Formation　of　an　intimate　electrode/electrolyte　interface　is　essential　for　solid　oxide　fuel　cells　(SOFCs).　In　this　study,　a　comparative　investigation　has　been　undertaken　to　study　the　interface　formation　between　a　La0.8Sr0.2MnO3　(LSM)　cathode　and　Y2O3-ZrO2　(YSZ)　electrolyte　by　high　temperature　sintering　and　by　cathodic　polarization　using　EIS,　SEM,　AFM　and　HAADF-STEM　techniques.　The　electrode/electrolyte　interface　formed　by　the　conventional　pre-sintering　process　is　characterized　by　the　formation　of　distinctive　convex　contact　rings　on　the　YSZ　surface　and　such　convex　contact　rings　are　due　to　the　cation　interdiffusion　such　as　manganese　species　between　LSM　and　YSZ.　Similar　to　the　thermally　induced　interface,　the　electrode/electrolyte　interface　can　also　be　formed　by　electrochemical　polarization　for　the　in　situ　assembled　LSM　cathode　on　YSZ　as　well　as　on　Gd2O3-CeO2　(GDC)　electrolytes　without　pre-sintering　at　high　temperatures.　The　polarization　induced　interface　has　smaller　contact　marks　due　to　the　much　finer　grain　size　of　the　as-prepared　LSM　electrodes.　Detailed　electrochemical　impedance　studies　indicate　that　both　thermally　and　polarization　induced　LSM/YSZ　interfaces　show　comparable　electrocatalytic　activity　and　behaviour　for　the　oxygen　reduction　reaction　with　similar　activation　energies.　The　present　study　clearly　demonstrates　the　formation　of　effective　electrode/electrolyte　interfaces　in　SOFCs　under　the　influence　of　cathodic　polarization　without　high　temperature　sintering　steps.　©　2016　The　Royal　Society　of　Chemistry.