An incommensurate modulated antiferroelectric phase is a key part of ideal candidate materials for the next generation of dielectric ceramics with excellent energy storage properties. However, there is less research carried out when considering its relatively low polarization response. Here, the incommensurate phase is modulated by stabilizing the antiferroelectric phase and the energy storage performance of the incommensurate phase under ultrahigh electric field is studied. The tape‐casting method is applied to construct dense and thin ceramics. La3+ doping induces a room‐temperature incommensurate antiferroelectric orthorhombic matrix. With little Cd2+, the extremely superior energy storage performances arose as follows: when 0.03, the recoverable energy storage density reaches ≈19.3 J cm‐3, accompanying an ultrahigh energy storage efficiency of ≈91% (870 kV cm‐1); also, a giant discharge energy density of ≈15.4 J cm‐3 emerges during actual operation. In situ observations demonstrate that these superior energy storage properties originate from the phase transition from the incommensurate antiferroelectric orthorhombic phase to the induced rhombohedral relaxor ferroelectric one. The adjustable incommensurate period affects the depolarization response. The revealed phase‐transition mechanism enriches the existing antiferroelectric–ferroelectric transition. Attention to the incommensurate phase can provide a reference for the selection of the next generation of high‐performance antiferroelectric materials.

Owing to the high power density, eco‐friendly, and outstanding stability, the lead‐free ceramics have attracted great interest in the fields of pulsed power systems. Nevertheless, the low energy storage density of such ceramics is undoubtedly a severe problem in practical applications. To overcome this limitation, the lead‐free ceramics with gradient structures are designed and fabricated using the tape‐casting method herein. By optimizing the composition and distribution of the gradient‐structured ceramics, the energy storage density, and efficiency can be improved simultaneously. Under a moderate electric field of 320 kV cm−1, the value of recoverable energy storage density (Wrec) is higher than 4 J cm−3, and the energy storage efficiency (η) is of ≥88% for 20‐5‐20 and 20‐10‐20. Furthermore, the gradient‐structured ceramics of 20‐10‐0‐10‐20 and 20‐15‐0‐15‐20 possess high applied electric field, large maximum polarization, and small remnant polarization, which give rise to ultrahigh Wrec and η on the order of ≈6.5 J cm−3 and 89–90%, respectively. In addition, the energy storage density and efficiency also exhibit excellent stability over a broad range of frequencies, temperatures, and cycling numbers. This work provides an effective strategy for improving the energy storage capability of eco‐friendly ceramics.

To meet the requirements of environmental friendliness, high-performance lead-free piezoelectric materials have become important materials for next-generation electronic devices. Here, lead-free and potassium-free NaNbO3 (NN)-based ceramics with high piezoelectric (d 33 = 361 ± 10 pC/N) and dielectric (εr = 4500) properties were obtained by tolerant preparation techniques. The excellent piezoelectric and dielectric properties can be attributed to the relaxor morphotropic phase boundaries (R–MPB) and coexisting domain regions, which are beneficial in lowering the free energy and greatly improving the dielectric response and domain switching capability. Furthermore, the d 33 of NaNbO3-10Ba(Ti0.7Sn0.3)O3-1.5NaSbO3 (NN-10BTS-1.5NS) ceramics can be maintained at 350 pC/N over the range of 25–80 °C with a change rate of less than 10%, exhibiting excellent temperature stability. Based on a series of in situ characterizations, the variations of the phase and domain structures of NN-based relaxor piezoelectric ceramics with temperature are clearly demonstrated. This work not only proposes new materials for sensors and actuators but also provides an excellent strategy for designing high-performance piezoelectric ceramics through phase and domain engineering.

Constructing the stepwise phase transition can delay the polarization process of antiferroelectric ceramics, possessing certain significance for improving the energy storage density. However, the common multiphase transitions are obtained in the rare-earth ions doped PbZrO3-based systems. In the present work, the multiphase transition can also be induced in the lanthanum-free Pb(Zr0.5Sn0.5)O3 matrix with mere doping of the alkali-earth metal ion Sr. The introduction of Sr endows the matrix with a higher lattice distortion and the reduced phase-transition temperature. Moreover, related to the induced stepwise electric field-induced phase transition, the energy storage properties are remarkably enhanced to 10.5 J/cm3 and 83.2% when the substitution content of Sr is 3 mol. %. Sr modification can adjust the phase structure by regulating the phase stability of the matrix and suppress the leakage current originating from the structural changes. This work provides a successful attempt that the phase structure and energy storage performance of antiferroelectric ceramics can also be effectively controlled through cheaper and simpler element modification. The optimized energy storage performance provides a new material selection for pulsed power devices.

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