Enhanced oxygen reduction reaction through Ca and Co Co-doped YFeO3 as cathode for protonic ceramic fuel cells.

Abstract Protonic ceramic fuel cells offer the potential for environmentally sustainable and cost-effective electric power generation. However, the power outputs of protonic ceramic fuel cells are far from the requirements due to the lack of active cathodes. In this work, porous thin sheets Ca x Y 1-x Fe 0.5 Co 0.5 O 3- δ (x = 0.1, 0.3 and 0.5) are synthesized by a modified pechini method and investigated as cathode materials for protonic ceramic fuel cells. Ca x Y 1-x Fe 0.5 Co 0.5 O 3- δ show high electrical conductivities and excellent chemical compatibility with Ba(Zr 0.1 Ce 0.7 Y 0.2)O 3 electrolyte. The maximum electrical conductivity of Ca 0.3 Y 0.7 Fe 0.5 Co 0.5 O 3- δ reaches 202 S cm−1 in air at 750 °C. The detailed mechanism for oxygen reduction reaction reveals that the rate-limiting step of oxygen reduction reaction is transformed from charge transfer to O 2 adsorption-dissociation with temperature rising or Ca doping. The composite cathode Ca 0.3 Y 0.7 Fe 0.5 Co 0.5 O 3- δ -Ba(Zr 0.1 Ce 0.7 Y 0.2)O 3 presents a relatively low polarization resistance of 0.07 Ω cm2 at 750 °C in air. The power density of the anode-supported cell of NiO Ba(Zr 0.1 Ce 0.7 Y 0.2)O 3 ∣Ba(Zr 0.1 Ce 0.7 Y 0.2)O 3 ∣Ca 0.3 Y 0.7 Fe 0.5 Co 0.5 O 3- δ-Ba(Zr 0.1 Ce 0.7 Y 0.2)O 3 is 798 mW cm−2 as the electrolyte thickness is about 150 μm. The prepared Ca x Y 1-x Fe 0.5 Co 0.5 O 3- δ oxides are promising candidates as high-performance cathodes for protonic ceramic fuel cells. Graphical abstract Image 1 Highlights • Increasing proper Ca doping at A -site is improving the conductivity of CYFC. • The detailed mechanism for oxygen reduction reaction is analyzed. • The R p of composite cathode C3YFC-BZCY was 0.07 Ω cm2 in air at 750 °C. • The peak power density is 798 mW cm−2 at 750 °C as the thickness of BZCY is 150 μm. [ABSTRACT FROM AUTHOR]