STRUCTURE CHARACTERIZATION AND ENERGY STORAGE EVALUATION OF MANGANESE-DOPED 0.7NBT-0.26ST-0.04BT CERAMICS

0.7(Na0.5Bi0.5)TiO₃-0.26SrTiO₃-0.04BaTiO₃ (0.7NBT-0.26ST-0.04BT) ceramics was chosen as the base material, and x mol% MnCO₃ (x=0, 0.1, 0.3, 0.5, 0.7) was externally introduced to investigate its effect on the phase structure, microstructure, dielectric and ferroelectric properties for energy storage. X-ray diffraction (XRD) analysis revealed that no diffraction peak location shifting but intensity weakening can be observed with manganese doping amount, indicating manganese did not enter the crystal lattice but form glass phases and/or impurities. Scanning electron microscopy (SEM) analysis showed that manganese doping promoted grain growth, and some liquid or precipitated impurity particles were found at grain boundaries, which was consistent with the results of XRD. Manganese doping can effectively suppress the dielectric loss near room temperature of the ceramics. When the doping amount of MnCO₃ was 0.5 mol% and the applied electric field was only 60 kV/cm, the optimal recoverable energy density and efficiency of the ceramics were 0.63 J/c³ and 65% respectively, presenting a valuable solid state energy storage ceramic capacitor material