| Dielectric ceramics with high dielectric constant and insulance have been widely investigated for realization of compact pulse forming line. In this thesis, SrTiO3 ceramic was selected as study material. Glass additives were added into SrTiO3 ceramic to improve the insulativity; Pr element was doped into SrTiO3 ceramic to enhance its dielectric constant; at last, added glass additive into the Pr-doped SrTiO3 ceramic with high dielectric constant for the purpose of electrical structure optimization, in order to achieve both high dielectric constant and high insulance.Several glass additives were used in this thesis:(1) amorphous SiO2 with D50 of 4.0μm, abbrevated as S; (2) Ba-Al-B-Si-O glass with D50 of 12.7μm, synthesized by solid state method, abbrevated as G; (3) Ba-Al-B-Si-O glass synthesized by a sol-gel method, abbrevated as SG, three glass powders with D50 of 6.1μm,2.2μm and 0.6μm, abbrevated as SG1, SG2 and SG3, respectively, were obtained by changing the milling time. The sintering, structure and dielectric properties of ceramics added with different glass additives were compared, respectively. Finally, SG2 additive was selected as glass additive for SrTiO3-based energy storage ceramics.The correlation between dielectric properties and electrical microstructure in SrTiO3-based energy storage ceramics was investigated. The impedance and dielectric properties of samples were measured. The results indicated that grain boundaries were dominant resistant part in samples, and that there were interfacial polarizations between grains and boundaries in samples. For SG2-added SrTiO3 ceramics, the SG2 additive distributed in grain boundaries, at one hand, improved the insulance of ceramics, which enhanced the energy storage performance of ceramics; at another hand, the insulating additive distributed in grain boundaries enhanced the interfacial polarizations between grains and grain boundaries, which influenced the dielectric properties of ceramics.With composition of PrxSr1-xTiO3, Pr-doped SrTiO3 ceramics were obtained using solid state method. The samples exhibited dielectric constant at 1kHz in a range of 310～4750, and the x=0.0100 composition sample showed the highest dielectric constant of 4750. The dielectric properties of ceramics were investigated, and the results exhibited that there were several dielectric relaxations in the range of -150～450℃in Pr-doped SrTiO3 ceramics, which indicated that defect polarization mechanism existed in ceramics. Impedance analysis showed that the Pr-doped SrTiO3 ceramics with high dielectric constant of order of 103 exhibited semiconducting grains, insulating interlayers and grain boundaries, which proved that interfacial polarization mechanism existed in ceramics.The correlation between oxygen vacancies and polarization mechanisms in Pr-doped SrTiO3 ceramics was investigated. After annealing in air at 1100℃for different time, the dielectric properties and electrical structure of Pr-doped SrTiO3 ceramics were investigated. The results revealed that dielectric relaxations in the range of -150～-450℃were all related to oxygen vacancies induced defect polarization mechanism. Through impedance analysis, it can be seen that ionization of oxygen vacancies enhanced the sermconducting behavior of grains in Pr-doped SrTiO3 ceramics, and that the sermconducting grains enhanced the interfacial polarization which resulted in high dielectric constant of ceramics. According to above results, the high dielectric constant of Pr-doped SrTiO3 ceramics was resulted from the oxygen vacancies existed in ceramics.The x=0.0100 composition with the highest dielectric constant among all PrxSr1-xTiO3 compositions, abbreviated as PSTO, was selected as study compostion. In order to enhance the insulance of PSTO samples, SG2 additive was added, to optimize the electrical structure of samples. Meanwhile, the dielectric loss of samples decreased obviously after adding SG2 additive. Added with 20vol.% SG2 additive, the sample revealed excellent dielectric properties as follow:room temperature dielectric constant and dielectric loss at 1kHz of 514 and 0.008, respectively, direct current resistivity of 6.231×109Ω·cm.
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