MgO-modified Sr0.7Ba0.3Nb2O6 ceramics for energy storage applications

We explored the phase structure, microstructure, dielectric and energy storage properties of MgO-modified strontium barium niobate Sr_0.7Ba_0.3Nb₂O₆-xwt%MgO (SBNMx; x?=?0–5) ceramics fabricated via conventional solid-state sintering precess. X-ray diffraction analysis indicates Mg²⁺ incorporates into lattice at x?=?0.5 and secondary phases come into formation for samples at x?≥?1, which results in the decrease of dielectric constant. There is also significant reduction of dielectric loss up to 0.002. Compared with pure SBN ceramics, the grain size of SBNMx ceramics becomes denser and more uniform, moreover, the dielectric breakdown strength shows increasing trend from 137?kV/cm to 226?kV/cm, which is in favor of the energy storage. SBNM0.5 ceramics presents the optimal energy storage performance: energy storage density of 0.93?J/cm³ and energy storage efficiency of 89.4% at 157?kV/cm, indicating that SBNM ceramics are prospective candidates for high voltage capacitor applications.