Microstructures and dielectric properties of Ba0.4Sr0.6TiO3 ceramics with BaO–TiO2–SiO2 glass–ceramics addition

• Ba0.4Sr0.6TiO3 ceramics with BaO–TiO2–SiO2 glass–ceramics addition were prepared.
• The glass phase inhabited the grain growth and improved the breakdown strength.
• The crystal phase inhibited the decrease of dielectric constant of ceramics.
• The energy density was increased by the common action of glass–ceramics.

The Ba0.4Sr0.6TiO3 energy storage ceramics with BaO–TiO2–SiO2 glass–ceramics additive were prepared via the solid state reaction route. The effects of glass–ceramics content on the sintering behavior, crystal structure, microstructure, dielectric property and energy storage property of Ba0.4Sr0.6TiO3 ceramics have been investigated. SEM-EDX spectra reveal that the glass phase in the BaO–TiO2–SiO2 glass–ceramics existed at grain boundary as liquid phase resulting in the decrease of sintering temperature. XRD results show that Ba0.4Sr0.6TiO3 ceramics exhibited a perovskite structure and emerged the secondary phase BaTi2Si2O8 from the crystal phase in the BaO–TiO2–SiO2 glass–ceramics. The ferroelectrics crystal phase BaTi2Si2O8 increased the dielectric constant of BaO–TiO2–SiO2 glass–ceramics, which inhibited the decrease of dielectric constant of Ba0.4Sr0.6TiO3 ceramics with BaO–TiO2–SiO2 glass–ceramics addition. The breakdown strength was notably improved due to the reduction of the grain size and the samples with 9 wt% glass–ceramics addition showed the highest average breakdown strength of 16.51 kV/mm, which was 1.8 times higher than that of pure Ba0.4Sr0.6TiO3 ceramics. The energy storage density of samples with 5 wt% glass–ceramics addition was 0.6045 J/cm3 attributed to the relatively high dielectric constant and breakdown strength.