Flexible　piezoelectric　energy　harvesters　(FPEHs)　can　convert　mechanical　energy　into　electric　energy　in　a　manner　that　powers　electronic　equipment　and　systems.　Structural　design　of　piezoelectric　fillers　in　organic–inorganic　piezocomposites　is　means　of　enhancing　the　power　generation　performance　of　FPEHs.　Herein,　a　design　strategy　of　piezoelectric　fillers　is　proposed:　decorating　Ag　nanoparticles　onto　Ba0.85Ca0.15Ti0.9Zr0.1O3　(BCZT)　particles,　forming　a　BCZT@Ag　heterostructure,　thus　obtaining　BCZT@Ag/poly(vinylidene　fluoride)　(PVDF)　piezocomposites.　An　extremely　high　piezoelectric　constant　d33　of　34　pC/N　is　achieved　in　the　BCZT@Ag/PVDF　sample,　which　is　2.6　times　higher　than　that　of　the　BCZT/PVDF　sample.　The　greatly　improved　piezoelectric　properties　are　attributable　to　enhanced　interfacial　polarization　via　BCZT@Ag　heterostructure　design.　More　poling　electric　voltage　is　applied　to　the　piezoelectric　filler　particles,　resulting　in　substantially　improved　poling　efficiency.　This　composite　approach　of　introducing　metal　particles　is　a　generic　design　method　and　can　be　extended　to　other　organic–inorganic　piezocomposite　systems.　©　2023　Elsevier　B.V.