High-k dielectric screen-printed inks for mechanical energy harvesting devices
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
There are a range of promising applications for devices that can convert mechanical energy from their local environment into useful electrical energy. Here, mechanical energy harvesting devices have been developed to scavenge low-frequency energy from regular biomotion such as joint movement and heel strike. Specifically, these harvesters exploit novel printed nanocomposite dielectric inks in combination with commercially available conductive elastomers to develop a low cost, high performance embodiment of a variable capacitance mechanism device. The filler of the nanocomposite dielectric ink, consists of high-k dielectric nanoparticles (barium titanate and strontium doped barium titanate) functionalised with poly(methyl methacrylate) to improve the interface with the epoxy matrix. Characterisation by thermogravimetric analysis coupled to mass spectrometry and X-ray photoelectron spectroscopy confirmed the successful covalent grafting of up to ca. 16 wt% poly(methyl methacrylate) onto the dielectric nanoparticle surfaces, with a thickness of approximately 14 nm, measured by transmission electron microscopy. The dielectric inks were screen printed onto copper-polyimide foils, resulting in large area and flexible five to twenty-micron thick films with dielectric constants up to 45. Nanoparticle polymer functionalisation improved the homogeneity and stability of the inks. Using these screen-printed dielectrics with the commercial conductive elastomer, the mechanical energy harvester prototype demonstrated high mechanical cycling stability and low leakage current. It provided a promising power density of 160 μW cm−3, at low frequency (0.5 Hz), over a 1000 cycles, making the device suitable for wearable applications. This type of harvester has two advantages over the state of the art: it is mechanically flexible for integration into wearables and can be produced at low cost with printing methods.
Date Issued
2022-02-07
Date Acceptance
2022-01-01
Citation
Materials Advances, 2022, 3 (3), pp.1780-1790
ISSN
2633-5409
Publisher
The Royal Society of Chemistry
Start Page
1780
End Page
1790
Journal / Book Title
Materials Advances
Volume
3
Issue
3
Copyright Statement
© 2022 The Author(s). Published by the Royal Society of Chemistry Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
License URL
Subjects
BARIUM-TITANATE
COMPOSITES
CONDUCTIVITY
CONSTANT
DENSITY
FILLER
Materials Science
Materials Science, Multidisciplinary
POLY(VINYLIDENE FLUORIDE)
POLYMER NANOCOMPOSITES
ROUTE
Science & Technology
STORAGE
Technology
Publication Status
Published
Date Publish Online
2022-01-08