This paper presents the polarization characteristics of electrochemical oxygen pumps (EOPs) during transfer oxygen from/to liquid lead-bismuth eutectic (LBE). A thick-walled (1.5 mm) one-end closed tube of yttria partially stabilized zirconia was used as a solid electrolyte. Three different electrode of air/LSM (lanthanum strontiummanganite), air/LSCF (lanthanum strontium cobalt ferrite) and LBE/PbO were compared. The polarization characteristics were obtained by linear sweep voltammetry in LBE at 450 degrees C at various dissolved oxygen concentrations in LBE. The EOP with LBE/PbO electrode showed negligible activation polarization compared to EOPs with other electrodes. However, with the LBE/PbO electrode a significant concentration polarization occurred at low current density, limiting its capacity for oxygen transfer from EOP to LBE. The oxygen transfer from LBE to EOP is limited by oxygen mass transfer from the LBE bulk to the solid electrolyte surface of EOPs, especially under low dissolved oxygen condition. (C) 2019 The Electrochemical Society.