Origin of the contact force-dependent response of triboelectric nanogenerators

Min, G., Xu, Y. , Cochran, P., Gadegaard, N. , Mulvihill, D. M. and Dahiya, R. (2021) Origin of the contact force-dependent response of triboelectric nanogenerators. Nano Energy, 83, 105829. (doi: 10.1016/j.nanoen.2021.105829)

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Abstract

Triboelectric nanogenerators (TENGs) have attracted significant interest as the alternative source of renewable energy. Their performance is believed to depend on the contact force, but its origin is yet to be established. Herein, we show that the origin lies in the real contact area Ar, probed with novel experiments specifically designed for this purpose. The open circuit voltage Voc, short circuit current I8c and Ar for a TENG, having two nominally flat tribo-contact surfaces, were found to increase with contact force/pressure. The Ar is notably small at low pressures (0.25% at 16 kPa) that are typically experienced in wearable applications. However, it increases 328 fold to as much as 82% when it saturates beyond about 1.12 MPa pressure - achievable for impact with ocean waves. Critically, Voc and I8c saturate at the same contact pressure as Ar suggesting that electrical output follows the evolution of the Ar. Assuming that tribo-charges can only transfer across the interface at areas of real contact, it follows that an increasing Ar with contact pressure should produce a corresponding increase in the electrical output. These results underline the importance of accounting for real contact area in TENG design to boost their performance, the distinction between real and nominal contact area in tribo-charge density definition, and the possibility of using TENGs as a self-powered pressure/load sensors. Crucially, the results indicate that the large contact pressures, readily available in applications such as road-tyre contact and wave energy, alone could be enough to boost the performance, thus avoiding the need for costly surface engineering to increase Ar.

Item Type:Articles
Additional Information:This work is supported in part by Engineering and Physical Sciences Research Council (EPSRC) through Engineering Fellowship for Growth (EP/M002527/1 and EP/R029644/1) and the Leverhulme Trust through Project Grant “Fundamental mechanical behavior of nano and micro structured interfaces” (RPG-2017-353).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Min, Guanbo and Dahiya, Professor Ravinder and Mulvihill, Dr Daniel and Xu, Dr Yang and Gadegaard, Professor Nikolaj
Creator Roles:
Xu, Y.Methodology, Conceptualization, Software, Validation, Formal analysis, Visualization, Investigation
Gadegaard, N.Supervision, Writing – review and editing, Funding acquisition
Mulvihill, D.Supervision, Conceptualization, Resources, Writing – original draft, Writing – review and editing, Project administration, Funding acquisition
Dahiya, R.Conceptualization, Funding acquisition, Resources, Writing – original draft, Writing – review and editing, Funding acquisition, Project administration, Supervision
Min, G.Investigation, Methodology, Software, Validation, Formal analysis, Visualization, Writing – original draft
Authors: Min, G., Xu, Y., Cochran, P., Gadegaard, N., Mulvihill, D. M., and Dahiya, R.
College/School:College of Science and Engineering
College of Science and Engineering > School of Engineering > Biomedical Engineering
College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Nano Energy
Publisher:Elsevier
ISSN:2211-2855
ISSN (Online):2211-3282
Published Online:26 January 2021
Copyright Holders:Copyright © 2021 Elsevier Ltd.
First Published:First published in Nano Energy 83:105829
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
170185Engineering Fellowships for Growth: Printed Tactile SKINRavinder DahiyaEngineering and Physical Sciences Research Council (EPSRC)EP/M002527/1ENG - Electronics & Nanoscale Engineering
301728Engineering Fellowships for Growth: Printed Tactile SKINRavinder DahiyaEngineering and Physical Sciences Research Council (EPSRC)EP/R029644/1ENG - Electronics & Nanoscale Engineering
302858Fundamental Mechanical Behaviour of Nano and Micro Structured InterfacesDaniel MulvihillLeverhulme Trust (LEVERHUL)RPG-2017-353ENG - Systems Power & Energy