Preparation And Energy-storage Behavior Of PT-BiMeO₃ Relaxor Ferroelectric Thin Films

PbTiO₃-BiMeO₃ is a relaxor ferroelectric material with perovskite structure.It has large saturation polarization,high Curie temperature and dielectric constant.It is considered to be a potential energy-storage material.In this dissertation,PbTiO₃-BiMeO₃ relaxor ferroelectric thin films were studied.We have investigated phase structure,microstructure,dielectric properties and energy-storage behavior of the films doped with different Me ions by optimizing the preparation process.?1-x?PbTiO₃-xBi(Mg_0.5Zr_0.5)O₃ dielectric properties and energy-storage behavior?1-x?PbTiO₃-xBi(Mg_0.5Zr_0.5)O₃?x=0.3,0.4,0.5 and 0.6?relaxor ferroelectric thin films were prepared on LaNiO₃?100?/Pt/TiO₂/SiO₂/Si?100?substrates by optimizing the preparation process of sol and the heat treatment process of thin films.The results show that the grain size of the films increases gradually by introducing Mg²⁺and Zr⁴⁺.For dielectric properties,with the increase of Bi(Mg_0.5Zr_0.5)O₃ content,the dielectric constant decreases gradually,and shows obvious relaxation behavior.The diffusion coefficient changes from 1.97 to 1.64 from x=0.4 to0.6.The leakage current density decreases gradually and the breakdown field strength increases continuously,from x=0.3 to 0.6,the breakdown field strength increases from 2368 kV/cm to3184 kV/cm.And the ferroelectric properties are improved.When x=0.4,the best energy-storage performance is obtained.Its energy-storage density can reach 32.3 J/cm³,energy-storage efficiency is 51.4%,and it has high dielectric constant and minimal dielectric loss.In addition,0.6PbTiO₃-0.4Bi(Mg_0.5Zr_0.5)O₃ has excellent energy-storage stability.?1-x?PbTiO₃-xBi(Mg_0.5Ti_0.5)O₃ dielectric properties and energy-storage behaviorThe?1-x?PbTiO₃-xBi(Mg_0.5Ti_0.5)O₃ thin films were prepared on the LaNiO₃?100?/Si?100?substrate by sol-gel method.The results show that the dielectric constant of the film has little change with temperature,showing excellent dielectric temperature stability.With the increase of Bi(Mg_0.5Ti_0.5)O₃ content,the relaxation performance increases gradually,and the dispersion coefficient increases from 1.82 to 1.96.Generally,the increase of relaxation is helpful to improve the polarization difference of thin film materials and consequently improve the energy-storage performance.Ultra-high energy density of 51.0 J/cm³ was obtained at 2900kV/cm with the thin films x=0.5.In addition,the film has good frequency stability and temperature stability,and the rate of change of frequency stability and temperature stability is less than 2.8%.Energy-storage stability of 0.5PbTiO₃-0.5Bi(Mg_0.5Ti_0.5)O₃ flexible films0.5PbTiO₃-0.5Bi(Mg_0.5Ti_0.5)O₃ flexible relaxor ferroelectric thin films were fabricated on LaNiO₃?100?/nickel foil substrates by sol-gel method.At 1950 kV/cm,the energy-storage density was 25.8 J/cm³,the energy-storage efficiency was 59.6%,and it has excellent frequency stability and temperature stability of energy-storage performance.The dielectric properties and energy-storage stability of thin films were measured under different bending radius.It was found that the bending radius had little effect on the dielectric properties and energy-storage behavior of the thin films.Under different bending radius,the change rates of the energy-storage density and energy-storage efficiency were 1%and 1.3%,respectively.After 5000 bending cycles,it was found that the energy-storage behavior of the film remained stable,and the change rate of energy-storage density and energy-storage efficiency were 1%and 0.7%,respectively.