AI Summary & Key Takeaways
AI InsightOxygen partial pressure-related polarization experiments suggest that the adsorption-desorption process and the reactions controlled by the atomic oxygen diffusion process followed by charge transfer are the cathode reaction rate-limiting steps.
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Özet
Öz This study reports the effect of vanadium on the crystal structure and electrical and electrochemical properties of La$_{0.6-x}$V$_{x}$Sr$_{0.4}$MnO$_{3-\delta \, }(x =$ 0.005--0.1) perovskite-based cathode materials in solid oxide fuel cells. Crystal structure, morphology, and porosity of prepared cathode materials are characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. Using XPS analysis it was established that the La$^{3+}$ cation is exchanged by the V$^{4+/5+}$ cation in the perovskite structure. This ion replacement improves the ionic conductivity and catalytic activity for oxygen reduction reaction in the perovskite structure, presumably due to the smaller size of the V$^{4+/5+}$ cation than the La$^{3+}$ ion. Oxygen partial pressure-related polarization experiments suggest that the adsorption-desorption process and the reactions controlled by the atomic oxygen diffusion process followed by charge transfer are the cathode reaction rate-limiting steps.