Manganese and vanadium impregnated anode systems for intermediate temperature solid oxide fuel cells

Abstract

Solid Oxide Fuel Cells (SOFC) are environmentally friendly electrochemical energy producing devices that convert chemical energy into electrical energy by oxidizing a fuel. Exhibiting high efficiency in converting fuel to electricity and the tolerance to wide variety of fuels make them promising devices and preferable over other types of fuel cells. However, to avoid using expensive catalysts such as platinum or ruthenium, high temperature operation becomes an obligation which is one of the most common drawbacks of a SOFC. A typical SOFC is composed of three main compartments, an anode, an electrolyte and a cathode. Not only there is a need for compartments with similar thermal expansion coefficients, but also novel materials should be constructed to have a better capacity in a SOFC as well. Therefore, this study focused on the anode compartment and aimed to analyze its performance under different conditions. Since oxidation takes place in the anode part, increasing oxidation capacity could be an effective way to optimize the cells. To do so, a practical technique, impregnation, was applied to the anode part. Transition metals, manganese and vanadium with multiple oxidation states are selected. Possible increase in the oxidation capacity is one of the principle reasons why Mn and V are good candidates for impregnation. Both conventional and impregnated cells were characterized by X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM) and their performance tests were implemented by Linear Sweep Voltammetry (LSV) and Electrochemical Impedance Spectroscopy (EIS). After characterization and performance tests, it has been concluded that as a practical technique, impregnation works well in this system under H2 and CH4 fuels and one can end up with a noteworthy enhancement of anode performance in the intermediate temperature range for a SOFC.