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In this work, Na0.5Bi4.5Ti3.94–xMn0.06NbxO15+y bismuth‐layered ferroelectric ceramics were prepared by a solid‐state reaction method. The effect of Nb5+ content on crystal morphology, electrical properties, and piezoelectric performance were systematically investigated. The results show that the introduction of Nb5+ into Na0.5Bi4.5Ti3.94–xMn0.06NbxO15+y ceramics to replace Ti4+ increases the ratio of b/a lattice parameter, leading to the TiO6 octahedral distortion and the structural transformation tendency from the orthorhombic to tetragonal phase, which facilitates dipole movements of Na0.5Bi4.5Ti3.94–xMn0.06NbxO15+y ceramics. Therefore, the ferroelectric properties of Na0.5Bi4.5Ti3.94–xMn0.06NbxO15+y ceramics are improved, and an enhanced piezoelectric coefficient of 30 pC/N combining great temperature stability with d33 value higher than 25 pC/N in the temperature range of 25°C–450°C has been realized in Na0.5Bi4.5Ti3.94–xMn0.06NbxO15+y ceramics with x = 0.08 mol. Our work provides a good model for designing lead‐free ultrahigh Curie temperature piezoelectric devices that can be practically applied in extremely harsh environments. [ABSTRACT FROM AUTHOR]

Flexible pressure sensors play an important role in flexible robotics, human-machine interaction (HMI), and human physiological information. However, most of the reported flexible pressure sensors suffer from a highly nonlinear response and a significant decrease in sensitivity at high pressures. Herein, we propose a flexible novel iontronic pressure sensor based on monolayer molybdenum disulfide (MoS2). Based on the unique structure and the excellent mechanical properties as well as the large intercalation capacitance of MoS2, the prepared sensor holds an ultra-high sensitivity (Smax = 89.75 kPa−1) and a wide sensing range (722.2 kPa). Further, the response time and relaxation time of the flexible sensor are only 3 ms, respectively, indicating that the device can respond to external pressure rapidly. In addition, it shows long-term cycling stability (over 5000 cycles with almost no degradation) at a high pressure of 138.9 kPa. Finally, it is demonstrated that the sensor can be used in physiological information monitoring and flexible robotics. It is anticipated that our prepared sensor provide a reliable approach to advance the theory and practicality of the flexible sensor electronics. [ABSTRACT FROM AUTHOR]