The use of identical electrodes for both the cathode and the anode in a symmetrical solid oxide fuel cell (SSOFC) can simplify the preparation process and increase the durability of the cell, but it is also demanding on the properties of the electrode including stability, electric conductivity, and electrocatalysis. The doping of variable-valence Mn4+/3+2+ on the B site of stable SrTiO3 is explored in this study as both the cathode and the anode for an SSOFC. Though the limit of Mn doping in SrTiO3 is generally low, the additional Pr3+/4+ donor on the Sr site of SrTi0.5Mn0.5O3 was found to enhance the structure stability, electric conductivity, and electrocatalysis. The cell with Pr0.5Sr0.5Ti0.5Mn0.5O3 electrodes excels under H2, propane, or CH4/H2 fuel, providing the cocatalyst was infiltrated on the anode side. The polarization resistance value of Pr0.5Sr0.5Ti0.5Mn0.5O3 was 0.27 Ω·cm2 as the cathode and 0.33 Ω·cm2 for the SSOFC using H2 fuel. The performance under CH4/H2 fuel can be boosted to above 0.9 W cm-2 if Ni/ceria was loaded onto the anode to enhance the methane reforming. This work contributes to a perovskite anode with high Mn doping in SrTiO3 for application in SSOFC for natural gas with renewable H2 injection.
Keywords: electrocatalysis; hydrocarbon fuel; mixed ionic−electronic conductor; perovskite electrode; symmetrical solid oxide fuel cells.