Enhancing the Energy Density of Tricritical Ferroelectrics for Energy Storage Applications.

Recently, tricritical ferroelectrics have been drawn tremendous attention, owing to their ultrahigh dielectric permittivities of up to εr > 5 × 10⁴, and their consideration for prototype materials in the development of high-performance energy storage devices. Nevertheless, such a materials system suffers from the disadvantage of low breakdown strength, which makes its energy density far from the satisfactory level for practical application. In this paper, a material-modification approach has been reported, for improving the dielectric strength for tricritical ferroelectric materials Ba(Ti1-xSnx)O₃ (BTS) through doping with Bi1.5ZnNb1.5O₇ (BZN) additives. The results suggest that the electric strength has been largely improved in the modified tricritical ferroelectric material (BTSx-yBZN), and the associated energy density reaches Ue = 1.15 J/cm³. Further microstructure investigation indicates that the modified tricritical ferroelectric material exhibits homogenous fine grains with perovskite structure in crystal symmetry, and the BZN may help to form a special structure that could enhance the breakdown strength. The findings may advance the material design and development of high-energy storage materials.