Preparation Of Barium Titanate Based Ferroelectric Ceramicsand Electrical Performance Studies

Due to the rapid development of electronic information technology,the electronic information industry has higher and higher requirements for the electrical performance of ferroelectric ceramic capacitors,as well as for the miniaturization and large capacity of electric energy storage components.Currently,most of the commercial lead-based ferroelectric ceramics on the market,although possessing high electrical performance,cause immeasurable damage to the environment.Therefore,It is particularly important to develop lead-free ferroelectric ceramics with environment-friendly properties.Barium titanate(Ba_1-xSr_xTi O₃,BST)is a solid solution of barium titanate and strontium titanate.It has the advantages of high dielectric constant,low dielectric loss,and better energy storage performance.In this paper,based on the barium titanate series ferroelectric ceramics,the second component of the solid solution is used for doping control to improve the BST electrical properties of ferroelectric ceramics.The related properties are tested and comprehensively analyzed.（1-x）Ba_0.7Sr_0.3Ti O₃-x Bi(Zn_0.5Ti_0.5)O₃ ferroelectric energy storage ceramics（abbreviated as（1-x）BST-x BZT,where x=0.05,0.10,0.15,0.20）were prepared by conventional solid-state method and the related tests and system analysis were carried out.The results show that by introducing BZT,the average grain size and dielectric constant of BST are effectively reduced,the residual polarization strength P_r of BST ceramics is suppressed,and the breakdown field strength E_b is increased,and the P-E loop becomes"fine".The 0.85BST-0.15BZT ferroelectric ceramic has a recoverable energy storage density of 2.18J/cm³ and an energy storage efficiency of 94.40%under 240k V/cm electric field.In addition,the frequency stability of the ceramic is maintained at a high level from 5Hz to 500Hz when the applied electric field is 200 k V/cm.0.85BST-0.15BZT ceramics have a power density of 16.47MW/cm³ and a discharge time of0.49μs in the 180k V/cm charge/discharge test.（1-x）Ba_0.7Sr_0.3Ti O₃-x Bi(Mg_0.5Zr_0.5)O₃ ferroelectric energy storage ceramics（abbreviated as（1-x）BST-x BMZ,where x=0.05,0.10,0.15,0.20）were prepared by the traditional solid-state method,and detailed tests and system analysis were carried out.The introduction of Mg²⁺and Zr⁴⁺into BST for partial ion substitution has a good effect,which greatly reduces the grain size,reduces the maximum value of the dielectric constant peak,and enhances the relaxation performance.The introduction of BMZ destroyed the long-range order structure of ferroelectric domains within a certain range,and then caused many polar nano-regions.In 0.85BST-0.15BMZ ceramics,recoverable energy storage density of 3.06J/cm³ and a high energy storage efficiency of 94.04%were obtained at the same time.At the same time,excellent frequency stability is achieved in the frequency range from 10Hz to 200Hz when an electric field of 200k V/cm is applied.In addition,the 0.85BST-0.15BMZ ceramic also exhibited a significant power density of 18.19MW/cm³ and a fast discharge time(t_0.9=1.06μs)at a 200k V/cm electric field.（1-x）Ba_0.7Sr_0.3Ti O₃-x Bi(Mg_0.5Ti_0.5)O₃ ferroelectric energy storage ceramics（abbreviated as（1-x）BST-x BMT,where x=0,0.05,0.15,0.20,0.25）were prepared by the traditional solid-state method and the related tests and comprehensive analysis were carried out.The results show that（1-x）BST-x BMT has a standard ABO₃ structure,the increase of BMT reduces its average grain size,resulting in the decrease and broadening of the dielectric constant peak,the introduction of BMT improves the breakdown field strength E_b of BST ceramics,the optimal component0.80BST-0.20BMT ceramics achieve 2.44J/cm³ reversible energy storage density and 76.25%energy storage efficiency under 300k V/cm electric field.In addition,the recoverable energy density and energy efficiency of 0.80BST-0.20BMT ferroelectric ceramics also have good frequency stability in the test frequency range from 5Hz to 500Hz.0.80BST-0.20BMT ferroelectric ceramics also exhibit electrical characteristics of high power density（P_D=16.06MW/cm³）and short discharge time(t_0.9=0.95μs)under 200k V/cm electric field..In summary,the electrical properties of the three ferroelectric ceramics prepared in this work are different,and the strontium barium titanate based ferroelectric ceramics have certain application potential in the field of environmentally friendly capacitor engineering.