Improved Dielectric and Energy Storage Properties of Ba 0.8 Ca 0.2 TiO 3 Ceramics by Doping Ba(Mg 1/3 Nb 2/3 )O 3

Lead‐free Ba 0.8 Ca 0.2 TiO 3 – x mol%Ba(Mg 1/3 Nb 2/3 )O 3 (abbreviated as BCT20– x BMN, x  = 0–8) ceramics are fabricated by a conventional solid‐state reaction method. All BCT20– x BMN 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– x BMN 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 −3 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.