High-Temperature Energy Storage Properties of Bi_0.5Na_0.5TiO₃-0.06BaTiO₃ Thin Films

Bi0.5Na0.5TiO3-0.06BaTiO(3) (BNT-BT) thin films were prepared via both chemical solution (CSD) and pulsed laser deposition (PLD). The structural, dielectric, and ferroelectric properties were investigated. High stability of the dielectric permittivity or TCC (Delta epsilon/ epsilon" (150 degrees C) <= +/- 15%) over a wide temperature range from room temperature to 300 degrees C was obtained. Distinctly, the CSD film showed high TCC stability with variation of similar to 5% up to 250 degrees C. Furthermore, the CSD film showed an unsaturated ferroelectric hysteresis loop characteristic of the ergodic relaxor phase. However, the PLD one exhibited an almost saturated loop characteristic of the coexistence of both ergodic and non-ergodic states. The energy storage properties of the prepared films were determined using P-E loops obtained at different temperatures. The results show that these films exhibited a stable and improved energy storage density comparable to ceramic capacitors. Moreover, the CSD film exhibited more rigidity and better energy storage density, which exceeded 1.3 J/cm(3) under a weak applied field of 317 kV/cm, as well as interesting efficiency in a large temperature range. The obtained results are very promising for energy storage capacitors operating at high temperatures.