BaTiO₃ (BT)-based piezoceramics with large temperature-stable strains and low hysteresis are urgently needed for high-precision actuators because of increasing environmental problems. Here, tetragonal [001]_c-textured (Ba_0.98Ca_0.02)(Ti_0.96Sn_0.04)O₃ (BCTS) ceramics with a texture degree (F₀₀₁) of ~98% were obtained via the templated grain growth (TGG) method. A large maximum unipolar strain (S_max) of ~0.24% with a low strain hysteresis (H_s) of ~3.8% and an optimized piezoelectric strain coefficient (d₃₃*) of ~1124 pm·V⁻¹ are simultaneously achieved in the textured BCTS ceramics. Moreover, the variation in the strain response is less than 20% from room temperature (RT) to 100 °C for the textured ceramics. The underlying mechanism for the optimized strain performance could be attributed to the synergetic effect of the polarization extension and a fine domain structure. This work provides new insight for achieving a balance of multiple strain properties (large strain, low hysteresis, and high-temperature stability) in BT-based ceramics, showing the widespread application prospects of lead-free ceramics in high-precision actuators.

Combining layers with high breakdown resistance and high polarization is a promising approach for designing dielectric capacitors with high energy density and efficiency. However, such combinations often accompany strong interfacial polarization, magnification of local electric fields, leading to premature breakdown. This work addresses this issue via controlled formation of diffusospheres. We constructed multilayer heterogeneous films using two Bi_0.5Na_0.5TiO₃ (BNT)-based substances with high breakdown resistance and high polarization properties. Experimental results and finite element simulations demonstrate that the energy storage capacity of these films effectively harnesses the advantages of both phases. Notably, the interface polarization is minimal. Instead, a solid solution-like diffusosphere, formed by the mutual diffusion of ions between the two phases, plays a crucial role. The diffusosphere acts as a transition zone, mitigating charge aggregation at the interfaces and optimizing the relaxor and breakdown characteristics of the capacitor. With six diffusospheres, the multilayer heterogeneous capacitor achieves a recoverable energy storage density of 94 J/cm³, a significant advancement in BNT-based energy storage films. This work proposes and validates the concept of diffusospheres and their role in reducing interfacial polarization in multilayer heterogeneous films, enhancing the understanding of heterogeneous composite structures and advancing the field of dielectric energy storage.

The inferior temperature stability of piezoelectric response is the main drawback of KNN-based ceramics. Here, the Ba-doped 0.97(K_0.48Na_0.52)(Nb_0.96Sb_0.04)O₃-0.03Ba_x(Bi_0.5Ag_0.5)_1-xZrO₃ (abbreviated as KNNS-BBAZ) textured ceramics were prepared by the template grain growth (TGG) method. Excellent comprehensive properties (d₃₃=(406 ± 15) pC/N, T_C = 274 ℃, strain is 0.17%) were achieved in KNNS-BBAZ textured ceramics with x = 0.2. Meanwhile, its piezoelectric and strain properties also show superior temperature stability (d₃₃ maintained within ±20% change in a wide temperature range from 25 ℃ to 200 ℃ and strain variation was less than 5% in the temperature range from room temperature to 165 ℃). The high O-T phase transition temperature (T_O-T is 110 ℃) induced by incorporating Ba ions accounts for the enhanced temperature stability of piezoelectric properties. In addition, the crystal texture always maintains the contribution of piezoelectric anisotropy to the piezoelectric properties during elevated temperature, which significantly improved the temperature stability of piezoelectric properties. This work provides an effective strategy for simultaneously achieving high piezoelectric response and excellent temperature stability in KNN-based ceramics.

For glass-ceramics, how to realize the collaborative optimization of BDS and permittivity is the key to improve the energy storage density. In this work, ZrO₂ is introduced into BPKNAS glass-ceramics as nucleating agent to promote crystal development of glass-ceramics and then achieve high permittivity. When 1.5 mol% ZrO₂ is added, the glass-ceramics have the highest permittivity (~128.59) and meanwhile possess high BDS (1948.90 kV/cm) due to the dense microstructure. Therefore, BPKNAS-1.5ZrO₂ glass-ceramics has the highest theoretical energy storage density (21.62 J/cm³). Moreover, the permittivity variation of BPKNAS-1.5ZrO₂ glass-ceramics is less than 6 % in the wide temperature range from −80 to 300 ℃, showing excellent temperature stability. In addition, BPKNAS-1.5ZrO₂ glass-ceramics possesses ultrahigh power density, which reaches up to 382.40 MW/cm³ in overdamped circuit. The above evidence shows that BPKNAS-1.5ZrO₂ glass-ceramics with ultrahigh energy storage density and power density is very competitive in the field of energy storage applications.