BNT-ST-based relaxors have been widely studied due to their excellent energy storage performance, such as large spontaneous polarization, high energy efficiency, and good relaxation performance. However, The P-E loops of BNT-ST based relaxors exhibits strong nonlinear characteristics, which severely restricts the enhancement of its energy density. In order to enhance the energy density of BNT-ST based relaxor ferroelectric ceramics, weak nonlinear engineering is introduced. NaNbO₃ antiferroelectric was introduced into BNT-ST based relaxor ferroelectric ceramics, effectively weakening its strong nonlinear characteristics and significantly enhancing the discharge energy density under low electric fields. The relevant research findings were published in the Journal of Alloys and Compounds (JCR Q1) titled "Weak nonlinearity engineering induced excellent low-field energy storage performance in BNTST-based lead-free relaxors ".

Fig. 1. Schematic diagram of a linearity optimization route to enhance energy storage performance.

Fig. 2. (a) XRD patterns of (1-x)BNTST-xNN ceramics, (b) the magnified patterns of the (200) peak.

Fig. 3. Microstructures of (1-x)BNTST-xNN ceramics: (a) x = 0, (b) x = 0.02, (c) x = 0.06, (d) x = 0.10, (e) x = 0.14; (f) the grain size and standard deviation versus NN content. with room temperature and 10 Hz measured up to Eb; (d) Wdis and Eb values relative to different samples.

Fig. 4. Temperature dependence of dielectric constant and dielectric loss for (1-x)BNTST-xNN ceramics from 0.1 kHz to 1 MHz within the temperature range of − 100–400℃: (a) x = 0, (b) x = 0.02, (c) x = 0.06, (d) x = 0.10, (e) x = 0.14; (f) Temperature dependence of dielectric permittivity and dielectric loss for (1-x)BNTST-xNN ceramics at 1 kHz from −100 – 400℃, the illustration in (f) is the TCC of (1-x)BNTST-xNN ceramics

Fig. 5. (a) P-E loops of (1-x)BNTST-xNN ceramics under 200 kV/cm and 10 Hz. (b) The Weibull distributions of Eb. (c) P−E loops of (1-x)BNTST-xNN ceramics measured at largest electric field before breakdown of each sample. (d) Wdis and η as functions of the electric field of (1-x)BNTST-xNN ceramics measured at 10 Hz. (e) Comparison of the comprehensive energy storage performance (including the Wdis, Eb, ΔP, η and εr@120 kV/cm) between BNTST and 0.90BNTST-0.10NN ceramics. (f) Comparison of Wdis/Eb and η between this work and other reported lead-free ceramics with superior energy storage (Wdis >4 J/cm3)

Fig. 6. (a) P-E loops of 0.90BNTST-0.10NN ceramics measured at 120 kV/cm after various cycles. (b) Wdis and η as functions of measured cycles calculated from (a). (c) P-E loops of 0.90BNTST-0.10NN ceramics measured at 120 kV/cm under various frequencies. (d) Wdis and η as functions of frequencies calculated from (c). (e) P-E loops of 0.90BNTST-0.10NN ceramics measured at 120 kV/cm within the temperature range of 25–130℃. (f) Wdis and η as functions of temperature calculated from (e).

Fig. 7. DC-bias performance of (1-x)BNTST-xNN ceramics at different temperatures: (a) x = 0, (b) x = 0.02, (c) x = 0.06, (d) x = 0.10, (e) x = 0.14. (f) The dielectric constant at 120 kV/cm as functions of the temperature.

作者：李欣恒¹，朱超琼^1,*，李澳宇，梁岚青，李世恒，许成，蔡子明^*，冯培忠

链接：https://www.sciencedirect.com/science/article/pii/S0925838824033401?via%3Dihub

DOI：10.1016/j.jallcom.2024.176753