Large energy-storage density with good dielectric property in bismuth sodium titanate-based thin films

Abstract In this study, energy-storage and dielectric performances of x mol% (x = 0, 2, 4, 6) Fe-doped 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 (abbreviated as 0.94BNT-0.06BT-Fex) ferroelectric thin films were prepared through sol-gel process. Fe-doped BNT-BT thin films were found to have slimmer hysteresis with higher maximum polarization (Ps), lower remanent polarization (Pr), higher breakdown strength and much larger dielectric constant. Optimal energy-storage properties were obtained for 0.96BNT-0.04BT-Fe2 thin films, with a breakdown strength, energy-storage density and efficiency of 2500 kV/cm, 33 J/cm3, 67.8%, respectively. Simultaneously, the leakage mechanisms of the 0.96BNT-0.04BT-Fex were investigated, and influences of the oxygen vacancies on the leakage current as well as breakdown strength were discussed. The outstanding properties of our thin film indicate its usage in advanced high-energy-storage capacitors.