Energy-storage properties of low-temperature Co-fired BNT-ST/AgPd multilayer lead-free ceramic capacitors

A lead-free 0.6Bi(0.5)Na(0.5)TiO(3)-0.4SrTiO(3) ceramic doped with Nb2O5, CuO and MnO2 additives (BNSr(0.4)TNbxCu(0.8)Mn(0.15)) was synthesized at a relatively low firing temperature of 1050 degrees C. Using this composition, multilayer ceramic capacitors with AgPd inner electrodes were successfully prepared by a tape-casting method for energy storage applications. Due to the high polarization P-max and low hysteresis, the largest recoverable energy storage density W-rec value of 1.9 J/cc and high efficiency eta of 89% were obtained in the BNSr0.4TNb2.5Cu0.8Mn0.15 composition under a low electric field of 170 kV/cm. The multilayer BNSr0.4TNb2.5Cu0.8Mn0.15/Ag75Pd25 capacitors contain 30 active layers, in which the thickness of a single ceramic layer was approximately 27 mu m. Under a low electric field of 270 kV/cm, excellent energy storage performance was observed in multilayer capacitors, with a W-rec of 2.83 J/cc and eta of 85%. The capacitors demonstrate the temperature insensitive properties that the variation in W-rec was less than 5% between 25 degrees C and 100 degrees C. These results indicate that this ceramic capacitor is a promising candidate for lead-free energy storage applications. (C) 2020 Elsevier B.V. All rights reserved.