Improved electrocatalytic properties of La0.3Ca0.7Fe0.7Cr0.3O3- electrodes for oxygen reduction reaction: The effect of electrode thickness

Abstract Three-electrode half-cells with La0.3Ca0.7Fe0.7Cr0.3O3-δ porous electrodes were prepared by screen-printing technology. The electrodes with thicknesses ranging from ∼12 to ∼62 μm exhibited similar microstructures. The electrocatalytic properties of the electrodes for oxygen reduction reaction were investigated with respect to electrode thickness. The contributions of various electrode processes to the overall electrode polarization were resolved, among which the dissociative adsorption of molecular oxygen on the surface made the most substantial contribution. A significant dependence of the electrocatalytic properties on electrode thickness was detected. Tuning electrode thickness was demonstrated to be effective in optimizing the electrocatalytic properties. The electrode with a thickness of ∼43 μm achieved the optimal electrocatalytic properties among the electrodes investigated. At 800 °C in air, this electrode showed a polarization resistance of ∼0.06 Ω⋅ cm2, an exchange current density of 797 mA⋅ cm−2 and an overpotential of 9.3 mV under an applied cathodic current density of 200 mA⋅ cm−2.