Enhancing the energy storage density of Bi0.5Na0.5TiO3 thin films by adding an amorphous alumina

The energy storage density of ferroelectric capacitors is mainly determined by their polarization and breakdown strength . In this work, the energy storage performance of BNT thin films was enhanced by introducing an amorphous alumina to construct Al 2 O 3 -Bi 0.5 Na 0.5 TiO 3 (AO-BNT) heterojunctions by sol-gel process. The results reveal that the Bi 0.5 Na 0.5 TiO 3 /Al 2 O 3 /Bi 0.5 Na 0.5 TiO 3 (BNT/AO/BNT) structure significantly improves the breakdown strength of BNT, the breakdown electric field is increased from 1050 to 3082 kV/cm, and the energy storage density is also increased from 8.7 to 19.9 J/cm 3 . This is mainly due to the built-in electric field formed by the opposite double-heterojunction can counteract part of the external electric field, and this capacitor-like structure concentrated more applied electric field on the amorphous alumina with better breakdown ability, thus provides a new way to improve the energy storage performance of dielectric ferroelectric capacitors.