PLZT film capacitors for power electronics and energy storage applications

Ceramic film capacitors with high dielectric constant and high breakdown strength hold special promise for applications demanding high power density. By means of chemical solution deposition, we deposited a parts per thousand 2-mu m-thick films of lanthanum-doped lead zirconate titanate (PLZT) on LaNiO3-buffered Ni (LNO/Ni) foils and platinized silicon (PtSi) substrates. The dielectric properties and energy storage performance of the resulting samples were determined under a high level of applied electric field. X-ray diffraction stress analysis revealed that PLZT on LNO/Ni bears a compressive stress of a parts per thousand 370 MPa while PLZT on PtSi endures a tensile stress of a parts per thousand 250 MPa. Compressive stress was found to lead to heightened polarization, improved tunability, increased irreversible domain wall motion, and enhanced breakdown strength for PLZT deposited on the LNO/Ni as compared with the PtSi substrate. We observed a tunability of a parts per thousand 55 and a parts per thousand 40 % at room temperature under 100 kV/cm applied field, remanent polarization of a parts per thousand 23.5 and a parts per thousand 7.4 A mu C/cm(2), coercive electric field of a parts per thousand 25.6 and a parts per thousand 21.1 kV/cm, and dielectric breakdown strength of a parts per thousand 2.6 and a parts per thousand 1.5 MV/cm for PLZT deposited on LNO/Ni foils and PtSi substrates, respectively. A high recoverable energy density of a parts per thousand 85 J/cm(3) and energy conversion efficiency of a parts per thousand 65 % were measured on the PLZT film grown on LNO/Ni.