Electrochemical Investigation of Composite Nano La0.6Sr0.4Co0.2Fe0.8O3-δ Infiltration into LSGM Scaffold Cathode on LSGM Electrolyte

As a potential intermediate temperature SOFC cathode, a nano La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) infiltrated into a porous La 0. 8 Sr 0. 2 Ga 0. 8 Mg 0. 2 O 3-δ (LSGM) scaffold cathode was evaluated in combination with a LSGM electrolyte. A XRD analysis revealed resistive phases of LaSrGa 3 O 7 and LaSrGaO 4 present in the LSCF/LSGM binary system with sintering over 950 o C. To fabricate a nano catalyst infiltrated into the LSGM scaffold cathode, the porous LSGM scaffold is formed at high temperature (1250 o C). Nano catalysts are coated on the scaffold surface using an infiltration technique and fired at 850 o C in air. The cathode polarization resistance (R p ) of nano LSCF infiltrated into the LSGM scaffold cathode was 0.02 Ωcm 2 , 0.11 Ωcm 2 , and 0.66 Ωcm 2 at 800 o C, 700 o C, and 600 o C, respectively. To improve the oxygen reduction reaction, a Pt/LSCM composite solution was infiltrated into the LSGM scaffold cathode. However, the R p of the nano Pt/LSCM composite infiltrated into the LSGM scaffold cathode was increased to 0.90 Ωcm 2 at 700 o C, despite the Pt has higher electrochemical activity for oxygen reduction than LSCF (R p for LSCM infiltration was 0.317 Ωcm 2 at 700 o C).