A comparative study on the composite cathodes with proton conductor and oxygen ion conductor for proton-conducting solid oxide fuel cell

Abstract Proton-conducting solid oxide fuel cell (H–SOFC) is more competitive compared to oxygen-conducting SOFC (O–SOFC) due to its lower conductive activation energy, higher fuel conversion rate, and higher Nernst potential. However lack of suitable cathode is hindering its application. A double perovskite Nd(Ba0·75Ca0.25)Co1·5Fe0·4Ni0·1O5+δ (NBCCFN) has been prepared and evaluated as a potential cathode with a peak power density of 882.2 mW cm−2 for the anode supported single cell with NBCCFN-based composite cathode. NBCCFN exhibits high electrical conductivity, high oxygen vacancies and lower thermal expansion coefficient. Single cell in which the cathode is composited with Gd0.1Ce0·9O2-δ (GDC) presents lower the polarization resistances and higher the peak power densities than that with BaZr0·1Ce0·7Y0.1Yb0.1O3-δ (BZCYYb). Our results and corresponding distribution of relaxation time (DRT) analysis suggest that enhancing the oxygen reduction and diffusion processes of cathode is an effective way to improve the performance of H–SOFC.