Flexible Lead-Free Piezoelectric Composite Materials for Energy Harvesting Applications

Vincent L. Stuber*, Daniella B. Deutz, James Bennett, David Cannel, Dago M. de Leeuw, Sybrand van der Zwaag, Pim Groen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

38 Citations (Scopus)
132 Downloads (Pure)


Vibrational piezoelectric energy harvesters are being investigated to replace batteries in embedded sensor systems. The energy density that can be harvested depends on the figure of merit, d33g33, where d33 and g33 are the piezoelectric charge and voltage coefficient. Commonly used piezoelectric materials are based on inorganic ceramics, such as lead zirconium titanate (PZT), as they exhibit high piezoelectric coefficients. However, ceramics are brittle, leading to mechanical failure under large cyclic strains and, furthermore, PZT is classified as a Substance of Very High Concern (SVHC). To circumvent these drawbacks, we fabricated quasi 1–3 potassium sodium lithium niobate (KNLN) ceramic fibers in a flexible polydimethylsiloxane (PDMS) matrix. The fibers were aligned by dielectrophoresis. We demonstrate for the structured composites values of d33g33 approaching 18 pm3 J−1, comparable to that of state-of-the-art ceramic PZT. This relatively high value is due to the reduced inter-particle distance in the direction of the electric field. As a confirmation, the stored electrical energy for both material systems was measured under identical mechanical loading conditions. The similar values for KNLN/PDMS and PZT demonstrate that environmentally friendly, lead-free, mechanically compliant materials can replace state-of-the-art environmentally-less-desirable ceramic materials in piezoelectric vibrational energy harvesters.

Original languageEnglish
Pages (from-to)177-185
Number of pages9
JournalEnergy Technology
Issue number1
Publication statusPublished - 2019

Bibliographical note

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.


  • alkaline niobates
  • dielectrophoresis
  • energy harvesting
  • lead-free piezoelectric materials
  • quasi 1–3 composites
  • quasi 1-3 composites


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