Bi2O3-based　composite　cathodes　of　solid　oxide　fuel　cells　are　generally　sintered　at　a　low　temperature　of　750-800　degrees　C,　but　the　detailed　information　regarding　the　generation　of　electrode/electrolyte　interface　and　its　effect　on　the　polarization　performance　are　scarcely　known.　Here　we　assemble　nanostructured　10-40　wt%　Er0.4Bi1.6O3　decorated　Sm0.95CoO3-delta　(ESB-SmC)　composite　cathodes　on　8　mol%　yttria-stabilized　zirconia　electrolyte　without　sintering　at　high　temperatures　and　the　best　performance　is　obtained　on　20　wt%　ESB　decorated　SmC,　achieving　a　peak　power　density　of　1.66　W　cm(-2)　at　750　degrees　C.　We　adopt　a　stepwise　annealing　approach　under　open　circuit　and　polarization　conditions,　so　as　to　in　situ　evaluate　the　extent　of　electrode/electrolyte　interface　generation.　The　results　show　that　under　open　circuit　conditions,　the　electrode/electrolyte　interface　of　20　wt%　ESB　decorated　SmC　electrode　can　be　generated　by　annealing　at　750　degrees　C　and　higher,　but　the　polarization　remarkably　accelerates　the　interface　generation　at　lower　temperatures　of　600-700　degrees　C.　The　present　study　provides　new　insights　into　the　electrode/electrolyte　interface　generation　and　polarization　performance　of　bismuth　oxide　based　composite　cathodes　under　the　operating　conditions　of　solid　oxide　fuel　cells.