Output Performance Of Triboelectric Nanogenerators Research Articles

Significantly Enhanced Output Performance of Triboelectric Nanogenerators via Charge Storage and Release Strategy.

As a novel energy harvesting technology, bettering the output performance of triboelectric nanogenerators (TENGs) is vital. Although quite a number methods to increase charge density have been proposed, challenges such as high impedance matching and low output current persist, severely limit the energy utilization efficiency of TENGs. Here, a new power management circuit (PMC) is proposed that through charge storage and release strategy. This circuit first excites the surface charge of the TENG using the charge excitation circuit, and then releases the stored charge through a self-triggered switch. Compared to a standard TENG, the output current of the TENG with this PMC is increased by a factor of 1108, the impedance is decreased from 100 MΩ to 10 kΩ, and the energy utilization efficiency is markedly improved. This work affords a reference for enhancing the output performance of TENG, reducing impedance, and broading the utility attainable of TENGs.

High‐performance triboelectric nanogenerators boosted by synergistically aligned piezoelectric/conductive composite nanofibers

AbstractTo address the need for efficient, flexible, and wearable power sources for portable electronics, a high performance triboelectric nanogenerator (TENG) was proposed by incorporating vertically‐aligned barium titanate (BaTiO3)/antimony tin oxide (ATO) nanofibers in polydimethylsiloxane (PDMS) negative triboelectric layer, where BaTiO3 served as piezoelectric material, and ATO served as conductive filler. Silver‐coated conductive fabric was used as electrode to ensure integrability and wearability. By strategically coupling the triboelectric effect of PDMS, the piezoelectric effect of BaTiO3 nanofibers, and the charge transfer effect of ATO nanofibers, the TENG exhibited the optimum output voltage and current of approximately 119 V and 28 μA, and power density of 11.74 μW/cm2, respectively. This device demonstrates its potential applications in energy supply by effectively illuminating 174 commercial green LEDs and charging capacitors for powering electronics. Additionally, the successful integration of the TENG into a smart fencing jacket highlights its utility in practical applications.Highlights TENGs with vertically‐aligned BaTiO3/ATO composite nanofibers was constructed. The output performance of TENGs were enhanced by coupling triboelectric and piezoelectric effects. Conductive ATO nanofibers were incorporated to enhance charge transfer for performance enhancement. A smart fencing jacket with scoring system was developed using the wearable TENG.

An enclosed solid-liquid triboelectric nanogenerator based on Janus-type TPU nanofibers

Various environmental factors such as high humidity, rain, snow, and other conditions restrict the practical use of triboelectric nanogenerator (TENG). Herein, Janus-type thermoplastic polyurethane (TPU) nanofiber films with good hydrophobicity were fabricated by side-by-side electrospinning. The output performance of TENG based on Janus-type TPU nanofiber films was much higher than that made of normal TPU nanofiber films. A flexible enclosed TENG was prepared that maintained its output performance regardless of external humidity. What’s more, liquid metal gallium (Ga) was injected into the enclosed TENG and used as the tribo-material. The addition of Ga to the enclosed TENG increased its output performance to reach a peak voltage of 282 V and current of 6.0 μA. The enclosed TENG was able to power light-emitting diodes (LEDs) even when immersed in water, demonstrating its potential for using under high-humidity conditions.

High-Strength and High-Toughness Supramolecular Materials for Self-Healing Triboelectric Nanogenerator.

The development of self-healing materials provides a new opportunity and challenge for advancing triboelectric nanogenerators (TENGs). However, the low strength and low toughness of self-healing triboelectric materials often result in the deformation or breakage of TENG under high mechanical loads, thereby limiting their potential applications. Herein, a new strategy for fabricating self-healing triboelectric materials is reported, which introduces cross-linking networks with hydrogen bonds and metal coordination bonds. The desired high performance can be achieved by simply adjusting the molar ratio of the metal to the ligand. When the molar ratio is 1:2, the tensile strength, toughness, and elongation atbreak of the material reached 13.7MPa, 76.9MJ m-3, and 1321%, respectively. Furthermore, its self-healing efficiency can reach 74% at 70°C in 6 h. Working in contact-separation mode, the electrical output can reach 164V, 18.2µA, 57.5 nC, with a maximum power density of 2.54W m-2. Notably, even if it is sheared, the electrical output performances of TENG can be completely recovered to the original state. In addition, the developed TENG exhibits excellent output stability over 10000 contact separation cycles. This study presents a promising approach for the development of stretchable smart generators.

Enhancing triboelectrification via multiscale roughness dependent thermal dissipation

Polymer-based triboelectric nanogenerators (TENGs) have held promise due to their excellent interfacial conformity and ease of fabrication. However, the role of surface roughness in triboelectricity requires further study. In this study, we have manipulated the nano-/micro-scale roughness configuration in polydimethylsiloxane (PDMS) over a wide range of extents using various sandpaper-based templates. According to the power spectral density analysis, the spatial frequency of template-free PDMS exhibits several distinct bandwidth regions each with different fractal dimensions significantly higher than 2, despite having the lowest roughness value. In contrast, most template-based PDMS shows an entire spatial frequency region that scales nearly with a single power factor corresponding to a fractal dimension as low as 2, despite slight increases in roughness values. Consequently, the surface temperature gradient and output performance of TENG increased, following the trend of fractal dimension and roughness, but the surface potentials have remained almost invariant. However, excessive increases in the surface roughness cause the spatial frequency to be divided once again into several different bandwidth regions with different cutoffs and higher fractal dimensions. These results suggest that the performance of TENG can be controlled by tuning both surface roughness and self-affine properties over multiple scales. Specifically, adhesive interaction becomes dominant on surfaces with lower fractality, enhancing TENG performance due to the expanded contact area. This study sheds light on the relationship among triboelectricity, thermal dissipation, and topography.

Aluminosilicate-based material fabricated from fly ash for energy harvesting application

A triboelectric nanogenerator (TENG) is an emerging energy harvesting technology that utilizes the combination of triboelectrification and electrostatic induction to collect wasted mechanical energy and convert it into electricity. In this work, an aluminosilicate (AS)-based composite, considered as a potential alternative to cement material, has been developed for the fabrication of TENGs. Herein, the AS material is synthesized through the alkali activation of fly ash using a mixture of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) solutions as activating agents. The electrical output of AS TENGs can be optimized by tuning the liquid-to-solid powder (L/S) ratio during the fabrication of AS composites. The AS composites fabricated at different L/S ratios exhibit the variations in dielectric properties, surface morphology and microstructure. It is found that a high dielectric constant is not the only requirement for achieving optimal TENG output performance. The contribution of dielectric properties and microstructures of the AS composites on TENG performance is discussed. The AS composite with an optimal L/S ratio of 0.5 results in the highest TENG power output density of 2.78 W/m2. Additionally, the versatility of AS TENG to harvest mechanical energy and its application as a power source for portable electronic device are demonstrated. This research has proposed the promising aspect of AS composites as alternative construction materials capable of harvesting mechanical energy, which is essential for the development of green and sustainable power sources.

Rationally Improved Surface Charge Density of Triboelectric Nanogenerator with TiO2-MXene/Polystyrene Nanofiber Charge Trapping Layer for Biomechanical Sensing and Wound Healing Application.

Triboelectric nanogenerators (TENGs) have become reliable green energy harvesters by converting biomechanical motions into electricity. However, the inevitable charge leakage and poor electric field (EF) of conventional TENG result in inferior tribo-charge density on the active layer. In this paper, TiO2-MXene incorporated polystyrene (PS) nanofiber membrane (PTMx NFM) charge trapping interlayer is introduced into single electrode mode TENG (S-TENG) to prevent electron loss at the electrode interface. Surprisingly, this charge-trapping mechanism augments the surface charge density and electric output performance of TENGs. Polyvinylidene difluoride (PVDF) mixed polyurethane (PU) NFM is used as tribo-active layer, which improves the crystallinity and mechanical property of PVDF to prevent delamination during long cycle tests. Herein, the effect of this double-layer capacitive model is explained experimentally and theoretically. With optimization of the PTMx interlayer thickness, S-TENG exhibits a maximum open-circuit voltage of (280V), short-circuit current of (20µA) transfer charge of (120 nC), and power density of (25.2 µW cm-2). Then, this energy is utilized to charge electrical appliances. In addition, the influence of AC/DC EF simulation in wound healing management (vitro L929 cell migration, vivo tissue regeneration) is also investigated by changing the polarity of trans-epithelial potential (TEP) distribution in the wounded area.

Reduced graphene oxide/TiO2 hybrid synergistically enhanced polyimide nanofibers with high triboelectric output and thermal charge stability

The output performance of triboelectric nanogenerators (TENGs) can drop dramatically in high temperature environments because of the thermionic emission effect. To enhance the thermal charge stability and expand the working temperature of TENG, polyimide nanofibers (PINF) were synergistically enhanced by the electron trapping mechanism of reduced graphene oxide (rGO) and interfacial polarization of TiO2. With the multiple enhancement effect of polyimide/rGO/TiO2 composite nanofibers (PRTNF) on triboelectric output, PRTNF-TENG generated an open circuit voltage of 228.26 V and a short circuit current of 5.22 μA, which were 3.80 and 3.48 times higher than those of PINF-TENG. The effective output of polymer-based TENG was investigated from 25 − 300 °C. Compared to room temperature, the PRTNF-TENG can maintain 19.45 % (44.39 V) and 18.20 % (0.95 μA) of the voltage and current at 300 °C, respectively, and still drive 50 commercial LEDs. Furthermore, PRTNF-TENGs were applied as self-powered sensors for firefighters to provide real-time motion monitoring and ambient temperature detection. This PRTNF-TENG has broad application prospects for energy harvesting and smart electronic monitor in harsh environments such as fire and space.

High performance triboelectric nanogenerator for wave energy harvesting through the gas-assisted method

Triboelectric nanogenerators (TENGs) have unparalleled performance advantages in the low-frequency range and become an emerging technology for efficient wave energy harvesting. There are various methods to improve the output performance of triboelectric nanogenerators, but the output effect and manufacturing convenience of the TENGs cannot be balanced, which limits their promotion and application in a wider field. Here, a gas-assisted triboelectric nanogenerator (GA-TENG) for harvesting wave energy is reported, which has high performance through a gas-assisted method. The gas-assisted device is mainly composed of two airbags and a flexible substrate to increase the actual contact area between the triboelectric layers, which increases the open-circuit voltage (Voc) and transferred charge (Qsc) by 7.99 and 13.86 times, respectively, compared to the rigid substrate. The power density of GA-TENG can reach 20.4 W/m3 under the wave frequency of 1 Hz. In addition, the applications of GA-TENG are successfully demonstrated, including powering three lamps of 3 W, a wireless temperature and humidity sensor, and a water level monitoring module. This work provides a design scheme for wave energy harvesting and a universal method for TENG to harvest renewable energy efficiently.

Stretchable Unsymmetrical Piezoelectric BiO2-x Deposited-Hydrogel as Multimodal Triboelectric Nanogenerators for Biomechanical Motion Harvesting.

Enhancing the output performance of triboelectric nanogenerators (TENGs) is essential for increasing their application in smart devices. Oxygen-vacancy-rich BiO2-x nanosheets (BiO2-x NSs) are advanced-engineered nanomaterials with excellent piezoelectric properties. Herein, a stretchable unsymmetrical BiO2-x NSs deposited-hydrogel made of polyacrylamide (PAM) as a multimodal TENG is rationally fabricated, and the performance of TENG can be tailored by controlling the BiO2-x NSs deposition amount and spatial distribution. The alteration of resistance caused by the Poisson effect of PAM/BiO2-x composite hydrogel (H-BiO2-x) can be used as a piezoresistive sensor, and the piezoelectricity of BiO2-x NSs can effectively enhance the density of transfer charge, thus improving the output performance of the H-BiO2-x-based TENG. In addition, the chemical cross-linking between the BiO2-x NSs and the PAM polymer chain allows the hydrogel electrode to have a higher tensile capacity (867%). Used for biomechanical motion signal detection, the sensors made of H-BiO2-x have high sensitivity (gauge factor = 6.93) and can discriminate a range of forces (0.1-5.0 N) at low frequencies (0.5-2.0Hz). Finally, the prepared TENG can collect biological energy and convert it into electricity. Consequently, the improved TENG shows a good application prospect as multimodal biomechanical sensors by combining piezoresistive, piezoelectric, and triboelectric effects.

The regulation and its application of the charge decay rate in triboelectric nanogenerator.

The decay rate of charge in the friction layer is one of the key factors affecting the output performance of triboelectric nanogenerators (TENG). Reducing the decay rate of the triboelectric charge can increase the charge-carrying capacity of the friction layer and improve the output current and voltage of the TENG. This makes a friction generator more suitable for discontinuous driving environments. In contrast, increasing the decay rate of the charge in the friction layer can greatly improve the recovery time of the device, although it reduces the output performance of the generator. This is conducive to the application of friction generator in the field of sensors. In this study, polystyrene (PS) and carbon nanotubes (CNTs) were added to polyvinylidene fluoride (PVDF) nanofibers to adjust the charge decay time in the friction layer, thereby regulating the output performance of the friction generator and sensor. When the amount of added PS in the PVDF nanofiber reached 20%, the charge density on the friction surface increased by 1.9 times, and the charge decay time decreased by 64 times; when 0.1 wt% CNTs were added in the PVDF nanofiber, the charge decay time increased by more than 10 times. The former is more conducive to improving the power generation performance of the TENG, and the latter significantly improves the stability and repeatability of TENG-based sensors.&#xD.

Highly Tribo-Positive Nylon-11 Film Fabricated by Multiscale Structural Regulation through a Roll-to-Roll Processing.

Triboelectric polymers have attracted extensive attention due to their great electron-accepting and electron-donating properties in contact electrification as well as their flexible and low-cost merits and have become promising electrode materials in triboelectric nanogenerators (TENGs). However, most research has exclusively focused on improving the electron capture capability of the triboelectric layer, neglecting to enhance the electron-donating capability, which leads to a low output performance of TENG and limits its practical application. In this study, we developed a method to fabricate highly tribo-positive Nylon-11 film through roll-to-roll processing. Paired with the poly(tetrafluoroethylene) triboelectric layer, the transferred charge density of contact-separation TENG based on Nylon-11 film prepared by this method reaches 291.1 μC/m2, which has been improved by 12.4% compared with the conventional compression molding sample. The novel fabricating method can regulate the surface functional groups to achieve higher surface potential and obtain a favorable pseudohexagonal crystal phase, leading to an increasing transferred charge density in triboelectrification. Additionally, it has been analyzed that higher chemical potential of materials can facilitate the transfer of electrons from the triboelectric polymer surface. This study provides a nonadditive, simple, and effective strategy to fabricate excellent tribo-positive material, which can significantly enhance the performance of TENG.

Cellulose-Based Triboelectric Nanogenerator Prepared by Multi-Fluid Electrospinning for Respiratory Protection and Self-Powered Sensing

A cellulose-based triboelectric nanogenerator (TENG) with fiber–wave–arch structure was prepared through a multi-fluid electrospinning process for air filtration and wind sensing. The TENG is composed of a cellulose nanocrystals (CNC)/zein membrane and a cyanoethyl cellulose (CEC)/polyvinylidene fluoride (PVDF) membrane. The results show that the addition of CEC improves the output performance and filterability of TENG. At the same time, the reduced diameter and high roughness of CEC/PVDF nanofibers improve the output performance of the TENG. The TENG with a 6 wt% CEC/PVDF solution concentration has the highest output performance with a short-circuit current of 3.30 μA and an open-circuit voltage of 10.01 V. The particle filtration of 12 wt% CEC/PVDF TENG is the best, showing an efficiency of 98.84% and a pressure drop of 50 Pa. The TENG also has a good formaldehyde filtration capability with an efficiency of 92% at 0.25 mg/m3. The TENG shows great potential in self-powered sensor applications.

Predicting the Output Performance of Triboelectric Nanogenerators Using Highly Representative Data‐Based Neural Networks

Triboelectric nanogenerators (TENGs) are promising potential sustainable power sources for wireless sensing networks within the Internet of Things (IoT) realm. Developing an efficient TENG evaluation model, characterized by high speed, accuracy, and representativeness, facilitates its integration into practical applications, which is urgent and lack of investigation currently. Herein, an artificial intelligence (AI) based evaluation model is developed to predict the performance of freestanding rotational TENGs (FR‐TENGs) for demonstration. An accurate and representative train dataset is essential for development of AI‐based evaluation model, which has been generated using finite element analysis and equivalent circuit simulation alongside the non‐dominated sorting genetic algorithm II. Through comprehensive experiments and simulations, the accuracy of the model has been verified in predicting the power output performance of FR‐TENGs, which has 99.6% (three design parameters) and 99.2% (seven design parameters) maximum train set accuracy. More importantly, the predicted results from the AI‐based evaluation model have notably expanded the coverage of data and significantly expedited the generation time from days to seconds. Herein, the use of AI in assessing the performance of TENGs is enhanced. The TENG design process can be significantly simplified, while maintaining a high evaluation model accuracy, thus promising advancements of IoT applications in future.

Development of flexible high-performance PDMS-based triboelectric nanogenerator using nanogratings

This article investigates the performance of a contact-mode Triboelectric Nanogenerator (TENG) utilizing polydimethylsiloxane (PDMS) with nano gratings as a dielectric in a metal-dielectric configuration. The evaluation encompasses the impact of gratings, tapping frequency, various load conditions, and contact area on the TENG performance. The fabrication involves spin-coating PDMS onto a master mold to create the device. Experimental measurements reveal a significant enhancement of 97% in open-circuit voltage by introducing gratings on PDMS. Furthermore, as the tapping frequency increases from 1 Hz to 3 Hz, there is a corresponding rise of 108% in output voltage. The influence of load resistance on TENG output performance demonstrates its ability to drive different loads efficiently. Moreover, enlarging the contact area of the device substantially increases the open-circuit voltage. A device with a 400 mm2 contact area can generate a voltage of 80 V at a low frequency of 3 Hz, indicating the importance of considering device size and contact area for specific applications. A practical circuit integrating a TENG with a full-wave bridge rectifier demonstrates energy harvesting capabilities by successfully illuminating a light-emitting diode (LED) and charging various capacitors. The fabricated devices exhibit better performance along with a cost-effective and easy fabrication process.

One-click fabrication of triboelectric nanogenerators through multiple fused filaments fabrication

The efficiency and cost of manufacturing large-scale triboelectric nanogenerators (TENG) plays an important role in determining the application of TENG in various fields. However, the commonly employed direct ink writing (DIW) technique encounters challenges in the manufacturing process, such as difficulties in achieving automatic material switching, intricate procedures, and high costs. In this paper, we have developed a conductive polymer filament comprising thermoplastic polyurethane/polylactic acid/carbon nanotubes/graphene (TPCG) and proposed a one-click preparation approach for building TENG utilizing Fused Filament Fabrication (FFF) technology. This approach can automatically switch multiple printing materials and thus efficiently prepare TENG without any human intervention. The influence of printing parameters on the output performance of TENG was investigated. As a demonstration, we utilized the one-click method to construct a self-powered cathodic protection system, effectively safeguarding Q235 carbon steel from corrosion. This work presents an advanced TENG fabrication solution based on the developed TPCG conductive polymer filament, enhancing production efficiency and promoting the development of standardized and scalable manufacturing processes.

Unveiling the mechanism of lignin nanofiller in boosting the performance of triboelectric nanogenerators

Lignin has been demonstrated as the tribopositive nanofillers in boosting the triboelectric performances of biopolymer-based triboelectric nanogenerators (TENGs). However, the complex structures of lignin caused the unclear understanding how the molecular structures of lignin affected the output performances of TENGs. Herein, for the first time, five fractionated lignin with different structures were innovatively employed as the tribopositive nanofillers in CMC. Computational simulations and experimental results verified that the lignin with more S units, A-type linkage and large molecular weight give rise to the higher dielectric constant as well as the triboelectric performances. Relying on this principle, the acetone lignin possessed the highest dielectric behavior and the constructed TENG delivered the maximum Voc of 204.34 V, Isc of 6.86 µA, Qsc of 70.27 nC and instantaneous output power density of 836.64 mW/m2 under contact frequency of 1 Hz. Moreover, such biofilm can be dissolved in water and the regenerated film delivered stable output performances at least 5 times. Our findings not only provided the in-depth understanding of the relationship between triboelectrification behaviors and molecular structures of lignin, but also boosted the rational designing high-performance lignin-based tribopositive nanofillers for self-powered sensing or mechanical energy harvesting.

Effect of commercial P25 TiO2 doping in polydimethylsiloxane tribo-film on the output performance of triboelectric nanogenerator and its application

Polydimethylsiloxane (PDMS) is a popular tribo-layer film for triboelectric nanogenerator (TENG) often used for mechanical energy harvesting to collect sustainable energy. Material doping in PDMS is a feasible method for performance enhancement of TENG. Different dielectric materials in TENG involved in time-consuming and complex chemical process. Here, we propose a PDMS-TENG doped with a commercially available and non-toxic dielectric material P25 TiO2 with fast process. The dielectric triboelectric layer is casted by PDMS with doped TiO2 (TiO2@PDMS) at a precisely controlled concentration and combined into TENG with aluminium sheet (TiO2@PDMS-Al-TENG). The optimal TiO2@PDMS-Al-TENG occurred at 0.45 wt% of P25 TiO2. In comparison to the non-doped PDMS-Al-TENG, the open-circuit voltage increased by 223 %, the short-circuit current increased by 263 %, and the output power increased by 692 %. TiO2@PDMS-Al-TENG can be applied to drive electrical appliances. This demonstrates that using commercially available low-cost TiO2 can enhance power generation performance enough for PDMS-Al-TENG at a fast process and be widely used in the power generation thin films.

Enhancing the Output Performance of Triboelectric Nanogenerator Through Regulation of its Internal Nano-Architecture.

Triboelectric Nanogenerator (TENG) has proven highly effective in converting mechanical energy into electrical energy. Previous research on manipulating microstructure for performance enhancement primarily focused on the surface of TENGs. In this study, an innovative bottom-up strategic design to control the internal nano-architecture for the enhanced output of TENG is proposed. This multiscale structural design strategy consists of defect chemistry (angstrom-scale), surface modification (nano-scale), and spatial regulation of nanoparticles (meso-scale), which helps explore the optimal utilization of TENG's internal structure. After fine-tuning the nano-architecture, the output voltage is significantly increased. This optimized TENG serves as a robust platform for developing self-powered systems, including self-powered electrochemical chlorination systems for sterilization. Additionally, through the utilization of multiscale simulations (density functional theory, all-atom molecular dynamics, and dissipative particle dynamics), the underlying mechanisms governing how the optimized nanoparticle-polymer interface and spatial arrangement of nanoparticles influence the storage and transfer of charges are comprehensively elucidated. This study not only demonstrates the effectiveness of manipulating internal nano-architecture to enhance TENG performance for practical applications but also provides invaluable insights into structural engineering for TENG advancement.

Flexible Triboelectric Nanogenerators based on Hydrogel/g-C3N4 Composites for Biomechanical Energy Harvesting and Self-Powered Sensing.

Flexible and stretchable triboelectric nanogenerators (TENGs) have been rapidly advanced owing to the demand for portable and wearable electronic devices that can work under universal or motional circumstances. While versatile materials can be applied in a TENG as dielectric materials, flexible and cost-effective electrodes are crucially important for the output performance of TENGs. Herein, we developed a poly(vinyl alcohol) (PVA) hydrogel TENG doped with a novel two-dimensional material, graphitic carbon nitride (g-C3N4), which could act as both a cost-effective flexible electrode and a positive dielectric for TENG with different morphologies. The measured peak-to-peak open-circuit voltage of the TENG reached 80 V at a dopant concentration of 2.7 wt % in single-electrode mode, which is far higher than that of the pristine PVA hydrogel TENG. As a demonstration of the application, the g-C3N4/PVA hydrogel TENG can be adopted as electronic skin to monitor the movement of the human body. Low-frequency mechanical energy-harvesting devices in different morphologies including discoid flake shape, tube shape, and spiral shape in the single-electrode mode or contact-separation mode have been designed, fabricated, and evaluated. All of these merits of the proposed hydrogel TENG after doping two-dimensional (2D) material g-C3N4 have demonstrated their promising potential for versatile applications in biomechanical energy harvesting and self-powered sensing.