Remarkably enhanced recoverable energy density in lead-free relaxor Ba0.94Ca0.06Ti1−xSnxO3 ceramics by the synergistic effect of nano-domains and refined grains

Abstract

High-performance dielectric ceramic capacitors is a promising candidate in energy storage devices. In this work, the energy storage performance of Ba0.94Ca0.06Ti1−xSnxO3 (x = 0.04, 0.08, 0.12, 0.16) ceramics was systematically studied. Through modifying Sn4+ doping content, the breakdown strength of the ceramics is enhanced by 112.3% from 133.4 kV/cm (Ba0.94Ca0.06Ti0.96Sn0.04O3) to 283.2 kV/cm (Ba0.94Ca0.06Ti0.84Sn0.16O3). Accordingly, the recoverable energy density is greatly increased by 276.2%, that is, from 0.42 J/cm3 grow to 1.58 J/cm3. The enhanced energy storage properties could be ascribed to the following aspects: (1) the doping of Sn4+ with a larger ionic radius inhibits the migration of grain boundaries and therefore refines grains, resulting in a higher activation energy and a larger Eb; (2) the long range polar order is broke and polar nano-regions are formed, giving rise to lower energy barrier and smaller Pr; (3) the weakened ferroelectricity and delayed polarization saturation lead to higher Wrec owing to the fact that Sn4+ with d10 electronic configurations substitutes Ti4+ with d0. Our work provides a novel approach for enhancing energy storage performance in dielectric ceramic capacitors.