Improved Dielectric and Energy Storage Properties of Ba_0.8Ca_0.2TiO₃ Ceramics by Doping Ba(Mg_1/3Nb_2/3)O₃

Abstract

Lead-free Ba 0.8 Ca 0.2 TiO 3 -xmol%Ba(Mg 1/3 Nb 2/3 )O 3 (abbreviated as BCT20-xBMN, x ¼ 0-8) ceramics are fabricated by a conventional solid-state reaction method. All BCT20-xBMN ceramics have pure perovskite phases which gradually change from tetragonal phase to cubic phase. The average grain size decreases significantly from %23 to %1.2 μm with the increase in BMN content. The T m corresponding to the dielectric maximum of BCT20-xBMN decreases with the increase in x, and the room temperature dielectric constant increases significantly. The recoverable energy storage density W rec and efficiency η% are enhanced to 0.17 J cm À3 and 81.3% for BCT20-6BMN due to the reduced remanent polarization by BMN doping. The W rec increases with increasing temperature and shows peak values near the T m . The η% of BCT20-6BMN and BCT20-7BMN has good temperature stability due to enhanced relaxor behavior.