Development of lanthanum strontium cobalt ferrite composite cathodes for intermediate- to low-temperature solid oxide fuel cells

Solid oxide fuel cells (SOFCs) offer high energy conversion, low noise, low pollutant emission, and low processing cost. Despite many advantages, SOFCs face a major challenge in competing with other types of fuel cells because of their high operating temperature. The necessity to reduce the operational temperature of SOFCs has led to the development of research into the materials and fabrication technology of fuel cells. The use of composite cathodes significantly reduces the cathode polarization resistance and expands the triple phase boundary area available for oxygen reduction. Powder preparation and composite cathode fabrication also affect the overall performance of composite cathodes and fuel cells. Among many types of cathode materials, lanthanum-based materials such as lanthanum strontium cobalt ferrite (La1-xSrxCo1-yFeyO3-δ) have recently been discovered to offer great compatibility with ceria-based electrolytes in performing as composite cathode materials for intermediate- to low-temperature SOFCs (IT-LTSOFCs). This paper reviews various ceria-based composite cathodes for IT-LTSOFCs and focuses on the aspects of progress and challenges in materials technology

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