Lead lanthanum zirconate titanate ceramic thin films for energy storage

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.