IET Nanodielectrics最新文献

{"title":"Frequency-tunable resonant hybrid vibration energy harvester using a piezoelectric cantilever with electret-based electrostatic coupling","authors":"Yue Feng,&nbsp;Zilong Zhou,&nbsp;Haosun Luo,&nbsp;Ruiguo Wang,&nbsp;Yanhui Han,&nbsp;Ying Xiong","doi":"10.1049/nde2.12043","DOIUrl":"10.1049/nde2.12043","url":null,"abstract":"<p>Hybrid vibration energy harvesting technology converts vibration energy into electricity using multiple transduction mechanisms to improve output power. A frequency-tunable resonant hybrid vibration energy harvester using a piezoelectric cantilever with electret-based electrostatic coupling is proposed in this article. The electrostatic coupling including electrostatic force coupling and electrical damping coupling is introduced by an electret film placed below the cantilever, where the electrostatic force acting on the cantilever realises a tunable resonant frequency and additional electrical damping boosts power output. A coupling electromechanical model is derived using Euler–Bernoulli beam theory and Kirchhoff's law. By investigating the static and dynamic stability of cantilever, the maximum electret surface potential is defined to prevent the pull-in phenomenon. The damping of the device is evaluated, and the optimal electret surface potential is determined to obtain the matching of the electrical and mechanical damping for maximum power output. The resonant frequency of hybrid vibration energy harvester can be adjusted in range of 176.1 rad/s by changing the electret surface potential and resistive load. The experimental output power of hybrid vibration energy harvester was 5.2 μW, 27.4 times higher than that of the individual piezoelectric generator. The proposed hybrid vibration energy harvester exhibits a promising potential to power microelectronic devices and wireless sensor network node.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"6 2","pages":"46-56"},"PeriodicalIF":2.7,"publicationDate":"2023-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48510556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the measurement method of polyimide electrical properties for flexible solar wing","authors":"Qian Wang,&nbsp;Shuyue Ma,&nbsp;Sichen Qin,&nbsp;Jiawei Zhang,&nbsp;Rui Liu","doi":"10.1049/nde2.12047","DOIUrl":"10.1049/nde2.12047","url":null,"abstract":"<p>Flexible solar wings with high energy density, lightweight, small size and large deployment area are one of the first choices for next-generation spacecraft. However, the flexible solar wings are subjected to irradiation in space and tensile mechanical stress, which produce the charge accumulation effect and result in electrostatic discharge. It is necessary to establish a test method for the conductivity and space charge behaviour of polyimide under tensile stress. The stress–strain characteristics of polyimide under different tensile stresses are studied by the authors. The longitudinal length-strain characteristics and transverse thickness evolution characteristics under different stresses are also obtained. The results show that the variation of film thickness with tensile force is only about 1% before the yield point. The polyimide films from 50 to 200 μm thick have similar yield and tensile strengths. The ultimate stress of the specimen decreases from approximately 126 to 103 MPa with increasing thickness. The thickness model of polyimide under tensile stress were obtained, which could accurately calculate the voltage amplitude applied on the specimens for measuring the conductivity under different tensile stresses. A basis for investigating the stress–strain characteristics of polyimide films under different tensile stresses are provided, which will facilitate the formulation selection and performance improvement of polyimide for flexible solar wings of spacecraft.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"6 3","pages":"97-104"},"PeriodicalIF":2.7,"publicationDate":"2023-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45397062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced breakdown strength of the BaTiO3/polypropylene nanocomposite film based on the biaxial stretching process","authors":"Ming-Sheng Zheng,&nbsp;Wei-Wei Lu,&nbsp;Xing Yang,&nbsp;Zhi-Min Dang","doi":"10.1049/nde2.12046","DOIUrl":"10.1049/nde2.12046","url":null,"abstract":"<p>The significant progresses of polymer-based nanocomposites with improved dielectric performances are urgently calling for an effect way to realise commercial production. Up to now, the biaxial stretching technology is still a powerful method to produce the high-performance dielectric films applied in the film capacitors due to its full-blown applications. In this work, a classical composite system of BaTiO₃/polypropylene was applied to reveal the connection between the microstructure changes and dielectric properties of the corresponding nanocomposite films in the biaxial stretching process. The permittivity of BT-30 wt% nanocomposite reached 2.8 at 10³ Hz after stretching, and its breakdown strength reached 340 MV/m. In addition, the breakdown strength of BT-10 wt% nanocomposite could even be promoted to 452 MV/m, which was 1.3 times higher than that before stretching. The microstructure test demonstrated that the rearrangement of nanofillers, high crystallinity and the oriented polypropylene crystals were advantageous to the improvement of breakdown strength for the stretched nanocomposite films. Therefore, the application of biaxial stretching technology into the preparation of nanocomposite dielectric film is an enormous potential way for the energy storage film capacitors.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"6 3","pages":"159-164"},"PeriodicalIF":2.7,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12046","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42659676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High temperature energy storage and release properties of polyimide nanocomposites simulated by considering charge trapping effects","authors":"Poxin Wang,&nbsp;Daomin Min,&nbsp;Xiaofan Song,&nbsp;Ziwei Gao,&nbsp;Yutao Hao,&nbsp;Shihang Wang,&nbsp;Wenfeng Liu","doi":"10.1049/nde2.12044","DOIUrl":"10.1049/nde2.12044","url":null,"abstract":"<p>Dielectric energy storage capacitors with excellent high temperature resistance are essential in fields such as aerospace and pulse power. However, common high-temperature resistant polymers such as polyimide (PI) and polyether sulfone have low energy storage densities and energy efficiencies at high temperature, which are greatly limited in practical applications. The polymer nanocomposites prepared by doping modification can regulate the charge injection and transport process, and improve the high-temperature energy storage performance. However, the quantitative relationship between charge injection and charge trapping and the energy storage performance of linear polymer nanocomposites still needs further study. An energy storage and release model considering the charge trapping effects is constructed by the authors. We simulate the high-temperature energy storage properties of polyimide nanocomposite dielectrics (PI PNCs) with different charge injection barriers and trap parameters at 150°C. A triangular voltage is applied to the electrodes at both sides of the PI PNCs, the electric displacement-electric field loop is simulated, and the discharged energy densities and energy efficiencies are calculated. The simulation results are consistent with the experimental results. Increasing the charge injection barrier, deep trap energy and deep trap density can effectively reduce the charge injection and the carrier mobility, thereby improving the discharged energy densities and energy efficiencies of dielectric capacitors. In the case of low charge injection barrier (1.3 eV), with the increase of deep trap energy (0.7–1.5 eV) and deep trap density (1 × 10²¹–1 × 10²⁵ m⁻³), the discharged energy density changes from 0.20 to 1.44 Jcm⁻³, the energy efficiency changes from 9.0% to 99.9%, and the high-temperature energy storage performance improves significantly. This research provides theoretical and model support for the improvement of the high-temperature energy storage performance of nanocomposites.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"6 3","pages":"86-96"},"PeriodicalIF":2.7,"publicationDate":"2023-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48121119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved energy storage property in polyvinylidene fluoride-based multilayered composite regulated by oriented carbon nanotube@SiO2 nanowires","authors":"Na Zhang,&nbsp;Hang Zhao,&nbsp;Chuying Zhang,&nbsp;Shuyan Gao,&nbsp;Tongguang Zhu,&nbsp;Jinbo Bai","doi":"10.1049/nde2.12045","DOIUrl":"10.1049/nde2.12045","url":null,"abstract":"<p>High-performance dielectric capacitors are essential components of advanced electronic and pulsed power systems for energy storage. Because of their high breakdown strength and excellent flexibility, polymer-based capacitors are regarded as auspicious energy storage material. However, the energy storage capacity of polymer-based capacitors is severely limited due to their low polarisation and low dielectric permittivity. The modified Stöber method was used to construct two types of CNT@SiO₂ (CS) one-dimensional core-shell structured nanowires with different shell thicknesses. By integrating the procedures of solution mixing, melt blending, hot-stretching orientation and hot pressing, sandwich-structured poly (vinylidene fluoride) (PVDF)-based composites were fabricated. The CS core-shell nanowires dispersed in the inter-layer serve as electron donors, leading to a high permittivity, while two PVDF outer layers provide the favourable overall breakdown strength. The insulating SiO₂ shell can effectively limit the migration of carriers and keep the dielectric loss at a relatively low level in the composites. The CS/PVDF composite exhibited an enhanced discharged density (~6.1 J/cm³) and breakdown strength (~241 kV/mm) when the interlayer filled with as small as 1 wt% CS nanowires with the SiO₂ shell thickness of 8 nm, which is 203% and 18.7 % higher than pure PVDF (~2.01 J/cm³ at 203 kV/mm), respectively. This research presents a practical strategy for designing and fabricating advanced polymer film capacitor energy storage devices.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"6 1","pages":"19-31"},"PeriodicalIF":2.7,"publicationDate":"2023-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12045","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46193159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic enhancement of dielectric properties of polymer matrix composites by micro-nano bicomponent ceramics and conductive particles","authors":"Dongyi Wu,&nbsp;Yue Zhai,&nbsp;Haiping Xu,&nbsp;Lihe Guo","doi":"10.1049/nde2.12039","DOIUrl":"10.1049/nde2.12039","url":null,"abstract":"<p>Barium titanate (BaTiO₃, BT) was co-doped by solid-state sintering with niobium pentoxide (Nb₂O₅) and cobalt trioxide (Co₃O₄) as dopants. The modified barium titanate containing Nb and Co (BTNC) with larger particle size (0.5–1 μm) and silver powder (Ag) with smaller particle size (25 nm) were co-filled with polyvinylidene fluoride (PVDF) to prepare (BTNC-Ag)/PVDF three-phase composites. The morphology and crystal structure of composites were characterised by scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. SEM shows that when the volume ratio of BTNC and Ag in the composite is 4:1, the two fillers have good dispersion in polymer matrix and could intersperse with each other to reduce voids. XRD patterns display that the filling of BTNC and Ag powders was conducive to promoting the enhancement of the diffraction peaks of <i>β</i> phase and <i>γ</i> phase in PVDF. The dielectric properties of the composites are effectively enhanced through the synergistic effect of the micro-nano bicomponent ceramic BTNC and conductive particles Ag co-filled polymer PVDF. When the volume ratio of filler (BTNC:Ag = 4:1) to matrix PVDF is 2/1, the dielectric properties of the composite are the best, the dielectric constant reaches 134.1 at 10² Hz and the dielectric loss is 0.04.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"6 1","pages":"1-8"},"PeriodicalIF":2.7,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44297968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electric field distribution around asymmetric agglomerate model reconstructed from FIB–SEM images of epoxy nanocomposite","authors":"Kazuma Tagawa,&nbsp;Muneaki Kurimoto,&nbsp;Toru Sawada,&nbsp;Shigeyoshi Yoshida,&nbsp;Takahiro Umemoto,&nbsp;Hirotaka Muto","doi":"10.1049/nde2.12042","DOIUrl":"10.1049/nde2.12042","url":null,"abstract":"<p>This study focussed on determining the electric field distribution formed by asymmetric agglomerates in order to elucidate the mechanism by which large agglomerates reduce the dielectric breakdown strength of nanocomposites. Epoxy nanocomposite sample was prepared by adding 2.5 vol% of TiO₂ nanoparticles with a primary particle size ranging from 30 to 50 nm. The three-dimensional (3D) structure of the epoxy nanocomposites with a thickness of 5 μm was analysed via focussed ion beam and scanning electron microscopy. The 3D reconstruction was performed using 250 observation images, and a 3D model of the particle in the observational range was obtained. The electric field distribution for the 3D model of the agglomerate with the largest size was determined using the finite element method. In addition, we constructed a calculation model that effectively accommodate changes in the direction of the applied electric field. Subsequently, we examined the changes in the maximum electric field intensity around the agglomerate.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"6 1","pages":"9-18"},"PeriodicalIF":2.7,"publicationDate":"2023-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12042","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46659268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resilient electret film-based vibrational energy harvesters with a V-shaped counter electrode","authors":"Xiaoya Yang,&nbsp;Xingchen Ma,&nbsp;Chuan Ding,&nbsp;Gerhard M. Sessler,&nbsp;Heinz von Seggern,&nbsp;Mario Kupnik,&nbsp;Ying Dai,&nbsp;Pengfei He,&nbsp;Xiaoqing Zhang","doi":"10.1049/nde2.12040","DOIUrl":"10.1049/nde2.12040","url":null,"abstract":"<p>Vibrational energy harvesters, which can convert mechanical energy distributed widely in the surrounding environment to electrical energy in a convenient, eco-friendly and sustainable way, have attracted great attention in both academia and industry. In this study, a resilient electret film-based vibrational energy harvester with a V-shaped counter electrode is introduced, simulated and constructed. A negatively charged fluorinated polyethylene propylene (FEP) electret film with a wavy shape was adopted in the devices, achieving simultaneously a stable embedded biased voltage and a large tensile deformation during vibration. The influences of the factors on the performance of the device, including the initial stretching state of the resilient electret film, seismic mass and depth of the V-shape counter electrode, were analyzed comprehensively with finite element simulation and compared to experiments. Further, the structure of the device was optimised for generating a high output power, and a good agreement between the simulation and experimental data was achieved. Additionally, the resonant frequency of the device can be easily tuned between 28 and 68 Hz by merely adjusting the initial stretching state of the wavy FEP electret film, guaranteeing great superiority for broad bandwidth energy harvesting applications. For an optimised energy harvester with a volume of only 15 × 5 × 1.7 mm³ and a tiny seismic mass of 25 mg, and a normalized output power referring to 1 × <i>g</i> (<i>g</i> is the gravity of the Earth) up to 547 μW was obtained at its resonant frequency of 28 Hz. These results demonstrate that such a miniaturised vibrational energy harvester is a promising electrical energy supplier for low-power-consumption electronic devices, in particular in wireless sensor networks.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"6 2","pages":"36-45"},"PeriodicalIF":2.7,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12040","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43269199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rigid/flexible molecular structure-induced polyimide aerogels with ultralow permittivity and thermal insulation properties","authors":"Xiaodi Dong,&nbsp;Baoquan Wan,&nbsp;Lin Qiu,&nbsp;Ming-Sheng Zheng,&nbsp;Jiefeng Gao,&nbsp;Jun-Wei Zha","doi":"10.1049/nde2.12041","DOIUrl":"10.1049/nde2.12041","url":null,"abstract":"<p>A series of high-performance linear and cross-linked polyimide (PI) aerogels with different molecular structures have been successfully synthesised using the freeze-drying process. In this study, the comprehensive regulation of microstructure, thermodynamic, thermal insulation and dielectric properties of PI aerogels are achieved by controlling the rigid/flexible structure and composition of polymerised monomers. The increase in rigidity of PI molecular structure could promote the formation of denser pores, which is beneficial to improve the thermodynamic and thermal insulation properties of aerogels. Notably, the cross-linked PI aerogel prepared by introducing cross-linking agent (tris(4-aminophenyl) amine, [TPA]) into linear PI exhibits high thermal stability (<i>T</i>_<i>d</i>5% &gt; 560°C), excellent ultralow permittivity (<i>ε</i>_<i>r</i> = 1.31, <i>f</i> = 10⁶ Hz) and good thermal insulation property (<i>k</i> = 0.056 W/m · K). This innovative strategy promotes the wider application of the cross-linked polyimide aerogel in the field of integrated circuits and aerospace exploration.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"6 3","pages":"76-85"},"PeriodicalIF":2.7,"publicationDate":"2022-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47440867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal stability of piezoelectricity in polylactide polymers and related piezoelectric minimotor application","authors":"Jinxi Zhang,&nbsp;Yonggui Wang,&nbsp;Junyuan Tian,&nbsp;Xiangchen Xu,&nbsp;Weidong Wang,&nbsp;Kailiang Ren","doi":"10.1049/nde2.12038","DOIUrl":"10.1049/nde2.12038","url":null,"abstract":"<p>Piezoelectric polymers have been widely used in a variety of applications, including tactile sensors, energy harvesting, polymer actuators, and biological devices. In this investigation, we fabricated the PLLA (poly(L-lactic Acid)-based bimorph structures for piezoelectric motor applications. First, a strain measurement setup was established to measure the strain of the PLLA and PDLA film at different temperatures. The effective piezoelectric constants <i>d</i>₁₄ calculated for the PLLA and PDLA films were 10.2 pC/N and 9.4 pC/N, respectively. Furthermore, the PLLA films showed a strong thermostability of piezoelectricity at 130°C. The PLLA bimorph minimotor showed the maximum load of 1.2 g and the maximum torque of 0.019 cN·m. The minimotors were capable of rotating a plastic hemisphere container in the clockwise and counterclockwise directions at 65 V voltage. Due to the light weight, low driving voltage, and thermal stability, the PLLA/PDLA motors show a great promise in future Braille display, robots, and mini-digital camera applications.</p>","PeriodicalId":36855,"journal":{"name":"IET Nanodielectrics","volume":"5 3-4","pages":"132-138"},"PeriodicalIF":2.7,"publicationDate":"2022-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/nde2.12038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43881955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}