Triboelectric Nanogenerator Device Research Articles

Investigation of laser-textured triboelectric nanogenerator for vibration sensing of machine tools

The breakdown of any industrial mechanical system can be predicted and identified using vibration sensing. Piezoelectric material-based vibration sensors are commercially available, but their use is limited by their reliance on external power sources and intricate data-gathering systems. Recently, contact electrification-based triboelectric nanogenerators (TENGs), which are reliable, affordable, and lightweight devices, have been developed as vibration sensors. The TENG is a high-voltage output device; however, its lower current output restricts its practical applications. In this work, we report a novel laser texturing technique for output enhancement of polytetrafluoroethylene (PTFE)- and aluminum (Al)-based TENG for machinery vibration sensing applications. An Nd3+: YAG pulse laser was used for texturing the PTFE sheet. A 50% spatial spot overlap with laser fluences of 10 and 50 J cm−2 was chosen to investigate the impact on the TENG electrical output. As compared to pristine TENG, the open-circuit voltage and short-circuit current of laser-textured (LT) TENG increased from 308 V to 368 V and 12.64 µA to 19.16 µA, respectively. The TENG device was attached to a lathe and a milling machine to sense the change in vibration state with respect to various machining parameters. Moreover, the proposed LT performance-enhanced TENG has excellent potential and broad applications in the fields of machinery monitoring, fault detection, and the Internet of Things and Industry 4.0.

High-performance triboelectric nanogenerators incorporating chlorinated zeolitic imidazolate frameworks with topologically tunable dielectric and surface adhesion properties

Triboelectric nanogenerator (TENG), a device that can convert mechanical energy into electricity based on the principle of triboelectrification, has gained tremendous attention since its first discovery in 2012. Although TENG has versatile applications in energy harvesting and self-powered sensing, its commercialization is still limited by the low power output. Recently, metal-organic frameworks (MOFs), with their large surface area and excellent tunability, have been explored to enhance the electrical performance of TENG. Herein, we synthesized nanoparticles of hydrophobic zeolitic imidazolate framework ZIF-71 (RHO topology) and its non-porous counterpart ZIF-72 (LCS topology), which were subsequently incorporated in a polydimethylsiloxane (PDMS) matrix as filler materials. By modifying the topology of ZIF nanofillers, we found the dielectric constant and surface adhesion of composites are both enhanced, thereby generating significantly higher triboelectric output. Moreover, we show the resultant ZIF/PDMS nanocomposite films exhibit enhanced triboelectric properties and long-term stability under cyclic mechanical loading. After integrating the prepared nanocomposite films into TENG devices, we accomplished the peak output voltage and current of 578 V and 19 μA for thin films (3 ×3 cm2, thickness ∼0.33 mm), respectively, by embedding 1 wt % of ZIF-72 nanoparticles into PDMS matrix, with an instantaneous maximum power density of ∼5 W m−2. In this study, the mechanism of improved TENG performance by incorporating MOF nanoparticles has, for the first time, been revealed through nanoscale-resolved mechanical and chemical studies. Furthermore, the practicality of MOF-based TENG was demonstrated by harvesting energy from oscillatory motions, for powering up commercial microelectronics, transmitting electrical signals remotely, and functioning as a self-powered Morse code generator.

Flexible composite material for self-powered applications via triboelectricity and mechanoluminescence: PDMS/ZnS:Cu composites

Triboelectricity and mechanoluminescence (ML) arise from the same physical processes of charge separation and recombination within the material. By measuring both phenomena simultaneously, researchers can gain insights into the nature and extent of charge separation and recombination, as well as the correlation between mechanical stress and light emission. This work shows that a composite based on polydimethylsiloxane (PDMS)/ ZnS:Cu particles possess the ideal ML and can also generate electric output by contact electrification. Using mechanoluminescent materials in wearable devices offers a non-invasive and reliable way to measure mechanical deformation and stress, generating crucial data for a wide range of applications. The single-electrode mode-based triboelectric nanogenerator (TENG) was developed to realize the simultaneous ML and TENG output. During pressing motion, the PDMS/ ZnS: Cu-based TENG device delivered an electrical output of 210 V and 800 nA. Furthermore, the bending motion was then utilized to demonstrate the simultaneous ML and TENG output during various self-powered applications, such as the monitoring of bent body parts, finger joints, and harnessing wind flow.

Highly Flexible Triboelectric Nanogenerator Based on PVDF Nanofibers for Biomechanical Energy Harvesting and Telerehabilitation via Human Body Movement

In this epoch of the Internet of Things, devices that scavenge mechanical energy and convert it into usable electrical energy are in high demand. Moreover, biomechanical energy harvesting from human motion is a very promising and clean method for powering wearable gadgets. Here a highly flexible triboelectric nanogenerator (TENG) based on electrospun polyvinylidene fluoride (PVDF) nanofibers with paper as counter material is fabricated. The assembled triboelectric nanogenerator displayed excellent output electrical performances consisting of an output voltage of 430 V, a short circuit current density of 0.9 mA/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , and a peak power density of 0.6 W/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The flexible TENG device is capable of powering different electronic gadgets such as a calculator and digital thermometer. Additionally, the capability of the same to harness biomechanical energy effectively from human motion, such as finger tapping, wrist flexion, and elbow bending, is demonstrated, which can be effectively used in telerehabilitation.

EVA/PZT‐Composite‐Based Triboelectric Nanogenerator for Energy Harvesting

The development of triboelectric nanogenerators (TENGs) has experienced rapid advancement in the past decade. In the present study, ethylene vinyl acetate (EVA) polymer and lead zirconium titanate (PZT) are taken as the host materials. The EVA–PZT elastomer composites are fabricated using different weight percentages (2.5%, 5.0%, 7.5%, and 10.0%) of PZT in EVA by solvent casting. The X‐ray diffraction investigation of these films reveals the presence of the PZT material and the formation of composites. TENGs have the potential to revolutionize energy harvesting and provide a sustainable energy source for a variety of applications. The electrical output performance of the single‐electrode‐mode‐based TENG is examined. The maximum output of 60 V and 165 nA is produced by the EVA–PZT 7.5 wt%/Al‐based TENG device. Further, TENG is used to power devices and gather biomechanical energy.

Biocompatible, breathable and degradable microbial cellulose based triboelectric nanogenerator for wearable transient electronics

Advances in the processing of natural biomaterials have brought to the fore new approaches for the development of biofriendly and sustainable triboelectric nanogenerators (TENGs). In particular, bacterial cellulose (BC)-based TENGs have attracted considerable attention even though they still lack the key combination for transient wearable electronics. Herein, we report on a novel and facile method for in situ chemical modification of BC for the fabrication of degradable, breathable and biocompatible triboelectric nanogenerators (TENG). To achieve that, nanocoatings of polydopamine, polypyrrole or SiO2 have been used to decorate BC nanofibrils and thus tune the surface potential of the BC layer. Such a modification enables the repositioning of BC in the triboelectric series, allowing for the fabrication of various BC-based TENG devices. Polydopamine based BC TENG is found to exhibit superior performance (when coupled with a PVDF as negative triboelectric) with a maximum output voltage of ∼1010 V and a power density of ∼8.7 W/m2, a 7-fold enhancement in the power density as compared to pristine BC (VOC = 530 V and Pout = 1.1 W/m2). It is worthmentioning that all the nanocoated-BC films are found to be breathable, bio-/hemo-compatible and degradable, fulfilling the main criteria for transient electronics. As a proof of concept, we also demonstrate an on-body biomechanical energy harvester based on a single electrode All-BC TENG with the capability to generate an output voltage of 40 V upon physical motion. This TENG technology provides a unique combination of properties and has the potential to be implemented in wearables electronics and in vivo applications.

Self-powered arctic satellite communication system by harvesting wave energy using a triboelectric nanogenerator

Previous studies reported that the electrical output of triboelectric nanogenerator (TENG) materials is higher at low temperatures (below −20 °C) than at room temperature, indicating that a TENG device may be suitable in low-temperature environments such as the Arctic Ocean. However, research on TENG systems for extreme weather conditions (temperatures as low as) −40 °C is lacking. This paper presents the design of Arctic-TENG, which efficiently generates electricity to power a satellite communication system in Arctic Ocean conditions. Arctic-TENG was designed for low-temperature operations and performs better at cold temperatures than at room temperature. Using an out-of-water wave simulator at 0.2 Hz, the peak power density of Arctic-TENG reached 21.4 W/m3. Realistic energy requirements were obtained by implementing a satellite communication system, and the available energy from Arctic-TENG was measured and evaluated considering the available wave energy in the Arctic Ocean. The total energy generated per year from Arctic-TENG is 8.59 kJ. One Arctic-TENG can transmit 540 bytes of data per day over a year, which demonstrates the power supply capability of Arctic-TENG for long-term operation of a satellite communication system.

Chicken skin based Milli Watt range biocompatible triboelectric nanogenerator for biomechanical energy harvesting

This work reports a high-performance, low-cost, biocompatible triboelectric nanogenerator (TENG) using chicken skin (CS). The device is suitable to power wearable devices, which is critical to adapt electronics in monitoring, predicting, and treating people. It also supports sustainability by providing a cost-effective way to reduce the poultry industry's waste. It has been shown here that CS-derived biowaste is an effective means of generating tribopositive material for TENGs. The CS contains amino acid functional groups based on (Glycine, Proline, and Hydroxyproline), which are essential to demonstrate the electron-donating ability of collagen. The skin was cut into 3 × 3 cm2 and used as the raw material for fabricating the TENG device with a stacking sequence of Al/Kapton/spacing/CS/Al. The chicken skin-based TENG (CS-TENG) is characterized at different frequencies (4–14 HZ) using a damping system. The CS-TENG produces an open-circuit voltage of 123 V, short-circuit current of 20 µA and 0.2 mW/cm2 of a power density at 20 MΩ. The biocompatible CS-TENG presents ultra-robust and stable endurance performance with more than 52,000 cycles. The CS-TENG is impressively capable of scavenging energy to light up to 55 commercial light-emitting diodes (LEDs), a calculator, and to measure the physiological motions of the human body. CS-TENG is a step toward sustainable, battery-less devices or augmented energy sources, especially when using traditional power sources, such as in wearable devices, remote locations, or mobile applications is not practical or cost-effective.

Fabrication of amino and fluorine functionalized graphene-based polymer composites to enhance the electromechanical conversion efficiency of TENGs for energy-harvesting applications

The two main factors hindering the practical utilization of triboelectric nanogenerators (TENGs) are low power density and high internal impedance. To address this issue, TENGs with high electromechanical conversion efficiency must be developed. Several techniques have been investigated to improve the TENGs output performance, including surface modifications (physical or chemical) and embedded charge-trap nanomaterials (dielectric or conductive). Herein, we introduce the novel amino-functionalized reduced graphene oxide (AFGO) and graphite-fluorinated polymer (FG) pillars to enhance the tribo-positivity and tribo-negativity of polyurethane (PU) and Ecoflex (EC), respectively. The surface positive-potential of PU is increased almost 2.2 times (from 201 V to 480 V) and negative-potential of Ecoflex is increased 2.1 times (from −848 V to −1813 V) with incorporating AFGO and FG pillars. Functionalized graphene and graphite-based pillars synergistically enhance surface charges (owing to the presence of –NH2 and -F terminating groups) and minimize triboelectric loss (owing to their conductive nature). The effects of the AFGO and FG contents on the electrical performance were studied systematically. The optimized PUAFGO2/EC15FG-TENG exhibited the maximum electrical output performance with an open-circuit potential of 434 V, a short-circuit current of 11. 2 µA, a power density of 1.18 Wm−2 at a load of 40 MΩ, and a charge density of 17.5 µCm−2. The PUAFGO2/EC15FG-TENG showed a mechanical conversion efficiency of 95% and successfully operated 33 LEDs and a stopwatch. Owing to this effectivity, even under low pressures, with a high sensitivity of 9.5 VPa−1 and high mechanical stability, the proposed TENG device could be used as a biomechanical energy harvester in the near future.

Self-Repairing and Energy-Harvesting Triboelectric Sensor for Tracking Limb Motion and Identifying Breathing Patterns.

The increasing prevalence of health problems stemming from sedentary lifestyles and evolving workplace cultures has placed a substantial burden on healthcare systems. Consequently, remote health wearable monitoring systems have emerged as essential tools to track individuals' health and well-being. Self-powered triboelectric nanogenerators (TENGs) have exhibited significant potential for use as emerging detection devices capable of recognizing body movements and monitoring breathing patterns. However, several challenges remain to be addressed in order to fulfill the requirements for self-healing ability, air permeability, energy harvesting, and suitable sensing materials. These materials must possess high flexibility, be lightweight, and have excellent triboelectric charging effects in both electropositive and electronegative layers. In this work, we investigated self-healable electrospun polybutadiene-based urethane (PBU) as a positive triboelectric layer and titanium carbide (Ti3C2Tx) MXene as a negative triboelectric layer for the fabrication of an energy-harvesting TENG device. PBU consists of maleimide and furfuryl components as well as hydrogen bonds that trigger the Diels-Alder reaction, contributing to its self-healing properties. Moreover, this urethane incorporates a multitude of carbonyl and amine groups, which create dipole moments in both the stiff and the flexible segments of the polymer. This characteristic positively influences the triboelectric qualities of PBU by facilitating electron transfer between contacting materials, ultimately resulting in high output performance. We employed this device for sensing applications to monitor human motion and breathing pattern recognition. The soft and fibrous-structured TENG generates a high and stable open-circuit voltage of up to 30 V and a short-circuit current of 4 μA at an operation frequency of 4.0 Hz, demonstrating remarkable cyclic stability. A significant feature of our TENG is its self-healing ability, which allows for the restoration of its functionality and performance after sustaining damage. This characteristic has been achieved through the utilization of the self-healable PBU fibers, which can be repaired via a simple vapor solvent method. This innovative approach enables the TENG device to maintain optimal performance and continue functioning effectively even after multiple uses. After integration with a rectifier, the TENG can charge various capacitors and power 120 LEDs. Moreover, we employed the TENG as a self-powered active motion sensor, attaching it to the human body to monitor various body movements for energy-harvesting and sensing purposes. Additionally, the device demonstrates the capability to recognize breathing patterns in real time, offering valuable insights into an individual's respiratory health.

Contact electrification of porous PDMS-nickel ferrite composites for effective energy harvesting

Energy harvesting technologies are becoming popular owing to their usage in the operation of low-power consumer electronics and as an alternative power source. Specifically, triboelectric nanogenerators (TENGs) have drawn much attention as they can efficiently scavenge waste mechanical energy into electrical output. Careful material selections can further improve the performance of TENGs. In this work, a spinel ferrite material with the chemical formula NiFe2O4 (NFO abbreviated further) is synthesized using a solid-state reaction route. The structural and magnetic property of the NFO has been studied, showing the cubic symmetry and ferromagnetic nature of the sample. The 3D tomography images of the PDMS-NFO composites were carried out using X-ray tomographic microscopy. To enhance the performance of the TENGs, we adopted a porous media by evaporation of water during the curing process of PDMS-NFO composites. A single-electrode operating mode was adopted for TENG fabrication. The electrical response of the device was carried out using different wt% and frequencies. The 12 wt% of NFO in PDMS (PN12 device) delivered a voltage, current, and charge of 60 V, 300 nA, and 34 nC, respectively. The charge density of the plain and porous composite-based TENG was compared to confirm the enhancement of the charge produced on the triboelectric layers. The commercial capacitors and energy harvesting based on a smart home were demonstrated using the TENG devices.

Fabrication of CuO-NP-Doped PVDF Composites Based Electrospun Triboelectric Nanogenerators for Wearable and Biomedical Applications.

A flexible and portable triboelectric nanogenerator (TENG) based on electrospun polyvinylidene fluoride (PVDF) doped with copper oxide (CuO) nanoparticles (NPs, 2, 4, 6, 8, and 10 wt.-% w.r.t. PVDF content) was fabricated. The structural and crystalline properties of the as-prepared PVDF-CuO composite membranes were characterized using SEM, FTIR, and XRD. To fabricate the TENG device, the PVDF-CuO was considered a tribo-negative film and the polyurethane (PU) a counter-positive film. The output voltage of the TENG was analyzed using a custom-made dynamic pressure setup, under a constant load of 1.0 kgf and 1.0 Hz frequency. The neat PVDF/PU showed only 1.7 V, which further increased up to 7.5 V when increasing the CuO contents from 2 to 8 wt.-%. A decrease in output voltage to 3.9 V was observed for 10 wt.-% CuO. Based on the above results, further measurements were carried out using the optimal sample (8 wt.-% CuO). Its output voltage performance was evaluated as a function of varying load (1 to 3 kgf) and frequency (0.1 to 1.0 Hz) conditions. Finally, the optimized device was demonstrated in real-time wearable sensor applications, such as human motion and health-monitoring applications (respiration and heart rate).

3D printed triboelectric nanogenerator for underwater ultrasonic sensing

The underwater ultrasound power measurement has become necessary due to the rapid development of sonochemistry and sonocatalysis. This article presents construction of novel triboelectric nanogenerator (TENG) and its application for a detection of ultrasonic waves in water. The device was 3D printed using widely available and cost-effective materials. TENG consisted of the device housing and movable polymer pellets confined between flat electrodes. The device housing and pellets were 3D printed via stereolithography (SLA) and fused deposition modelling (FDM) methods, respectively. The pellets moved periodically driven by the ultrasonic waves leading to generation of an alternating voltage signal. The electric response of TENG was calibrated using a commercially available ultrasonic power sensor. The open-circuit voltage output of TENG was registered in different sections of the ultrasonic bath in order to determine the distribution of the acoustic power. TENG electric responses were analyzed by applying the fast Fourier transform (FFT) and fitting the theoretical dependence to experimental data. The main peaks in the frequency spectra of the voltage waveforms corresponded to the fundamental excitation frequency of the ultrasonic bath. TENG device, presented in this paper, can be successfully applied as a self-powered sensor for detection of ultrasonic waves. It enables precise control of the sonochemical process and reduction of power losses of the ultrasonic reactor. 3D printing technology has been confirmed to be fast, easy, and scalable method of fabrication of the ultrasonic sensors.

Biodegradable, transparent, and antibacterial alginate-based triboelectric nanogenerator for energy harvesting and tactile sensing

The utilization of natural biomaterials in the construction of triboelectric nanogenerators (TENG) has significant implications for the advancement of sustainable self-powered devices. Sodium alginate (SA), an eco-friendly and biodegradable triboelectric material with excellent transparency, is considered an ideal material for wearable TENGs. In this work, we report a biodegradable, transparent, and antibacterial SA-based TENG for mechanical energy harvesting and self-powered tactile sensing. The addition of glycerol, an environment-friendly additive, can enhance flexibility and adhesiveness of the SA, which resulted in well-transferred AgNWs/SA electrodes with high transparency and conductivity. The major parameters that affect the output performance of the fabricated TENG are investigated, including the frequency, thickness and area of the triboelectric layers. The output voltage, transferred charge, and peak power of the TENG could reach up to 53 V, 18 nC, and 4 μW, respectively, which is sufficient to power small electronic devices. In addition, the fabricated TENG device also shows excellent antibacterial and biodegradable capabilities. Finally, the TENG is demonstrated to be an effective self-powered tactile sensor for pressure mapping, human movement monitoring, and wearable human–machine interfacing. This work provides a new strategy to design flexible transparent TENGs with biodegradable SA and paves the way for developing next-generation self-powered transient electronics.

A 3D-printed millifluidic device for triboelectricity-driven pH sensing based on ZnO nanosheets with super-Nernstian response

This paper suggests a straightforward and rapid fabrication method applying the integration of 3D printing and triboelectric nanogenerator (TENG) technologies to realize milli/microfluidic multipurpose devices. The proposed liquid-solid TENG device is served as an energy harvester and sensor at the same time with flexibility in operation modes. Accordingly, an innovative ethylene vinyl acetate (EVA)-made millifluidic pH sensor is fabricated based on zinc oxide nanosheets as a showcase of the functional adaptability of the ubiquitous device, and its performance is analyzed and compared with contemporary electrochemical pH sensors. High crystallinity of the nanosheets with an incline to (103) orientation in parallel with high levels of oxygen vacancies provides capacity for surface charge accumulation at the nanosheet-aqueous solution interface and the ensuing ultrahigh sensitivity of the triboelectric sensor. The millichannel is optimized in terms of sensing surface area, flow rate, and hydrophobicity properties by opting for appropriate geometry, TENG operation modes, and materials. Despite the finding that quasi-single-electrode mode TENG experiences a higher response (8.12 × Nernst limit) in comparison with quasi-contact-separation configuration (4.14 × Nernst limit), the latter enjoys superior linearity, stability, repeatability, reproducibility, and reliability characteristics corresponding to R2 of 98.93%, drift rate of 13 mV/h, relative standard deviation (RSD) of 1.23% in third hysteresis loop, 2.24%, and maximum standard error of ±0.2 pH units across multiple trials, respectively, in a wide pH range of 2–13. Time- and cost-effectiveness, user-friendliness, self-powering, portability, and biocompatibility of the device could be asserted as considerable advantages to open the door for feasibly realizing the new generation of real-life and point-of-care devices.

Wearable Triboelectric Nanogenerator with Ground-Coupled Electrode for Biomechanical Energy Harvesting and Sensing.

Harvesting biomechanical energy for electricity as well as physiological monitoring is a major development trend for wearable devices. In this article, we report a wearable triboelectric nanogenerator (TENG) with a ground-coupled electrode. It has a considerable output performance for harvesting human biomechanical energy and can also be used as a human motion sensor. The reference electrode of this device achieves a lower potential by coupling with the ground to form a coupling capacitor. Such a design can significantly improve the TENG's outputs. A maximum output voltage up to 946 V and a short-circuit current of 36.3 μA are achieved. The quantity of the charge that transfers during one step of an adult walking reaches 419.6 nC, while it is only 100.8 nC for the separate single-electrode-structured device. In addition, using the human body as a natural conductor to connect the reference electrode allows the device to drive the shoelaces with integrated LEDs. Finally, the wearable TENG is able to perform motion monitoring and sensing, such as human gait recognition, step count and movement speed calculation. These show great application prospects of the presented TENG device in wearable electronics.

Cold spray direct writing of flexible electrodes for enhanced performance triboelectric nanogenerators

Triboelectric nanogenerator (TENG) is an emerging energy harvesting device to effectively harness various mechanical energy sources. In TENG technology, polymers are of particular interest as tribo-negative materials owing to their unique properties (e.g., charge storage capability, impact resistance, flexibility, low cost, recyclability, etc.). Despite significant advances, one major challenge for TENG is to develop high-performance back electrodes that are conformably attached to the tribo-negative polymer substrates to fully exploit the potential of TENG in energy harvesting. To this end, the present study is aimed to employing direct “cold spray” particle deposition as just one-step fabrication method for high-performance electrodes on flexible polymers. In this regard, Tin (Sn) particles are directly written on the polymer (PET) surface by cold spraying to achieve conformal electrodes with high-adhesive strength and stable electrical conductivity. The resulting electrodes are thoroughly characterized in terms of microstructure, adhesion strength, and electrical performance. Arc-shaped TENG devices with both traditional aluminum (control) and cold-sprayed Sn electrodes are fabricated, followed by evaluating the TENGs' performance. Owing to the strong adhesion and micro-roughness (i.e., Ra = 4.865 μm) of the Sn electrodes, electricity generation performance was found to be improved by ≈2.4 folds as compared to the control TENG. The TENG with Sn electrode can generate an open-circuit output voltage of up to 243 V with a maximum output power of 130 mW/m2, thereby indicating the promising potential of the cold spray technique in TENG technology.

A Robust Triboelectric Nanogenerator Resistant to Humidity and Temperature in Ambient Environment

Triboelectric nanogenerator (TENG) is an energy harvesting technology from widespread mechanical energy based on the combined effects of triboelectrification and electrostatic induction. TENG devices are promising to be integrated into human daily life and their stability in the ambient environment is quite crucial to guarantee robust output. This requirement is increasing exponentially for powering various wearable/portable electronics and still remains as a challenge. Herein, contact and separation mode‐based, humidity‐ and temperature‐resistant TENG (HT‐TENG) is fabricated utilizing ethylene vinyl acetate and polytetrafluoroethylene tape as frictional layers. By harvesting biomechanical energy, the device could generate peak‐to‐peak open circuit voltage of ≈210 V and short‐circuit current of ≈12.85 μA, respectively. The as‐fabricated device is tolerant to fluctuating relative humidity ranging from 10% to 60% and temperature ranging from 10 to 60 °C. Further, the device is shown to charge 22 and 47 μF commercial capacitors to 3 V using rectifier bridges, glowing light‐emitting diodes, powering digital wrist watches, and a calculator. Thus HT‐TENG as an efficient power source reliably operates not only in typical conditions, but also in desert and frigid environments, thereby extending the applicability and commercialization of the device in the global environments.

A Highly Wearable Single-electrode Mode Triboelectric Nanogenerator Made of Flexible Polyvinylidene Fluoride Transparent Film for Muscular Motion Monitoring

The present study reports the design and fabrication of a single-electrode mode triboelectric nanogenerator (TENGs) which can overcome the drawbacks present in the conventional triboelectric nanogenerator which works on two electrodes and two dielectric layers. The proposed concept eliminates the dual electrodes thereby reducing the complexity of the device and the higher fabrication cost enabling the device to be used for extended applications. The fabricated TENG device uses Polyvinylidene fluoride (PVDF) as the active material that is capable to generate the electrical response upon contact with the human skin when the device was worn on the skin. The device generates the highest electrical output of ~ 50 V and a current of ~ 600 nA under a 1 Hz operating frequency. The device also shows good stability and durability by powering continuously for 300 s without any interruption in its electrical output response. The device shows its applicability in utilizing it powering low-power electronic devices, bio-mechanical energy scavenging upon actuated by hand and foot tapping, as well as demonstrated for the self-powered muscular monitoring system. The study greatly expands the opportunity of using TENGs for applications in the field of healthcare, bio-medical, and the Internet of Things (IoT).

PDMS/PVDF- MoS2 based flexible triboelectric nanogenerator for mechanical energy harvesting

A green energy generating device that can meet the energy requirements of future technologies without contaminating our environment is increasingly in demand. These devices can harvest energy from ambient sources that are already present in our surroundings. Triboelectric nanogenerator (TENG) has received a lot of attention as a potential sustainable source of power for smart devices, and numerous methods have been explored to enhance its output performance. In this work, we have fabricated a high performance TENG based on MoS2 filled PVDF for harvesting mechanical energy. Effect of MoS2 loading into the PVDF matrix was studied as a function of MoS2 wt% (0, 3, 5, 7, 10%). It has been observed that the fraction of crystalline β-phase and the dielectric constant of PVDF got enhanced after the addition of MoS2. In addition to the dielectric constant, the surface roughness of the MoS2 filled PVDF sample increases, which further contribute to the enhanced triboelectric performance. The TENG device with 7 wt % of MoS2 in PVDF matrix as one of the layer and PDMS as second layer in the vertical contact-separation geometry generates the maximum triboelectric output voltage and current of 189 V and 1.61 μA respectively, while the bare PVDF based TENG generates an output voltage and current of 107 V and 0.88 μA respectively. The TENG with 7 wt % of MoS2 also generates a maximum power density of 104.5 μWcm−2. Further, effect of the tapping frequency and the contact force was also analysed on the PDMS/PVDF-MoS2 based TENG with 7 wt% of MoS2. The triboelectric output voltage and current were also found to be increased with the rise in frequency and the contact force and generated a maximum voltage of ∼211 V. This study proposes an effective approach for enhancing the performance of triboelectric nanogenerator by changing the filler concentration. The fabricated TENG demonstrated the practical application, by powering electronic stopwatch and scientific calculator.