Energy storage performance of high-entropy SBN-based tungsten bronze-structure ceramic

In the realm of high-power and pulse power electronic devices, lead-free dielectric ceramics have emerged as crucial components owing to their exceptional power density and ultra-fast charge-discharge capabilities. In this study, the high-entropy strategy was combined with bandgap engineering, to synthesize tungsten bronze- structured high-entropy lead-free dielectric ceramics with the formula of Sr0.475Ba0.475- La0.1Hf0.1Ti0.1Sb0.2TaxNb1.6-xO6 (Tax, where x varies from 0 to 0.3). The high-entropy strategy employed in this study effectively promotes cationic disorder and disrupts the long-range ferroelectric order, thereby intensifying the ferroelectric relaxation phenomenon. Additionally, the diminished grain size, augmented conductivity activation energy, and broadened bandgap collectively result in a remarkable increase in breakdown electric field strength. Remarkably, within the specific composition of Sr0.475Ba0.475La0.1Hf0.1Ti0.1Sb0.2Ta0.3Nb1.3O6 (x = 0.3) ceramics, outstanding energy storage parameters are achieved. A recoverable energy density of 5.22 J center dot cm-3 and an efficiency rate of 83.4 % are observed. Furthermore, a current density of approximately 1077.49 A center dot cm-2 and a power density of approximately 193.95 MW center dot cm-3 are attained, underscoring the superior performance of these materials. It is worth noting that the Ta0.3 ceramic sample exhibits a discharge time of only 13.8 ns, while maintaining excellent temperature stability within a range from 30 degrees C to 180 degrees C with a Delta Wdisof less than 10 %. These attributes position it as a potential candidate for an ultrafast charge-discharge pulse power capacitor. This research presents a promising methodology in advanced design of dielectric ceramics possessing outstanding energy storage capabilities and favourable temperature stability, paving the way for future advancements in high-power and pulse power electronic devices.