High-performance lead-free piezoelectric ceramics with knockdown strain hysteresis are key components of high-precision actuators. However, high strain hysteresis in BaTiO₃-based ceramics results in stability degradation, lifespan reduction, and inferior positioning accuracy. Therefore, in this work, a (1−x)Ba(Sn_0.11Ti_0.89)O₃–xSrTiO₃–0.6 wt% MnO₂ (BST–xST) composition is elaborately designed to reduce strain hysteresis. Ultralow strain hysteresis (4.8%) is achieved by adjusting the phase structure and domain configuration. The transmission electron microscopy (TEM) results revealed that the composition consists of a rhombohedral–orthorhombic–tetragonal–cubic (R–O–T–C) four-phase, nanodomains, and active polar nanoregions (PNRs). Moreover, the piezoresponse force microscopy (PFM) results revealed that these active PNRs can respond quickly to applied electric field stimuli. These findings provide a feasible path to prepare piezoelectric compositions with ultralow strain hysteresis.

The growing global demand for sustainable solutions to address energy and environmental challenges has spurred significant interest in catalytic technologies. Piezocatalysis has emerged as a sustainable technology for environmental remediation and energy conversion because of its unique characteristics of harvesting mechanical energy into electrochemical energy. Versatile BiFeO₃ (BFO) stands out among a range of piezocatalysts for its distinctive integration of piezoelectric, multiferroic, and optical properties. This review critically examines piezocatalytic mechanisms, including energy band theory, screening charge effects, and displacement current theory, revealing the intricate roles of internal charges, screening charges, and piezoelectric electrons in driving catalytic reactions. Furthermore, the evolution of BFO-based piezocatalysis is systematically reviewed, emphasizing its structural characteristics, representative synthesis methods, performance optimization strategies, and diverse applications, such as organic pollutant degradation, H₂ production, H₂O₂ generation, CO₂ reduction, and sterilization. In particular, the underestimated ferroelectric polarization effect of BFO on CO₂ reduction is critically analyzed and elaborated. This review identifies critical challenges and outlines future research directions to advance high-efficiency BFO-based piezocatalytic systems. Overall, this comprehensive analysis underscores the potential of BFO in piezocatalysis, bridging materials engineering with practical applications and offering insights into future advancements.

Piezoelectric PZT ceramics with high piezoelectric properties and good thermal stability are urgently desired concerning the practical application. New compositions of LiNbO₃ modified Pb(Ni_1/3Nb_2/3)O₃PbZrO₃PbTiO₃ ceramics have been prepared in this study. The effects of the introduction of the LiNbO₃ on the system were comprehensively investigated in terms of the phase structure, microstructure, electric properties, and thermal stability behavior of the ceramics. All compositions are located in the morphotropic phase boundary (MPB) region, and the ratio of the rhombohedral (R) phase increases obviously with the increase of LiNbO₃ concentration. With increasing the LiNbO₃ content, the piezoelectric properties were significantly enhanced. The sample added with 2% (in mole) LiNbO₃ shows excellent electric properties, including T_m = 185 ℃, ε_r= 5,643, k_p = 0.626, Q_m = 51, d₃₃ = 902 pC/N. More importantly, no thermal depolarization behavior was observed in the temperature range of 25–100 ℃. For PNN-PZT-x%LN ceramics, which is mainly attributed to the pinning effect resulted by the (Li'_Pb - Nb_Zr=Ti^·) defect dipoles.