Efficiently enhanced energy storage performance of Ba2Bi4Ti5O18 film by co-doping Fe3+ and Ta5+ ion with larger radius

We present an efficient strategy, that is the co-substitution of Fe 3+ and Ta 5+ ions with large radius for Ti 4+ ion, to enhance energy storage performance of Ba 2 Bi 4 Ti 5 O 18 film. For the films co-doped with Fe 3+ and Ta 5+ ions, the maximum polarization under the same external electric field is improved because the radius of Fe 3+ and Ta 5+ ions is larger than that of Ti 4+ ion. Moreover, due to the composition and chemical disorder, the relaxor properties are also slightly improved, which can not be achieved by the film doped with Fe 3+ ions only. What is more, for the films doped with Fe 3+ ion only, the leakage current density increases greatly due to the charge imbalance, resulting in a significant decrease in breakdown strength. It is worth mentioning that the breakdown strength of Fe 3+ and Ta 5+ ions co-doped film does not decrease due to the charge balance. Another important point is the recoverable energy storage density of the films co-doped with Fe 3+ and Ta 5+ ions has been greatly improved based on the fact that the maximum external electric field does not decrease and the maximum polarization under the same external electric field increases. On top of that, the hysteresis of the polarization has also been improved. Finally, the co-doped films with Fe 3+ and Ta 5+ ions have good frequency and temperature stability.