From Material to Device: Advances in Bi₄Ti₃O₁₂-Based Ceramics for Next-Generation High-Temperature Piezoelectric Sensors and Transducers

Piezoelectric materials are essential functional components widely employed across diverse technological fields. With increasing demands from aerospace, nuclear, and other extreme-environment industries, the development of piezoelectric materials capable of reliable operation at elevated temperatures has become a critical research focus. Bismuth titanate (Bi₄Ti₃O₁₂, BIT), an Aurivillius-type layered ferroelectric, has emerged as a leading candidate for high-temperature piezoelectric applications owing to its high Curie temperature (∼675°C) and large spontaneous polarization (∼50 µC/cm²). This review comprehensively examines the crystal structure and electrical properties of BIT and systematically summarizes key strategies for enhancing its performance, including optimization of fabrication processes, composition control (A-site, B-site, and co‑substitution), microstructure tailoring (grain size and grain orientation engineering), and the design of intergrowth structures. Furthermore, recent advances in high‑temperature piezoelectric devices based on BIT, such as ultrasonic transducers and composite materials, are discussed. The paper also addresses persistent challenges, such as limited densification, insufficient piezoelectric response, and dielectric losses, and proposes potential solutions. This work aims to provide a valuable reference for the design and application of BIT‑based materials in next‑generation high‑temperature piezoelectric systems.