Enhancing dielectric permittivity for energy-storage devices through tricritical phenomenon

Abstract

Although dielectric energy-storing devices are frequently used in high voltage level, the fast growing on the portable and wearable electronics have been increasing the demand on the energy-storing devices at finite electric field strength. This paper proposes an approach on enhancing energy density under low electric field through compositionally inducing tricriticality in Ba(Ti,Sn)O3 ferroelectric material system with enlarged dielectric response. The optimal dielectric permittivity at tricritical point can reach to εr = 5.4 × 104, and the associated energy density goes to around 30 mJ/cm3 at the electric field of 10 kV/cm, which exceeds most of the selected ferroelectric materials at the same field strength. The microstructure nature for such a tricritical behavior shows polarization inhomogeneity in nanometeric scale, which indicates a large polarizability under external electric field. Further phenomenological Landau modeling suggests that large dielectric permittivity and energy density can be ascribed to the vanishing of energy barrier for polarization altering caused by tricriticality. Our results may shed light on developing energy-storing dielectrics with large permittivity and energy density at low electric field.

Structure‐property relationships in BiScO3–PbTiO3–PbMg1/3Nb2/3O3 ceramics near the morphotropic phase boundary

“…It is known that near singular elements of phase diagrams (in particular the tricritical points) the functions of response, for example ε/ε 0 , have extremums . The enhancement of the dielectric response was observed close to the assumed tricritical points in the (1− x )Ba(Zr 0.2 Ti 0.8 )O 3 ‐ x (Ba 0.7 Ca 0.3 )TiO 3 , Ba(Ti,Sn)O 3 solid solutions and in the ceramics of the multicomponent system on the basis of PMN–PT . The existence of a crossover from the second to the first‐order phase transition for x > 0.42 evidenced by the characteristic behavior of the dependencies d (ε/ε 0 )/d T (Figure ).…”

Multifunctional barium titanate ceramics via chemical modification tuning phase structure

“…The nearly vanishing of energy barrier for polarization switching indicates the large polarizability even if the small external electric field is applied, finally leading to the giant dielectric response near this point. For instance, relative to pure BT with first‐order phase transition, the larger dielectric response and more flattened free energy profile are shown in Ba(Ti 1‐ x Sn x )O 3 system with critical point (Figure 12F‐G2) 212 . In this system, high‐resolution STEM directly observes the formed polar nanoregions and nanoscale polarization inhomogeneity due to the Sn 4+ substitution‐induced local chemical heterogeneity (Figure 12H).…”

Recent Progress on BaTiO3-Based Piezoelectric Ceramics for Actuator Applications

“…It should be noted that the reason for such a dispute stems from the challenge in accurate determination of the position of the triple point and the tricritical point. Further investigations are required in order to solve the discrepancy [77][78][79][80]. …”