Piezoelectric　energy　harvesting　is　a　promising　means　to　realize　self-powered　microelectronic　devices.　However,　the　low　power　density　severely　restricts　its　development.　The　key　challenge　lies　in　manipulating　ferroic　domain　structure　in　order　to　overcome　thermodynamic　constraints　(high　piezoelectric　constant　d　together　with　high　dielectric　constant　epsilon)　of　piezoelectric　materials,　and　obtain　a　high　figure　of　merit　for　energy　harvesting　(transduction　coefficient　=　d(2)/epsilon).　Here,　we　propose　a　new　strategy　to　decouple　between　epsilon　and　d,　and　thus　enhance　the　salient　figure　of　merit　for　polycrystalline　ceramics　by　manipulating　the　intragranular　structure.　We　fabricated　high-quality　ferroelectric/metal　(Ba0.85Ca0.15Ti0.9Zr0.1O3/Ag,　BCTZ/Ag)　lead-free　piezocomposites　with　intragranular　structure,　in　which　the　electrostrictive　coefficient　(Q)　is　substantially　enhanced,　leading　to　stable　piezoelectric　coefficient.　Meanwhile,　the　non-ferroelectric　metal　Ag　phase　distributed　in　BCTZ　ferroelectric　grains　results　in　the　sharp　drop　of　dielectric　constant.　The　transduction　coefficient,　current　density　and　power　density　of　BCTZ/0.03Ag　sample　are　up　to　10000　x　10(-15)　m(2)/N,　1.04　mu　A/mm(2)　and　3.62　mu　W/mm(3),　outperforming　state-of-the-art　lead-free　piezoelectric　ceramics.　This　work　provides　a　new　paradigm　for　the　design　of　high-performance　lead-free　piezoelectric　energy　harvesting　materials.　(C)　2021　Acta　Materialia　Inc.　Published　by　Elsevier　Ltd.　All　rights　reserved.