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An acetic-acid-based sol-gel method was used to deposit lead lanthanum zirconate titanate (PLZT, 8/52/48) thin films on either platinized silicon (Pt/Si) or nickel buffered by a lanthanum nickel oxide buffer layer (LNO/Ni). X-ray diffraction and scanning electron microscopy of the samples revealed that dense polycrystalline PLZT thin films formed without apparent defects or secondary phases. The dielectric breakdown strength was greater in PLZT thin films deposited on LNO/Ni compared with those on Pt/Si, leading to better energy storage. Finally, optimized dielectric properties were determined for a 3-μm-thick PLZT/LNO/Ni capacitor for energy storage purposes: DC dielectric breakdown strength of ∼1.6 MV/cm (480 V), energy density of ∼22 J/cc, energy storage efficiency of ∼77%, and permittivity of ∼1100. These values are very stable from room temperature to 150 °C, indicating that cost-effective, volumetrically efficient capacitors can be fabricated for high-power energy storage.

The energy storage properties of antiferroelectric (AFE) Pb0.96La0.04Zr0.98Ti0.02O3 (PLZT 4/98/2) thin films were investigated as a function of temperature and applied electric field. The results indicated that recoverable energy density (Ure) and charge-discharge efficiency (η) of PLZT (4/98/2) depend weakly on temperature (from room temperature to 225 °C), while Ure increases linearly and η decreases exponentially with increasing electric field at room temperature. These findings are explained qualitatively on the basis of the kinetics of the temperature-induced transition of AFE-to-paraelectric phase and the field-induced transition of AFE-to-ferroelectric phase, respectively. The high Ure (≈61 J/cm3) and low leakage current density (≈3.5 × 10−8 and 3.5 × 10−5 A/cm2 at 25 and 225 °C, respectively) indicate that antiferroelectric PLZT (4/98/2) is a promising material for high-power energy storage.

Antiferroelectric (AFE) Pb0.92La0.08Zr0.95Ti0.05O3 (PLZT) films were grown on nickel foils with lanthanum nickel oxide buffer by chemical solution deposition. We observed field-induced AFE-to-ferroelectric (FE) phase transition. The electric field for the AFE-to-FE phase transition (EAF ≈ 270 kV/cm) and that for the reverse phase transition (EFA ≈ 230 kV/cm) were measured at room temperature on samples with PLZT films of ≈1-µm thickness. Relative permittivity of ≈560 and dielectric loss of <0.05 were measured near zero DC bias field. Hysteresis loop analysis showed that energy densities of ≈53 and 37 J/cm3 can be stored and recovered from the film-on-foil capacitors at 25 and 150 °C, respectively. Highly accelerated life tests were conducted. The projected mean time to failure is >5000 h when the capacitors are operated at room temperature with an applied field of ≈300 kV/cm.

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