With the increasing demand for devices in miniaturization, accuracy, and low power consumption, developing microdevices in the form of piezoelectric thin films is significant for microelectromechanical systems (MEMS) applications. Piezoelectric thin films offer advantages of miniaturization and low power consumption, holding immense potential in MEMS, especially with advancements in micro-nanomanufacturing technologies. In this review, we highlighted the compelling piezoelectric properties and summarized the latest research progress of thin films, with an emphasis on recent advances in piezoelectric MEMS. We mainly introduced the recent developments on different types of piezoelectric MEMS (piezo-MEMS), along with the descriptions of piezoelectric effects, film preparation, film properties, and device indicators. We have emphasized the comparison of MEMS with different piezoelectric materials and methods for improving devices. The recent achievements of piezoelectric thin films in MEMS applications and the future development of MEMS applications are also reviewed.

Piezoelectric accelerometers have been widely used because of their large range, simple structure, stable performance, and other advantages. With the improvement of science and technology, the application field is expanding, but there are still some problems in high-temperature environments and low-frequency vibration conditions. Under high-temperature environments, the piezoelectric material will undergo depolarization or resistance change, resulting in sensor failure. Aerospace instruments, water conservancy platforms, and other fields require high-precision instruments with vibration amplitudes of the order of a few microns in the range of 0.01–1 Hz, which require low-frequency and ultra-low-frequency sensors for the measurements. Therefore, how to increase the operating temperature and reduce the noise of piezoelectric accelerometers has become a problem that needs to be solved. This paper reviews the structure, principle, application range, and material selection of piezoelectric components of different types of piezoelectric accelerometers and summarizes the current problems and future research priorities.

Compared to batteries and electrochemical capacitors, dielectric capacitors are widely studied because of their huge advantages in terms of charging/discharging speed and power density. In this work, high-entropy (Bi_0.2Na_0.2Sr_0.2Ba_0.2Ca_0.2)TiO₃ lead-free relaxor-ferroelectric ceramics were prepared by both conventional sintering (CS) and spark plasma sintering (SPS). The results showed that the ceramic prepared by SPS obtained a high energy storage density of 6.66 J/cm³ and a satisfied energy storage efficiency of 77.2% under an electric field of 430 kV/cm. This is directly related to the high density, fine grains, number of oxygen vacancies, and composition uniformity of the SPS samples. This study provides a new path for the preparation of high-entropy dielectric energy storage ceramics with high energy storage properties.