Enhanced energy density and electric cycling reliability via MnO2modification in sodium niobate-based relaxor dielectric capacitors

© 2020 World Scientific Publishing Co. Pte Ltd. All rights reserved. Sodium niobate (NaNbO3)-based dielectrics have received much attention for energy storage applications due to their low-cost, lightweight, and nontoxic nature. The field-induced metastable ferroelectric phase in NaNbO3-based dielectrics, however, leads to a large hysteresis of the polarization-electric field (P-E) loops and hence deteriorate the energy storage performance. In this study, the hysteresis was successfully reduced by introducing Bi3+and Ti4+into A-site and B-site of NaNbO3, respectively. MnO2addition was added to further increase the ceramic density and enhance the cycling reliability. As a result, a high recoverable energy density of 4.3 J/cm3and a high energy efficiency of 90% were simultaneously achieved in the ceramic capacitor at an applied electric field of 360 kV/cm. Of particular importance is that the ceramic capacitor exhibits a stable energy storage properties over a wide temperature range of -70 to 170 °C, with much improved electric cycling reliability up to 105cycles.