Preparation And Energy Storage Properties Of Entropy-Stabilized Perovskite Oxide Ferroelectric Thin Films

In the field of energy storage,dielectric capacitors made of ferroelectric materials have extremely high-power density and play an irreplaceable role in pulse power systems.The dispersion phase transition behavior of ferroelectric materials is beneficial for improving energy storage performance,so developing new ferroelectric materials with dispersion phase transition behavior has become a widely concerned topic for current researchers.Entropy-stabilized perovskite oxide ferroelectric materials exhibit dispersed phase transitions due to disordered chemical composition at the atomic scale,providing a new approach for developing high energy storage performance ferroelectric materials.Therefore,they have been widely studied in ferroelectric energy storage ceramics.Compared with bulk ceramics,thin film materials with low crystallization temperature and small volume are more in line with the development trend of miniaturization of electronic devices.In addition,thin film materials have more excellent electrical properties than bulk ceramics,so studying entropy stable perovskite oxide ferroelectric thin films is of great research significance for developing dielectric materials with excellent energy storage performance.In this study,The(Pb_0.25Ba_0.25Sr_0.25Ca_0.25)Ti O₃（PBSCT）entropy-stabilized perovskite oxide ferroelectric thin films were prepared on Pt（111）/Ti/Si O₂/Si substrates by sol-gel method.The main research content is as follows:（1）The PBSCT entropy-stabilized perovskite oxide ferroelectric thin films were successfully prepared on Pt（111）/Ti/Si O₂/Si substrates by a sol-gel method,and the influence of precursor solution on the performance of the film was explored.The results show that adding acetylacetone to the precursor solution and excessive addition of 5 mol%Pb can effectively improve the microstructure of the film,thereby significantly improving the leakage behavior of the films.（2）The effects of annealing temperature on the phase structure,microstructure,and electrical properties of PBSCT thin films were studied.The results show that when the annealing temperature is above 700℃,the film can form a single-phase,while when the annealing temperature is below 700℃,a second phase appears,indicating that entropy and enthalpy jointly determine the formation of single-phase.When the annealing temperature is750℃,the thin film is dense and has good electrical properties.At an electric field intensity of 1010 k V/cm,the energy storage density of PBSCT thin film can reach 4.56 J/cm³,which is much higher than the entropy stable oxide ceramics of other systems.（3）On the basis of equimolar ratio PBSCT thin films,component design was carried out to increase the molar ratio of Pb in PBSCT components,and the effects of Pb molar ratio on the microstructure and electrical properties of PBSCT films were studied.The results indicate that increasing the Pb molar ratio is beneficial for regulating the polarization behavior of the thin film.The thin films with a Pb molar ratio of 0.34 have an energy storage density of 6.92J/cm³ under a 1010 k V/cm electric field,which is 52%higher than the PBSCT thin film with equal molar ratio.