Structure and energy storage properties of Mn-doped (Ba,Sr)TiO3–MgO composite ceramics

The search for materials with high dielectric breakdown strength and discharged energy density for high power capacitors has been widely explored. In this work, composite ceramics of Ba0.4Sr0.6(Ti0.996Mn0.004)O3–x wt% MgO (0 ≤ x ≤ 6) were prepared by conventional solid state sintering process. Structure and energy storage properties were investigated in detail. It was found that the discharged energy density (Wrec) and energy storage efficiency (η) was obviously enhanced in Mn-doped in Ba0.4Sr0.6TiO3 with MgO addition. As the concentration of MgO increased, the breakdown electric field (Eb) of Ba0.4Sr0.6(Ti0.996Mn0.004)O3–MgO composite was greatly improved. The Ba0.4Sr0.6(Ti0.996Mn0.004)O3–2 wt% MgO ceramic exhibited excellent energy storage properties with a Wrec ~ 2.014 J/cm3 and a η ~ 88.6% at a high Eb ~ 300 kV/cm. This work significantly increased the Eb and Wrec of BST-based materials for high power energy storage applications.