Dielectric properties and electrocaloric effect of high-entropy (Na0.2Bi0.2Ba0.2Sr0.2Ca0.2)TiO3 ceramic

By Y. Pu, Qianwen Zhang, Run Li, Min Chen, Xinyi Du, Shiyu Zhou. 2019

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Single-phase homogeneous (Na0.2Bi0.2Ba0.2Sr0.2Ca0.2)TiO3 powder with high configurational entropy was synthesized by using a solid-state method. Calculations of thermodynamic parameters and related experiments indicate that both entropy and enthalpy drive the formation of a stable system. To further research the material's performance, we sintered the powder into a ceramic, which exhibited relaxation behavior because of the disorder of the microscopic composition. In addition, an applied electric field of 145 kV/cm produces a discharge energy density of 1.02 J/cm3. Meanwhile, the adiabatic temperature is 0.63 K at 60 kV/cm. These properties suggest that the electrocaloric effect of the (Na0.2Bi0.2Ba0.2Sr0.2Ca0.2)TiO3 ceramic is attractive for applications such as solid-state refrigeration and energy storage. High-entropy perovskite oxides are also highly tolerant to ions, and their properties can be tailored by tuning their composition, making them attractive for a broad range of applications.

Subfields: Materials Chemistry, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/465b921c594c060e6a4edf4f941fa10ef8ad7614