Pb/Bi-free Tungsten Bronze-Based Relaxor Ferroelectric Ceramics with Remarkable Energy Storage Performance

Abstract

In this study, a Pb/Bi-free Sr2KNb5O15-based tungsten bronze relaxor ceramic system was developed for possible energy storage applications via the site engineering technology. The introduction of Ta at the Nb site enhanced the breakdown strength and relaxor nature of the Sr2KNb5O15 ceramic. An extremely high energy storage density (∼3.84 J/cm3) accompanied by a remarkable energy storage efficiency (∼93.2%) was obtained under an applied electric field of 410 kV/cm in the composition of Sr2KNb4.2Ta0.8O15. Meanwhile, the ceramic exhibited a relatively wide frequency stability (1–500 Hz) and thermal stability (30–120 °C) and displayed a remarkable fatigue endurance after 104 cycles. Even more surprisingly, the Sr2KNb4.2Ta0.8O15 ceramic processed excellent discharging performances with a short discharge time (τ0.9 < 75 ns), a large discharge current density (1019 A/cm2), and an amazing power density (125.6 MW/cm3). The impressive performances demonstrated that the Sr2KNb4.2Ta0.8O15 tungsten bronze ceramic might be a potential Pb/Bi-free dielectric material for high-power pulse capacitor applications.

Fantastic Energy Storage Performances and Excellent Stability in BiFeO3–SrTiO3-Based Relaxor Ferroelectric Ceramics

“…Moreover, minor changes in the P max and P r can be noticed as the temperature increases from 30 to 140 °C, resulting in superior thermal stability of the 0.7­(BF-ST)-0.3SBT ceramic with a slight change of W rec and η less than 5.5% and 3.3% respectively Figure g compares the temperature-dependent η and W rec of this work with that of some recently reported lead-free ceramics. ,− As shown, the 0.7­(BF-ST)-0.3SBT ceramic displays superior thermal stability with significant ESP ( W rec = 3.51–3.43 J/cm 3 and η = 83.8–82.0%) in the temperature range from 30 to 140 °C, which makes it an up-and-coming candidate in the energy storage application field.…”

Superior Energy Density Achieved in Unfilled Tungsten Bronze Ferroelectrics via Multiscale Regulation Strategy

“…e) The comparison of W rec and η values of SLBNT and other recently reported lead‐free bulk ceramics. [ 17,18,22–24,27–29,38–53 ]…”

Enhancing Energy Storage Performance in Lead-Free Bismuth Sodium Niobate-Based Tungsten Bronze Ceramics through Relaxor Tuning

“…The triangular C sites with 9-coordination are generally empty. 18 According to the filling conditions of A, B, and C sites, the TTB structure can be divided into three different types: fully filled tungsten bronze structure, filled tungsten bronze structure, and unfilled tungsten bronze structure. The disorder of multiple ions occupying the A1, A2, and B sites makes the performance of TTB ceramics more flexible and adjustable.…”

“…Alkali metal ions and alkaline earth metal ions with large ionic radii occupy the 15-coordination A1 and 12-coordination A2 sites, while Nb 5+ , Ta 5+ , Zr 4+ , Ti 4+ , and other ions with small ionic radii occupy the 6-coordination B sites. The triangular C sites with 9-coordination are generally empty . According to the filling conditions of A, B, and C sites, the TTB structure can be divided into three different types: fully filled tungsten bronze structure, filled tungsten bronze structure, and unfilled tungsten bronze structure.…”