In　this　study,　(Ba0.85Ca0.15)(Ti0.9Zr0.1)O-3　(BCTZ)　lead-free　ceramics　with　enhanced　energy　density　were　prepared　by　two-step　sintering.　All　ceramics　fall　into　the　rhombohedral-orthorhombic-tetragonal　(R-O-T)　phase　boundary　near　room　temperature,　and　a　dense　microstructure　with　an　intermediate　grain　size　was　observed.　The　enhanced　piezoelectric　and　energy　harvesting　properties　were　attained　over　a　wide　grain　size　range　of　10-15　mu　m,　benefiting　from　the　construction　of　the　R-O-T　phase　boundary.　Most　interestingly,　the　maximum　values　of　d(33)　and　d(33)　x　g(33)　(530　pC　N-1　and　9720　x　10(-15)　m(2)　N-1)　can　be　achieved　at　1500/1350　degrees　C　with　a　grain　size　of　13.7　mu　m.　The　interpretation　of　the　underlying　mechanism　related　to　domain　and　defect　engineering　has　been　investigated　systematically.　Furthermore,　a　high　output　power　of　99　mu　W　and　an　energy　conversion　efficiency　of　10%　were　obtained　at　a　simple　cantilever　energy　harvester　fabricated　from　a　1500/1350　degrees　C　specimen　under　an　acceleration　of　1.0g,　making　the　current　system　very　promising　for　piezoelectric　energy　harvesting　applications.