Realizing Super‐High Piezoelectricity and Excellent Fatigue Resistance in Domain‐Engineered Bismuth Titanate Ferroelectrics

Abstract

Bismuth titanate (BIT) is widely known as one of the most prospective lead‐free ferroelectric and piezoelectric materials in advanced high‐temperature sensing applications. Despite significant advances in developing BIT ferroelectrics, it still faces major scientific and engineering challenges in realizing super‐high performance to meet next‐generation high‐sensitivity and light‐weight applications. Here, a novel ferroelectric domain‐engineered BIT ceramic system is conceived that exhibits super‐high piezoelectric coefficient (d33 = 38.5 pC N−1) and inverse piezoelectric coefficient (d33* = 46.7 pm V−1) at low electric field as well as excellent fatigue resistance (stable up to 107 cycles). The results reveal that the introduction of high‐density layered (001)‐type 180° domain walls with flexible polarization rotation features and the formation of small‐size multi‐domain states with low energy barriers are mainly responsible for the excellent electrical performance. To the best of knowledge, it is the first time to reveal such intriguing domain structures in BIT ceramics in detail, especially from the atomic‐scale perspective by using atomic number (Z)‐contrast imaging in combination with atomic‐resolution polarization mapping. It is believed that this breakthrough conduces to comprehensively understand structural features of ferroelectric domains in BIT ceramics, and also opens a window for future developments of super‐high performance in bismuth layer‐structured ferroelectrics via domain engineering.

High-Entropy Strategy for Improved Mechanical and Energy Storage Properties in BaTiO3–BiFeO3-Based Ceramics

“…Furthermore, the grain boundary conductivity can be reflected by a significant reduction in overall impedance at higher temperatures (see Figure S2), a phenomenon widely recognized as thermal activation . The Arrhenius law can be used to calculate the electrical conductivity’s activation energy ( E a ): , wherein k B is Boltzmann’s constant, σ 0 is a pre-exponential factor, σ denotes electrical conductivity, T refers to the measured temperature, l stands for the ceramic’s thickness, and S is a cross-sectional region of the ceramic whereas R refers to the real-part impedance ( Z ’) extrapolated intercept. Figure d shows that the plot of ln σ vs 1000/ T , Equation can be used to match the solid line.…”

“…Furthermore, the grain boundary conductivity can be reflected by a significant reduction in overall impedance at higher temperatures (see Figure S2), a phenomenon widely recognized as thermal activation. 14 The Arrhenius law can be used to calculate the electrical conductivity's activation energy (E a ): 14,30 = i k j j j j j y…”