High　temperature　piezoelectric　energy　harvester　(HT-PEH)　is　an　important　solution　to　replace　chemical　battery　to　achieve　independent　power　supply　of　HT　wireless　sensors.　However,　simultaneously　excellent　performances,　including　high　figure　of　merit　(FOM),　insulation　resistivity　(rho)　and　depolarization　temperature　(T-d)　are　indispensable　but　hard　to　achieve　in　lead-free　piezoceramics,　especially　operating　at　250　degrees　C　has　not　been　reported　before.　Herein,　well-balanced　performances　are　achieved　in　BiFeO3-BaTiO3　ceramics　via　innovative　defect　engineering　with　respect　to　delicate　manganese　doping.　Due　to　the　synergistic　effect　of　enhancing　electrostrictive　coefficient　by　polarization　configuration　optimization,　regulating　iron　ion　oxidation　state　by　high　valence　manganese　ion　and　stabilizing　domain　orientation　by　defect　dipole,　comprehensive　excellent　electrical　performances　(T-d　=　340　degrees　C,　rho(250)　(degrees　C)　＞　10(7)　Omega　cm　and　FOM2(50　degrees　C)　=　4905　x　10(-15　)m(2)　N-1)　are　realized　at　the　solid　solubility　limit　of　manganese　ions.　The　HT-PEHs　assembled　using　the　rationally　designed　piezoceramic　can　allow　for　fast　charging　of　commercial　electrolytic　capacitor　at　250　degrees　C　with　high　energy　conversion　efficiency　(eta　=　11.43%).　These　characteristics　demonstrate　that　defect　engineering　tailored　BF-BT　can　satisfy　high-end　HT-PEHs　requirements,　paving　a　new　way　in　developing　self-powered　wireless　sensors　working　in　HT　environments.