Advanced composites based on relaxor-ferroelectric single crystals: from electromechanical coupling to energy-harvesting applications

Abstract

Domain-engineered relaxor-ferroelectric single crystals with compositions near the morphotropic phase boundary are considered as a key component for modern high-performance piezo-active composites. The advantages of using the relaxor-ferroelectric single crystals of solid solutions of (1 − x)PbIJMg 1/3 Nb 2/3 )O 3 − xPbTiO 3 and (1 − y)Pb(Zn 1/3 Nb 2/3 )O 3 − yPbTiO 3 in piezo-active composites of 2-2 and 1-3 configurations are discussed by taking into account the complex relationships between the outstanding properties of the components and the effective parameters of the composite structure as a whole. Examples of their high piezoelectric activity, strong electromechanical coupling, large piezoelectric anisotropy, and large hydrostatic parameters of the composites demonstrate how the relaxor-ferroelectric single-crystal component improves the effective parameters and promotes the formation of non-monotonic volume-fraction dependences of particular effective parameters that are of interest for a variety of piezotechnical applications, such as transducers, sensors, hydrophones, and energy-harvesting devices. CrystEngCommThis journal is

1‐3‐Type Composites Based on Ferroelectrics: Electromechanical Coupling, Figures of Merit, and Piezotechnical Energy‐Harvesting Applications

“…Composites based on ferroelectrics (FEs) are heterogeneous materials that belong to a group of active dielectrics and form an important group of modern smart materials. This group is vast due to the large number of components that may be used in the composites and these components have a strong influence on the physical properties, electromechanical coupling, and energy‐harvesting characteristics . The piezoactive components that are often used to manufacture composites with predictable properties include FE ceramics and domain‐engineered single crystals (SCs) that exhibit important piezoelectric properties in their poled state.…”

“…This group is vast due to the large number of components that may be used in the composites and these components have a strong influence on the physical properties, electromechanical coupling, and energy‐harvesting characteristics . The piezoactive components that are often used to manufacture composites with predictable properties include FE ceramics and domain‐engineered single crystals (SCs) that exhibit important piezoelectric properties in their poled state. Undoubtedly, the piezoelectric properties and electromechanical coupling are of interest due to the opportunities to convert mechanical energy into electrical energy and vice versa .…”

“…This opens up a variety of possibilities to employ advanced piezoactive composites as elements for energy‐harvesting devices . A number of piezoactive composites are of significant interest due to their ability to vary and tailor the microgeometry, effective piezoelectric properties, their anisotropy, hydrostatic, energy‐harvesting, and other parameters over a wide range …”

“…The connectivity of the composite based on FE is crucial for influencing the piezoelectric response and electromechanical coupling . Particular examples that have been experimentally studied in recent decades include composites with connectivities such as 1‐3, 2‐2, 0‐3, 3‐1, 3‐2, and 3‐3 . In these composites, at least one (first) component is FE and this often influences the effective properties of the composite to a significant extent.…”

“…A modification of the matrix and a formation of the composite structure therein (see insets 3–5 in Figure ) leads to changes in the effective properties of the composite that can be termed a “1‐3‐type composite”. These changes lead to improvement of specific parameters of the 1‐3‐type composite in comparison to its conventional 1‐3 equivalent.…”