Excellent Output Performance Research Articles

Effects of metal nanoparticles on the performance of PDMS based triboelectric nanogenerators

Energy harnessing gadgets which employ triboelectric effect have garnered global attention due to excellent output performance compared to other nanogenerators for various applications. In this article, an attempt has been made to modify the properties of poly dimethyl siloxane (PDMS), which is a tribo material by embedding it with metal nanoparticles of different conductivity and in different weight percent. TENGs based on metal nanoparticle/PDMS composite films are fabricated and electrical characteristics were examined. This study reveals that the filler with best conductivity exhibits excellent properties. Presence of silver nanoparticles increased the permittivity of the tribolayer from 5.3 to 16.9 for 20 wt% filler at 1 kHz. Electrical studies of silver/PDMS composite film gave appreciable results; 5.1 μA (Isc), 33.6 V (Voc), 72.2 μW power at 8 MΩ with 10 N force at an excitation frequency of 10 Hz.

Layered gallium telluride for inducing mode-locked pulse laser in thulium/holmium-doped fiber

In this work, layered gallium telluride (GaTe) was used as a saturable absorber (SA) to initiate the generation of mode-locked pulses in a Thulium/Holmium-doped fiber (THDF) laser. The GaTe solution has been embedded onto the surface of fabricated D-shaped fiber by using the drop-casting method. This action was taken to allow the strong nonlinear interaction between the GaTe solution and the evanescent field of the wave propagating in the D-shaped fiber. The nonlinear optical absorption for the prepared GaTe/D-shaped based SA exhibits a modulation depth of 31.35%, saturation intensity of 3.35 kW/cm2, and a non-saturable loss of 68.65%. A stable mode-locked pulse laser was observed with a repetition rate of 10.71 MHz at a threshold pump power of 281.0 mW. The soliton pulse generated from the proposed THDFL cavity centered at 1946.24 nm with a spectral bandwidth of 2.92 nm. The mode-locked pulse produced pulse duration of 1.396 ps and a signal-to-noise ratio (SNR) value of 63 dB. Overall, the excellent output performance of the laser-generated in this work has shown the credibility of the GaTe/D-shaped based SA device as another possibility for ultrafast laser application.

A flexible and robust double-helix tubular cloth/carbon fibers piezoresistive sensor for human motion detecting

Cloth-based piezoresistive sensors with weaved microstructures have become very attractive wearable electronics due to their cost-effectiveness, high sensitivity, and simple fabrication. Here, a double-helix tubular cloth/carbon fibers (CFs) piezoresistive sensor (DTCPS) is successfully produced and tightly encapsulated by a polyethylene heat shrinkable tube that reveals prominent reliability (20000 s fatigue tests) and agile response speed (response time of 31 ms). Owing to the synergistic effect of microstructures of tubular cloth and relatively large contact area of CFs, the DTCPS demonstrates the wide pressure measurement range from 3 N to 480 N and the high sensitivity of 0.178 N−1 (3 N ∼ 330 N). Considering the excellent output performances, the DTCPS is used to detect the human motion postures and is possibly expected to be applied in the fields of artificial intelligence and individualized medical care.

Enhanced mechanical, thermal, and output performance in sandwich-structured copper calcium titanate/polyimide nanocomposites for triboelectric nanogenerator

The key to fabricating high-performance triboelectric nanogenerator (TENG) is the preparation of electrode materials with excellent mechanical, thermal, and output performances. Herein, polyimide (PI) with high dielectric constant copper calcium titanate (CCTO) was used as the outer layer, and pure PI as the intermediate charge storage layer was used to prepare X-Y-X sandwich-structured copper calcium titanate/polyimide (CCTO/PI) nanocomposites for TENG electrodes. The results show that at 7 wt% of CCTO content, the tensile strength, T5%; short-circuit current; and open-circuit voltage of CCTO/PI-PI-CCTO/PI (7-0-7) nanocomposite were improved by 358%, 122%, 723%, and 249%, respectively, compared with those of pure PI. It is anticipated that the present work will advance a method of optimizing electrode materials for triboelectric generators.

A fluorine-rich phenolic polyurethane elastomer with excellent self-healability and reprocessability and its applications for wearable electronics

Polyurethane elastomers with covalent adaptable networks (PU-CANs) based on the dynamic urethane bond have attracted remarkable attention owing to their reprocessability, adaptability, and self-healability. However, it is still a formidable challenge to achieve excellent dynamics at low temperatures since the urethane bond energy is usually high. Herein, a fluorinated phenolic polyurethane (FPPU) elastomer with CANs based on phenol-carbamate bonds was successfully designed and prepared. Subsequently, the effects of fluorine atoms on the mechanical properties, thermal stability, reprocessability, and self-healability, surface free energy, and hydrophobicity of the prepared elastomers were systematically investigated. The FPPU elastomer showed notch-insensitivity, remarkable self-healable efficiency (98%), low dynamic dissociation temperature (60°C), excellent reprocessability, and low surface energy (62 MJ m−2) compared with non-fluorinated counterpart phenolic polyurethane elastomer (APPU). Based on the above-mentioned features, FPPU was selected as an elastic substrate to assemble into a triboelectric nanogenerator (TENG) to harvest energy from natural motion. This TENG exhibited an excellent electrical output performance with a peak open-circuit voltage of 103 V, a peak short-circuit current of 4.7 µA and a peak short-circuit charge of 43 nC. In addition, the TENG possessed high self-cleaning and reprocessing efficiency. Furthermore, a stretchable and self-healing composite conductor based on FPPU was fabricated for flexible electronic devices.

Ultra-robust tribo- and piezo-electric nanogenerator based on metal organic frameworks (MOF-5) with high environmental stability

Isoreticular metal–organic frameworks (IRMOFs) as a subseries of metal-organic frameworks (MOF) have excellent thermal and chemical stability, tuneable porosity, and high surface area as compared to other MOFs. IRMOFs' appealing properties can lead to their usefulness in the fabrication of tribo- and piezo-electric nanogenerators. For the first time, this paper applies metal-organic frameworks (MOF-5 or IRMOF-1) for fabricating tribo- and piezo-electric nanogenerator for energy harvesting. The MOF-5 based tribo-electric nanogenerator (TENG) produces an excellent output performance with the open-circuit voltage of 484 V, short-circuit current of 40 µA, and maximum instantaneous power of 3174 µW. Here, the proposed TENG presents a stable performance under adverse environmental conditions such as temperature and humidity, showing its robustness under harsh environmental conditions. The fabricated TENG device is utilized to charge the various commercial capacitors, power up the light-emitting diodes (LEDs) and drive low-power electronic devices such as a calculator and stopwatch. In addition, the MOF-5 is further studied for fabricating piezo-electric nanogenerator (PENG). The fabricated PENG device with 5 wt% MOF-5 blended in PDMS yields an open-circuit voltage of 27 V, short-circuit current of 2.9 µA, and maximum instantaneous power of 5.76 µW, respectively. Furthermore, the PENG device is utilized to charge the various commercial capacitors and power up the LEDs. These results demonstrate that MOF-5 can be applied for fabricating ultra-robust TENG for a harsh environmental condition, and also an effective way towards piezo-electric nanogenerators.

Low-grade heat energy harvesting system based on the shape memory effect and hybrid triboelectric-electromagnetic nanogenerator

Low-grade heat energy is a kind of widely existing energy, due to the limitation of the collection technology, most of the energy is wasted. It would be vital to harvesting this kind of energy by effective acquisition techniques. With the shape memory effect of Shape memory alloy (SMA), a low-grade heat energy harvesting system based on the hybrid triboelectric-electromagnetic nanogenerator is proposed. A ring SMA is embedded in two round wheels, in which the high-temperature wheel (HTW) is immersed in the low-grade heat source. The ring can only rotate around the wheels due to the shackles of wheels when the SMA in the HTW is heated and straightened out. The working principle of deformation and rotation of the SMA at transformation temperatures is studied and analyzed with three aspects, including infrared detection, temperature simulation, and force analysis. Moreover, a soft-contact freestanding rotation triboelectric nanogenerator and electromagnetic generators are designed at both sides of the low-temperature wheel to generate high voltage and high current, respectively. Benefiting from the power of nearly 4.3 mW of the system, some small electrical devices, and a self-powered wireless sensor network are successfully powered. Considering the excellent output performance of the system, the system is expected to be a reliable and effective device for large-scale low-grade heat energy harvesting in the future.

Nanostructured Broadband Solar Absorber for Effective Photothermal Conversion and Electricity Generation

Photothermal conversion is an environmentally friendly process that harvests energy from the sun and has been attracting growing research interest in recent years. However, nanostructured strategies to improve light capture performance deserve further development, and the application of solar heating effects for clean energy needs to be explored. Herein, a multiscale nanomaterial was prepared by in situ polymerizing the polyaniline (PANI) nanoparticles into porous anodic aluminum oxide (AAO) membrane. As a result, the as-prepared PANI-AAO shows broadband solar absorption and provides a platform for efficient photothermal conversion. What is more, we introduced a typical thermoelectricity generator (TEG) with excellent output performance and combined it with PANI-AAO to prepare a solar thermoelectric generator (s-TEG). The s-TEG harvests solar energy and converts it into electricity, showing an outstanding power generation capability in outdoor conditions. Thus, the nanostructured broadband solar absorber and the integrated solar thermoelectric generator offer a promising candidate for a sustainable and green energy source in the future.

Metal-organic framework-derived nanoporous carbon incorporated nanofibers for high-performance triboelectric nanogenerators and self-powered sensors

Metal-organic frameworks (MOFs), which are highly crystalline materials, possess several intriguing properties but have remained largely unexplored for triboelectric nanogenerators (TENGs). Herein, MOF-derived cobalt-based nanoporous carbon (Co-NPC) incorporated polyvinylidene fluoride (PVDF) composite nanofibers (NFs) are proposed as a highly electronegative tribomaterial for boosting the performance of TENGs in the mechanical energy harvesting applications. Co-NPC, with a high surface area and excellent nanoporosity, greatly improved the electroactive β-phase formation and the dielectric constant of the PVDF composite NFs. As a result, the surface potential and charge trapping capability of the composite NFs increased by 4 and 9.5 times, respectively, resulting in a significant enhancement of the TENG performance. The as-fabricated Co-NPC/PVDF NF-based TENG (CNP-TENG) showed an excellent power density (19.24 Wm-2) and sustainably powered small electronics by harvesting biomechanical energy. The CNP-TENG exhibited excellent output performance at 95% relative humidity (RH) and exhibited stable output for long-term operations (> 60k cycles). Besides energy harvesting, the CNP-TENG was demonstrated as a self-powered pressure sensor with ultra-high sensitivity of 6.39 V/kPa that applied for diverse motion sensing and smart home control system applications. This study successfully introduced MOF-derived nanomaterials to enhance the energy harvesting performance of TENG which paved the way for a new pool of tribomaterials.

An ultraweak mechanical stimuli actuated single electrode triboelectric nanogenerator with high energy conversion efficiency.

Triboelectric nanogenerator (TENG) as a new energy harvester has attracted significant attention due to its excellent output performance and high energy conversion efficiency at low-frequency, small-amplitude and weak-force compared with a traditional electromagnetic generator. Here, an ultraweak mechanical stimuli actuated single electrode triboelectric nanogenerator (UMA-TENG) has been studied with an atomic force microscope. The electrical output and force curve of UMA-TENG were studied at first, as well as the maximum output performance and highest energy conversion efficiency. Then the influence of the driving frequency, separation distance and motion amplitude was investigated, respectively. Moreover, by introducing an external switch to reach a cycle of maximized energy output, the maximum energy conversion efficiency of the UMA-TENG was up to 73.6% with an input mechanical energy of 48 pJ. This work demonstrates that the TENG shows excellent performance in ultraweak mechanical stimuli and could broaden the applications of the TENG in sensors, actuators, micro-robotics, micro-electro-mechanical-systems, and wearable electronics.

Eco-friendly pectin polymer film-based triboelectric nanogenerator for energy scavenging.

Inspired by the desire to solve the energy-related issues in remote sensing applications, internet of things, wireless autonomous devices, and self-powered portable electronic devices, triboelectric nanogenerators (TENGs) have been highly promoted. However, for use in the specified applications, especially in wearable and biomedical devices, environmental-friendly materials are required. Herein, an eco-friendly pectin polymer is used as a positive triboelectric material to fabricate a TENG with excellent output performance. Working in conjunction with a polyimide, the polyimide and microarchitected pectin (MA@pectin) polymer film-based TENG (PP-TENG) generated open circuit voltage (VOC), short circuit current (ISC), and charge density (QSC) of ∼300 V, 14 μA, and 70 μC cm-2, respectively, exhibiting remarkable enhancement compared to the TENG based on polyimide/pristine pectin polymer (VOC, ISC, and QSC of 170 V, 7.6 μA, and 47 μC cm-2, respectively) under similar operating conditions. The output performance of the PP-TENG is particularly reliant on the pectin concentration, indicating an optimum concentration of 9 wt%. The improved performance of the PP-TENG was systematically analyzed and explained in terms of pectin concentration, dielectric constant, and surface roughness. Furthermore, the PP-TENG can power portable electronic devices and light-emitting diodes to prove the capability of the TENG in practical applications. The fabricated PP-TENG is anticipated to be a sustainable energy harvester via a low-cost and facile approach.

An integrally underwater self-healable droplet-based triboelectric nanogenerator

An integrally underwater self-healable droplet-based TENG is fabricated with excellent output performance recovery, even when it repairs in water.

Construction of high-performance triboelectric nanogenerators based on the microstructures of conical nanoneedles

A triboelectric nanogenerator (TENG) based on a hot-embossed PHB membrane and ePTFE membrane displays excellent output performance.

Effects of Inlet Gas Allocations on Performance of an Active Drainage Flow Field Proton Exchange Membrane Fuel Cell.

In developing a proton exchange membrane fuel cell, a high current density is encountered, thus requiring a novel flow field with great drainage performance. Our previous study proposed a novel compound flow field called an active drainage flow field with three inlets, which has an excellent output and drainage performance. Furthermore, the influence of muti-inlet reactant gas allocation on the three inlets is discussed in this study. The results showed that the small mass flow in the active drainage (AD) channel causes a waste of active area, while the large mass flow in the AD channel causes under-ribs convection. Considering the output and drainage performance, the 15% AD mass flow case shows the best performance under the high relative humidity investigation.

Self-powered AC electrokinetic microfluidic system based on triboelectric nanogenerator

The AC electrokinetic technology, such as AC electroosmosis, induced-charged electroosmosis, dielectrophoresis, etc., can precisely manipulate trace fluids and has been widely used in lab on a chip. However, the power supplies used in AC electrokinetic experiments are mostly function generators or other large-scare instruments, which is an obstacle to portability. Encouragingly, triboelectric nanogenerator (TENG) with the characteristics of portable, green, and simple structure is a potential opportunity for AC electrokinetic microfluidic operation. We have designed a self-powered AC electrokinetic microfluidic system based on vertical contact-separation mode TENG for the first time. The TENG, as a power supply, costs only 2 cents and maintains excellent output performance after millions of working cycles. Through the combination of TENG and microfluidic chip, this system successfully realizes AC electroosmotic flow and induced-charged electroosmotic flow in the microchannel and completes the effective mixing of two fluids at low frequencies (<10 Hz). Furthermore, we have achieved precise control of particle behavior, including focusing, deflection, and separation under manual operation. Therefore, the self-powered AC electrokinetic microfluidic system designed in this work not only expands the application fields of TENG but also provides a new power solution for AC electrokinetic microfluidic operation. This system is expected to get rid of the need for large-scale power supply in traditional methods and has broad application prospects in the fields of portable detection, micro-reaction, and micro-bioanalysis.

An omnidirectional stretchable hyper-elastic dielectric composed triboelectric textile for energy harvesting

Textile-based triboelectric nanogenerators (T-TENGs) have been favorable devices to harvest human motion energy because of their excellent flexibility and high efficiency at low frequency. However, T-TENGs integrated with the conventional composite electrodes will suffer serious degradation on conductivity under stretching state. Herein, an omnidirectional stretchable triboelectric textile based on liquid metal (LM) electrodes has been proposed. By virtue of the excellent liquidity of LM and high stretchability of Ecoflex film, the triboelectric textile shows an ultimate elongation of 660% and maintains a small resistance (0.678 Ω) under 200% stretching. Additionally, by introducing TiO2 particles into the Ecoflex to improve the dielectric constant, the triboelectric textile obtained a ∼ 40% growth on short-circuit current and generated a high peak-peak power density of 15.4 W/m2 at 3 Hz and 30 N. Based on the excellent output performance, the triboelectric textile can continuously drive low-power electronics under palm flapping, ensuring the feasibility for energy harvesting from human motion.

Novel Recycled Triboelectric Nanogenerator Based on Polymer‐Coated Trash Soda Can for Clean Energy Harvesting

AbstractResearchers are striving to find the best possible ways to decompose or recycle generated waste to create a pollution‐free environment. Besides the problem of waste pollution, efficient energy generation is another challenging issue across the world. To counter both these problems in a single shot, a unique strategy of reusing and recycling trash soda cans and disposable plastic cups in a simple function change (Funchange) triboelectric nanogenerator (TENG) with a surplus advantage of no chemical processing is presented. The Funchange TENG device presents an excellent output performance with an open circuit voltage, short circuit current, and instantaneous power of 519 V, 82 µA, and 12.25 mW, correspondingly. Further, the fabricated nanogenerator exhibits excellent stability for about 72 000 cycles. This approach of applying trash materials for ultrarobust, high‐performance TENG will pave the path toward sustainable, facile, clean, and environmentally friendly energy scavenging.

A novel piecewise tri-stable stochastic resonance system with time-delayed feedback and its application

It is of great significance to judge whether mechanical equipment has faults, so it is necessary to study the extraction of mechanical fault characteristic signals. Stochastic resonance (SR) has been applied diffusely in feature extraction because of its excellent output performance, but there are few studies on SR with time-delay feedback (TF) terms. In some cases, the output of the system will be improved when the TF term is added to the SR system, so it is meaningful to study the SR with TF term. Because piecewise tri-stable system has good characteristics of overcoming output saturation, on the basis of piecewise tri-stable SR (PTSR), the time-delay feedback PTSR (TFPTSR) is proposed, and for purpose of further studying the internal mechanism of this system, its generalized potential function and the law that the parameter causes its change are derived and studied. Then the probability density function (PDF) of the proposed model and its mean first-passage time (MFPT) are calculated and compared with the variation of the generalized potential function together with the Signal to noise ratio (SNR), through such research, the difficulty of the system to produce stochastic resonance and the degree of the output performance are directly related to the system parameters. Finally, the proposed TFPTSR method processes the same signal as the PTSR method, and it is found that the TFPTSR method can get better output SNR.

All-Fiber-Structured Triboelectric Nanogenerator via One-Pot Electrospinning for Self-Powered Wearable Sensors.

With the rapid development in wearable electronics, self-powered devices have recently attracted tremendous attention to overcome the restriction of conventional power sources. In this regard, a simple, scalable, and one-pot electrospinning fabrication technique was utilized to construct an all-fiber-structured triboelectric nanogenerator (TENG). Ethyl cellulose was co-electrospun with polyamide 6 to serve as the triboelectric positive material, and a kind of strongly electronegative conductive material of MXene sheet was innovatively incorporated into poly(vinylidene fluoride) nanofiber to act as a triboelectric negative material. The assembled all-fiber TENG exhibited excellent durability and stability, as well as excellent output performance, which reached a peak power density of 290 mW/m2 at a load resistance of 100 MΩ. More importantly, the TENG was capable of harvesting energy to power various light-emitting diodes (LEDs) and monitoring human movements as a self-powered sensor, providing a promising application prospect in wearable electronics.

Multi-layered BTO/PVDF nanogenerator with highly enhanced performance induced by interlaminar electric field

The flexible piezoelectric nanogenerator (PNG) has been spotlighted as a promising candidate for sustainable power source in wireless portable device. Here, a multi-layered BaTiO3 (BTO) /poly(vinylidene fluoride) (PVDF) PNG has been designed by spin coating and layer by layer assembled method. Benefited from the composite strategy and interlaminar electric field effect, the typical four-layered BTO/PVDF nanogenerator contained with 20 wt% BTO nanoparticles represents excellent output performance with voltage of 14.22 V (about 6.49 times than that of 1 layered PNG), current of 2.42 μA, and maximum power of 11.55 μW. The dielectric constant and residual polarization of the PNG vary with the number of piezoelectric layers, which is suspected as the root cause for the enhancement of piezoelectric and output performance. In addition, 4000 pressing-releasing cycles test, finger tapping and foot striking measurements also demonstrated excellent stability of the synthesized BTO/PVDF PNG, showing their great potential in wireless sensing and wearable device applications.