Aluminum impregnated zinc oxide engineered poly(vinylidene fluoride hexafluoropropylene)-based flexible nanocomposite for efficient harvesting of mechanical energy

Confronting the depletion of fossil fuel energy as well as pollution generated from chemical batteries, associated with the increasing number of electronic equipment and the internet of things, results in a high requirement of lightweight, low cost, sustainable, and durable power devices. Currently, a flexible and self-powered piezoelectric energy harvester (PZEH) is a suitable alternative, which may be easily integrated with small electronics to realize real-time sustainable energy generation. Therefore, a novel PZEH has been fabricated at room temperature (30 degrees C) using Al-doped ZnO (Al@ZnO) incorporated poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) nanocomposites. Al@ZnO enables nucleation of electroactive phase within PVDF-HFP (10PALZO) exhibited polarity at a much higher fraction (FEA] >90%) compared to neat PVDF-HFP (FEA] = 63.8%). Piezoelectric energy harvesting capability of the device has been investigated under gentle repeated human finger tapping. Optimized Al@ZnO-PVDF-HFP composite (with 10 wt% loading)-based PZEH delivered a high value of open-circuit output voltage similar to 22 V. Such high output value infers a good energy conversion efficiency of the device. For further enhancement of the performance of the device, the 10PALZO nanocomposite was placed under a high electric field of 2.4 MVcm(-1) resulting in an open circuit output voltage of similar to 26 V. In addition to that, the proposed nanocomposite exhibits a good energy storage efficiency (10PALZO-P) which further enhanced to 111.2 mu Jcm(-3) (at 1 Hz) after poling under an electric field 2.4 MVcm(-1). This increment in the output value is due to the improved polarization induced by Al@ZnO within the PVDF-HFP matrix. These results highlight that the filler can efficiently maximize the device performance thereby developing new efficient energy harvesting materials

Ferroelectric and Dielectric Properties of ZnFe2O4-Pb(ZrTi)O-3 Multiferroic Nanocomposites

Magnetoelectric composites of zinc ferrite and soft lead zirconate titanate (PZT) having formula 0.5 ZnFe2O4-0.5 PZT were synthesized by sol-gel technique. X-ray diffraction analysis was carried out to confirm the coexistence of individual phase. TEM micrographs were taken to confirm the formation of nanosized powders and SEM micrographs were taken to study the morphology of the sintered pellets. Dielectric and P-E hysteresis loops were recorded, respectively, to confirm the ferroelectric properties of the composites

Phase transition and enhanced magneto-dielectric response in BiFeO3-DyMnO3 multiferroics

This work is partially supported by DST fast track Project No. SR/FTP/PS-16/2009. Dhiren K. Pradhan acknowledges IFN (NSF Grant No. EPS—01002410) for fellowship. The work at UPR was supported by National Science Foundation (NSF DMR 1410869) and Institute for Functional Nanomaterials (IFN).We report systematic studies on crystal structure and magneto-dielectric properties of (1 − x) BiFeO3-x DyMnO3 (0.0 ≤ x ≤ 0.2) nanoceramics synthesized by auto-combustion method. Rietveld refinement of X-ray diffraction data indicates a structural transition from R3c to R3c + Pn21a at x = 0.1. Field emission scanning electron micrographs display a decrease in grain size with increase in x. The presence of dielectric anomalies around antiferromagnetic transition temperature implies the magnetoelectric coupling. Dielectric measurements showed decrease in magnetic ordering temperature with increasing x in agreement with differential scanning calorimetry results. A significant increase in magnetization has been found with increasing DyMnO3 substitution. Magneto-impedance spectroscopy reveals a significant change (∼18%) in dielectricpermittivity at H = 2 T for x = 0.2.Peer reviewe

Preparation and Evaluation of Structural, Microstructural and Electrical Properties of Polymer-Ceramic Composite

Ferroelectric ceramic-polymer composites are considered as promising materials for applications in sensors, actua-tors and hydrophones. They are attractive for application as they exhibit high piezoelectric and pyroelectric res-ponse, low acoustic impedance matching with water and human skin and their properties can be tailored to various requirements. The advantage of composites over conventio-nal ceramics is that they have better mechanical shock resistance and more durable. The simplest ceramic-polymer composite is that which consists of ceramic particles dispersed in a polymer matrix (0-3 connectivity). The present investigation concentrates in the preparation and characterization of 65 PMN-35 PT-PVDF composites

Surface Modified Zinc Ferrite (ZF) / Polyvinylidene fluoride (PVDF) Nanocomposite: A Novel Material for Application as a Flexible Energy Harvester

A simple cost effective method to enhance the electroactive phase of PVDF by developing nanocomposite with surface modified ascorbic acid assisted phase pure Zinc Ferrite (ZF(ASC)) has been demonstrated. High energy storage density (0.271 J/cm(3)) and piezoelectric energy harvesting performance (similar to 2.20 V output voltage with single finger impact of human touch) was obtained after polling 1.5 wt% surface modified Zinc Ferrite nanoparticle loaded nanocomposite. There is a possibility of transformation of nonpolar phase to electroactive phase in PVDF which has occurred due to the orientation effect of -CH2 bond in PVDF over the surface modified nanoparticle. (C) 2017 Elsevier Ltd. All rights reserved

Charge Compensation Mechanism and Multifunctional Properties of Bi1-xBaxFeO3 (x=0, 0.05, 0.1) Ceramics

The charge compensation mechanism of Ba2+ ion doped BiFeO3 (BFO) has been studied here in detail. The most common problem of high leakage current of ceramic BFO was noticeably resolved by significant reduction of charge defects through Ba2+ doping. The leakage current density of Bi1-xBaxFeO3 (x = 0, 0.05, 0.1) was found to be reduced to similar to 3.13 x 10(-8) A cm(-2) for x = 0.1 from a value of 2.26 x 10(-4) A cm(-2) for x = 0 at an applied field of 500 V cm(-1). This reduction of leakage current was caused by the reduction of charge defects which was verified through the X-ray photoelectron spectroscopy (XPS). The dielectric and ferroelectric properties of undoped and Ba2+ doped BFO were also studied here explicitly and correlated with charge compensation mechanism. The structural and vibrational characterization proved the phase pure formation and the presence of metal-oxide bonds. The optical characterization showed the reduction in energy band gap with increased Ba2+ doping in BFO (2.18, 1.71 and 1.56 eV for x = 0, 0.05 and 0.1, respectively). Another common problem of BFO, namely low remanent magnetization, was also significantly resolved through Ba2+ doping in it and the strong antiferromagnetic BFO started showing weak ferromagnetic nature with increased doping concentration. (C) 2022 The Electrochemical Society (''ECS''). Published on behalf of ECS by IOP Publishing Limited

Improved dielectric and touch sensing performance of surface modified zinc ferrite (ZF)/Polyvinylidene fluoride (PVDF) composite

The continuous demand of fabricating self-powered body implantable devices have raised the development of new lead free polymer-ceramic composites. Herein, we have fabricated Zinc Ferrite (ZF)/Polyvinylidene Fluoride (PVDF) composite by simple solution casting technique. The inherent difficulty of compatibility between two phases (polymer and ceramic) for homogeneous film was addressed by addition of two different modifiers: Sodium dodecyl sulphate (SDS) and Tetraethyl orthosilicate (TEOS). Similarity in the piezo/ferro electrical properties between the externally poled unmodified nanocomposite with that of the surface modified composites were observed which were basically attributed to higher dispersion of nanoparticles in the polymer matrix and improved interfacial interaction between organic and inorganic matrix. It indicates that a self polarization effect has been induced in the surface modified composites. The mechanism for the interaction between two phases was discussed on the basis of zeta potential results and spectroscopic analysis. Further, external poled MSDS-ZF(C)-PVDF composite offered the highest energy storage density (0.25 Jcm(-3)), whereas poled TEOS modified ZF-PVDF composite exhibited an output open circuit voltage of 2.2 V with power density of 3.7 mu Wcm(-3) under repeated single finger touch. (c) 2017 Elsevier B.V. All rights reserved

Influence of nanoparticle size on nucleation of electroactive phase and energy storage behaviour of zinc ferrite/ poly(vinylidene fluoride) nanocomposite

The incorporation of different size of nanoparticles in polymer matrix plays a dominating role in determining the overall structural, microstructural and electrical properties of the fabricated composites. In this paper, an investigation was done in order to establish the effect of incorporating different size of zinc ferrite (ZF) nanoparticles in poly(vinylidene fluoride) (PVDF) matrix. The incorporated spherical ZF nanoparticle induced nucleation of electroactive phases in PVDF matrix by means of electrostatic interaction between the surface charge of the filler and the dipoles of PVDF. The fraction of nucleated electroactive phases is strongly dependent on the size of the nanoparticles. There is a critical size of the nanoparticle, below which the nucleation efficiency of the filler diminishes as it may be swelled by the polymer macromolecules. On the other hand, if the filler size is too large, there is a possibility of formation of mixed conformation of polar and nonpolar phase. Further, this behaviour was correlated with the electrical response of composite where nanoparticle with the critical radius incorporated PVDF composite, exhibited maximum dielectric and ferroelectric property. Finally, a number of participating dipoles of polymer chain interact with ZF nanoparticle of different size were calculated by a model analysis and were represented schematically

Flexible, hybrid nanogenerator based on Zinc Ferrite nanorods incorporated poly(vinylidene fluoride-co-hexafluoropropylene) nanocomposite for versatile mechanical energy harvesting

Herein, an efficient, low-cost, scalable in-situ poled fabrication strategy to construct a large area, highly sensitive, flexible piezocomposite nanogenerator comprising of rod shaped Zinc Ferrite (ZF-R) and Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) was developed. ZF-R with an average length of 330 nm was synthesized via a facile two-pot hydrothermal method and its PVDF-HFP-based composites with different weight ratio were prepared. Fabricated 3 wt% ZF-R incorporated PVDF-HFP flexible piezocomposite (3H) was used as an effective nanogenerator which could generate an output voltage of 8.5 V and current density similar to 0.5 mu A/cm(2) upon repetitive mechanical stresses. The generated power could enlighten 21 commercial light emitting diodes (LEDs). Furthermore, 3H demonstrated the capability to monitor height with level of accuracy upto +/- 3 cm. Moreover, this flexible hybrid film can scavenge environmental sensations such as air flow (maximum 3.2 V peak to peak voltage) and muscular vibration when integrated with arm, wrist and finger in conjunction with superior integratebility and nontoxicity. Thus, this nanocomposite can be explored for application as ultrasensitive height monitor, mechanical energy scavenger and effective power source for driving portable electronics and wearable devices