The Preparation And Energy Storage Properties Of PbZrO₃-based Antiferroelectric Thin Film

Energy-storage capacitor is one of the most important components of high pulse powersystem, which is an important developing direction. Perovskite antiferroelectric (AFE)materials usually display high energy storage density due to their uniqueelectric-field-induced phase transformation between ferroelectric and AFE. Hence, AFEmaterials show potential applications in high energy storage capacitors and have become ahotspot in the world. PbZrO3(PZ)-based AFE material is expected to become one of the newgeneration energy storage medium materials in pulse high power technology due to their hightheoretic energy storage density and long service life. As we know, improvement of theenergy storage density for AFE material is beneficial to increase the power and reduce theweight and volume of pulse power. Some researchers have improved the energy storagedensity of PZ thin films to some extent through enhancing polarization by doping method.However, there is still a certain gap between the above results and practical applicationrequirements. Therefore, it is necessary to further improve the energy storage density of PZAFE thin film. In this thesis, we focus on preparing and improving the energy storageproperties of PZ thin film. The main contents and results are summarized as follows:1. Preparation and characterization of single PZ AFE thin filmsThe PZ thin films were deposited on the Pt(111)/Ti/SiO2/Si substrates by sol-gel. Toobtain the most optimized anneal parameter of PZ thin films, we prepared and investigatedthe PZ thin films which were anealed at different temperature for different time. The resultsshow that the PZ thin films annealed at700oC for20min exhibit the best properties with Pmaxof70.3μC/cm2and maximum energy storage density of13.52J/cm3at the electric field of500kV/cm.2. Preparation and energy storage properties of different types of PZ/BT-BMTmultilayered thin filmsWe combine the PZ AFE thin films and the0.88BaTiO3-0.12Bi(Mg0.5,Ti0.5)O3(BT-BMT)ferroelectric thin films with high εrand Edbto form different types of multilayered thin films,whose microstructures and electrical properties were investigated. For the PZ/BT-BMTbilayered thin films, their Pmaxand maximum energy storage density are90.9μC/cm2and15.3J/cm3, respectively; For the PZ/BT-BMT/PZ trilayered thin films, their Pmaxand maximumenergy storage density are92.2μC/cm2and19.9J/cm3, respectively; For the P/B/P/B/P/Bmultilayered thin films, their Pmaxand maximum energy storage density are95.7μC/cm2and 24.7J/cm3, respectively. The above results reflect that combination of BT-BMT ferroelectricthin films is an effective method to improve energy storage performance of PZ AFE thinfilms.3. Optimizing the annealing process and studying the energy storage properties ofPZ/BT-BMT miltilayered thin filmsTo further improve the energy storage properties, the PZ/BT-BMT multilayered thinfilms were prepared using a modified annealing method, in which each layer of themultilayered thin films was annealed at700oC for3min after being dried at180oC for3minand pyrolyzed at400oC for5min, and the final multilayered thin films were annealed at700oC for10min (We call them as the layer-by-layer annealed multilayered thin films. For thethin films prepared by the primary annealing method, we call them as the one-step annealedmultilayered thin films). Compared with the one-step annealed multilayered thin films, thelayer-by-layer annealed multilayered thin films exibit better energy storage performance,which can be attributed to their higher degree of the preferential orientation in polarization.The maximum energy storage density of the layer-by-layer annealed PZ/BT-BMT/PZtrilayered thin films and P/B/P/B/P/B multilayered thin films reach28.4J/cm3and33J/cm3,respectively.