Energy storage properties of ultra fine-grained Ba0.4Sr0.6TiO3-based ceramics sintered at low temperature

Fine-grained Ba0.4Sr0.6TiO3 ceramics with and without dopants were fabricated by two-step sintering method. Densities of fine-grained ceramics were found lower than those of coarse-grained ceramics, while the breakdown strength improved. With ZnO-Li2O sintering aids doped, the sintering temperature of ceramics decreased to 1200 °C. Their grain size is 219 nm, energy density is 0.564 J/cm3 and AC breakdown strength is 198.8 kV/cm, which is close to Ba0.4Sr0.6TiO3 ceramics obtained by SPS, and much higher than normal BST ceramics. The polarization of ceramics under the same electric field decreases with miniaturization of grain size, but the energy storage efficiency increases. Although smaller polarization due to small grain size is a disadvantage to energy density of bulk material, the features of low sintering temperature, traditional sintering route and small grain size jointly make the utilization in multilayer devices possible, thereby larger energy density can be achieved.