG device with improved performance toward large‐scale blue energy harvesting from the water waves.

A sinusoidal alternating output of a triboelectric nanogenerator array with asymmetric-layer-based units.

A triboelectric nanogenerator (TENG) shows great promise for the energy of the new era. In this study, we present a triboelectric nanogenerator array assembled with multiple asymmetric-layer-based triboelectric units with a sinusoidal alternating output. It raises the possibility that large-scale triboelectric energy may be developed as an alternative energy source. Moreover, we systematically analyzed the device operation to show that the internal capacitance effect controlled the output waveforms. Finally, by tuning the internal capacitance, a TENG array with performances of both stable sinusoidal alternating output and high power density is obtained based on the quantitative evaluations. The optimized TENG array can produce a maximum conversion efficiency of 60% and a load power density of 1.53 kW m-3.

Large‐Scale and Washable Smart Textiles Based on Triboelectric Nanogenerator Arrays for Self‐Powered Sleeping Monitoring

AbstractSleeping disorder is a major health threatening in high‐pace modern society. Characterizing sleep behavior with pressure‐sensitive, simple fabrication, and decent washability still remains a challenge and highly desired. Here, a pressure‐sensitive, large‐scale, and washable smart textile is reported based on triboelectric nanogenerator (TENG) array as bedsheet for real‐time and self‐powered sleep behavior monitoring. Fabricated by conductive fibers and elastomeric materials with a wave structure, the TENG units exhibit desirable features including high sensitivity, fast response time, durability, and water resistance, and are interconnected together, forming a pressure sensor array. Furthermore, highly integrated data acquisition, processing, and wireless transmission system is established and equipped with the sensor array to realize real‐time sleep behavior monitoring and sleep quality evaluation. Moreover, the smart textile can further serve as a self‐powered warning system in the case of an aged nonhospitalized patients falling down from the bed, which will immediately inform the medical staff. This work not only paves a new way for real‐time noninvasive sleep monitoring, but also presents a new perspective for the practical applications of remote clinical medical service.