Energy storage properties of multilayer thin films based on relaxor-ferroelectric (Ba0.9Sr0.1)(Zr0.4Ti0.6)O3 and paraelectric Sr(Zr0.1Ti0.9)O3 layers

Lead-free dielectric film capacitors with high recoverable energy-storage density (Ur) and large energy efficiency (η) are highly desired for the development of next-generation energy-storage devices for environmental sustainability. In this work, the impact of inserting SrZr0.1Ti0.9O3 layers in the structure and properties of [(Ba0.9Sr0.1)Zr0.4Ti0.6O3/SrZr0.1Ti0.9O3]N = 4/(Ba0.9Sr0.1)Zr0.4Ti0.6O3 ([BSZT/SZT]N = 4/BSZT) multilayer films was systematically investigated. The results indicated that both maximum polarization and breakdown strength are enhanced in the multilayer structure. This is attributed to the strain gradient, dielectric constant gradient, and interface blocking effect in the interfaces between relaxor BSZT and paraelectric SZT layers. Consequently, a high Ur of about 107.3 J/cm3 and an excellent η of about 84.2% were achieved in the multilayer films (Ur and η values were about 73.7 J/cm3 and 73.1%, and 40.9 J/cm3 and 89.6%, respectively, for the single-layered BSZT and SZT films).