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High-performance PZT-based Stretchable Piezoelectric Nanogenerator
摘要： Stretchable piezoelectric nanogenerators (SPNG) are highly desirable for power supply of flexible electronics. Piezoelectric composite material is the most effective strategy to render piezoelectric nanogenerators stretchable. However, the generated output performance is unsatisfactory due to the low piezoelectric phase proportion. Here we demonstrate a high-performance Pb(Zr0.52Ti0.48)O3 (PZT) -based stretchable piezoelectric nanogenerator (HSPG). The proposed HSPG exhibits excellent output performance with a power density of ~81.25μW/cm3, dozens of times higher than previously reported results. Mixing technique, instead of conventional stirring technology, is used to incorporate PZT particles into solid silicone rubber. The filler distribution homogeneity in matrix is thus remarkably improved, allowing higher filler composition. The PZT proportion in composite can be increased to 92wt% with satisfactory stretchability of 30%. Based on the excellent electrical and mechanical properties, the proposed HSPG can be attached to human body to harvest body kinetic energy with multiple deformation modes. The obtained energy can be used to operate commercial electronics or be stored into a capacitor. Therefore, our HSPG has great potential application in powering flexible electronics.
关键词： energy harvesting,PZT,Piezoelectric composite,stretchable nanogenerator
更新于2025-11-21 11:18:25
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Tailored nanocomposite energy harvesters with high piezoelectric voltage coefficient through controlled nanowire dispersion
摘要： Composites composed of piezoelectric nanomaterials dispersed in a flexible polymer have emerged as promising materials for highly durable and flexible energy harvesters and sensors. Although piezoelectric materials in their bulk form have a high electromechanical coupling coefficient and can efficiently convert mechanical energy to electrical energy, the ceramic form has low fracture toughness and thus they are limited in certain applications due to difficulty in machining and conforming to curved surfaces. Recently, additive manufacturing processes such as direct write, have been developed to incorporate piezoelectric nanowires into a polymer matrix with controlled alignment to realize printed piezoelectrics. Given the multiphase structure of a nanocomposite, it is possible to control the material structure such that the piezoelectric coupling and dielectric properties can be varied independently. In this paper, experimentally validated finite element (FE) and micromechanics models are developed for calculation and optimization of the piezoelectric voltage coefficient, g31, of a nanocomposite. It is shown that by using high aspect ratio nanowires with controlled alignment, the piezoelectric coupling can be disproportionately increased with respect to the dielectric constant which yields a g31 coefficient that can be enhanced more than seven times compared to the bulk piezoelectric material. Moreover, it is demonstrated that the use of high aspect ratio nanowires in the energy harvester resulted in significant improvement on the output electrical power of an energy harvester.
关键词： Energy harvesting,Nanowires,Finite element modeling (FEM),Voltage coefficient,Piezoelectric,The Mori-Tanaka method,Direct write,Nanocomposite
更新于2025-11-14 17:28:48
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A Wide Temperature Insensitive Piezoceramics for High-Temperature Energy Harvesting
摘要： One of the key challenges in the development of high-temperature energy harvesting (HTEH) technology is to clarify the relationship between temperature-dependent material parameters and device power generation capabilities. However, at present, the research on temperature stability of piezoceramics mainly relies on thermal annealing technology, which cannot follow the actual temperature dependence of the piezoelectricity, and it is even more difficult to predict the temperature stability of HTEH. To shed light on this field, here, (1-x)BiScO3-xPbTiO3 system was chosen for building HTEH material, and the temperature dependent electrical parameters, such as d33, εr, and g33, have been measured by multiple in-situ techniques. It was found that the synergistic effect of d33 and εr with temperature helps to obtain a stable g33 value in a wide temperature range. Moreover, in the mode of the cantilever-type energy harvester, a stable output voltage was obtained at x=0.64 harvester with less than 20% change over a broad temperature range of 100-250 oC, and it was verified that the temperature stability of g33 is crucial to the operation stability of HTEH devices.
关键词： in-situ techniques,piezoelectric materials/properties,energy harvesting,thermal properties
更新于2025-11-14 17:28:48
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A dual-band efficient circularly polarized rectenna for RF energy harvesting systems
摘要： A multilayered circularly polarized (CP), dual-band, stacked slit-/slotted-patch antenna with compact size and with compact rectifier is offered for RF energy harvesting systems. The compact dual-band CP antenna size is able to achieve by stacking slotted-circular-patch (SCP) on the substrate above the tapered-slit-octagon patch (TSOP). Dual-band CP radiation is realized by stacking the SCP on the TSOP and the microstrip feedline with metallic-via to SCP. Eight-tapered-slit with length difference of 6.25% are embedded along the octagonal directions symmetrically on the TSOP from the patch's center and two unequal size circular slots are embedded in diagonal axis onto SCP to produce dual-orthogonal modes with almost equal magnitude for CP waves. The designed antenna is realized measured gain of greater than 5.2 dBic across the band (0.908-0.922 GHz) with maximum gain of 5.41 dBic at 0.918 GHz and gain of greater than 6.14 dBic across the band (2.35-2.50 GHz) with maximum gain of 7.94 dBic at 2.485 GHz. An overall antenna volume is 0.36λo × 0.36λo × 0.026λo (λo is free space wavelength at 0.9 GHz). A compact composite right-/left-handed (CRLH) based rectifier with dual-band at 0.9 and 2.45 GHz is designed, prototyped, and measured. The right-handed (RH) part of the CRLH transmission line (TL) is formed by a microstrip line. The left-handed (LH) part of the CRLH-TL is formed by lumped components. The measured RF-DC conversion efficiency is 43% at 0.9 GHz and 39% at 2.45 GHz with rectifier size of 0.18λo × 0.075λo × 0.0002λo at 0.9 GHz.
关键词： slotted-patch,stacked antenna,energy harvesting,rectenna,rectifier,circular polarization,dual-band
更新于2025-09-23 15:23:52
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Multiphysics vibration FE model of piezoelectric macro fibre composite on carbon fibre composite structures
摘要： This paper presents a finite element (FE) model developed using commercial FE software COMSOL to simulate the multiphysical process of piezoelectric vibration energy harvesting (PVEH), involving the dynamic mechanical and electrical behaviours of piezoelectric macro fibre composite (MFC) on carbon fibre composite structures. The integration of MFC enables energy harvesting, sensing and actuation capabilities, with applications found in aerospace, automotive and renewable energy. There is an existing gap in the literature on modelling the dynamic response of PVEH in relation to real-world vibration data. Most simulations were either semi-analytical MATLAB models that are geometry unspecific, or basic FE simulations limited to sinusoidal analysis. However, the use of representative environment vibration data is crucial to predict practical behaviour for industrial development. Piezoelectric device physics involving solid mechanics and electrostatics were combined with electrical circuit defined in this FE model. The structure was dynamically excited by interpolated vibration data files, while orthotropic material properties for MFC and carbon fibre composite were individually defined for accuracy. The simulation results were validated by experiments with < 10% deviation, providing confidence for the proposed multiphysical FE model to design and optimise PVEH smart composite structures.
关键词： Energy harvesting,Multiphysics,FE,CRFP,MFC,COMSOL
更新于2025-09-23 15:23:52
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Enhancing pyroelectric properties in (Pb1-1.5La )(Zr0.86Ti0.14)O3 ceramics through composition modulated phase transition
摘要： Currently, there is an urgent need of extraordinary comprehensive pyroelectric materials for the wide application in detectors and energy harvesters. In this study, the (Pb1-1.5xLax)(Zr0.86Ti0.14)O3 (abbreviated as PLZT, x = 0.02, 0.03, 0.04 and 0.05) ceramics located in ferroelectric-antiferroelectric (FE-AFE) phase boundary were designed and synthesized by using conventional solid-state reaction method. The microstructures, phase structures, dielectric, ferroelectric, thermal depolarization and pyroelectric properties of the PLZT ceramics with different La content were investigated thoroughly. The XRD results show that the PLZT ceramics change from FE phase to AFE phase with increasing La content. The significant improvement of pyroelectric coefficient and figures of merit (FOMs) are achieved in the PLZT ceramics with the increase in La content because of the increased metastable ferroelectric phase under the application of electric field. The (Pb0.955La0.03)(Zr0.86Ti0.14)O3 (x = 0.03) ceramic exhibits not only high of and high depolarization temperature (Td) of 179 ℃ but also excellent FOMs with ???? = , ???? = , and ???? = 3 47 5 ???? ? . In addition, the highest of is achieved in (Pb0.94La0.04)(Zr0.86Ti0.14)O3 (x = 0.04) ceramic. These results demonstrate that the PLZT ceramics of x = 0.03 and 0.04 are promising candidates for pyroelectric applications.
关键词： ferroelectric/antiferroelectric material,energy harvesting,(Pb,La)(Zr,Ti)O3 ceramics,pyroelectric properties
更新于2025-09-23 15:23:52
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Online Policies for Energy Harvesting Receivers With Time-Switching Architectures
摘要： In the real-world, it is virtually impossible to have non-causal knowledge of future events. Research in energy harvesting (EH) systems that assumes knowledge of future energy arrivals falls short in terms of practical utility, pointing to the need for online strategies. In addition, the modeling and analysis for EH transmitter and receiver are inherently different. Compared with EH transmitter, EH receiver has received less attention. In this paper, we formulate Markov decision process problems and perform online optimization to maximize the number of bits decoded for an EH receiver with a time-switching architecture, which harvests energy from both a dedicated transmitter and other sources. We consider both infinite and finite horizon scenarios. For the infinite horizon, we provide an upper bound on the average expected reward. Then, we find an optimal policy which can achieve performance arbitrarily close to this bound. For the finite horizon, we first provide a policy obtained from standard backward induction with space quantization. Its performance can be close to optimal online performance as the number of quantization intervals increases, at the cost of relatively high computational complexity. Then, by carefully restricting the state space, we present a computationally efficient policy, which achieves comparatively good performance.
关键词： Infinite horizon,Markov decision process,Energy harvesting,Online optimization,Finite horizon
更新于2025-09-23 15:23:52
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Metal–Insulator–Metal Diodes: A Potential High Frequency Rectifier for Rectenna Application
摘要： Metal–insulator–metal (MIM) diodes are among the most promising candidates for applications in the high frequency regime. Owing to the tunneling dominant current conduction mechanism, they facilitate femtosecond fast switching time, which has drawn great research attention for many potential high-speed applications and especially as a rectifier in rectenna based energy harvesting. Since its advent in the early 1960s, a lot of development has occurred in various aspects of design, fabrication and characterization of MIM diodes for rectenna applications. In this work, a detailed study on MIM diodes is conducted emphasizing the advancements in design and fabrication of MIM diodes and future challenges from the point of view of their application in rectennas. In addition, the fabrication and characterization of a graphene (Gr) based Al/AlOx/Gr MIM diode are also presented herein, exhibiting highly asymmetric current–voltage characteristics with large current density and a good degree of nonlinearity. An asymmetricity exceeding 2500 and the corresponding current density up to (cid:2) 1 A/cm2 were obtained at a voltage bias of 1 V. The peak nonlinearity was (cid:2) 3.8, whereas the zero bias resistance was as low as (cid:2) 600 X. These performance metrics are highly desirable for rectification operation and hence the as-fabricated Al/AlOx/Gr MIM diode holds great promise for its potential use as a rectifying element in rectennas.
关键词： MIM diode,terahertz,energy harvesting,tunneling
更新于2025-09-23 15:23:52
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Surface potential tailoring of PMMA fibers by electrospinning for enhanced triboelectric performance
摘要： Triboelectric generators rely on contact-generated surface charge transfer between materials with different electron affinities to convert mechanical energy into useful electricity. The ability to modify the surface chemistry of polymeric materials can therefore lead to significant enhancement of the triboelectric performance. Poly(methyl methacrylate) (PMMA) is a biocompatible polymer commonly used in medical applications, but its central position on the triboelectric series, which empirically ranks materials according to their electron-donating or electron accepting tendencies, renders it unsuitable for application in triboelectric generators. Here, we show that the surface potential of PMMA fibers produced by electrospinning can be tailored through the polarity of the voltage used during the fabrication process, thereby improving its triboelectric performance, as compared to typically spin-coated PMMA films. The change in surface chemistry of the electrospun PMMA fibers is verified using X-ray photoelectron spectroscopy, and this is directly correlated to the changes in surface potential observed by Kelvin probe force microscopy. We demonstrate the enhancement of triboelectric energy harvesting capability of the electrospun PMMA fibers, suggesting that this surface potential modification approach can be more widely applied to other materials as well, for improved triboelectric performance.
关键词： Energy harvesting,Triboelectric generator,Surface chemistry,Kelvin probe force microscopy,Electrospinning,Poly(methyl methacrylate)
更新于2025-09-23 15:23:52
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Internal-field-dependent low-frequency piezoelectric energy harvesting characteristics of in situ processed Nb-doped Pb(Zr,Ti)O3 thin-film cantilevers
摘要： Piezoelectric thin-film-based cantilevers have been investigated for higher energy-harvesting performance with simplified processing steps. Here, a simple in situ film deposition process of heavily Nb-doped lead zirconate titanate (PZT) films, which does not require annealing and poling, has been demonstrated to verify the possibility of use of the resultant films as energy-harvesters specifically for low frequency vibrating sources. The in situ domain formation of the films during the deposition was demonstrated from the apparent shifts of the capacitance-electric field curves, indicating the presence of internal electric fields. The so-called imprint behavior was found to be directly related to the performance of piezoelectric energy harvesting. As an optimal example, 12 mol% Nb-doped cantilever harvesters that showed the largest imprint behavior exhibited the best values of ~19.1 GPa figure-of-merit and ~1436 mWcm?3g?2 power density, which are competitive compared to other reported values.
关键词： Thin films,Cantilevers,Piezoelectric energy harvesting,Nb-doping,PZT
更新于2025-09-23 15:23:52