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 ε _r > 5 × 10 ⁴ , 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 _1-x Sn _x )O ₃ (BTS) through doping with Bi _1.5 ZnNb _1.5 O ₇ (BZN) additives. The results suggest that the electric strength has been largely improved in the modified tricritical ferroelectric material (BTS _x -yBZN), and the associated energy density reaches U _e = 1.15 J/cm ³ . 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.