Nature Communications, Published online: 20 July 2026; doi:10.1038/s41467-026-75708-z The authors construct tungsten bronze–perovskite composites with a SiO₂ coating, forming a dual-core-shell architecture. This design yields a high energy density of 23.2 J/cm³ and 92.8% efficiency in multilayer ceramic capacitors, due to enhanced polarization and breakdown strength, alongside excellent thermal and fatigue stability.