Oleic acid was used to improve electrochemical performance of electrodes. Charge and discharge tests were performed at various current densities (25-150mA/㎠) using unit cells with oleic acid-treated electrodes. At higher current densities than 75mA/㎠, the efficiencies of cells with oleic acid-treated electrodes were higher than that of the reference electrode. As the current density increased, the efficiency difference between the electrode treated with oleic acid and the reference electrode gradually increased. When the charge / discharge test was performed for 100 cycles at a current density of 100mA/㎠, the cell using the oleic acid-treated electrode showed a smaller voltage efficiency reduction than the cell using the reference electrode.