An　electrostatic　capacitor　for　energy　storage　is　an　important　basic　component　of　pulse　power　electronics.　The　electrical　breakdown　strength　(Eb)　of　normal　ferroelectrics　is　low,　which　limits　their　application　in　dielectric　energy　storage.　Constructing　a　0-3-type　composite　dielectric,　that　is,　introducing　an　insulating　metallic　oxide　into　the　ferroelectric　matrix,　can　greatly　enhance　Eb.　Unfortunately,　an　intergranular　secondary　phase　typically　forms　that　causes　large　attenuation　of　the　dielectric　constant,　which　leads　to　limited　improvement　of　energy　storage　performance.　In　this　work,　a　composite　ceramic　with　an　intragranular　segregation　structure　was　intentionally　designed　using　the　BaTiO3-BaZrO3-CaTiO3　(BCZT)　system　as　an　example.　Compared　with　those　of　a　BCZT　solid　solution　without　a　secondary　phase　and　a　BCZT　composite　with　a　grain-boundary　secondary　phase,　the　rationally　designed　BCZT　composite　with　an　intragranular　secondary　phase　delivered　a　large　recoverable　energy　density　of　5.86　J/cm3　and　high　efficiency　of　86.7%　at　a　moderate　electric　field　of　550　kV/cm.　Such　performance　was　achieved　because　the　intragranular　segregation　structure　displayed　delayed　saturation　polarization　with　a　high　Eb.　This　microstructural　engineering　strategy　is　generally　applicable　to　optimize　composite　dielectrics　to　meet　the　demands　of　high-performance　energy　storage　capacitors.　©　2024　American　Chemical　Society.