A-site defect dipole design for enhanced polarization toward optimized energy storage performance in BaTiO3-based ceramics

The intrinsic trade-off between high polarization and low hysteresis limits the practical application of BaTiO 3 -based ceramics as energy storage capacitors. Herein, we demonstrate a defect dipole design strategy to manipulate the polarization behavior and optimize the comprehensive energy storage characteristics. By co-doping with La 3+ and Na + ions at the A-site, the ordered (La Ba · - Na Ba ′) defect dipoles are constructed, which provide extrinsic polarization while coupling with the intrinsic dipoles to amplify macroscopic polarization as revealed by density functional theory (DFT) calculations. Moreover, these defect dipoles suppress oxygen vacancies ( V O · ) via the electron-pinned defect-dipole (EPDD) effect, thereby reducing carrier concentration and directly suppressing polarization hysteresis. Ultimately, a high efficiency ( η ) of 90.35% and enhanced recoverable energy density of 7.08 J/cm 3 are achieved, presenting an effective defect dipole design strategy for optimizing comprehensive energy storage performance.