High energy storage performance of (Na0.5Bi0.5)TiO3 thin film induced by stress engineering

Relaxor ferroelectrics are the primary candidates for high-performance energy storage dielectric capacitors. Here, stress engineering, which was realized by optimizing the lattice mismatch between (Na 0.5 Bi 0.5 )TiO 3 film and SrRuO 3 /(La 0.5 Sr 0.5 )CoO 3 bottom electrodes, was used to enhance the energy storage performance of (Na 0.5 Bi 0.5 )TiO 3 relaxor ferroelectric film. As a result, in-plane compressive stress caused by the lattice mismatch between (Na 0.5 Bi 0.5 )TiO 3 film and (La 0.5 Sr 0.5 )CoO 3 bottom electrode leads to a large W rec of 45.7 J/cm 3 with η of 79.4% at 2000 kV/cm in (Na 0.5 Bi 0.5 )TiO 3 film, which is 54.4% higher than that of (Na 0.5 Bi 0.5 )TiO 3 film with in-plane tensile stress. In addition, the W rec of (Na 0.5 Bi 0.5 )TiO 3 film with in-plane compressive stress shows good thermal stability and frequency stability with variations of 5.8% at 30–120 °C and 6.9% at 0.2–20.0 kHz. This work may provide some new perspectives for the design of dielectric capacitors with high energy storage performance. • Stress engineering is realized in NBT relaxor ferroelectric films. • The in-plane compressive stress contributes to increased polarization in NBT film. • W rec and η reach 45.7 J/cm 3 and 79.4 % in NBT@LSCO films. • W rec and η of NBT@LSCO films have good thermal stability and frequency stability.