Modelling and fabrication of porous sandwich layer barium titanate with improved piezoelectric energy harvesting figures of merit

Ellingford

et al. 2019

Adv Funct Materials

111

Dielectric elastomers are of interest for actuator applications due to their large actuation strain, high bandwidth, high energy density, and their flexible nature. If future dielectric elastomers are to be used reliably in applications that include soft robotics, medical devices, artificial muscles and electronic skins, there is a need to design devices that are tolerant to electrical and mechanical damage. In this paper, we provide the first report of self-healing of both electrical breakdown and mechanical damage in dielectric actuators using a thermoplastic methyl thioglycolate modified styrene-butadiene-styrene (MGSBS) elastomer. The self-healing functions are examined from the material to device level by detailed examination of the healing process, and characterisation of electrical properties and actuator response before and after Complete Manuscript

Section: Modeling Of Self-healing Mgsbs Elastomer Before and After Brmentioning

confidence: 99%

Electrical and Mechanical Self‐Healing in High‐Performance Dielectric Elastomer Actuator Materials

Ellingford

et al. 2019

Adv Funct Materials

111

“…However, when pores with a significantly lower permittivity than the bulk ferroelectric are introduced into the microstructure, the applied electric field concentrates in the low-permittivity pore region, which leads to an inhomogeneous electric field distribution throughout the structure [12,[23][24][25][26]. The fields are reported to be particularly inhomogeneous close to pore-ceramic interfaces, where low-field regions exist on boundaries aligned parallel to the poling field Ef vector, and high-field regions occur perpendicular to the Ef vector [27].…”

Section: Introductionmentioning

confidence: 99%

Understanding the effect of porosity on the polarisation-field response of ferroelectric materials

et al. 2018

Self Cite

This paper combines experimental and modelling studies to provide a detailed examination of the influence of porosity volume fraction and morphology on the polarisation-electric field response of ferroelectric materials.The broadening of the electric field distribution and a decrease in the electric field experienced by the ferroelectric ceramic medium due to the presence of low-permittivity pores is examined and its implications on the shape of the hysteresis loop, remnant polarisation and coercive field is discussed. The variation of coercive field with porosity level is seen to be complex and is attributed to two competing mechanisms where at high porosity levels the influence of the broadening of the electric field distribution dominates, while at low porosity levels an increase in the compliance of the matrix is more important. This new approach to understanding these materials enables the seemingly conflicting observations in the existing literature to be clarified and provides an effective approach to interpret the influence of pore fraction and morphology on the polarisation behaviour of ferroelectrics. A new general rule to describe the relationship between the polarisation and porosity is also proposed. Such information provides new insights in the interpretation of the physical properties of porous ferroelectric materials to inform future effort in the design of ferroelectric materials for piezoelectric sensor, actuator, energy harvesting, and transducer applications.

“…Although grain size [140,141] and oxygen activity [142,143] were found to play a significant role in piezoelectric properties and microstructures of BaTiO 3 ceramics, it is difficult to determine the optimal conditions experimentally. [147] Huang and Gao [148] investigated the temperature-induced domain switching and stress concentration of multilayer ferroelectric devices based on a phase field approach and finite element method. [144] Narita et al [145] developed the phase field simulation framework to study the effects of grain size and oxygen vacancy density on the poling of unpoled BaTiO 3 polycrystals and on the piezoelectric coefficient and permittivity of poled BaTiO 3 polycrystals.…”

Section: Ferroelectric/piezoelectric Behaviormentioning

confidence: 99%

A Review on Piezoelectric, Magnetostrictive, and Magnetoelectric Materials and Device Technologies for Energy Harvesting Applications

2017

In the coming era of the internet of things (IoT), wireless sensor networks that monitor, detect, and gather data will play a crucial role in advancements in public safety, human healthcare, industrial automation, and energy management. Batteries are currently the power source of choice for operating wireless network devices due to their ease of installation; however, they require periodic replacement due to capacity limitations. Within the scope of the IoT, battery maintenance of the trillion sensor nodes that may be implemented will be practically infeasible from environmental, resource, and labor cost perspectives. In considering individual self-powered sensor nodes, the idea of harvesting energy from ambient vibrations, heat, and electromagnetic waves has recently triggered noticeable research interest in the academic community. This paper gives an overview of energy harvesting materials and systems. Three main categories are presented: piezoelectric ceramics/polymers, magnetostrictive alloys, and magnetoelectric (ME) multiferroic composites. State-of-the-art harvesting materials and structures are presented with a focus on characterization, fabrication, modeling and simulation, and durability and reliability. Some perspectives and challenges for the future development of energy harvesting materials are also highlighted.