Preparation And Properties Of Barium Strontium Titanate And Zinc Bismuth Niobate In High Energy Storage Density Thin Film Capacitors

Although wind energy,solar energy,tidal energy and other new energy have been converted into electricity to alleviate the energy crisis,the problem of power storage technology has not been solved,the problem of electric energy storage technology has not been solved.Capacitor is the core unit of electric energy storage,traditional capacitors have seriously hindered the development of these industries because of their large size,low energy storage density and high loss.High energy storage density thin film capacitors have large dielectric constant,low loss and high breakdown voltage,which can make energy storage capacitors smaller,higher energy storage density and longer service life.In this paper,two kinds of dielectric thin films barium strontium titanate and bismuth zinc niobate which can be used in thin film capacitors were prepared by sol-gel method.Barium strontium titanate Ba_0.5Sr_0.5TiO₃?BST?and bis-zinc niobate Bi_1.5ZnNb_1.5O₇?BZN?films with perovskite structure have the advantages of high dielectric constant,low tangent loss,large energy storage density and high transmittance.In the preparation of BST and BZN dielectric films,the effects of different annealing temperatures on the structure and properties of BST and the effects of pH of the precursor solution on the structure and properties of BZN were studied,and the relationships among material composition,crystal structure,dielectric properties,energy storage density and transmittance were established.The primary research details and consequences are as below:?1?BST dielectric films were prepared on FTO glass substrate by improved sol-gel method,the polycondensation reaction of CA-EG during the sol formation process was explained,and the influence of annealing temperature on the crystal structure and electrical properties was studied.When annealing temperature is 600?,the relative strength of BST thin films diffraction peak is the largest,the most narrow,half peak crystallization degree is highest,the minimum deviation of the binding energy of membrane element,the binding energy of phase difference is the most close to the theoretical value,the film has the best electrical properties,dielectric constant is 80,the highest voltage breakdown value of 1.85 MV/cm,the minimum voltage loss tangent is 0.008,the highest energy storage density of 1.21 J/cm³,the highest average optical transmittance was 87.2%.?2?In the preparation of BZN dielectric thin films on FTO glass substrate,Nb2O5 is used instead of niobium ethanol,which reduces the cost of Nb solution and optimizes the Nb-CA process.The effect of pH value of precursor solution on its crystal structure,electrical properties and optical properties was studied by controlling the pH value of the precursor solution with citric acid and ammonia.It is found that when the precursor liquid pH=5 is used,the relative intensity of the diffraction peak of the BZN film is the highest,the half peak is the narrowest,the crystallization degree is the highest,the binding energy offset of the film elements is the smallest,and the phase difference of the binding energy is the closest to the theoretical value.At this time,the BZN films have the best electrical properties,the dielectric constant is 120,the loss tangent is 0.003,the tuning rate is 14.8%,and the energy storage density is 9.82×10² J/cm³,87.2%of the average optical transmittance.