Synergistic Function via Amorphous and Nanoscale Polarization Heterogeneous Regions in (1-x)BaTiO3 -xBi(Ni0.5 Zr0.5 )O3 Thin Film with Ultrahigh Energy Storage Capability and Stability.

Abstract

Dielectric film capacitors are considered as potential candidates for advanced power electronics technology due to their extremely high-power densities and outstanding mechanical and thermal stability, but the further improvement of energy storage density is still needed. Here, a strategy is proposed to enhance the energy storage properties by introducing nanoscale polarization regions into amorphous films, which can significantly improve the maximum polarization and maintain a high breakdown strength. The (1-x)BaTiO3 -xBi(Ni0.5 Zr0.5 )O3 ((1-x)BT-xBNZ) thin films are fabricated by the sol-gel method and the amorphous films with nanoscale polarization regions are obtained by adjusting the preparation process. Consistent with the conjecture, amorphous phase and nanoscale polarization regions in the (1-x)BT-xBNZ films are clearly observed by electron diffraction. Results show that giant recoverable energy density of 103.7 J cm-3 with high energy efficiency of 88.3% are simultaneously achieved at 8.3 MV cm-1 in 0.92BT-0.08BNZ thin films. Furthermore, the 0.92BT-0.08BNZ thin film exhibits excellent thermal stability in a wide temperature range of 20-200°C, ∆Wrec /Wrec20°C < 2.2%. This work provides a novel method for dielectric thin film capacitors applied in high temperature and electric field.