摘要
Among the lead-free compositions identified as potential capacitor materials, BiScO_(3)-BaTiO_(3) (BS-BT)relaxor dielectrics exhibit good energy storage performance. In this research, 0.4BS-0.6BT is consideredas the parent composition, with NaNbO_(3) (NN) addition intended to substitute the A and B site cations.The NN modified BS-BT ceramics exhibit excellent temperature stability in terms of their dielectricproperties, with the room-temperature dielectric constant on the order of 500e1 000 and variation lessthan 10% up to 400 C. In addition, NN has a high band-gap energy leading to increased breakdownstrength and energy storage properties in modified compositions. The highest breakdown strength wasachieved for 0.4BS-0.55BT-0.05NN, being on the order of 430 kV/cm, and a high energy density of 4.6 J/cm3 with high energy efficiency of 90% was simultaneously achieved. Of particular importance is that thevariation of the energy density was below 5% due to the temperature-insensitive dielectric constant,while ~90% energy efficiency was retained over the temperature range of 25e160 C. The improvedtemperature stability with NN addition makes this composition promising for high temperaturecapacitor and dielectric energy storage applications.
