Ruddlesden-Popper　oxide　La2NiO4+&　delta;　(LNO)　has　a　high　ionic　conductivity　and　good　thermalmatch　withthe　electrolyte　of　solid　oxide　fuel　cells　(SOFCs);　however,　LNO　suffersfrom　performance　decay　owing　to　the　La　surface　segregation　under　theoperation　conditions　of　SOFCs.　Herein,　we　report　an　in　situ　electrochemicaldecoration　strategy　to　improve　the　electrocatalytic　activity　and　durabilityof　LNO　cathodes.　We　show　that　the　electrochemical　polarization　leadsto　in　situ　construction　of　the　LNO@Pt　core-shell　structure,significantly　suppressing　the　detrimental　effect　of　La　surface　segregationon　the　LNO　cathode.　The　initial　peak　power　density　of　a　single　cellwith　the　LNO　cathode　is　0.71　W　cm(-2)　at　750　&　DEG;C,increasing　to　1.39　W　cm(-2)　by　the　in　situ　constructionof　the　LNO@Pt　core-shell　structure　after　polarization　at　0.5A　cm(-2)　for　20　h.　The　LNO@Pt　core-shell　structureis　also　highly　durable　without　noticeable　performance　degradationover　the　duration　of　the　test　for　180　h.　The　findings　shed　light　onthe　design　and　fabrication　of　highly　active　and　durable　LNO-basedcathodes　for　SOFCs.