High Electrical Output Research Articles

Membraneless Photocatalytic Fuel Cell with Double Photoelectrodes for Simultaneous Electricity Generation and Pollutant Degradation

Environmental pollution and new energy development have become topics of increasing concern. Herein, a visible-light-driven photocatalytic fuel cell (PFC) with double photoelectrodes was constructed for simultaneous electricity generation and pollutant degradation, in which graphitic carbon nitride (g-C3N4) generated on W/WO3 nanorod arrays (W/WNR/g-C3N4) was used as the photoanode and Fe3+-doped CuBi2O4 thin film on indium tin oxide (ITO) conductive glass (ITO/CBFeO) was used as the photocathode. The experimental results showed that the WO3/g-C3N4 Z-scheme structure and one-dimensional WNR rod-like structure could effectively suppress the recombination of photogenerated charge carriers and enable W/WNR/g-C3N4 to present a good photocurrent response under visible light irradiation. The Fermi level mismatch between the W/WNR/g-C3N4 photoanode and ITO/CBFeO photocathode could improve the transfer of photogenerated electrons from the photoanode to the photocathode across the external circuit, enabling the constructed PFC to afford high electricity output and good efficiency for pollutant degradation. The short-circuit current density and maximum power density could reach 620 μA cm−2 and 110 μW cm−2, respectively, while the degradation ratio of oxytetracycline reached 97.6% in 90 min. Therefore, the proposed PFC system provides a new way to generate electric energy and degrade pollutants simultaneously.

Effects of nanofluids on the photovoltaic thermal system for hydrogen production via electrolysis process

In this study the photovoltaic hybrid thermal system has been fabricated for an effective increase in production of electric output. Further the PV/T system also designed to produce the hydrogen from the water through electrolysis process. Several studies reported drastic reduction in the electric output due to high cell temperatures. Nevertheless, these effects are reduced by introduction of the nanoparticles. This study also examines the nanofluids MWCNT and Fe2O3 as the passive cooling agent for higher electric output production without any major energy loss. The nanoparticles are dispersed in the water at the optimum fashions to increase the thermal and electrical efficiency of the system. Both MWCNT and Fe2O3 nanofluids were passed to the hybrid system at the flow rate of 0.0075 kg/s and 0.01 kg/s. The highest electrical output and thermal efficiency has been obtained at 12.30 P.M. With regard to the production of hydrogen, the maximum productions were observed from 12.15 P.M. to 13.00 P.M.. Implementation of this method compensates the energy loss with superior electrical output compared to previous conventional method. By compelling the results, 0.01 kg/s subjected to be efficient on the electricity production and the hydrogen generation. Further, employing the electrolyzer as the attached to the hybrid system produces the hydrogen, which can be stored for future use as the promising source of energy.

Boosting moisture induced electricity generation from graphene oxide through engineering oxygen-based functional groups

Harvesting energy from ubiquitous moisture is attracting growing interest for directly powering electronic devices. However, it is still challenging to fabricate high-performing moisture-electric generators (MEGs) with high and stable electric output. Herein, we report a simple strategy to modify the oxygen-based groups of graphene oxide using hydrochloric acid treatment, which boosts the electric output based on the device structure of graphene oxide/polyvinyl alcohol (GO/PVA) MEGs. The resulting MEG enables a stable voltage of 0.85 V and a current of 9.28 μA (92.8 μA∙cm-2), which are among the highest values reported so far. More excitingly, electric output gets further improved by simply assembling four MEG units in series or parallel. Moreover, the MEG shows great commercial potential for flexible and wearable applications. Driven by these advancements, the assembled MEGs can successfully power sensors and calculators. This work opens a new era of advance for a new energy conversion technology able to directly powering electronic devices.

Cu-Ni-Based Alloys from Nanopowders as Potent Thermoelectric Materials for High-Power Output Applications

A new approach for the development of thermoelectric materials, which focuses on a high-power factor instead of a large figure of merit zT, has drawn attention in recent years. In this context, the thermoelectric properties of Cu-Ni-based alloys with a very high electrical conductivity, a moderate Seebeck coefficient, and therefore a high power factor are presented as promising low-cost alternative materials for applications aiming to have a high electrical power output. The Cu-Ni-based alloys are prepared via an arc melting process of metallic nanopowders. The heavy elements tin and tungsten are chosen for alloying to further improve the power factor while simultaneously reducing the high thermal conductivity of the resulting metal alloy, which also has a positive effect on the zT value. Overall, the samples prepared with low amounts of Sn and W show an increase in the power factor and figure of merit zT compared to the pure Cu-Ni alloy. These results demonstrate the potential of these often overlooked metal alloys and the utilization of nanopowders for thermoelectric energy conversion.

Enhanced piezoelectric performance of electrospun PVDF nanofibers by regulating the solvent systems

In recreant years, the attention of researchers has been focused on enhancing the electrical outputs of energy harvesting devices. This study reports the generation and characterization of electrospun polyvinylidene fluoride (PVDF) nanofiber webs obtained from different solvents (Acetone (ACE), ACE: N, N-dimethylformamide (DMF) /3:1, ACE: DMF/1:1, ACE: DMF/1:3, and DMF). These electrospun webs will be used as active layers for piezoelectric nanogenerator (PENG). We found that fibers electrospun using DMF have the highest phase content (F(β)), while fibers electrospun using ACE have the lowest one. Furthermore, the results show that PENG based on fiber web electrospun using DMF has the highest electrical outputs, whereas, the lowest electrical outputs were for PENG based on fiber web electrospun using ACE. We believe this work can serve as a good reference for investigating the effect of solvent systems on diameters of fibers, crystalline phases, and piezoelectric properties.

A graphene nanoplatelets-based high-performance, durable triboelectric nanogenerator for harvesting the energy of human motion

Triboelectric nanogenerators (TENGs) have been widely investigated to harness mechanical energy that is driven by repetitive human motion. Conventional human motion-driven TENGs are mostly based on contact–separation (CS) mode, but their energy harvesting performance is limited due to the high crest factor (the ratio of the peak to the RMS value of output voltage). Here, we demonstrate a new rolling type triboelectric nanogenerator (RL-TENG), exhibiting the lower crest factor than CS mode TENGs, using a metal layer and graphene nanoplatelets-doped PDMS. These additions helped improve the dielectric constant and the charge storage capacity of the TENG, which led to a high electrical output while minimizing surface damage. As compared to a pristine TENG, our device, a RL-TENG, generated an open-circuit peak voltage of 75.2 V, which was almost 15 times higher than that of the pristine device, and a short-circuit peak current of 7.36μA, which was 12 times higher. With a dual-side double-belt TENG (DB-TENG), these values were improved to 164 V and 10μA. Lastly, our device was used in a real-life application, to harvest mechanical energy from the movement of the human elbow while walking, and was able to produce a high voltage output of up to 821 V. These results show that the DB-TENG can be used for high-efficiency harvesting of energy from human motion.

Optimization for Compact and High Output LED-Based Optical Wireless Power Transmission System

Optical wireless power transmission (OWPT) is a technology that supplies energy remotely. Due to the great advantages of long transmission distances, high directionality, no electromagnetic interference noise, and loose safety regulations, light emitting diode (LED) based OWPT systems become appropriate candidates for powering various applications, especially for the Internet of things (IoT). In this paper, improved LED-OWPT systems are proposed based on a collimation scheme for optimizing the system dimension and output. In a single LED configuration, the system dimension is compressed by 46% while the high transmission efficiency is maintained. As for the LED-array system, the dimension is compressed by 56%, and the output is enhanced by 40%. In the experiment, a high electricity output of 532 mW is achieved at 1 m transmission distance. In addition, the effect of misalignment between LED and lens and the potential of long-distance transmission are clarified in the LED-array OWPT system.

Hydrogel‐based triboelectric nanogenerators: Properties, performance, and applications

The development of triboelectric nanogenerators (TENGs) in 2012 revolutionized the vision of environmental energy harvesting. Nowadays, TENG assembly, working mode, and material selection are investigated continuously in order to obtain high-performance and long-lasting devices. Hydrogels are flexible and stretchable water-swollen 3D polymer networks, which can be tailored to conduct electricity and render outstanding mechanical properties. Hydrogels have been used to develop novel flexible wearable TENGs. Here, we review the current knowledge concerning hydrogel-based TENGs, including an overview of relevant hydrogel characteristics, hydrogel-based TENG performance, and their practical applications. The single-electrode TENG working mode is the most popular in hydrogel-based TENGs as they can be easily attached and stretched for biomechanical energy harvesting. Hydrogel-based TENGs have demonstrated to be capable of delivering high electrical output (250-400 V, ≥10 μA) and being robust enough for devices that last for several months. Biomechanical energy sensing and harvesting, smart farming, biomedical, and human–machine control interfaces are investigated as potential applications of hydrogel-based TENGs. Interestingly, energy harvesting from human motion is of particular interest for this type of TENG due to its outstanding stretchability, strength, and additional physical properties, such as self-healing ability. In most cases, the devices are capable of powering small electronics entirely from harvested biomechanical energy. Biomedical applications involved wound healing acceleration driven by TENG-powered electrical stimuli and disease monitoring, including implantable devices. Despite showing promising electrical performance, controlling water evaporation is still challenging to maintain the mechanical and conductive properties of hydrogel-based TENGs. On the other hand, fully biodegradable TENGs are largely unexplored, as well as many applications, such as blue energy harvesting, the internet of things, and others. The next steps in this line of research must focus on addressing the main challenges of hydrogel-based TENGs and filling the application knowledge gaps.

Harnessing wind and solar PV system to build hybrid power system

Electricity is the most important consideration for individual needs. Natural crossover power architecture using photovoltaic and wind is presented in this study, together with a Cuk direct current-direct current (DC-DC) converter, third phase inverter, and an inductors capacitors (LC) filter. Due to its natural disposal and availability in India, wind power and photovoltaics are ideal for the hybrid system. Hybrid power structures, on the other hand, reduce the risk of damage to equipment in sustainable stock storage since they have a higher electrical output. MATLAB Simulink was used to demonstrate this hybrid application. Before connecting the entire DC voltage frame with the main lattice of the power frame, blocks such as the wind model, PV model, Cuk converter, inverter, and LC channel are built individually. Information limitations for participating in varying levels of irradiance and variations in wind speed. The results show that the hybrid system has a considerably more reliable standard in terms of energy efficiency than an independent framework. Furthermore, the hybrid system's Cuk DC-DC converter, three-phase standard-based inverter, and LC channel can minimise power switching power.

Layer-by-Layer Self-Assembled Thin Films for Triboelectric Energy Harvesting under Harsh Conditions

With the rapid growth in triboelectric nanogenerator (TENG) technology, selecting appropriate tribomaterial (TM) with high electrical output performance and a cheap fabrication technique is vital for sustainable nanogenerator operations. Thus, we prepared an electrostatic bonded thin poly(diallyldimethylammonium chloride) and poly(4-styrene-sulfonic acid) multilayered-based film as a potential positive TM via facile and cheap layer-by-layer (LbL) self-assembly fabrication technique. The high electrical output performance of the LbL-TENGs depends on the number of BL films was optimized by changing the number of bilayers (BLs) from 10 to 50. The 30 BL TENG shows a significant voltage of 189 V and a current density of 17 mA m–2 under the harsh environment of 65% RH, indicating the sustainability of the LbL-TENG device. Furthermore, the single-electrode mode of the optimized TENG exhibited an impressive TENG performance of 215 V and 79 mA m–2 and lit up 39 green light-emitting diodes just by tapping the TENG by hand.

Surface modified hybrid ZnSnO3 nanocubes for enhanced piezoelectric power generation and wireless sensory application

Piezoelectric Nanogenerators (PENGs), which can convert ambient mechanical stimuli into electrical energy, are held in high regard due to their cost-effectiveness, energy harvesting applications, and potential as self-powered sensors. We report an aluminum-doped zinc stannate (ZnSnO3) PENG that can achieve high electrical outputs with respect to the external force. In order to enrich the piezoelectric mechanics, a low-temperature solution method was adopted in our work to synthesize ZnSnO3 nanocubes with an average side length of only 30 – 55 nm. Furthermore, ZnSnO3 was doped with 1–5 wt% of aluminum nanoparticles. We report that 2 wt% of aluminum doped ZnSnO3 showed the highest electrical output in terms of open circuit voltages and short circuit current. The nanogenerator device achieved an average open-circuit voltage of 80–175 V with a frequency range of 60 BPM (Beats Per Minute) to 240 BPM, an unprecedented electrical output in comparison to current ZnSnO3-based PENGs. With the presented high output-to-size ratio taken into consideration, the device was mounted in a helmet and tested as an energy harvester and wireless human motion sensor, which can generate electric charge as well as detect human movements and transmit the corresponding signals wirelessly. Our work is indicative of a promising smart helmet using organic-inorganic hybrid materials.

Experimentally Verified Analytical Models of Piezoelectric Cantilevers in Different Design Configurations.

This paper deals with analytical modelling of piezoelectric energy harvesting systems for generating useful electricity from ambient vibrations and comparing the usefulness of materials commonly used in designing such harvesters for energy harvesting applications. The kinetic energy harvesters have the potential to be used as an autonomous source of energy for wireless applications. Here in this paper, the considered energy harvesting device is designed as a piezoelectric cantilever beam with different piezoelectric materials in both bimorph and unimorph configurations. For both these configurations a single degree-of-freedom model of a kinematically excited cantilever with a full and partial electrode length respecting the dimensions of added tip mass is derived. The analytical model is based on Euler-Bernoulli beam theory and its output is successfully verified with available experimental results of piezoelectric energy harvesters in three different configurations. The electrical output of the derived model for the three different materials (PZT-5A, PZZN-PLZT and PVDF) and design configurations is in accordance with lab measurements which are presented in the paper. Therefore, this model can be used for predicting the amount of harvested power in a particular vibratory environment. Finally, the derived analytical model was used to compare the energy harvesting effectiveness of the three considered materials for both simple harmonic excitation and random vibrations of the corresponding harvesters. The comparison revealed that both PZT-5A and PZZN-PLZT are an excellent choice for energy harvesting purposes thanks to high electrical power output, whereas PVDF should be used only for sensing applications due to low harvested electrical power output.

3D printed bidirectional rotatory hybrid nanogenerator for mechanical energy harvesting

In the world of automotive technologies, a tremendous amount of small-scale rotational energy is wasted and not being converted into a usable energy form. A rotatory triboelectric nanogenerator can be a fortune technology to harvest such waste mechanical energy and convert it into electricity. In this regard, we developed a fully three-dimensional (3D) printed bidirectional rotatory hybrid nanogenerator (BR-HNG) to convert waste rotational energy into electricity, via a contact and separation mode mechanism. Initially, a single HNG was fabricated with porous sodium niobate and polydimethylsiloxane polymer (i.e., NaNbO3/PDMS) composite film, which was operated vertically against the aluminum to optimize a high and stable electrical output. After the robust and stability test of the single HNG, multiple HNGs were integrated into a 3D printed bidirectional rotatory frame to harvest the rotational energy. It was observed that the BR-HNG had a stable and high electrical direct current voltage of 37.5 V. Furthermore, the BR-HNG was attached to a bicycle to harvest the rotational energy while bicycling in everyday human life and power up various portable electronics.

Scalable fabrication of stretchable and washable textile triboelectric nanogenerators as constant power sources for wearable electronics

The textile-based triboelectric nanogenerator (tTENG) is one of the most promising energy harvesting devices for realizing self-powered smart textiles and wearable electronics. Herein, we report a scalable machine-knitting fabrication of stretchable, washable and breathable tTENGs for harvesting human motion energies. A plating stitch technique is employed to fabricate tTENGs using various common yarn materials and working in different modes (coplanar sliding mode and contact-separation mode). The tTENG can output voltage up to 232 V and power density up to 66.13 mW/m 2 . Furthermore, it can constantly power different wearable electronics by integrating with a small-size power management module, which converts the irregular AC output to a stable DC output and improves the energy utilization of tTENG. The stretchability, washability and air permeability of the tTENG are also demonstrated. These findings provide a practically viable textile-based power source that holds great promise in future self-powered wearable electronics and smart textiles. A stretchable, washable and breathable textile-based triboelectric nanogenerator is fabricated by a scalable knitting method for harvesting human motion energies, which can provide continuous power to different small electronics with the aid of a small-sized power management module. This work presents a feasible and practical power alternative for wearable electronics and E-textiles. • Scalable fabrication of stretchable, washable and breathable textile triboelectric nanogenerators (tTENG) is demonstrated. • The tTENG generates high electrical outputs by harvesting human motion energies. • The tTENG can constantly power different wearable electronics with the aid of a small-size power management module.

Dielectric liquid-based self-operating switch triboelectric nanogenerator for current amplification via regulating air breakdown

Triboelectric nanogenerators (TENG) can harvest mechanical energy by using the displacement current generated by a time-variant electric field. Owing to the simple fabrication, low cost, and the suitability of a wide range of materials for such devices, TENGs can be used as a power source for self-powered systems and existing portable electronics. Nevertheless, the generation mechanism of TENGs must be optimized to overcome the current limitations caused by the air breakdown on triboelectric materials. Therefore, a dielectric liquid-based self-operating switch triboelectric nanogenerator (DLSS–TENG) was created, which can control the field emission on the electrode surface through the movement of the dielectric liquid. The movement of the dielectric material plate regulates the air breakdown by acting as a self-operating switch, which can enhance the current output of the TENG. Because dielectric liquids exhibit a large Debye length, which screens the electrostatic charge, they can be used to generate a distinctively high electrical output. The DLSS–TENG can charge a commercial capacitor by generating a closed-circuit current of up to 56 mA and open-circuit voltage of 100 V for a 0.5 Hz low-frequency mechanical input. The generation mechanism of the proposed DLSS–TENG can overcome the current electrical limitation by regulating the air breakdown. • Triboelectric nanogenerator (TENGs) utilizing movement of dielectric liquid as self-operating switch. • Dielectric liquid-based TENG developed in this study can produce amplified current output through field emission. • Working mechanism for TENGs covered with various liquids such as water, ethyl alcohol, mineral oil, and silicone oil.

A whirligig-inspired intermittent-contact triboelectric nanogenerator for efficient low-frequency vibration energy harvesting

Triboelectric nanogenerator (TENG) has overwhelming dominance in the exploitation of low-frequency vibration energy, but the sparse pulsed output, material abrasion in contact-mode TENG and output decline in noncontact-mode TENG limit the output power and electrical stability. Herein, we report a rotational intermittent-contact TENG (IC-TENG) that is realized on the basis of a slideable rope-driven rotor to achieve efficient exploitation of low-frequency vibrations. The rope-driven rotor can start to spin and transform low-frequency vibrations to high-speed rotation through a whirligig-like dynamics mechanism without the requirement of any hand operation, which enables frequency-multiplied and high electric output of the IC-TENG. Moreover, owing to the constantly replenished tribo-charges produced by the intermittent sliding contact between the rotator and stator in the rope-driven rotor, the IC-TENG exhibits high electrical stability, whose normalized electric output stabilizes at around 81%, whereas the normalized electric output of noncontact-mode TENG attenuates continuously to 48% over a 10-day span. The frequency-multiplied electric output and superior electrical stability make the IC-TENG a promising technology for harnessing ambient low-frequency vibration energy. This work demonstrates a novel strategy for TENG to achieve high electric output and in the meanwhile long-term stability.

Large-Scale Lever-Based Triboelectric Nanogenerator for Sensing Lateral Vibration and Wrist or Finger Bending for Controlling Shooting Game.

With advances in internet of things technology and fossil fuel depletion, energy harvesting has emerged rapidly as a means of supplying small electronics with electricity. As a method of enhancing the electrical output of the triboelectric nanogenerator, specialized for harvesting mechanical energy, structural modification to amplify the input force is receiving attention due to the limited input energy level. In this research, a lever structure was employed for delivering the amplified input force to a triboelectric nanogenerator. With structural optimization of a 2.5 cm : 5 cm distance ratio of the first and second parts using two lever structures, the highest electrical outputs were achieved: a VOC of 51.03 V, current density of 3.34 mA m−2, and power density of 73.5 mW m−2 at 12 MΩ in the second part. As applications of this triboelectric generator, a vertical vibration sensor and a wearable reloading trigger in a gun shooting game were demonstrated. The possibility for a wearable finger bending sensor with low-level input was checked using a minimized device. Enhanced low-detection limit with amplified input force from the structural advantage of this lever-based triboelectric nanogenerator device can expand its applicability to the mechanical trigger for wearable electronics.

Abrasion and Fracture Self‐Healable Triboelectric Nanogenerator with Ultrahigh Stretchability and Long‐Term Durability

AbstractSince triboelectrification results from materials in physical contact, the durability of triboelectric nanogenerators (TENGs) must be improved. However, it still poses challenges to continuously repair surface abrasion even when self‐healable materials are introduced. In this study, an ultrastretchable TENG (US‐TENG) that simultaneously heal the fracture and abrasion at room temperature is fabricated. By incorporating hydrogen bonds and dynamic metal‐ligand coordination into polydimethylsiloxane chains, the synthesized elastomers possess ultrahigh stretchability (10 000%) and remarkable self‐healing property (100% efficiency) at room temperature. Working in contact‐separation mode, the electrical outputs with 2 × 2 cm2 area can reach 140 V, 40 nC, 1.5 µA, respectively. Besides, the US‐TENG shows a stretchability of 1800% with high electrical outputs. Even if it is stretched to break or scratched to wear out, it can recover its electrical outputs in 20 min and 2 h at room temperature, respectively. Finally, the application of the US‐TENG as flexible power sources and self‐powered pressure sensors is demonstrated. This designed strategy with ultrahigh stretchability and excellent self‐healing properties can meet the wide applications of flexible and wearable electronics for long‐term use.

Using the sun to co-generate electricity and freshwater

Using the sun to co-generate electricity and freshwater

Two-Dimensional MOF Modulated Fiber Nanogenerator for Effective Acoustoelectric Conversion and Human Motion Detection.

The real-time application of piezoelectric nanogenerators (PNGs) under a harsh environment remains a challenge due to lower output performance and poor durability. Thus, the development of flexible, sensitive, and stable PNGs became a topic of interest to capture different human motions including gesture monitoring to speech recognition. Herein, a scalable approach is adapted where naphthylamine bridging a [Cd(II)-μ-I4] two-dimensional (2D) metal-organic framework (MOF)-reinforced poly(vinylidene fluoride) (PVDF) composite nanofibers mat is prepared to fabricate a flexible and sensitive composite piezoelectric nanogenerator (C-PNG). The needle-shaped MOF was successfully synthesized by the layering and diffusion of two different solutions. The incorporation of single-crystalline 2D MOF ensures a large content of electroactive phases (98%) with a resultant high-magnitude piezoelectric coefficient of 41 pC/N in a composite nanofibers mat due to the interfacial specific interaction with -CH2-/-CF2- dipoles of PVDF. As an outcome, C-PNG generates high electrical output (open-circuit voltage of 22 V and maximum power density of 24 μW/cm2) with a very fast response time (tr ≈ 5 ms) under periodic pressure imparting stimuli. Benefiting from bending and twisting functionality, C-PNG is capable of scavenging biomechanical energy by mimicking complex musculoskeletal motions that broaden its application in wearable electronics and fabric integrated medical devices. In addition, C-PNG also demonstrates an efficient acoustic vibration to electric energy conversion capability with an improved power density and acoustic sensitivity of 6.25 μW and 0.95 V/Pa, respectively. The overall energy conversion efficiency is sufficient to operate several consumer electronics without any energy storage unit. This acoustic observation is further validated by the finite element method-based theoretical simulation. Overall, the 2D MOF-based device design strategy opens up a new possibility to develop a human-motion compatible energy generator and a self-powered acoustic sensor to power up electronic gadgets as well as low-frequency noise detection.