Synergistic Optimization in a 0.90BaTiO<sub>3</sub>–0.08Bi(Ni<sub>0.5</sub>Zr<sub>0.5</sub>)O<sub>3</sub>–0.02BiFeO<sub>3</sub> Thin Film with High Breakdown Strength and Energy Density
Rui Huang, Hongye Wang, Cheng Tao, Hua Hao, Zhonghua Yao, Hanxing Liu, Minghe Cao
Abstract
Amorphous thin films have attracted wide attention owing to their high breakdown strength in the field of dielectric ceramic thin-film energy storage. However, improving the polarization strength has been a great challenge for amorphous films due to the inverse relationship between polarization and breakdown strength. Herein, a concept of ternary synergistic optimization design is proposed and proved to be an effective strategy to improve this challenge. BaTiO3–Bi(Ni0.5Zr0.5)O3–BiFeO3 amorphous films are prepared by a sol–gel method. BaTiO3 is chosen as the main component, taking advantage of its large spontaneous polarization. The introduction of Bi(Ni0.5Zr0.5)O3 facilitates the formation of nanoscale crystalline regions. For BiFeO3, Fe2+ and Fe3+ incorporation into thin films bound oxygen vacancy defects and enhanced the polarization, which further improved the energy storage performance. As a result, 0.90BaTiO3–0.08Bi(Ni0.5Zr0.5)O3–0.02BiFeO3 thin film achieves an energy storage density of 114.3 J cm–3 and energy storage efficiency of 87.0%, together with excellent thermal stability in a temperature range of 20–150 °C. This work provides a universal method to improve the polarization and energy storage properties of amorphous films.