Energy Harvesting Devices Research Articles

Preparation of Chitin Nanofibers and Natural Rubber Composites and Their Triboelectric Nanogenerator Applications.

Triboelectric nanogenerators (TENGs) have gained significant attention as promising energy-harvesting devices that convert mechanical energy into electrical energy through charge separation induced by friction and electrostatic induction. In this study, we explore the utilization of biowaste shrimp shell-extracted chitin nanofiber (ChNF) as a viable eco-friendly material for TENG applications. Composite materials were prepared by incorporating ChNF into natural rubber (NRL) at loading levels of 0.1 and 0.2 wt% (NRL/ChNF) to form the TENG triboelectric layer. ChNFs with a uniform width of approximately 10-20 nm were successfully extracted from the shrimp shells through a simple mechanical procedure. The NRL/ChNF composites exhibited enhanced mechanical properties, as evidenced by a higher Young's modulus (3.4 GPa) compared to pure NRL. Additionally, the NRL/ChNF composites demonstrated an increased dielectric constant of 3.3 at 0.1 MHz. Moreover, the surface potential difference of NRL increased from 0.182 V to 1.987 V in the NRL/ChNF composite. When employed as the triboelectric layer in TENG, the NRL/ChNF composites exhibited significant improvement in their output voltage, with it reaching 106.04 ± 2.3 V. This enhancement can be attributed to the increased dielectric constant of NRL/ChNF, leading to enhanced charge exchange and charge density. This study presents a straightforward and environmentally friendly technique for preparing sustainable natural materials suitable for energy-harvesting devices.

Programming quadric metasurfaces via infinitesimal origami maps of monohedral hexagonal tessellations: Part I

The control of the shape of complex metasurfaces is a challenging task often addressed in the literature. This work presents a class of tessellated plates able to deform into surfaces of preprogrammed shape upon activation by any flexural load and that can be controlled by a single actuator. Quadric metasurfaces are obtained from infinitesimal origami maps of monohedral hexagonal tessellations of the plane, that is pavings in which all tiles are congruent to each other. Monohedral tessellated portions can be joined together to obtain more complex shapes, which can be locally synclastic or anticlastic and can have a certain roughness. We broaden previous work by providing a complete characterization of all the three known types of monohedral tessellations composed by irregular hexagons. The proposed two-dimensional structures may have applications in prosthetics, tissue engineering, wearable devices, energy harvesting devices, tunable focus mirrors and adaptive facades. The study is divided in two parts. In Part I, after introducing the discrete kinematics of tessellated plates, it is proved analytically that essentially each type of monohedral hexagonal tessellation possesses only one deformation mode. Afterwards, several numerical examples are provided to demonstrate the variety of achievable surface shapes. In Part II, first the metasurfaces corresponding to assigned tile geometries are given a continuum description, which establishes that the continuous interpolant is always a quadric. Then, experimental results on fabrication, assembly and surface accuracy are reported.

Energy Harvesting in Electric Power Systems for Data Communication Purposes

Aiming to illuminate the path towards integrating energy harvesting (EH) technologies into modern electric power systems, thereby enabling more efficient and sustainable energy solutions, this paper explores energy harvesting within electric power systems and points out its potential to power data communication purposes. In this sense, we examine the overarching principles of EH in these systems, spotlighting both the merits and limitations associated with energy extraction across varying voltage levels and electric signal frequency bands. Central components of EH devices, alongside a spectrum of harvesting methodologies, are thoroughly reviewed. Also, we showcase a case study that provides a quantitative assessment of EH potential in electric power systems. The manuscript culminates in a forward-looking analysis of EH, considering emerging technologies that promise to redefine the landscape. These include integrating hybrid power line and wireless systems, strategies for optimal power allocation, enhancements in physical layer security, the innovative concept of negawatts, advancements in harvesting circuit designs and applying non-orthogonal multiple access techniques

Application of nanogenerators in acoustics based on artificial intelligence and machine learning

As artificial intelligence (AI) advances, it is critical to give conventional electronics the capacity to “think,” “analyze,” and “advise.” The need for intelligent, self-powered devices has increased due to recent significant developments in the computer field, namely, in the fields of AI and machine learning (ML). The use of nanogenerators in the area of acoustics is examined in this Review, with an emphasis on how they might be integrated with ML and AI. Innovative energy-harvesting devices called nanogenerators are able to produce electrical power from outside sources, such as vibrations in the air or mechanical movements. The study examines a number of acoustic applications for nanogenerators, such as energy harvesting, sound detection, noise monitoring, and acoustic sensing. Furthermore, the research highlights how AI and ML techniques enhance the performance of nanogenerators and enable more efficient acoustic applications through data analysis and model training. At the end of this Review, the future development prospects of nanogenerators based on AI and ML were discussed.

Efficient Zn-based pn-junction thermoelectric device for energy harvesting

Efficient Zn-based pn-junction thermoelectric device for energy harvesting

Terminalia Chebula Fruits Powder as Tribopositive Material for High‐Performance Triboelectric Nanogenerator

Triboelectric nanogenerator (TENG) has generated a lot of attention for developing self‐powered/battery‐free technology. These kinds of energy harvesting devices are required for a sustainable future. In this work, the TENG is developed by using the Terminalia Chebula (T. Chebula) biomaterial as tribopositive material. The physiochemical characterizations suggest that T. Chebula has hydroxyl and carbonyl groups which are important to get tribopositivity from the material. The T. Chebula tribopositive material has been tested for the TENG with different electronegative layers such as polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), and polydimethylsiloxane (PDMS). The T. Chebula/PTFE device exhibited a higher output performance. This pair was used for the area and frequency‐dependent studies. In the present case, 16 cm2 device area and 5 Hz frequency conditions show outstanding device performance. Furthermore, the device has been employed for operating low‐power electronic devices such as LEDs and a calculator which operated without any degradation. These results suggested that T. Chebula is a potential tribopositive material for sustainable energy harvesting technology.

An inclined pedal type piezoelectric energy harvester for pedestrian flow and vehicle safety monitoring

This paper proposed an inclined pedal-type piezoelectric energy harvester for pedestrian monitoring and vehicle safety monitoring (IPEH). The IPEH exterior adopts an inclined pedal design, the steel ball is placed inside its cylindrical channel to excite the piezoelectric patches to harvest and convert external mechanical energy. IPEH can be placed under the brake pedal of a car for the function of vehicle safety monitoring. IPEH can also be fixed on the road as an energy harvester and monitoring device, harvesting pedestrian trampling energy and monitoring the density of pedestrian traffic in realtime. The influence of the steel ball diameter and spring layout on the output performance of the prototype is studied in this paper. Under the best parameters of the prototype assembly, the maximum output voltage is 165.6 Vpp, and the maximum output power is 463.7 mW. In the application experiment, the practicability in energy harvesting applications of IPEH is verified through the experiment of lighting LEDs and charging capacity, and the monitoring ability of IPEH was verified by simulating the experiment of different human flow walking and vehicle braking. It provides a new idea for the subsequent application of piezoelectric equipment in traffic auxiliary facilities and intelligent sensing equipment.

Hybrid Piezoelectric/Triboelectric Wearable Nanogenerator Based on Stretchable PVDF-PDMS Composite Films.

Hybrid piezoelectric/triboelectric nanogenerators combine the merits of piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs), possessing enhanced electrical output and sensitivity. However, the structures of the majority of hybrid nanogenerators are rather complex in integrating both functions, limiting their practical application in wearable electronics. Herein, we propose to construct a piezoelectric/triboelectric hybrid nanogenerator (PT-NG) with a simple structure based on a composite film to simultaneously achieve the coupling of piezoelectric charge generation and triboelectrification with improved energy conversion efficiency. The composite film consists of electrospun PVDF nanofibers embedded in the surface of the PDMS film, which not only forms a rough nanomorphology on the surface of PDMS but also provides structural protection to the PVDF nanofibers by PDMS during compressive deformation. The results have shown that the PT-NG can generate much higher electrical outputs than individual TENG and PENG devices. The PT-NG devices exhibit a high level of mechanical-to-electrical energy conversion efficiency with superior performance in charging capacitors and functioning as self-powered wearable sensors for the detection of different signals from finger movement, the recognition of various gestures, and the monitoring of respiration. More importantly, the composite device possesses an impressive structure durability, maintaining its layered structure over 5000 testing cycles without noticing any obvious damage on the nanofibers or detachment between the layers. Our results have demonstrated that the combining of piezoelectric nanofibers and triboelectric substrate is an efficient way to fabricate highly efficient energy harvesting devices for intelligent identification and health monitoring.

Velocity-Controlled Piezoelectric Switching Energy Harvesting Device

The main purpose of this paper is to design the interface circuit of the piezoelectric energy harvesting device which can be suitable for a resistive load o a capacitive load. The vibrating velocity is detected to control the active rectifier to make the power factor correction of the piezoelectric layers. However, there are switching losses in the active rectifier in practice. The dead time and an inductor are thus taken into consideration to minimum the switching loss. The proposed circuit can increase 4 times than typical interface circuit of the piezoelectric layer, and can increase the charging speed of the capacitive storage buffer as well.

Dynamic analysis of a novel multilink-spring mechanism for vibration isolation and energy harvesting

Due to technical limitations, existing vibration isolation and energy harvesting (VIEH) devices have poor performance at low frequency. This paper proposes a new multilink-spring mechanism (MLSM) that can be used to solve this problem. The VIEH performance of the MLSM under harmonic excitation and Gaussian white noise was analyzed. It was found that the MLSM has good vibration isolation performance for low-frequency isolation and the frequency band can be widened by adjusting parameters to achieve a higher energy harvesting power. By comparison with two special cases, the results show that the MLSM is basically the same as the other two oscillators in terms of vibration isolation but has better energy harvesting performance under multistable characteristics. The MLSM is expected to reduce the impact of vibration on high-precision sensitive equipment in some special sites such as subways and mines, and at the same time supply power to structural health monitoring devices.

Energy efficiency optimization in a parallel relay-assisted UWOC system with simultaneous lightwave information and power transfer.

In this paper, we investigate the energy efficiency optimization for a parallel relay-assisted underwater wireless optical communication (UWOC) system with simultaneous lightwave information and power transfer (SLIPT) over an aggregate channel. In this system, relay nodes are equipped with energy harvesting devices, getting energy from the direct current component of the received signal transmitted by the source node. These nodes utilize the harvested energy to transmit the signal to the destination node with the decoding and forwarding strategy. The harvested energy for each relay node is derived by the Gauss-Laguerre quadrature formula and the outage probability is deduced by the Meijer-G function. Then, the system's energy efficiency can be calculated and an energy efficiency maximization problem is built up with respect to the bias current. We propose a three-level-iteration algorithm to solve this problem. In the first level, the Dinkelbach method is used to represent energy efficiency in a parametric subtractive form. In the second level, we use the penalty function method to convert the object function and constraint. In the third level, the objective function is transformed into a quadratic function by using a successive convex approximate method, thereby solving for the bias current. The effects of system parameters on energy efficiency are also analyzed. Theoretical results and Monte Carlo simulations suggest that employing the solved bias current can significantly improve the system's energy efficiency.

Piezoelectricity performance and β-phase analysis of PVDF composite fibers with BaTiO3 and PZT reinforcement

Piezoelectric composite fibers have various applications such as energy harvesting and human body monitor devices. Therefore, the construction of fibers that have the highest piezoelectric efficiency while using materials with the least toxicity is of great importance for health. Consequently, in the research a head PZT/PVDF (Lead Zirconate Titanate/Polyvinylidene fluoride) and Lead free BaTiO3/PVDF (Barium Titanate/Polyvinylidene fluoride) 0–3 connection type composites nanofibers were fabricated by Electrospinning method. Dielectric constant with Impedance analyzer, sensitivity with handmade device and their crystalline properties by using FTIR and XRD, were compared. The results showed, adding BaTiO3 will increase the percentage of β-Phase crystal formation more than adding PZT which subsequently leads to a higher dielectric constant.

Non-linear modeling of a bi-layer magnetostrictive cantilever considering [formula omitted]E effect

Magnetostrictive cantilever beams are reliable and straightforward energy harvesting devices for powering wireless sensors using environmental vibrations. However, despite their widespread use, a comprehensive analytical model encompassing both mechanical and electromagnetic main features is still lacking. The mechanical-to-magnetic coupling of a magnetostrictive beam, with its various working conditions and nonlinear characteristics, can be effectively approximated by the Euler–Bernoulli (E–B) equation with damping (viscous and Kelvin–Voigt) coupled with a non-linear magnetostrictive model. In this study, we propose a practical and convenient model for a general concept device designed to convert vibrations into electrical energy. The model is thoroughly compared with experimental measurements aimed to prove the goodness of the approach rather than energy harvesting highest performance.

Printed and Stretchable Triboelectric Energy Harvester Based on P(VDF‐TrFE) Porous Aerogel

AbstractDeveloping energy harvesting devices is crucial to mitigate the dependence on conventional and rigid batteries in wearable electronics, ensuring their autonomous operation. Nanogenerators offer a cost‐effective solution for enabling continuous operation of wearable electronics. Herein, this study proposes a novel strategy that combines freeze‐casting, freeze‐drying, and printing technologies to fabricate a fully printed triboelectric nanogenerator (TENG) based on polyvinylidene fluorid‐etrifluoroethylene P(VDF‐TrFE) porous aerogel. First, the effects of porosity and poling on the stretchability and energy harvesting capabilities of P(VDF‐TrFE) are investigated, conducting a comprehensive analysis of this porous structure's impact on the mechanical, ferroelectric, and triboelectric properties compared to solid P(VDF‐TrFE) films. The results demonstrate that structural modification of P(VDF‐TrFE) significantly enhances stretchability increasing it from 7.7% (solid) to 66.4% (porous). This modification enhances output voltage by 66% and generated charges by 48% for non‐poled P(VDF‐TrFE) porous aerogel films compared to their non‐poled solid counterparts. Then, a fully printed TENG is demonstrated using stretchable materials, exhibiting a peak power of 62.8 mW m−2 and an average power of 9.9 mW m−2 over 100 tapping cycles at 0.75 Hz. It can illuminate light‐emitting diodes (LEDs) through the harvesting of mechanical energy from human motion. This study provides a significant advance in the development of energy harvesting devices.

Experimental Characterization of an AC–DC Boost for Energy Harvesting Device Based on Magnetostrictive Materials

Magnetostrictive alloys hold great promise for Energy Harvesting applications due to their inherent durability. However, their implementation often results in usable voltage ranges that fall significantly below common electronic standards like 1.6, 3.3, and 5 volts. Consequently, the utilization of electronic circuits becomes essential to amplify the voltage and enhance energy conversion efficiency. Over the past few decades, numerous conversion techniques have been devised for other intelligent materials, such as piezoelectrics, some of which have even made their way into commercial products. Surprisingly, there is a dearth of specialized techniques, if not a complete absence, tailored to magnetostrictive devices. Among potential solutions, a suitable AC–DC Boost converter stands out as a highly promising candidate for addressing this challenge, but this solution has never been fully characterized. Then, this paper presents thorough experimental validations of such a converter, driven by a real-time Arduino board equipped to measure source time periods and operate under various conditions. We present several cases demonstrating the circuit’s substantial potential for enhancing energy harvesting from magnetostrictive materials.

The effects of physical morphologies and strain rate on piezoelectric potential of boron nitride nanotubes: a molecular dynamics simulation

The growing demand for self-powered systems and the slow progress in energy storage devices have led to the emergence of piezoelectric materials as a promising solution for energy harvesting. This study aims to investigate the effects of chirality, length, and strain rate on the piezoelectric potential of boron nitride nanotubes (BNNTs) through molecular dynamics simulation. Accurate data and guidance are provided to explain the piezoelectricity of chiral nanotubes, as the piezoelectric potentials of these nanotubes have previously remained unclear. The present study focuses on calculating the effect of these parameters based on the atomic model. The observed results stem from the frequencies and internal deformations, as the axial frequencies and deformations exhibit more substantial modifications compared to transverse directions. The piezoelectricity was found to depend on chirality, with the order of BNNT piezoelectricity sufficiency being in the sequence of zigzag > chirality > armchair configurations. The length of the BNNTs was also found to influence piezoelectricity, while the strain rate had no effect. The results also indicate that BNNTs can generate power in the milliwatts range, which is adequate for low-power electronic devices and Internet of Things applications. This research provides valuable insights into the piezoelectricity of chiral nanotubes and offers guidance for designing efficient energy harvesting devices.

An Electrolyte-Free Thermo-Rechargeable Battery Made of Prussian Blue Analog Thin Films

Thermo-rechargeable batteries, or tertiary batteries, are prospective energy-harvesting devices that are charged by changes in the battery temperature. Previous studies on tertiary batteries have utilized an electrolyte solution, yet the volume of this electrolyte solution could be a disadvantage in terms of the heat capacity given to the tertiary batteries. To overcome this drawback, the performance of an electrolyte-free tertiary battery consisting of physically joined Na1.60Co[Fe(CN)6]0.902.9H2O (NCF90) and Na0.72Ni[Fe(CN)6]0.685.1H2O (NNF68) thin films was investigated for the first time. During thermal cycling between 5 °C and 15 °C, the thermal voltage (VTB) was observed to be 8.4 mV. This result is comparable to the VTB of conventional tertiary batteries that use electrolyte solutions made of NCF90 and NNF68 thin films.

Design, Optimization, and Application of Nonlinear Energy Sink in Energy Harvesting Device

Vibration control has been of great interest to scientists and engineers for many years. Although linear vibration absorbers have been shown to be effective in mitigating vibrations at specific frequencies, their vibration reduction effect is usually limited to a narrow frequency bandwidth. Nonlinear energy sinks have attracted attention due to their better vibration reduction effect over a wider frequency bandwidth. In practical applications, the nonlinear energy sink devices can effectively absorb, dissipate, and convert energy from broadband excitation, so as to achieve vibration reduction and energy harvesting. However, research on energy harvesting based on the nonlinear energy sink is less mature than in linear systems. Multiple parameters of device design (e.g., damping size) affect the actual performance of the nonlinear energy sinks, but there is no exact method to simplify the design of the multiparameter nonlinear energy sinks. Since it is more difficult to implement electromagnetic and electrostatic energy harvesters, more research has focused on piezoelectric energy harvesters. This paper summarizes the research on the nonlinear energy sink and energy harvesting technology, including the introduction of the nonlinear energy sink, energy harvesting based on the nonlinear energy sink, and its application in various fields of energy harvesting. The paper also summarizes some important methods for solving the dynamical equations, as well as their advantages and disadvantages. The conclusions provide an outlook on the subsequent research of the nonlinear energy sink technology, such as the introduction of piezoelectric materials with high energy density, the benefits of balanced vibration suppression and harvesting of vibration energy, and the self-tuning of parameters in complex environments. It provides a powerful reference for the popularization and application of energy harvesting technology based on nonlinear energy sinks.

Simulation study of ZnO nanorod geometry for the development of high-performance tactile sensors and energy harvesting devices

ZnO exhibits an excellent piezoelectric response and can transduce mechanical energy into electrical signals by applying pressure. In particular, vertically aligned ZnO nanorods were thought to be of great importance because of their higher value of piezoelectric coefficient along the z-direction. In this study, various geometries of ZnO nanorods are explored and their effect on the strength of piezoelectric output potential is simulated using COMSOL Multiphysics software. The simulation results show that out of many geometries and inclinations of ZnO nanorods, the highest piezoelectric output is demonstrated by the inclined ZnO nanorods due to the application of higher torque force or shear stress in similar applied force. The high torque force or shear stress at 60° orientation and optimized contributions from all the piezoelectric coefficients resulted in a high piezoelectric output potential close to 215 mV which is much higher than the vertically aligned ZnO nanorod which is approximately 25 mV.

Mechanical Vibration Energy Harvesting and Vibration Monitoring Based on Triboelectric Nanogenerators

Mechanical equipment is ubiquitous in industrial production, and the vibration energy generated by its operation usually cannot be effectively harvested, resulting in huge energy waste. Meanwhile, real‐time monitoring of machine operation can be achieved by collecting vibration information. Indeed, vibration energy harvesting and vibration monitoring are of great significance for the development of green energy and machine fault diagnosis. As an emerging power generation technology, triboelectric nanogenerator (TENG) has shown extraordinary potential in the field of vibration energy harvesting and vibration monitoring. First, the theoretical basis, working modes, and triboelectric materials are described. Then, TENG devices for vibration energy harvesting are classified and introduced based on the structural characteristics, and the main advantages and disadvantages are compared. Furthermore, the current research progress of a self‐powered vibration monitoring system based on TENG is introduced. Finally, the shortcomings of triboelectric nanogenerators in this field are analyzed and summarized, and future research directions and application scenarios are prospected.