Ultrahigh piezoelectricity in lead-free piezoceramics by synergistic design

TLDR: In this article, a synergistic design strategy is proposed to enhance the piezoelectricity in lead-free piezoceramics by flattening the Gibbs free energy density profile, via the coexistence of multiple phases and local structural heterogeneity.

About: This article is published in Nano Energy.The article was published on 2020-10-01 and is currently open access. It has received 85 citations till now. The article focuses on the topics: Piezoelectricity & Piezoelectric coefficient.

Figures

Figure 3 (a) Enlarged {110}p, {111}p, {200}p and {220}p peaks in the XRD patterns of BTSx. (b) phase fraction in BTSx as a function of x. (c) temperature dependence of dielectric permittivity (εr) for BTSx. (d) phase diagram of BTSx as function of x.

Figure 5 (a) Bright-field TEM micrograph of the domain structure in BTSx (x = 0.11) observed along <001> zone axis. (b) EDX mapping of Ba, Ti, Sn and Mn based on the HAADF-STEM image. (c) Ti cation displacement mapping within two neighboring domains. The scale bar measures 1 nm.

Figure 2 (a) Phase-field simulation of two-dimensional domain structure of RFEs with NPRs in nonpolar C phase without an external electric field. (b) Phase-field simulation of three-dimensional schematic of domain structure without an external electric field. (c) Phase-field simulation of two-dimensional domain structure of RFEs with an external electric field. (d) Three-dimensional schematic for the Landau free-energy profile of polarization rotation of RFEs for different polarizations within Landau theory under a four-phase coexistence condition. (e) Schematic of the respective [100], [101], and [111] polarization directions for the T, O, and R phases, respectively. (f) The Landau free-energy profiles of polarization extension for different polarization directions.

Figure 4 (a) The piezoelectric coefficient d33 and the planar eletromechanical coupling coefficient kp. (b) the unipolar strain vs. electric field (S-E) loops and corresponding maximum converse piezoelectric coefficient dS/dE. (c) bias field d33 * vs. electric field (d33 *-E) hysteresis loops and corresponding quasi-static positive and negative maximum d33 (d33 Emax and -d33 Emax) of BTSx ceramics as function of x. The temperature dependence of (d) d33 and kp, (e) S-E loops and dS/dE, (f) d33 *-E loops, d33 Emax and -d33 Emax. The comparison in the room temperature d33 of BTSx (x = 0.11) with (g) BT-based piezoelectrics 20,31-35 and (h) several typical PZT and leadfree piezoelectrics.14-17,21,36

Figure 1 (a) A comparison of d33 vs TC/Tm for piezoelectric ceramics. (b) The calculated the total-energy difference per unit cell (ΔE = Ei−EC, Ei: total energy of T, O and R phases; EC: total energy of C phase) of C, T, O and R BaTi1-xSnxO3 (0≤x≤0.2), Ba1-xCaxTiO3 (0≤x≤0.3), BaZrxTi1-xO3 (0≤x≤1) and PbZrxTi1-xO3 (0≤x≤1).