Microstructural Origin of the High-Energy Storage Performance in Epitaxial Lead-Free Ba(Zr0.2Ti0.8)O3 Thick Films.

ABSTRACT

In our previous work, epitaxial Ba(Zr0.2Ti0.8)O3 thick films (~1-2 µm) showed an excellent energy storage performance with a large recyclable energy density (~58 J/cc) and a high energy efficiency (~92%), which was attributed to a nanoscale entangled heterophase polydomain structure. Here, we propose a detailed analysis of the structure-property relationship in these film materials, using an annealing process to illustrate the effect of nanodomain entanglement on the energy storage performance. It is revealed that an annealing-induced stress relaxation led to the segregation of the nanodomains (via detailed XRD analyses), and a degraded energy storage performance (via polarization-electric field analysis). These results confirm that a nanophase entanglement is an origin of the high-energy storage performance in the Ba(Zr0.2Ti0.8)O3 thick films.