Structure and energy storage properties of Ti vacancies charge compensated Re ₂O₃-doped SrTiO₃ (Re = Pr, Nd, Gd) ceramics

By introducing Ti vacancies in advance for charge compensation, single cubic perveskite rare-earth doped strontium titanate ceramics with the formula Re _0.02Sr_0.98Ti_0.995O₃ (Re–STO, Re = Pr, Nd, Gd) were prepared via solid-state reaction method. All Re–STO ceramics sintered at 1,410 °C in air for 3 h showed a similar dense microstructure with the grain size lower than 10 μm. The room temperature dielectric constant ε _r of Re–STO ceramics was higher than 3,000 (@ 1 kHz) and changed <8 % within the applied bias electric field. Especially, the room temperature dielectric loss tanδ of Re–STO ceramics was lower than 0.02 (@ 1 kHz), and the average breakdown strength E _b surpassed 14 kV/mm, demonstrating that Re–STO ceramics could be very promising for high-voltage capacitor applications. The temperature stability of the ε _r of Re–STO ceramics was evaluated in a temperature range of −50 to 200 °C. Meanwhile, the energy storage density of Re–STO ceramics was investigated as a function of the applied bias electric field.