Ultrahigh energy storage in lead-free BiFeO3/Bi3.25La0.75Ti3O12 thin film capacitors by solution processing

Thin film ferroelectric capacitors (TFFCs) with excellent energy storage have attracted increasing attention due to the electronic devices toward miniaturization and integration. BiFeO3 (BF)/Bi3.25La0.75Ti3O12 (BL) based thin films are prepared by chemical solution deposition for energy storage. Ultrahigh energy storage with a recoverable energy density Ure of 54.9 J/cm3 and an efficiency η of 74.4% is observed in the bilayered BF/BL thin films. Further improvement of energy storage is realized in trilayered BL/BF/BL thin films with a Ure of 65.5 J/cm3 and an efficiency η of 74.2% at an electric field of 2753 kV/cm as well as excellent fatigue endurance up to 109 cycles. The results suggest that BF/BL based thin films can be used as lead-free TFFCs in energy storage applications.