Issue 3, 2022

High-k dielectric screen-printed inks for mechanical energy harvesting devices


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.

Graphical abstract: High-k dielectric screen-printed inks for mechanical energy harvesting devices

Supplementary files

Article information

Article type
28 Jul 2021
01 Jan 2022
First published
08 Jan 2022
This article is Open Access
Creative Commons BY license

Mater. Adv., 2022,3, 1780-1790

High-k dielectric screen-printed inks for mechanical energy harvesting devices

H. S. Leese, M. Tejkl, L. Vilar, L. Georgi, H. C. Yau, N. Rubio, E. Reixach, J. Buk, Q. Jiang, A. Bismarck, R. Hahn and M. S. P. Shaffer, Mater. Adv., 2022, 3, 1780 DOI: 10.1039/D1MA00661D

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