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The (Mg0.75Zn0.25)TiO3 ceramics with Ta2O5 additive were prepared with solid-state reaction method. Ta2O5 as an additive effectively lowered the sintering temperature to 1100 °C and improved the microstructure of the ceramics. Ta5+ was completely incorporated into the (Mg0.75Zn0.25)TiO3 lattice to form the ilmenite phase (R-3), alongside the emergence of a second phase, MgTi2O5. The increasing content of the second phase caused the cell volume of the main phase to increase. When the Ta2O5 content is less than 5 wt%, the density of the ceramics has the main effect on the εr, while above 5 wt%, the second phase plays a dominant role in the εr of the ceramics. The results showed that when the additive of Ta2O5 is 2 wt%, the ceramics sintered at 1100 °C for 3 h exhibited the excellent microwave dielectric properties of Q × f ~ 108,726 (at 7.9 GHz), εr ~ 18.73 and τf ~ − 59.76 ppm/°C. [ABSTRACT FROM AUTHOR]

In the field of dielectric energy storage, achieving the combination of high recoverable energy density (Wrec) and high storage efficiency (η) remains a major challenge. Here, a high‐entropy design in tungsten bronze ceramics is proposed with disordered polarization functional cells, which disrupts the long‐range ferroelectric order into diverse polar nanoregions (PNRs) characterized by composition fluctuation and cation displacement. These PNRs lower the domain‐switching barriers and weaken domain intercoupling, thereby playing a key role in delaying polarization saturation, reducing energy loss, and enhancing the breakdown electric field (Eb). Benefiting from the synergistic effects, at a large Eb of 760 kV cm−1, breakthrough energy storage performance is realized in tungsten bronze ceramics, including a record‐high Wrec of ≈10.6 J cm−3, an ultrahigh η of ≈96.2%, and a record‐high figure of merit of ≈279. These developments, along with superior mechanical properties, stability, and charge–discharge performance, fully demonstrate the feasibility of this strategy for realizing structural‐functional integration in tungsten bronze ceramics. [ABSTRACT FROM AUTHOR]