A novel layered perovskite Nd(Ba0.4Sr0.4Ca0.2)Co1.6Fe0.4O5+δ as cathode for proton-conducting solid oxide fuel cells

Abstract Layered perovskite structured-material Nd(Ba 0.4 Sr 0.4 Ca 0.2 )Co 1.6 Fe 0.4 O 5+δ has been synthesized and evaluated as promising cathode material for proton-conducting solid oxide fuel cells. High conductivity ranging from 750 to 2500 Scm −1 (100–800 °C) can be achieved by such prepared material. Its thermal-expansion coefficient is 19.706 × 10 −6  K −1 , which can be further optimized by mixing with proton conductor electrolyte BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ . Chemical compatibility between these two materials is identified, and the composite cathode's electrochemical property is thoroughly investigated. High power density as 926.323 mWcm −2 can be achieved at 750 °C by anode supported single cell with the composite cathode. Besides, the distribution of relaxation time method is applied to analyze the electrode reaction process. Oxygen adsorption, dissociation, reduction and diffusion of the Nd(Ba 0.4 Sr 0.4 Ca 0.2 )Co 1.6 Fe 0.4 O 5+δ -BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ composite cathode can be classified as the rate determining steps of the as-prepared full cell.