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• Achieving ultrahigh W rec of 10.0 J/cm3 and η of 91 % in BST-based ceramics. • The variation of relaxor feature is analyzed by multi-polarization mechanism model. • Simultaneously toughening and enhanced energy storage performance are realized. Lead-free ceramic capacitors offer ultrahigh power density and ultrafast discharging rates, making them critical energy storage components for advanced pulsed power systems. However, the greatest obstacle to broader applications remains the relatively low energy storage density. In this study, a relaxor ferroelectric ceramic based on (0.6-x)Ba 0.55 Sr 0.45 TiO 3 -0.4Bi 0.5 Na 0.5 TiO 3 -xSrZrO 3 ((0.6-x)BST-0.4BNT-xSZ) is prepared using the tape casting method, resulting in an excellent energy density (W rec ≈ 10.0 J cm−3) and high energy storage efficiency (η ≈ 91 %). The solid solution of linear dielectrics SrZrO 3 synergistically regulates both relaxor properties and breakdown strength. The variation of relaxor property was explored utilizing New Glass model and the multi-polarization model, with confirmation provided by piezoresponse force microscopy. Furthermore, the breakdown strength could be attributed to improvements in electric insulation and the widening of the bandgap. As SrZrO 3 content increases, the in-situ emergence of the second phase ZrO 2 , accompanied by a martensitic transformation, not only improves the fracture toughness of ceramics but also serves to elongate the breakdown path. Encouragingly, x = 0.20 ceramics also achieve excellent temperature stability (−95–125 ℃), frequency stability (1–1000 Hz), cycling reliability (1–106 cycles), and great charging-discharging properties. This multiscale synergic regulation strategy plays a guiding role in the screening of high-performance energy storage dielectric materials. [ABSTRACT FROM AUTHOR]

Pulse ceramic capacitors that request particularly high reliability and long lifetime forbid over-applied electric field, hence demanding high energy density (W re) and energy storage efficiency (η) at low electric field. In this work, we investigated a lead lanthanum zirconate titanate (PLZT) ceramic featuring both of tetragonal antiferroelectric phase (AFE T) and relaxor characteristic, which emerge in converged area of PLZT phase diagram (mole ratio of La reaches ~10%). Temperature dependent permittivity and XRD analysis proves the crossover trait in this structure. In this special relaxor-like AFE T structure, decent W re (1.2–1.3 J cm−3) and η (86–90%) are achieved at 12 V μ m−1. Equivalent dielectric constant (ε eq) is also introduced to illustrate nonlinear energy storage performance at different electric field. Compared to common dielectric materials, tunable ε eq in relaxor-like AFE T structure shows advantages of excellent low-field energy density and wide working span, leading to the convenience in size design of capacitors. Finally, good energy storage stability under various external field was verified: ~1.00 J cm−3 in W re and ~92% in η were stabilized under varied frequency (< ± 8.9%, 0.01–2000 Hz), temperature (< ± 9.8%, −60 to 120 ℃) and fatigue loading (< ± 9.8%, >108 times) at ~10 V μ m−1. [ABSTRACT FROM AUTHOR]

The phase boundaries of dielectric materials have constantly been valuable for instructing the design of phase structures, revealing correlations between compositions and structures, and attaining the desired functional properties for piezoelectric, pyroelectric, electrostriction, electrocaloric, energy storage and energy harvesting applications. We here observe a new type of phase boundary in a solid solution of xPbTiO3·(1 − x)Pb(Yb1/2Nb1/2)O3 (x = 0.00–0.20), which is between an antiferroelectric (AFE) phase and a relaxor ferroelectric (RFE) phase. x = 0.10 is confirmed as the phase boundary. XRD, TEM, PFM and Raman spectroscopy analysis reveal two fundamental traits of the phase structure: (1) the polar state changes from AFE to FE order; and (2) the domain range evolves from micrometer-sized to nanometer-sized, both of which are normally separated but coexist around the phase boundary. The intriguing phase structure contributes to the distinctive dielectric properties: (1) a broad compositional zone (x < 0.10 and x ≥ 0.14) features low remnant polarization, low hysteresis and highly reversible domain wall motion, and is expected to be utilized for dielectric energy storage and electrostriction applications; and (2) a narrow nonergodic RFE zone (0.10 ≤ x < 0.14) demonstrates remnant and maximum polarization, co-dominated by composition and temperature, and has potential for pyroelectric and electrocaloric applications. [ABSTRACT FROM AUTHOR]