Enhanced energy storage performance in Sr0.7La0.2Zr0.15Ti0.85O3-modified Bi0.5Na0.5TiO3 ceramics via constructing local phase coexistence

Dielectric capacitors with excellent energy storage performance are highly desirable for electronic industry. Although many excellent studies have been carried out on energy-storage dielectric materials, the explanation of their macroscopic electrical properties from the microscopic point of view remains scarce. In this work, (1-x)Bi0.5Na0.5TiO3-xSr0.7La0.2Zr0.15Ti0.85O3 ((1-x)BNT-xSLZT) relaxor ceramics are designed and fabricated. The recoverable energy density of 5.09 J/cm3 and efficiency of 88% are achieved in 0.67BNT-0.33SLZT ceramic. The ceramic also displays an excellent thermal stability in a wide temperature range (0–200 °C). The good performance of the ceramics is attributed to their heterogeneous structure which contains two different local phases after composition modification. Micro-structure is then validated by the Rietveld refinement and transmission electron microscopy analysis. Moreover, the decrease in domain size and enhancement in domain reversibility are also observed in the sample. The delayed polarization saturation and increased electric field strength significantly enhance the energy storage properties of the ceramics. This work indicates that constructing local phase coexistence is an effective method for obtaining high-performance energy storage ceramics, and may provide a guideline for designing and preparation of dielectric energy storage ceramics with superior properties.