Emergence of relaxor-like ferroelectric nature in nanograined Pb(Zr0.95Ti0.05)O3 ceramic thick films for energy storage applications

In this study, we demonstrated the nanostructuring of the ferroelectric (FE) phase of Pb(Zr_0.95Ti_0.05)O₃ (PZT-95/5) into a thick film with relaxor-like FE (RFE) characteristics. This transformation results in exceptionally high dielectric breakdown strength (E_DBS) and energy storage density properties. The high kinetic energy from aerosol deposition transformed the bulk PZT-95/5 from a normal FE system into a RFE system by forming a nanostructured grain with nanodomains within a nonpolar matrix. This nanostructure enables easy domain switching, resulting in low remanent polarization. The resulting high density of grain boundaries due to nanograin formation and the nonpolar structure act as barriers to charge flow, resulting in high breakdown strength. Collectively, these effects resulted in a significantly enhanced E_DBS of 5.6 MV/cm and a maximum polarization of 80 µC/cm². These properties, evidenced by slim hysteresis loops, demonstrate that the prepared PZT-95/5 thick film is a superior capacitive material with a high recoverable energy density of 116 J/cm³. Furthermore, the film exhibited reliable fatigue endurance up to 10⁷ cycles and thermal stability from room temperature to 140^°C. The film also exhibited a peak power density of 35 MW/cm³ under a practical electric field of 0.45 MV/cm (180 V) and a fast discharging speed (τ_0.9) of 230 ns. These properties, in addition to the minimal fabrication steps and superior capacitive characteristics, demonstrate the strong potential of the prepared PZT-95/5 thick film for use in next-generation energy storage devices.