Energy storage BaZr_0.2Ti_0.8O₃ bilayer relaxor ferroelectric ceramic thick films with high discharging efficiency and fatigue resistance

Excellent electric energy discharging efficiency and fatigue resistance are two critical factors in high energy storage capacitor for electronic device and high-power system with fast charging-discharging speed. Here, we report on designing and preparing the thick films of BaZr_0.2Ti_0.8O₃ (BZT20) bilayer ceramics (BLCs) (∼40 μm in thickness) using a tape casting method. In this ABO₃-structured perovskite ceramics, the B position of Ti was occupied by 20 mol% Zr atoms, which leads to order-disordering and random fields in the single phase with both the tetragonal (space group P4mm) and rhombohedral (space group m-3m). And therefore, the relaxors possess a heterogeneous polar state at the nanoscale and their long-range domains are disrupted. Consequently, a non-hysteretic arc-shaped unipolar polarization-electric frield loop (P-E loop) in which the curve obtained under a considerable high electric field of 80 MV m⁻¹ and the curve under depolarization are overlaped. As such, a large energy storage density (U_e) of ∼6.2 J cm⁻³ with the discharging efficiency of ∼98% and a considerable fatigue resistance over 22 k cycles at a wide temperature range from 253 to 393 K (−20 °C–120 °C) are obtained. The attractive electric performance of this BLCs films demonstrates that this sort of relaxor ceramics is one of promising materials for capacitors with little calorigenic electronic power areas.