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

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.