| Summary: | Recently, tricritical ferroelectrics have been drawn tremendous attention, owing to their ultrahigh dielectric permittivities of up to <i>ε<sub>r</sub></i> > 5 × 10<sup>4</sup>, 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(Ti<sub>1−<i>x</i></sub>Sn<i><sub>x</sub></i>)O<sub>3</sub> (BTS) through doping with Bi<sub>1.5</sub>ZnNb<sub>1.5</sub>O<sub>7</sub> (BZN) additives. The results suggest that the electric strength has been largely improved in the modified tricritical ferroelectric material (BTS<i><sub>x</sub></i>-<i>y</i>BZN), and the associated energy density reaches <i>U</i><sub>e</sub> = 1.15 J/cm<sup>3</sup>. 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.
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