High‐Entropy Tungsten Bronze Ceramics for Large Capacitive Energy Storage with Near‐Zero Losses

Abstract In the field of dielectric energy storage, achieving the combination of high recoverable energy density (W_rec) 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 (E_b). Benefiting from the synergistic effects, at a large E_b of 760 kV cm⁻¹, breakthrough energy storage performance is realized in tungsten bronze ceramics, including a record‐high W_rec 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.