Performance of Alternative Oxide Anodes for the Electrochemical Oxidation of Hydrogen and Methane in Solid Oxide Fuel Cells

Abstract

The electrode performances of the alternative oxides: La0.05Ca0.95Cr0.05Ti0.95O3‐δ‐8YSZ and Ce0.8TM0.2O2‐δ(TM=Mn, Co) for the direct electrochemical oxidation of methane are investigated to assess their potential as anode materials for efficient methane conversion in a SOFC. The electrochemical oxidation of hydrogen was also studied, for comparison. The oxides are characterised electrochemically with impedance spectroscopy in the frequency range from 10 mHz to 1MHz, using a three‐electrode geometry. They are compared to a standard Ni/8YSZ anode for the electrochemical oxidation of hydrogen. It is found that La0.05Ca0.95Cr0.05Ti0.95O3‐δ‐8YSZ demonstrates a poor electrochemical activity in both hydrogen and methane. However, the electrochemical activity of Ce0.8Mn0.2O2‐δ is promising, but the electronic conductivity needs to be increased, e.g., by adding a conducting oxide, before it can be used as an anode material in a SOFC.

Electrochemical performance and microstructure characterization of nickel yttrium‐stabilized zirconia anode

“…Polarization resistance increases with prolonged exposure to CH 4 and eventually, the Ni‐YSZ anode deteriorates completely. It is reasonable to assume that the carbonaceous deposition accompanies pore closure and/or encapsulation of the electrochemically active sites, causing the anode activity to decrease continuously with the cycling time 10. Correspondingly, the exchange current density decreased from 6.16 to 1.36 and eventually to 0 mA/cm 2 as shown in Table 2.…”

“…However, the current SOFCs designs encounters problematic issues, manufacturing expense, performance degradation over prolonged use, heat retention, limited operating temperature ranges, and materials compatibility. [8][9][10] In an SOFC, the state-of-the-art electrolyte is yttrium-stabilized zirconia (YSZ), a polycrystalline ceramic that allows oxide ions (O 2À ) to conduct through the electrolyte from the cathode to the anode compartment. 11,12 The most-frequently used anode materials in SOFC are porous metal and ceramic composite composed of Ni and nickel and yttrium-stabilized Correspondence concerning this article should be addressed to J. Liu at this current address: MSC 161, 700 University Blvd., Kingsville, TX; e-mail: kfjll00@tamuk.edu.…”

“…The advantages of SOFCs are ultrahigh energy conversion efficiency, ultralow emission of environmental pollutants, simplicity in design and operation, and flexibility of fuel supplies. However, the current SOFCs designs encounters problematic issues, manufacturing expense, performance degradation over prolonged use, heat retention, limited operating temperature ranges, and materials compatibility 8–10. In an SOFC, the state‐of‐the‐art electrolyte is yttrium‐stabilized zirconia (YSZ), a polycrystalline ceramic that allows oxide ions (O 2− ) to conduct through the electrolyte from the cathode to the anode compartment 11, 12.…”

Solid Oxide Fuel Cell Anode Materials for Direct Hydrocarbon Utilization

“…The performance was increased by relevant oxidation treatments. [ 206 , 207 ] R p of Ce 0.8 Mn 0.2 O 2 anode was 30 Ω cm 2 in wet CH 4 at 800 ° C. [ 208 ] A recent study demonstrated that Ce(Mn, Fe)O 2 -La(Sr)Fe(Mn) O 3 composite anodes reached 1 W cm − 2 at 800 ° C when fed with C 3 H 8 and C 4 H 10 . [ 48 ] GDC is catalytically active towards CH 4 oxidation and is almost free of the carbon deposition problem.…”

Gasified residual/waste biomass as solid oxide fuel cell feed for renewable electricity production

“…The possible Nickel-free, sulphur-tolerant replacement for SOFC anode materials like fluorite, rutile, tungsten bronze, pyrochlore, perovskite and spinel structures were indentified [42] and reviewed [43][44][45]. The direct oxidation of methane [46,47] or diesel fuel [48] over substituted perovskites anodes are reported as well. The all-perovskite (anode, electrolyte and cathode) SOFC may be of particular interest due to structural similarity of layers.…”