Fabrication Of Triboelectric Nanogenerator Research Articles

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.

Recent advances in high charge density triboelectric nanogenerators

Abstract Triboelectric materials with high charge density are the building-block for the commercial application of triboelectric nanogenerators (TENGs). Unstable dynamic processes influence the change of the charge density on the surface and inside of triboelectric materials. The charge density of triboelectric materials depends on the surface and the internal charge transfer processes. The focus of this review is on recent advances in high charge density triboelectric materials and advances in the fabrication of TENGs. We summarize the existing strategies for achieving high charge density in triboelectric materials as well as their fundamental properties. We then review current optimization methods for regulating dynamic charge transfer processes to increase the output charge density: first, increasing charge injection and limiting charge dissipation to achieve a high average surface charge density, and second, regulating the internal charge transfer process and storing charge in triboelectric materials to increase the output charge density. Finally, we present the challenges and prospects in developing high-performance triboelectric materials.

Nanosheet Zinc Oxide Synthesized by Solution-Immersion Method for Triboelectric Nanogenerator

Most global problems are being solved by using sustainable energy harvesting technologies to retain the social ecosystem in great condition. The triboelectric nanogenerator (TENG) which is a renewable energy harvesting device, collects the waste mechanical energy from its surroundings and performs the electric signal conversion. TENG have garnered increased attention in recent years by offering prospective use in energy harvesting technology. Particularly, there is a need for flexible energy conversion that serves as a power supply for portable electronic equipment. In this study, ZnO nanosheet thin film prepared on the flexible conductive aluminium foil through a low temperature immersion technique was used to generate electrical energy. The effect of heat treatment on ZnO nanosheet thin film was also investigated on the surface morphology, strutural properties and nanogerator performance. The high density of interconnected ZnO nanosheet were observed before and after heat treatment as confirmed by FESEM studies. The analysis using XRD confirmed that ZnO nanosheet thin film was successfully deposited on the aluminium foil. Additionally, the ZnO nanosheet thin films improved significantly with heat treatment, enhancing their crystalline quality. The triboelectric nanogenerator (TENG) was successfully constructed in contact and separation mode using Kapton tape on top and ZnO nanosheet thin film on the bottom to generate electricity by a force of hand pressing. The output electrical voltage of the device doubled from around 2 V to 4 V after underwent the heat treatment. This study provides an essential insight into fabrication of TENG using the ZnO nanosheet thin film through a clean and effective method for nanogenerator applications.

Self-strengthening and conductive cellulose composite hydrogel for high sensitivity strain sensor and flexible triboelectric nanogenerator

Triboelectric nanogenerators (TENGs) as promising energy harvesting devices have gained increasing attention. However, the fabrication of TENG simultaneously meets the requirements of green start feedstock, flexible, stretchable, and environmentally friendly remains challenging. Herein, the hydroxyethyl cellulose macromonomer (HECM) simultaneously bearing acrylate and hydroxyl groups was first synthesized and used as a crosslinker to prepare the chemically and physically dual-crosslinked cellulose composite hydrogel for an electrode material of stretchable TENG. Meanwhile, the in-situ polymerization of pyrrole endowed the hydrogel with satisfactory conductivity of 0.40 S/m. More impressively, the synergies of the cellulose rigid skeleton and the construction of the dual-crosslinking network significantly improved the mechanical toughness, and the hydrogel exhibited excellent self-strengthening through cyclic compression mechanical training, the self-strengthening efficiency reached 124.7 % after 10 compression cycles. Given these features, the hydrogel was used as wearable strain sensors with extremely high sensitivity (GF = 3.95) for real-time monitoring human motions. Additionally, the hydrogel showed practical applications in stretchable H-TENG for converting mechanical energy into electric energy to light LEDs and power a digital watch, and in self-powered wearable sensors to distinguish human motions and English letters. This work provided a promising strategy for fabricating sustainable, eco-friendly energy harvesting and self-powered electronic devices.

Electronically Robust Self-Assembled Supramolecular Gel as a Potential Material in Triboelectric Nanogenerators.

A series of self-assembling gluconamide conjugated naphthalimide amphiphiles (GCNA) was synthesized and the self-assembly of GCNA into gel rendered an increased electron density in naphthalimide moiety with an overall change in energy of 15.33×10-32 J via J-type aggregation. SEM analysis and X-ray diffraction underpinning the nanofibrillar formation, and rheological measurements confirmed the processablity and material fabrication. The enriched electron density in the aggregated GCNA4 via cooperative intermolecular non-covalent interactions makes it as effective electron donor in the fabrication of triboelectric nanogenerators (TENG). The TENG based on GCNA4-polydimethylsiloxane (PDMS) triboelectric pair generated an output voltage, current and power density of ∼250 V, 40 μA and ∼622 mW/m2 respectively, which is almost 2.4 times better in performance than the amorphous GCNA4 based TENG. The fabricated TENG can power-up 240 LEDs, wrist watch, thermometer, calculator and hygrometer.

Fabrication of triboelectric nanogenerators with multiple strain mechanisms for high-accuracy material and gesture recognition

Textile-based triboelectric nanogenerators (T-TENGs) have great potential in new-generation tactile sensors because their output signal is determined by the specific charge interaction between the target and triboelectric material.

Exalting energy scavenging for triboelectric nanogenerator using silicon carbide particles doped polyvinylidene difluoride nanocomposite

Polymer materials, particularly piezoelectric polymers, have been extensively studied and implemented in triboelectric nanogenerators (TENG) owing to their ferroelectric properties, low cost and easy synthesis etc. This research is a comprehensive analysis on a novel nanocomposite of polyvinylidene fluoride (PVDF)/silicon carbide (SiC) nanoparticles as a triboelectric material, and fabrication of TENGs using the SiC-PVDF nanocomposite and polyamide (PA6) membrane combination. The composite film obtained from the phase inversion method with varying concentration of SiC nanoparticles is studied and compared with the pristine film prepared by solution casting. The results show that the inclusion of SiC nanoparticles could greatly enhance the β-phase content of the PVDF films, and significantly increase surface roughness and porosity of the SiC-PVDF nanocomposites. The TENG made with a PVDF film with 6 wt% of SiC shows an open circuit voltage of 850 V and a short circuit current of 20 µA under a frequency of 3.5 Hz, 1100 V and 42 µA under a frequency of 15 Hz at a load of 5 N. The TENG has a high-power output of 12.25 mW at 3.5 Hz, which is four times higher than that of the TENG using the film prepared using the solution casting method. This work provides an effective strategy for enhancing the output power of PVDF/PA6 TENGs through the addition of SiC nanoparticles with great application prospects for low power electronics and as active sensors.

Density functional theory and experimental investigations of MWCNT-PDMS based triboelectric nanogenerator

The emergence of triboelectric nanogenerators (TENG) have transformed the landscape of self-powered electronics and sensing mechanisms by exploiting the remarkable potential of innovative functional nanomaterials. However, there is a lack of theoretical in-depth analysis of the triboelectric devices. Herein, for the first time, the triboelectric performance of Polydimethylsiloxane (PDMS) and Multi-walled Carbon Nanotubes (MWCNT) - PDMS based TENG is unveiled by rigorous investigation of electronic structures through density functional theory (DFT) computations. Experimentally, PDMS and MWCNT-PDMS thin films are fabricated that are used as tribo-negative layers in the fabrication of TENGs. Further, the material characterisations are performed for the fabricated nanocomposite films. The output performance of TENGs is realised by using a dynamic test platform that imitates the finger tapping mechanism and the influence of contact surface area (1 cm 2 , 4 cm 2 , 9 cm 2 , 16 cm 2 , 25 cm 2 ) between triboelectric layers on open circuit voltage (V oc ) of TENGs is investigated. The outcomes demonstrate linear increase in V oc corresponding to increase in contact area of TENG. With a contact area of 1 cm 2 , the maximum peak-to-peak open circuit voltage (V mpp ) is recorded to be 32.2 V and 94.2 V for PDMS and MWCNT-PDMS based TENG respectively. An increase in V mpp by ~65% is synergistically validated by ~95% decrease in band gap endowing to addition of MWCNT into PDMS elastomer. Importantly, the energy band gap analysis is quantified by calculating HOMO/LUMO states and density of states responsible for the development of electric potential which can be used for small power applications. • Analysing the enhancement in triboelectric performance of PDMS on addition of MWCNT using density functional theory (DFT) calculations. • MWCNT-PDMS based TENG exhibited ~65% higher open circuit voltage than pure PDMS TENG. • Band gap reduced by ~95% on incorporation of MWCNT into PDMS elastomer. • Increased DOS peak intensity in valence band and conduction band along with the shift towards fermi level provides assistance to charge transport in comparison to pristine PDMS • Experimental outcomes are synergistically validated by DFT findings.

Highly stable metal-organic framework UiO-66-NH2 for high-performance triboelectric nanogenerators

The high porosity, controllable size, high surface area, and chemical versatility of a metal-organic framework (MOF) enable it a good material for a triboelectric nanogenerator (TENG), and some MOFs have been incorporated in the fabrication of TENGs. However, the understanding of effects of MOFs on the energy conversion of a TENG is still lacking, which inhibits the improvement of the performance of MOF-based TENGs. Here, UiO-66-NH2 MOFs were found to significantly increase the power of a TENG and the mechanism was carefully examined. The electron-withdrawing (EW) ability of Zr-based UiO-66-family MOFs was enhanced by designing the amino functionalized 1,4-terephthalic acid (1,4-BDC) as ligand. The chemically modified UiO-66-NH2 was found to increase the surface roughness and surface potential of a composite film with MOFs embedded in polydimethylsiloxane (PDMS) matrix. Thus the total charges due to the contact electrification increased significantly. The composite-based TENG was found to be very durable and its output voltage and current were 4 times and 60 times higher than that of a PDMS-based TENG. This work revealed an effective strategy to design MOFs with excellent EW abilities for high-performance TENGs.

Animal Hair-Based Triboelectric Nanogenerator (TENG): A Substitute for the Positive Polymer Layer in TENG

A triboelectric nanogenerator (TENG) is a sustainable solution for the development of smart battery-less devices. It is clean, pollution-free, and cost-effective. Various studies have investigated the fabrication of TENGs using different materials. Biomaterials have great potential in this area. Hair, a natural biomaterial, is made of keratinized proteins having different chains of amino acids. These amino acids act as an active layer for the TENG. In this investigation, animal hair is used to fabricate an active layer of a TENG. This layer is tested with active layers of different biomaterials including egg shell membrane and cellulose from different sources (Bombax ceiba tree cotton, tissue paper cellulose), synthetic materials including Teflon (polytetrafluoroethylene—PTFE) and zinc oxide (ZnO), and metals including copper (Cu) and aluminium (Al). The TENG generated 200 volts peak-to-peak voltage using dog hairs and a PTFE combination. A series combination of 124 light-emitting diodes was also lighted with this TENG. Finally, a smart device was powered using this combination. This work provides a basis for further research using different biomaterials for TENG fabrication.

Large amplification of triboelectric property by allicin to develop high performance cellulosic triboelectric nanogenerator

Recently, cellulose has grabbed a tremendous attention in the fabrication of triboelectric nanogenerators (TENGs) because of their biodegradability and renewability. However, the weak surface polarity and inadequate surface functional groups severely limit its advancement towards high performance TENGs. This study unveils for the first time the majestic power of allicin extracted from garlic juice, in amplifying the triboelectric property of cellulose nanofibers (CNFs), aiming to develop a renewable high-performance cellulosic triboelectric nanogenerators (TENGs). Allicin was grafted onto CNF using a ‘thiol-ene’ click chemistry. It has been observed that after allicin modification, the CNF film became mechanically and thermally robust. The peak output voltage and current reached to 7.9 V and 5.13 μA, when modified film was used in a TENG, which was ~6.5 times greater than the pristine cellulose based TENG (1.23 V, 0.80 μA). Because of higher surface polarity, electron donating capacity and surface roughness of the modified film, the current density and power density increased from 0.2 to 1.28 µA/cm2 and 0.25 to 10.13 µW/cm2 i.e 6 and 41 times greater respectively, than the pristine cellulose TENG. Such large electrical enhancements surpasseed many recent reports on cellulose TENG. Furthermore, the allicin grafted TENG showed outstanding stability against humidity, long term cyclic load and environmental aging. These findings clearly demonstrated that tailoring the triboelectric performance by garlic juice could be a major breakthrough in the hunt for durable, high performance self-powered biodegradable TENGs.

Insight into Cigarette Wrapper and Electroactive Polymer Based Efficient TENG as Biomechanical Energy Harvester for Smart Electronic Applications

Here, we demonstrated an arc shaped flexible triboelectric nanogenerator (TENG) that efficiently harvests asymmetrical mechanical energy for powering several portable electronic devices. Here the fabrication of TENG is based on the integration of a cigarette wrapper, spongelike poly(vinylidene fluoride) (PVDF) film, and conducting carbon tape. Here, the spongelike PVDF film was prepared through nonsolvent induced phase separation (NIPS) technique (by simply spraying PVDF solution on a water surface in a Petri dish). Owing to the low density of the PVDF sponge and the cigarette wrapper, the final device with a volume of 6.6 cm3 shows a total mass of 1.259 g. The fabricated TENG exhibits open circuit voltage of ∼342 V and short circuit current of ∼8.1 μA on frequencies of ∼3.4 Hz without electrospinning and poling treatment under finger tapping, which gives a maximum area power density of ∼0.37 mW/cm2 at a load resistance of 40 MΩ. The TENG shows excellent durability without any change in output performance successively for 7 days (193200 cycles). Also, this device directly lit up 136 commercial LEDs instantly without any rectification unit and sensed different types of mechanical forces. With easy fabrication and cost-effective technique, this work paves a new and smart way to fabricate high performance TENG for powering portable electronic appliances.

Realizing the potential of polyethylene oxide as new positive tribo-material: Over 40 W/m2 high power flat surface triboelectric nanogenerators

The on-going research into the negative tribo-materials has led to significant improvements in the performance of triboelectric nanogenerators (TENGs), however, very little attention has been paid to the positive tribo-materials. This work reports on the use of poly(ethylene oxide) (PEO) as the positive tribo-material for the fabrication of TENGs and shows that PEO has much higher positive tribo-polarity than the existing choice of polyamide-6 (PA6). A 2 × 2 cm2 TENG comprising of spin-coated flat PEO and polydimethylsiloxane (PDMS) films produces a voltage of up to 970 V, a current density of 85 mAm−2, and a power of ~ 40 W m−2 under a 50 N contact force. Comparatively, the PA6/PDMS TENG only produces 630 V, 30 mAm−2, and a power of ~ 18 W m−2, showing the remarkable property of the PEO as the positive tribo-material. The results are further supported by the contact potential difference between PEO (1.26 V) and PA6 (0.87 V) obtained using Kelvin Probe Force Microscopy. Furthermore, the triboelectric behavior of PEO is explained in the context of the positively charged oxygen functional groups and the lower work function of PEO as compared to PA6. The work thus expands the current portfolio of materials used for triboelectric nanogenerators with great prospects.

A size-unlimited surface microstructure modification method for achieving high performance triboelectric nanogenerator

Triboelectric nanogenerator (TENG) is a promising mechanical energy harvesting device, which has many advantages such as low cost, high efficiency and easy fabrication. Surface modification on tribo-surface has been proved to be an efficient way to improve the output performance of TENG. However, the existing methods are time-consuming, high-cost and difficult for large-area processing, which, to some extent, limited the industrial production of TENG technology. In this work, we demonstrated a simple, fast and low-cost method, in which the tribo-surfaces of TENG were processed without size limitations to improve its output performance. Through this method, a large-scale treated TENG can be easily achieved and its output voltage and power can be increased by a factor of 3 and 5, respectively, providing us a size-unlimited, low-cost and time-saving surface micro-structure modification method for improving the output of TENG. This work showed great chance for industrial fabrication of TENG, which was crucial for sustainable power supply in the future.

Fabrication of triboelectric nanogenerator with textured surface and its electric output performance

Contact electrification between insulators, manifesting as static or triboelectricity is a well-known effect. The triboelectric nanogenerator (TENG) which is based on the contact triboelectricification and electrostatic induction provides a promising route for harvesting ambient mechanical energy and converting it into electric energy. The TENG which is due to its unique properties such as simple structures, low cost, high electric density etc., can offset or even replace the traditional power source for small portable electronics, sensors and so on. So far, the influence of factors on the output performance of TENG is still trapped in unsettled questions and under debate. In this paper, we prepare several textured polydimethylsiloxane (PDMS) films with micro rod array by model method and fabricate a TENG with a size of 2222 mm. The electric generation can be achieved with a cycled process of contact and separation between a polymer and metal electrode (PDMS and aluminum respectively in this study). Several influences as the surface structure and external load on the electrical output of the TENG are systematically studied by integrating use of experimenal tests and ANSYS simulation. Results show that the existence of micro rod array on the PDMS films effectively enlarges the contact area and provides more surfaces for charge storage and hence improve the output performance of TENG. When keeping the external load constant, the output increases with decreasing distance between micro rods. When the external load is 5 N and the distance is 15 m, the average output voltage and current as high as 88 V and 15 A can be achieved respectively, which is 1.5 times higher than the output generated when the distance is 50 m. The electrical output increases quasilinearly with the increase of the external load. Simulation results show that the micro rods of PDMS films are mainly compressed by normal load, which results in a bigger diameter of micro rods. The deformations of PDMS substrate leads to the lateral friction between the micro rods and the upper electrode, which produces more charges because of the friction. For 5 N normal load, the deformations of PDMS substrate and micro rods contribute to the sum of displacement vector and the deformations along Z-axis are 32.7 m and 21.3 m respectively, and are 4.96 and 5.04 times higher than the deformation at the load of 1 N. All the results in an enlarging surface area and the larger output correspondingly. Not only does this work present a new type of generator with micro rods on the PDMS surface, which can be an effective method to improve the electrical output of TENG, but also offers a unique point of view for further understanding of the working principle of TENG.

Self-packaging elastic bellows-type triboelectric nanogenerator

A triboelectric nanogenerator (TENG) is an emerging technology that utilizes a combination of the triboelectric effect and electrostatic induction to generate electricity in a unique way. An elastic component such as a spring or restorative polymer substrate is an essential component for the sustainable contact-separation process of a TENG. Here, a multifunction elastic bellows-type TENG that can be applied as the elastic component of a conventional TENG is reported. The packaged structure of the bellows can also be used to harvest mechanical energy itself. The single bellows-type TENG produces an open-circuit voltage of 132V and closed-circuit current of 22μA. This paper reports the results of the first study on the stiffness of the elastic components, introducing the minimum and maximum weights for the appropriate working conditions and future fabrication of TENGs. Furthermore, with the integration of traditional TENGs, a self-packaged hybrid TENG is able to light up 60 commercial light emitting diodes instantaneously. This bellows-type TENG is a potential solution to packaging a TENG for practical use, and harvesting mechanical energy in the near future.