Piezoelectric　energy　harvesting　technology　is　drawing　substantial　attention　as　an　eco-friendly　method　to　promote　energy　transformation,　which　is　at　the　forefront　of　current　scientific　research.　However,　the　difficulties　involved　in　obtaining　a　stable　output　voltage　(Vout)　and　a　controllable　output　current　density　(Iout)　represent　bottlenecks　in　the　development　of　piezoelectric　energy　harvesters　(PEHs)　for　practical　applications.　Here,　a　novel　strategy　that　couples　elastic　polarization　configuration　with　activity　rattling　space　in　lead-free　potassium　sodium　niobate-based　piezoceramics　is　proposed　to　break　through　this　barrier.　The　cantilever　beam-type　PEHs　assembled　using　the　rationally　designed　piezoceramic　system　show　a　stable　Vout　(approximate　to　22　V)　and　a　controllable　Iout　over　the　range　from　6.09　to　20.16　mu　A　cm-2,　which　is　sufficient　to　drive　multiple　types　of　wireless　sensors　that　have　the　same　rated　voltage　but　different　rated　current　requirements.　These　fantastic　power　generation　performances　are　associated　with　a　stable　piezoelectric　voltage　coefficient　(g33),　an　increasing　piezoelectric　charge　coefficient　(d33),　and　a　weakened　electrostrictive　coefficient　(Q33)　that　stem　from　polarization　configuration　optimization　in　combination　with　introduction　of　the　activity　rattling　space　design.　This　work　provides　a　good　approach　to　modulation　of　the　overall　performance　of　piezoelectric　materials　to　meet　the　demands　of　advanced　PEH　applications.　The　polarization　configuration　optimization　with　the　introduction　of　activity　rattling　space　design　brings　a　stable　piezoelectric　voltage　coefficient　(g33),　and　an　increasing　piezoelectric　charge　coefficient　(d33),　resulting　in　the　fantastic　power　generation　performances　with　a　stable　Vout　and　a　controllable　Iout　in　lead-free　KNNS-xBNZ　PEHs.　image