Developing nano‐ferroelectric materials with excellent piezoelectric performance for piezocatalysts used in water splitting is highly desired but also challenging, especially with respect to reaching large piezo‐potentials that fully align with required redox levels. Herein, heteroepitaxial strain in BaTiO3 nanoparticles with a designed porous structure is successfully induced by engineering their surface reconstruction to dramatically enhance their piezoelectricity. The strain coherence can be maintained throughout the nanoparticle bulk, resulting in a significant increase of the BaTiO3 tetragonality and thus its piezoelectricity. Benefiting from high piezoelectricity, the as‐synthesized blue‐colored BaTiO3 nanoparticles possess a superb overall water‐splitting activity, with H2 production rates of 159 μmol g−1 h−1, which is almost 130 times higher than that of the pristine BaTiO3 nanoparticles. Thus, this work provides a generic approach for designing highly efficient piezoelectric nanomaterials by strain engineering that can be further extended to various other perovskite oxides, including SrTiO3, thereby enhancing their potential for piezoelectric catalysis.

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Lead-free perovskite CaCu 3 Ti 4 O 12 (CCTO) dielectrics are extremely important candidates for capacitor−varistor dual-function materials. However, their overall success in applications is somewhat controlled by the longstanding issues such as relatively large dielectric loss and insufficiently high electric breakdown field. Herein, we report the success in the preparation of an optimized lead-free (1−x)CaCu 3 Ti 4 O 12 −xSrTiO 3 (CCTO− STO) composite system with improved dielectric and nonlinear properties via interface engineering. Interestingly, looking closer at the grain boundaries using transmission electron microscopy, it is found that an obvious interface region with a transition layer of a wrinkled structure is formed between the CCTO matrix phase and STO dopant phase. Significantly, all the composite ceramic samples present high permittivity in the order of about 10 3 to 10 4 , and the 0.9CCTO−0.1STO composite ceramic sample exhibits a lower dielectric loss of about 0.068 at room temperature and at 1 kHz. Excitingly, the optimized 0.9CCTO−0.1STO composite ceramic sample also exhibits a remarkably elevated breakdown field strength of about 14.03 kV/cm and a large nonlinear coefficient of about 16.11. The improvement in nonlinear properties with a high breakdown field strength and large nonlinear coefficient could be attributed to the interfacial effect in the composite structure, originating from the formation of the transition layer with a wrinkle structure at the interface between CCTO and STO phases. Such effects can result in great electrical heterogeneity caused by the higher resistance of the grain boundary and the enhanced potential barrier at the interface region. The new insights on the formation of the interfacial wrinkle structure near the phase boundaries of the CCTO−STO composite system and their effects on improvement of electrical properties can stimulate future research on lead-free CCTO−STO-based systems toward capacitor−varistor dual-function applications and may offer an effective way to design other lead-free dielectric materials as well.

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Dielectric energy storage materials are becoming increasingly popular due to their potential superiority, for example, excellent pulse performance as well as good fatigue resistance. Although numerous studies have focused on lead-free dielectric materials which possess outstanding energy storage characteristics, the results are still not satisfying in terms of achieving both large discharging energy density (W d) and high discharging efficiency (η) under low electric fields, which is crucial to be conducted in miniatured electronic components. Here, we adopt the strategy of domain engineering to develop sodium bismuth titanate (Bi0.5Na0.5TiO3)-based ceramics employed in the low-field situation. Remarkably, a large W d of 2.86 J/cm3 and an ultrahigh η of 90.3% are concurrently obtained in 0.94­(Bi0.5Na0.5)0.65(Ba0.3Sr0.7)0.35TiO3-0.06 Bi­(Zn2/3Nb1/3)­O3 system when the electric field is as low as 180 kV/cm. Additionally, the ceramic shows brilliant thermal endurance (20–160 °C) and frequency stability (0.1–100 Hz) with high W d (>1.48 J/cm3) together with an ultra-high η (>90%). What’s more, the ceramic displays a fast charge–discharge time (t 0.9 = 109.2 ns). The piezoresponse force microscopy (PFM) results reveal that the introduced Bi­(Zn2/3Nb1/3)­O3 disrupts the microdomains of (Bi0.5Na0.5)0.65(Ba0.3Sr0.7)0.35TiO3 ceramics and promotes the formation of nanodomains, leading to enhanced energy storage properties. The current work may arouse interest in developing low-field high-performing dielectric capacitors for energy storage application.