Improving Energy Storage Properties of Barium Zirconate Titanate Ceramics via Defect Dipole Engineering

Lead-free ceramic materials have been widely studied since dielectric capacitors became a key component for energy storage. In this work, we adopted defect dipole engineering and improved the energy storage performance of barium zirconate titanate (BZT) ceramics by doping them with MnO₂. With the increase in Mn content, the hysteresis loop changed from a conventional loop to a pinned hysteresis loop, resulting in a decrease in remnant polarization (P_r). When x = 0.02, the recoverable energy storage density (W_rec) reached 0.1561 J/cm² @ 40 kV/cm, a 59% increase from undoped BZT. Further, XPS and EPR analyses confirmed that many oxygen vacancies were generated. We also performed SEM and TEM characterization and observed the microstructures. These results are consistent with theories suggesting that the formation of the pinned hysteresis loop is attributable to oxygen vacancies and defect dipoles.