Investigation of Pr2NiMnO6‐Ce0.9Gd0.1O1.95 composite cathode for intermediate-temperature solid oxide fuel cells

The electrochemical performance of Pr2NiMnO6 (PNMO)-xCe0.9Gd0.1O1.95 (CGO) (x = 0–40 wt%) composite oxides as intermediate-temperature solid oxide fuel cell (IT-SOFC) cathode materials are evaluated. The electrochemical impedance spectroscopy (EIS) analysis results identify two consecutive electrode processes on the composite cathode. Among the various composites, PNMO-30CGO cathode exhibits the best electrochemical performance with the minimum polarization resistance of 0.23 Ω cm2 and the maximum exchange current density of 75 mA cm−2 at 700 °C in air. These values are almost constant even after 30-h operation. The oxygen reduction reaction (ORR) mechanism studies prove that the major rate-determining step is the charge-transfer process. Introducing CGO significantly improves the charge-transfer process, by increasing the triple phase boundary (TPB) length and oxygen vacancy concentration in the composite cathode.