High performance BiFe0.9Co0.1O3 doped KNN-based lead-free ceramics for acoustic energy harvesting

Ultrasonic driven wireless charging technology has recently gained increasing attention. High-performance potassium sodium niobate [(K, Na)NbO3, KNN] based ceramics and its potential application on energy harvesting device are presented in this work. A series of lead-free (0.964()K0.48Na0.52)Nb(0.96)Sb0.04O(3)-0.032(Bi0.5Na0.5) ZrO3-xBiFe(0.9)Co0.1O(3) [KNNS-BNZ-xBFC] piezo-ceramics are first designed and prepared to search for good piezoelectric properties, high Curie temperature and good thermal stability. Through content tailoring, the KNNS-BNZ-0.004BFC ceramic presents enhanced piezoelectric properties via the construction of rhombohedraltetragonal phase boundary near room temperature. Based on the synthesized ceramics, a high-output flexible ultrasound-based wireless energy harvesting device is further designed and manufactured to establish a connection among ceramics and practical application in lead-free KNN-based ceramics. The average ultrasound receiving sensitivity of the fabricated device is calculated to be similar to 1.5 Vpp center dot MPa 1, demonstrating the superior performances. An instantaneous power density of 52.07 mW/cm2 has been obtained from the incident ultrasound pressure of 1.90 MPa. Capacitor charging applications and the feasibility study of ex vivo characterizations under porcine tissue also demonstrate the good application prospect of the harvester. The above results exhibit great potential of the environmentally friendly KNN-based materials to be integrated in the implantable device for safe biomedical applications.