• Enhancing

    Accepted author manuscript, 1 MB, PDF-document


In this study, the influence of Li substitution on the piezoelectric performance of lead-free K0.5Na0.5NbO3 (KNN)-epoxy composites is explored. KNN piezoceramic particles modified with 0-12 mol% of Li are prepared via a double calcination technique, resulting in a perovskite particulate which transitions from an orthorhombic to tetragonal crystal structure between 6 and 9 mol% of Li, and contains a minor nonperovskite second phase from 6 mol%. A cuboid particle morphology is evident in all cases, though tetragonal KNN-based particles have formed with serrated edges and fractures. The particles are dispersed at 10 vol% in an epoxy matrix to develop both random and dielectrophoretically structured (K,Na,Li)NbO3-epoxy composites. The dielectric constant of the composites appears almost independent of Li content, while the piezoelectric charge constant of structured composites peaks before the polymorphic phase transition, at 3 mol% of Li. The peak in performance can be attributed to the increased primary particle size of the composition in combination with its single phase orthorhombic crystal structure. The enhancement of the energy harvesting figure of merit, derived from substituting 3 mol% of Li in the KNN particulate, makes these composites an interesting choice for flexible energy generators.

Original languageEnglish
Pages (from-to)1108–1117
Number of pages10
JournalJournal of the American Ceramic Society
Issue number3
Publication statusE-pub ahead of print - 2016

    Research areas

  • Energy harvesting, Lead-free ceramics, Piezoelectric materials/properties, Sensors

ID: 12015424