High energy storage density over a broad temperature range in sodium bismuth titanate-based lead-free ceramics

A series of (1-x)Bi(0.48)La(0.02)Na(0.48)Li(0.02)Ti(0.98)Zr(0.02)O(3)-xNa(0.73)Bi(0.09)NbO(3) ((1-x)LLBNTZ-xNBN) (x = 0-0.14) ceramics were designed and fabricated using the conventional solid-state sintering method. The phase structure, microstructure, dielectric, ferroelectric and energy storage properties of the ceramics were systematically investigated. The results indicate that the addition of Na(0.73)Bi(0.09)NbO(3) (NBN) could decrease the remnant polarization (P (r)) and improve the temperature stability of dielectric constant obviously. The working temperature range satisfying TCC (150 ) (°C) ≤±15% of this work spans over 400 °C with the compositions of x ≥ 0.06. The maximum energy storage density can be obtained for the sample with x = 0.10 at room temperature, with an energy storage density of 2.04 J/cm(3) at 178 kV/cm. In addition, the (1-x)LLBNTZ-xNBN ceramics exhibit excellent energy storage properties over a wide temperature range from room temperature to 90 °C. The values of energy storage density and energy storage efficiency is 0.91 J/cm(3) and 79.51%, respectively, for the 0.90LLBNTZ-0.10NBN ceramic at the condition of 100 kV/cm and 90 °C. It can be concluded that the (1-x)LLBNTZ-xNBN ceramics are promising lead-free candidate materials for energy storage devices over a broad temperature range.