Superior energy storage performance in (Bi_0.5Na_0.5)TiO₃-based lead-free relaxor ferroelectrics for dielectric capacitor application via multiscale optimization design

Abstract

Developing environmentally friendly lead-free dielectric ceramics with ultrahigh energy storage performance is fundamental to next-generation high-power capacitors but challenging as well. Herein, a record-breaking ultrahigh energy efficiency η of 97.8%...

Realizing high energy density and efficiency simultaneously in (Bi0.5Na0.5)0.7Sr0.3TiO3-based ceramics via introducing linear dielectric CaTiO3

“…S3 †. Similar to other BNT-based solid solutions, 27 four typical vibration modes are present in the Raman spectra: (i) A-site cations (<200 cm −1 ), (ii) Ti–O vibrations (200–400 cm −1 ), (iii) TiO 6 octahedral vibrations (400–700 cm −1 ), and (iv) A 1 (longitudinal optical) + E (longitudinal optical) (>700 cm −1 ) overlapping bands. With increasing CT concentration, the shifting of Raman peaks in 200–700 cm −1 to lower wavenumbers and the softening of Ti–O vibrations reveal the disorder and the anharmonic effects of the lattices, 67 which confirms the weakening of the ferroelectric state (decreasing the unit cell polarity).…”

“…3(a 2 )], implying a lattice shrink because of the smaller ionic radius of Ca 2+ ( r Ca 2+ = 1.34 Å, CN = 12) than that of [(Bi 0.5 Na 0.5 ) 0.7 Sr 0.3 ] 2+ ( r effective = 1.43 Å) in A-sites. 27 To further investigate the phase structure, the Rietveld refinement XRD patterns of ceramics are obtained with the Pbnm and R 3 c structures as the original models. A perfect matching result can be observed between the experimental data and calculated line, and the reliability factors [Fig.…”

“…Similar phenomena have also been reported in many ferroelectric ceramics. 27 To further reveal the effect of different grain sizes on E b , Fig. 5(d) provides the nominal electric field as a function of nominal charge density of the (1 − x )BNST- x CT ceramics.…”

“…Similar phenomena have been reported in other CT-modified systems. 27 Under this circumstance, considering the trade-off between Δ P , polarization saturation, and E b , a specific CT content is added to the BNST to regulate its energy storage performances. Ultimately, an expected result, delayed polarization saturation and enhanced E b can be obtained, giving rise to an ultrahigh W rec of 7.0 J cm −3 and a large η of 90.9%, which are obtained synchronously in BNST-based ceramics.…”

Simultaneous Enhancement of Energy Storage and Hardness Performances in (Na0.5Bi0.5)0.7Sr0.3TiO3-Based Relaxor Ferroelectrics Via Multiscale Regulation

“…The corresponding temperature-insensitive ε r plateau (Δε r /ε r150 °C ≤ ±15%) of the x = 0.10 is between 31.5 and 250.0 °C [Figure S4f]. In addition, the relaxor characteristics of this system are analyzed via fitting the diffusion coefficient γ based on the modified Curie–Weiss equation: , where ε m represents the maximum ε r , and C is a constant. As displayed in Figure S4g, all samples present a high γ value (>1.60), revealing a strong relaxor nature in this system.…”