Textile-based Triboelectric Nanogenerator Research Articles

A fully stretchable textile-based triboelectric nanogenerator for human motion monitoring

Triboelectric textiles with cost-effectiveness, wearable and manufacturability have indicated their potential applications in energy collection and posture recognition from human motions. Here, we present a fully stretchable textile-based triboelectric nanogenerator (FSTTN), which is developed by interacting between woven units of the silver-coated glass microspheres (GM@Ag)/ rubber electrode and the electrode@rubber triboelectric thread. Owing to the high mix ratio of GM@Ag and the remarkable stretchability of rubber matrix, the fabricated FSTTN (5 cm * 5 cm) produced open-circuit voltage of 7.3 V and short-circuit current of 0.39 μA at 100% strain, meanwhile, produced open-circuit voltage of 138 V and short-circuit current of 2.1 μA under the flapping frequency of 3 Hz, respectively. Considering the excellent output performances, the FSTTN can effectively collect tensile mechanical energy to power the commercial electronics, and easily be installed on the human body to monitor the motion posture. Therefore, this work provides a new approach for promoting the development of stretchable and wearable triboelectric textiles.

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.

Shape adaptable and highly resilient 3D braided triboelectric nanogenerators as e-textiles for power and sensing

Combining traditional textiles with triboelectric nanogenerators (TENGs) gives birth to self-powered electronic textiles (e-textiles). However, there are two bottlenecks in their widespread application, low power output and poor sensing capability. Herein, by means of the three-dimensional five-directional braided (3DB) structure, a TENG-based e-textile with the features of high flexibility, shape adaptability, structural integrity, cyclic washability, and superior mechanical stability, is designed for power and sensing. Due to the spatial frame-column structure formed between the outer braided yarn and inner axial yarn, the 3DB-TENG is also endowed with high compression resilience, enhanced power output, improved pressure sensitivity, and vibrational energy harvesting ability, which can power miniature wearable electronics and respond to tiny weight variations. Furthermore, an intelligent shoe and an identity recognition carpet are demonstrated to verify its performance. This study hopes to provide a new design concept for high-performance textile-based TENGs and expand their application scope in human-machine interfacing.

Continuous and Scalable Manufacture of Hybridized Nano-Micro Triboelectric Yarns for Energy Harvesting and Signal Sensing.

Textile-based triboelectric nanogenerators (TENG) that can effectively harvest biomechanical energy and sense multifunctional posture and movement have a wide range of applications in next-generation wearable and portable electronic devices. Hence, bulk production of fine yarns with high triboelectric output through a continuous manufacturing process is an urgent task. Here, an ultralight single-electrode triboelectric yarn (SETY) with helical hybridized nano-micro core-shell fiber bundles is fabricated by a facile and continuous electrospinning technology. The obtained SETY device exhibits ultralightness (0.33 mg cm-1), extra softness, and smaller size (350.66 μm in diameter) compared to those fabricated by conventional fabrication techniques. Based on such a textile-based TENG, high energy-harvesting performance (40.8 V, 0.705 μA cm-2, and 9.513 nC cm-2) was achieved by applying a 2.5 Hz mechanical drive of 5 N. Importantly, the triboelectric yarns can identify textile materials according to their different electron affinity energies. In addition, the triboelectric yarns are compatible with traditional textile technology and can be woven into a high-density plain fabric for harvesting biomechanical energy and are also competent for monitoring tiny signals from humans or insects.

All-textile wearable triboelectric nanogenerator using pile-embroidered fibers for enhancing output power

Textile-based triboelectric nanogenerators (TENGs) have received considerable attention for wearable applications owing to their significant advantages, such as flexibility, lightness, and breathability. Recently, several studies based on the modification of friction surfaces for improving the triboelectric output performance have been reported. However, previously reported methods require complicated fabrication processes and may deteriorate the intrinsic properties of a textile. Herein, we present a wearable TENG utilizing a textile composed of pile-embroidered (rough-textured) fibers as a contact surface. The deformability of the fibers originating from the suspended structure provides a large contact area that can participate in triboelectrification. This significantly increases charge density induced on the surface in response to a compressive force, resulting in a high output voltage of 113 V. The TENG also exhibits a high output power, which is 24 times higher than that of the TENG based on satin-embroidered (flat-textured) fibers. More importantly, owing to the conventional textile manufacturing process based on three-dimensional embroidery, the fabrication of our TENG is significantly simpler and more cost-effective than previously reported techniques. Experimental demonstrations as a wearable energy harvester highlight the utility of the TENG for generating electricity from various human motions. Based on ease of manufacturing and high output performance, the proposed harvester is a promising candidate as a low-cost power source for next-generation electronics, such as Internet of Things devices and self-powered smart clothing.

Large-scale fabrication of robust textile triboelectric nanogenerators

Smart energy textiles based on triboelectric nanogenerators (TENGs) are promising power supply and sensor arrays for wearable electronics and artificial intelligence. However, the challenges of the smart textile in large-scale industrialized production, facile and universal fabrication process, and enough robustness still remains. In this study, a textile-based triboelectric nanogenerator (t-TENG) is proposed through a facile and universal fabrication process. Liquid-metal/polymer core/shell fibers (LCFs) structure as the basic unit of TENG textiles, can be extensively achieved by pumping liquid metal into uniform ultrafine polymer hollow fibers, which contribute to the large-scale industrialized production of TENG textiles. In addition to gaining a high output, the t-TENG demonstrates excellent acid and alkali resistance, and high friction durability. Furthermore, profiting from the universal fabrication process, the polymer hollow fibers can be replaced by any type of fibers with various functions or colors according to practical applications (e.g., the silicone rubber could be an excellent choice for highly stretchable devices). Moreover, the fabricated t-TENGs demonstrate great capability in self-powered sensors for smart home controlling. All these advantages of the t-TENG exhibit its great potential for further application in wearable electronics and artificial intelligence and it will speed up the development of IoTs in the near future.

Structurally engineered textile-based triboelectric nanogenerator for energy harvesting application

Triboelectric nanogenerators (TENG) work on the principle of contact electrification and electrostatic induction to harvest electrical energy from a mechanical energy source. The textile fabric-based TENG device fabricated in the present study utilizes a few widely used textile materials like Teflon, nylon and fabric manufacturing technology. The integration of the aforementioned materials with a conductive element has been realized through a multilayer stitching technique. Each electrode of the TENG comprises various types of woven fabric samples prepared on a weaving loom, namely 1/1 plain weave, 2/2 matt weave, 3/1 twill and 5/1 twill weave. Each of the woven structures was analyzed on the basis of its corresponding electrical performance. The electrostructural relationship of the resultant TENG device was investigated by measuring values of instant open-circuit voltage (Voc) and short-circuit current (Isc), capacitor charge–discharge behavior, peak power density, etc. A strong correlation between the fabric weave pattern and its electrical performance was established. A maximum voltage output of 2.52 V in a 1/1 plain weave elevated to 10.93 V for a 5/1 twill weave. Through assessment of the capacitor charge–discharge behavior, the applicability and efficiency of the present TENG device as an energy harvesting unit were validated. The present study also signifies the importance of textile structural parameters in the development of an efficient wearable TENG device.

3D double-faced interlock fabric triboelectric nanogenerator for bio-motion energy harvesting and as self-powered stretching and 3D tactile sensors

Combining triboelectric nanogenerator (TENG) and textile materials, wearable electronic devices show great application prospects in biomotion energy harvesting and multifunctional self-power sensors in this coming intelligent era. However, fabrication method by rigidly stitching two or more individual fabrics together and working mode that must cooperate with external materials, make textile-based TENG bulky, stiff, uncomfortable and hinder their range of application. Here, by using a double needle bed flat knitting machine technology, a 3D double faced interlock fabric TENG (3DFIF-TENG) is designed as self-powered, stretchable and substrate-free wearable TENG sensors (such as a bending sensor to detect arm bending degree, pressure sensors) and energy harvesting devices. Besides, due to the unique 3D structure and after improving the structure by knitting a woven fabric-TENG in the middle layer, the 3DFIF-TENG can be further used as a multifunctional sensors, such as a 3D tactile sensor. Besides, by knitting a woven fabric-TENG in the middle layer of the 3DFIF-TENG, it can be further used as a multifunctional sensor, such as a 3D tactile sensor. The substrate-free and 3D structure design in this paper may provide a promising direction for self-powered, stretchable wearable devices in energy harvesting, human motion or robot movement detection, and smart prosthetics.

Textile-based freestanding triboelectric-layer nanogenerator with alternate positive and negative grating structure

This paper reports a novel design of textile-based triboelectric nanogenerator (TENG) with alternate grated strips of positive and negative triboelectric material operating in freestanding triboelectric-layer mode (pnG-TENG). Whereas most grating-structured TENGs operating in a freestanding triboelectric-layer mode comprise gratings of one type of triboelectric material separated by air gaps, this design presents a replacement of the air gaps by another triboelectric material with the opposite polarity to the existing triboelectric material. The pnG-TENG with 10 gratings of PTFE and nylon fabric delivers an open-circuit voltage of 250 V, a short-circuit current of 5.94 µA and a maximum peak power of 600 µW at a load resistance of ueoµΩ and a mechanical oscillation of 2 Hz. This corresponds to a maximum power density of 186 mW/m2, which is 1.73 and 2.20 times greater than the power generated by the TENG with single triboelectric material and the TENG with no grating, respectively.

Self-Sustainable Wearable Textile Nano-Energy Nano-System (NENS) for Next-Generation Healthcare Applications.

Wearable electronics presage a future in which healthcare monitoring and rehabilitation are enabled beyond the limitation of hospitals, and self‐powered sensors and energy generators are key prerequisites for a self‐sustainable wearable system. A triboelectric nanogenerator (TENG) based on textiles can be an optimal option for scavenging low‐frequency and irregular waste energy from body motions as a power source for self‐sustainable systems. However, the low output of most textile‐based TENGs (T‐TENGs) has hindered its way toward practical applications. In this work, a facile and universal strategy to enhance the triboelectric output is proposed by integration of a narrow‐gap TENG textile with a high‐voltage diode and a textile‐based switch. The closed‐loop current of the diode‐enhanced textile‐based TENG (D‐T‐TENG) can be increased by 25 times. The soft, flexible, and thin characteristics of the D‐T‐TENG enable a moderate output even as it is randomly scrunched. Furthermore, the enhanced current can directly stimulate rat muscle and nerve. In addition, the capability of the D‐T‐TENG as a practical power source for wearable sensors is demonstrated by powering Bluetooth sensors embedded to clothes for humidity and temperature sensing. Looking forward, the D‐T‐TENG renders an effective approach toward a self‐sustainable wearable textile nano‐energy nano‐system for next‐generation healthcare applications.

Textile-based triboelectric nanogenerator with alternating positive and negative freestanding grating structure

This paper reports a novel design of textile-based triboelectric nanogenerator (TENG) with alternate grated strips of positive and negative triboelectric material operating in freestanding triboelectric-layer mode, defined as a pnG-TENG. Whereas most grating-structured TENGs operating in a freestanding triboelectric-layer mode comprise gratings of one type of triboelectric material separated by air gaps, this design presents a replacement of the air gaps by another triboelectric material with the opposite polarity to the existing triboelectric material. This is predicted to increase performance by increasing the contact area of the generator. The pnG-TENG with 10 gratings of nylon fabric and PVC heat transfer vinyl delivers an RMS open-circuit voltage of 136 V, an RMS short-circuit current of 2.68 μA and a maximum RMS power of 125 μW at a load resistance of 50 MΩ, a mechanical oscillation of 2 Hz and a contact force of 5 N. This corresponds to a maximum RMS power density of 38.8 mW/m2, which is 1.94 and 6.43 times greater than the power generated by the TENG with a single triboelectric material and the TENG with no gratings, respectively.

Textile-based triboelectric nanogenerators with high-performance via optimized functional elastomer composited tribomaterials as wearable power source

Wearable power sources with high performance are attracting intensive attention, owing to their great potential in new-generation wearable electronics. Herein, we proposed a composited fabric with flexible functional elastomer layers (FEL@CF) and employed it as a negative tribomaterial in triboelectric nanogenerators (TENGs). The FEL@CF consists of a low-temperature vulcanized silicone (LTV) electrification layer, CNTs/Ecoflex nanocomposite layer, super-soft Ecoflex layer and conductive fabric substrate, which play critical roles on the output enhancement of FEL@CF-based TENG (abbreviated as FEL@CF-TENG). The effect of the thickness of the Ecoflex layer and CNTs content in the nanocomposite layer on the electrical performance of FEL@CF-TENG were systematically investigated. The FEL@CF with 180 μm thick Ecoflex layer and 1.6 wt% CNTs content was realized as an optimal sample to obtain optimum output signals. The high outputs (~490 V, ~43 μA, ~70 nC, 1.6 mW/cm2) were obtained from the optimal FEL@CF-TENG (2.5 × 2.5 cm2) under small force (~16 N) and low frequency (~1.5 Hz). The flexible FEL@CF-TENG can power for wearable electronics by harvesting biomechanical energy and operate in dual-electrodes mode (FEL@CF-DTENG) or single-electrode mode (FEL@CF-STENG). Especially, the power glove made of FEL@CF-STENG can contact with various daily-used objects for human motion energy harvesting. The durability and washability of FEL@CF-TENGs were also performed, exhibiting excellent stability even under harsh and complex conditions. All these merits of the FEL@CF-TENG not only provide a promising strategy for exploring high-performance wearable power source but also show great potential for applications in portable electronics and electronic textiles.

Development of textile-based triboelectric nanogenerators integrated with plastic metal electrodes for wearable devices

This study aimed to develop wearable devices of textile-based triboelectric nanogenerators (TENGs) integrated with plastic metal electrodes. The plastic metal electrodes were developed using Ga-In liquid alloy with glaze powders as the contact electrodes of the textile-based TENGs. Moreover, nylon and polyester textiles with different microstructures/nanostructures were selected as frictional electrodes in TENGs to achieve high flexibility, stability, and electric conductivity. The experimental results indicated that the maximum output voltage and current of the textile-based TENGs were 30.96 V and 3.07 μA, respectively, when the TENG comprised a nylon layer with embroidered square array patterns and a polyester layer with polyvinylidene fluoride nanofibers. Furthermore, these TENGs could generate a maximum output power of 13.97 μW when the external load resistance was 10 MΩ. After a continuous 7200 cycle operation with a reciprocating linear motion platform having a pneumatic cylinder, the textile-based TENG exhibited excellent stability and durability. The fabricated TENGs integrated in a commercial coat, shoe, kneecap, and wristband achieved biomechanical energy conversion functions with high electrical performance for practical applications of self-powered devices.

Triboelectric performances of self-powered, ultra-flexible and large-area poly(dimethylsiloxane)/Ag-coated chinlon composites with a sandpaper-assisted surface microstructure

Apart from the rapid development in macroscale green energies, such as wind energy and hydro energy, micro/nanoscale self-powered energy systems are increasingly attractive in wearable energy systems. To utilize the energy harvester more conveniently and effectively, an energy harvester, viz., single-electrode textile-based triboelectric nanogenerator (ST-TENG), is reported in this study. The ST-TENG is a polydimethylsiloxane (PDMS)/Ag-coated chinlon fabric (PACF) composite film with the surface microstructures induced by sandpapers. The PACF composite is self-powered based on the triboelectrification and electrostatic induction. The merits of ST-TENG include: (1) all the basic materials are flexible and scalable; (2) the resultant PACF is a free-standing composite film, which can be easily peeled off from the sandpaper substrate; (3) an extremely low-cost method was first introduced to fabricate the surface microstructures in flexible triboelectric nanogenerator though sandpapers; and (4) the as-fabricated PACF composite film can directly harvest energy though squeezing, warping and folding. Experimental results demonstrate that the ST-TENG can generate an average maximum output voltage of 46.52 V and a high-power density of 613 mW m−2 at the external resistance of 20 MΩ. Additionally, the ST-TENG can also be utilized to detect the variation of contact area, frequency and force.

Chemically surface-engineered polydimethylsiloxane layer via plasma treatment for advancing textile-based triboelectric nanogenerators

Energy-harvesting devices as basic components of independent power sources are highly promising for use in modern portable smart electronics. In this regard, the use of conductive textile substrates in triboelectric nanogenerators (T-TENG) that convert sustainable mechanical energy to electricity has emerged as an alternative option for efficient power generation. Here, we address the enhancement of the electrical performances of T-TENGs by employing chemically surface interface-engineered polydimethylsiloxane (SIE-PDMS) layers as coatings on highly conductive Ni-Cu textile substrates. Manipulation of the PDMS surface is a major approach in this work, where in-situ two-step reactive-ion plasma treatments were conducted with sequential Ar and CF4 + O2 plasmas. Structural observations identified the appearance of F on the SIE-PDMS after suitable CF4 +O2 plasma treatment, thus yielding enhanced output generation by the T-TENG through efficient surface charging ability, which was attributed to the large electronegativity of F. We anticipate that this simple fabrication approach may facilitate the development of highly wearable self-powered devices.

Progress in textile-based triboelectric nanogenerators for smart fabrics

Textile-based triboelectric nanogenerators (t-TENGs) are excellent choices of mechanical energy harvesting and self-powered sensing for wearable technology, especially for constructing smart fabrics. They combine advantages of textile for its flexibility, breathability, lightweight and TENG for its ease of fabrication and promising output performance. Many progresses have been made due to the surging interests. In this review, we will introduce the construction of t-TENGs briefly at first, including three dominant types of device structure and the new emerging design based on three-dimensionally textile. Investigation about the effect of textile processing method (weaving, knitting, sewing, etc.) and structure pattern on the t-TENG's performance is reviewed for further understanding and optimizing the device. Several great demonstrations about the washability and tailorability of t-TENGs are presented based on elevated material properties and rational device design, which is long-cherished for wearable electronics. Finally, the article ends with reviewing progresses in integrations of t-TENGs with other energy harvesting/storing technology for a more powerful textile energy source and construction of smart fabrics with diverse functions for emerging applications in wearable technologies.

Ultra-Flexible and Large-Area Textile-Based Triboelectric Nanogenerators with a Sandpaper-Induced Surface Microstructure.

Wearable triboelectric nanogenerators (TENGs) have attracted interest in recent years, which demand highly flexible, scalable, and low-cost features. Here, we report an ultra-flexible, large-scale and textile-based TENG (T-TENG) for scavenging human motion energy. The triboelectric layer was derived from the polydimethylsiloxane (PDMS) film with a cost-effective paper-induced rough surface via a facile doctor-blending technology. Ag-coated chinlon fabric (ACF) with ultra-flexible, large-scale and conductive characteristics was used as the electrode. The as-fabricated PDMS-based ACF (PACF) composites possess a 240 × 300 mm2 superficial area and remain highly flexible under mechanical squeezing, folding and even tearing deformation. The maximum output charge of ~21 μC and voltage of 80.40 V were therefore achieved to directly power 100 LEDs based on the high surface area of 762.73 mm2 which was rationally replicated from the sandpaper of the T-TENG. Moreover, the output voltage signal can be also used as a trigger signal of a movement sensor. Importantly, the explicit theoretical model corresponding to T-TENG was quantitatively investigated under different applied force, frequency and effective surface factor.

Skin-touch-actuated textile-based triboelectric nanogenerator with black phosphorus for durable biomechanical energy harvesting

Textiles that are capable of harvesting biomechanical energy via triboelectric effects are of interest for self-powered wearable electronics. Fabrication of conformable and durable textiles with high triboelectric outputs remains challenging. Here we propose a washable skin-touch-actuated textile-based triboelectric nanogenerator for harvesting mechanical energy from both voluntary and involuntary body motions. Black phosphorus encapsulated with hydrophobic cellulose oleoyl ester nanoparticles serves as a synergetic electron-trapping coating, rendering a textile nanogenerator with long-term reliability and high triboelectricity regardless of various extreme deformations, severe washing, and extended environmental exposure. Considerably high output (~250–880 V, ~0.48–1.1 µA cm−2) can be attained upon touching by hand with a small force (~5 N) and low frequency (~4 Hz), which can power light-emitting diodes and a digital watch. This conformable all-textile-nanogenerator is incorporable onto cloths/skin to capture the low output of 60 V from subtle involuntary friction with skin, well suited for users’ motion or daily operations.

A textile-based triboelectric nanogenerator with humidity-resistant output characteristic and its applications in self-powered healthcare sensors

Functional textiles have evoked great attention due to their promising applications in next-generation wearable and biomedical electronics. However, the constraints on the harsh operation environment and ineffective response to instantly reflect the physical status remain critical challenges. Herein, we develop a chitosan-based triboelectric nanogenerator (C-TENG) to harvest biomechanical energy from human motions, in which a nanostructured chitosan-glycerol film is utilized to promote the commercial textile into a multi-functional textile based on its transparency, flexibility, biocompatibility and adaptability to commercial fabrics. The output characteristics of the as-fabricated C-TENG are notably stable under various humidity conditions, distinguishing them from conventional TENGs. As the relative humidity (RH) changes from 20% to 80%, the electric output of the C-TENG remains unchanged, in contrast to the performance degradation observed for conventional TENGs. Moreover, the C-TENG can be further developed into various kinds of self-powered healthcare sensors for humidity, sweat, and gait phase detection. More importantly, the designed humidity sensor based on the C-TENG exhibits a promising advancement in sensitivity compared with conventional TENG-based humidity sensors. This work presents a new step in applying multi-functional textiles to wearable energy harvesters and self-powered sensors, which have high potential for future smart clothing products and personalized healthcare sensors.

Core-Shell-Yarn-Based Triboelectric Nanogenerator Textiles as Power Cloths.

Although textile-based triboelectric nanogenerators (TENGs) are highly promising because they scavenge energy from their working environment to sustainably power wearable/mobile electronics, the challenge of simultaneously possessing the qualities of cloth remains. In this work, we propose a strategy for TENG textiles as power cloths in which core-shell yarns with core conductive fibers as the electrode and artificial polymer fibers or natural fibrous materials tightly twined around core conductive fibers are applied as the building blocks. The resulting TENG textiles are comfortable, flexible, and fashionable, and their production processes are compatible with industrial, large-scale textile manufacturing. More importantly, the comfortable TENG textiles demonstrate excellent washability and tailorability and can be fully applied in further garment processing. TENG textiles worn under the arm or foot have also been demonstrated to scavenge various types of energy from human motion, such as patting, walking, and running. All of these merits of proposed TENG textiles for clothing uses suggest their great potentials for viable applications in wearable electronics or smart textiles in the near future.