A new Fe-doped Ca3Co4O9 cathode for protonic ceramic fuel cells

Fe-doped cobaltite Ca3Co4O9 (CCO) is modified to enhance the efficiency of CCO cathodes in protonic ceramic fuel cells (PCFCs). The Ca3Co3.8Fe0.2O9 (CCFO) material enhances the creation of oxygen vacancies, hydration, and proton migrations, as demonstrated by first-principles calculations. Subsequent investigations show that doping Fe into CCO improves the charger diffusion abilities and maintains compatible thermal expansion. A PCFC with a CCFO cathode demonstrates superior fuel cell performance, reaching 1790 mW cm−2 at 700 °C. This performance surpasses that of a cell with a CCO cathode and sets a new record for layer cobaltite in PCFCs. The composite cathode design hinders the performance of CCFO and CCO cathodes in PCFCs, indicating proton conduction in these oxides. This aligns with first-principles simulations, making them promising cathode options for PCFCs.