Primary radiation damage: A review of current understanding and models

Although extensive studies have been done on lead-free dielectric ceramics to achieve excellent dielectric behaviors and good energy storage performance, the major problem of low energy density has not been solved so far. Here, we report on designing the crossover relaxor ferroelectrics (CRFE), a crossover region between the normal ferroelectrics and relaxor ferroelectrics, as a solution to overcome the low energy density. CRFE exhibits smaller free energy and lower defect density in the modified Landau theory, which helps to obtain ultrahigh energy density and efficiency. The (1-x)Ba0.65Sr0.35TiO3-xBi(Mg2/3Nb1/3)O3 ((1-x)BST-xBMN) (x = 0, 0.08, 0.1, 0.18, 0.2) ceramic was synthesized by a solid-state reaction method. The solid solutions exhibit dielectric frequency dispersion, which suggests typical relaxor characteristics with the increasing BMN content. The crossover ferroelectrics of 0.9BST-0.1BMN ceramic possesses a high energy storage efficiency (η) of 85.71%, a high energy storage density (W) of 3.90 J/cm3, and an ultrahigh recoverable energy storage density (Wrec) of 3.34 J/cm3 under a dielectric breakdown strength of 400 kV/cm and is superior to other lead-free BaTiO3 (BT)-based energy storage ceramics. It also exhibits strong thermal stability in the temperature range from 25 to 150 °C under an electric field of 300 kV/cm, with the fluctuations below 3% and with the energy storage density and energy efficiency at about 2.8 J/cm3 and 82.93%, respectively. The enhanced recoverable energy density and breakdown strength of BT-based materials with significantly high energy efficiency make it a promising candidate to meet the wide requirements for high power applications.

Effective Strategy to Achieve Excellent Energy Storage Properties in Lead-Free BaTiO3-Based Bulk Ceramics

Energy storage performance of BaTiO3-based relaxor ferroelectric ceramics prepared through a two-step process

Dielectric ceramic capacitors, with the advantages of high power density, fast charge-discharge capability, excellent fatigue endurance, and good high temperature stability, have been acknowledged to be promising candidates for solid-state pulse power systems. This review investigates the energy storage performances of linear dielectric, relaxor ferroelectric, and antiferroelectric from the viewpoint of chemical modification, macro/microstructural design, and electrical property optimization. Research progress of ceramic bulks and films for Pb-based and/or Pb-free systems is summarized. Finally, we propose the perspectives on the development of energy storage ceramics for pulse power capacitors in the future.

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Progress and perspectives in dielectric energy storage ceramics

Energy storage performance of Bi0.5Na0.5TiO3-based relaxor ferroelectric ceramics with superior temperature stability under low electric fields

(Ba0.3Sr0.7)x(Bi0.5Na0.5)1-xTiO3 (BSxBNT, x = 0.3–V0.8) ceramics were prepared to investigate their structure, dielectric and ferroelectric properties. BSxBNT ceramics possess pure perovskite structure accompanied from a tetragonal symmetry to pseudo-cubic one with the increase of x value, being confirmed by X-ray diffraction (XRD) and Raman results. The Tm corresponding to a temperature in the vicinity of maximum dielectric constant gradually decreases from 110 °C (x = 0.3) to -45 °C (x = 0.8), across Tm = 36 °C (x = 0.5) with a maximum dielectric constant (ɛr = 5920 @1 kHz) around room temperature. The saturated polarization Ps gradually while the remnant polarization Pr sharply decreases with the increase of x value, making the P-E hysteresis loop of BSxBNT ceramics goes slim. A maximum difference between Ps and Pr (Ps-Pr) is obtained for BSxBNT ceramics with x = 0.5, at which a high recoverable energy density (Wrec = 1.04 J/cm3) is achieved under an applied electric field of 100 kV/cm with an efficiency of η = 77%. Meanwhile, the varied temperature P-E loops, fatigue measurements, and electric breakdown characteristics for the sample with x = 0.5 indicate that it is promising for pulsed power energy storage capacitor candidate materials.

https://link.springer.com/content/pdf/10.1007/s40145-020-0358-9.pdf

P-E hysteresis loop going slim in Ba 0.3 Sr 0.7 TiO 3 -modified Bi 0.5 Na 0.5 TiO 3 ceramics for energy storage applications

Antiferroelectric NaNbO3 (NN) is chosen to modify a compositionally optimized BNT-based relaxor ferroelectric ceramic, (Ba0.3Sr0.7)0.35(Bi0.5Na0.5)0.65TiO3 (BSBNT), having the formula (1 − x)BSBNT–xNN, in which x = 0, 0.02, 0.04, 0.06, 0.08, and 0.10. All dense ceramics are indexed to a pure pseudocubic phase and show strong relaxor characteristics. For the 0.94BSBNT–0.06NN ceramic, a high recoverable energy density of Wrec = 1.25 J cm−3 is obtained at room temperature due to an optimization of the polarization behavior. The temperature dependent P–E hysteresis loop measurement and the fast charge–discharge test under underdamped and overdamped circuit conditions both demonstrate its relatively good temperature stability of energy storage properties. Together with excellent cycling reliability up to 105 cycles, the 0.94BSBNT–0.06NN ceramic has much potential for solid state compact pulsed power capacitors.

Optimization of polarization behavior in (1 − x)BSBNT–xNN ceramics for pulsed power capacitors

Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures

The development of the ab initio molecular dynamics (AIMD) method has made it a powerful tool in describing ion–solid interactions in materials, with the determination of threshold displacement energies with ab initio accuracy, and prediction of a new mechanism for defect generation and new defective states that are different from classical molecular dynamics (MD) simulations. In the present work, this method is employed to study the low energy recoil events in Gd2Zr2O7 and Gd2Ti2O7. The weighted average threshold displacement energies in Gd2Zr2O7 are determined to be 38.8 eV for Gd, 41.4 eV for Zr, 18.6 eV for O48f, and 15.6 eV for O8b, which are smaller than the respective values of 41.8, >53.8, 22.6 and 16.2 eV in Gd2Ti2O7. It reveals that all the ions in Gd2Zr2O7 are more easily displaced than those in Gd2Ti2O7, and anion order–disorder is more likely to be involved in the displacement events than cation disordering. The average charge transfer from the primary knock-on atom to its neighbors is estimated to be ∼0.15, ∼0.11 to 0.27 and ∼0.1 to 0.13 |e| for Gd, Zr (or Ti), and O, respectively. Neglecting the charge transfer in the interatomic potentials may result in the larger threshold displacement energies in classical MD.

Xingcai Wang

Papers

Progress and perspectives in dielectric energy storage ceramics

P-E hysteresis loop going slim in Ba 0.3 Sr 0.7 TiO 3 -modified Bi 0.5 Na 0.5 TiO 3 ceramics for energy storage applications

Optimization of polarization behavior in (1 − x)BSBNT–xNN ceramics for pulsed power capacitors

Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures

Ab initio molecular dynamics simulations of ion–solid interactions in Gd2Zr2O7 and Gd2Ti2O7