Electrochemical evaluation of mixed ionic electronic perovskite cathode LaNi1-xCoxO3-δ for IT-SOFC synthesized by high temperature decomposition

The cobalt doped perovskite cathode material LaNi1-xCoxO3-δ (x = 0.4, 0.6, 0.8) synthesized by cost effective high temperature decomposition is investigated as mixed ionic electronic conductor (MIEC) for intermediate temperature solid oxide fuel cell (IT-SOFC). LaNiO3 is known for its high electronic conductivity and to introduce more oxygen vacancies for enhancing its ionic conductivity, Ni at B site is substituted by Co. XRD analysis showed perovskite structure for all samples with no additional phases, which was also confirmed by FTIR results. Microstructure analysis revealed well connected and porous structure for LaNi1-xCoxO3-δ (x = 0.6) compared to other compositions. The elemental analysis using EDX confirmed presence of lanthanum, nickel, and cobalt within all samples. No prominent weight loss was observed during TGA analysis. The highest value of conductivity was obtained for LaNi1-xCoxO3-δ (x = 0.6) due to its porous and networked structure of sub micrometric grains. The superior performance is attained for the cell based on LaNi1-xCoxO3-δ (x = 0.6) cathode with maximum power density of 0.45 Wcm−2 compared to other composition which can be attributed to its well connected and porous structure that caused enhanced electrochemical reaction at triple phase boundary (TPB). It was therefore deduced that LaNi1-xCoxO3-δ (x = 0.6) is promising composition to be used as MIEC cathode for IT-SOFC.