Our results demonstrate that such dual-phase composites PBC–GDC produced in one step can be considered a promising cathode material for intermediate/low-temperature solid oxide fuel cells. The HF and LF of the composite cathodes have no perceptible difference, showing that the charge transfer and gas diffusion processes play insignificant role in the cathode reaction 22. The maximum power density of lab-scale electrolyte-supported cell with PBC–10 wt% GDC cathode reaches 1302, 938, 549 and 235 mW cm −2 at 850, 750, 650 and 550 ☌, respectively. The GDC introduction significantly decreases the charge transfer resistance of the PBC–GDC composite cathode. The charge transfer process on the electrode surface is the rate-limiting step based on the dependence of polarization resistance at different oxygen partial pressures, where the impedance analysis technique, the distribution of relaxation times (DRT), is devoted to describing the complex electrode reaction processes. When measured in a symmetrical cell configuration in the air at 600 ☌, PBC–10 wt% GDC electrode shows an area-specific resistance of 0.394 Ω cm 2, which is about 78% lower than that of bare PBC electrode under the same situations. The introduction of the cubic GDC phase can guide the oxygen transport among PBC particles with different orientations. The coherent interface structure is formed between PBC and GDC particles, which is beneficial to alleviate the lattice thermal expansion. Co-containing cathodes are well known ability to operate at high temperature in SOFCs technology. The electrochemical properties of La0.6Sr0.4Co0.2Fe0.8O3-based cathodes are studied as model electrodes for proton ceramic fuel cells. The SCN cathode was also prepared by solid state reaction (SSR) at the same temperature with a maximum power density of 204 mW/cm 2, which is much lower in comparison with a new liquid phase SCN cathode. Here, we report a dual-phase cathode material, double perovskite structure PrBaCo 2O 5+ δ (PBC) and fluorite structure Gd 0.1Ce 0.9O 2− δ (GDC), successfully synthesized using a one-pot method, with remarkable oxygen reduction reaction activity and low polarization resistance under IT-SOFC service conditions. From the observed oxygen partial pressure dependence, the rate-determining step of the above cathode polarization reaction is principally ascribed to the oxygen reduction reaction. Chem.One challenge facing the development of high-performance cathodes for solid oxide fuel cells is the slow oxygen reduction kinetics. Yoo, Phase stability and oxygen transport properties of mixed ionic–electronic conducting oxides, Ph.D. Tsur, Solid State Ionics 188, 104 (2011)ī.A. The central phenomenon of an electrochemical process in an electrochemical device is the transfer of charge at a phase boundary between an electronically conducting phase called electrode and an ionically conducting phase called electrolyte. The most common cathodic reactions in terms of electrons transfer are given below: 1. Unlike an anodic reaction, there is a decrease in the valence state. Electrons released by the anodic reactions are consumed at the cathode surface. Traversa, Solid State Ionics 181, 1043 (2010) Cathodic reactions are reduction reactions which occur at the cathode. Bonanos, Solid State Ionics 79, 161 (1995) Iwahara, Solid State Ionics 77, 289 (1995) From the observed oxygen partial pressure dependence, the rate-determining step of the above cathode polarization reaction is principally ascribed to the oxygen reduction reaction. The results indicate that the cathode performance of La 0.6Sr 0.4Co 0.2Fe 0.8O 3-δ–BaCe 0.9Y 0.1O 3-δ is enhanced mainly due to the extension of the effective triple phase boundary, whereas that of La 0.6Sr 0.4Co 0.2Fe 0.8O 3-δ–BaZr 0.8Y 0.2O 3-δ is lowered due to the poor proton conductivity along the percolated BaZr 0.8Y 0.2O 3-δ particles. The electrochemical properties of La 0.6Sr 0.4Co 0.2Fe 0.8O 3-δ-based cathodes are studied as model electrodes for proton ceramic fuel cells.
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