Effect of oxygen partial pressure on the electrochemical impedance of La0.8Sr0.2MnO3−δ/Zr0.92Y0.08O2 porous composite anodes in solid oxide electrolysis cell

► Three processes related to oxygen contribute to the EIS at the LSM/YSZ anode. ► Increasing porosity will separate the impedance arcs at different frequencies. ► The positions of peaks move to lower frequency with the increase of porosity.