Influence of composition and Cu impregnation method on the performance of Cu/CeO2/YSZ SOFC anodes

Abstract

In this study, we report on how different impregnation procedures affect the distribution and morphology of the Cu component in Cu/CeO 2 /YSZ composite anodes and how this affects anode performance. Two different methods for Cu addition to the porous YSZ anode were investigated: impregnation using aqueous solutions of Cu(NO 3 ) 2 and impregnation using aqueous solutions of Cu(NO 3 ) 2 plus urea. The latter method produced a homogeneous distribution of Cu throughout the anode while the former resulted in a higher concentration of Cu near the exposed surface relative to that in the bulk. Studies of the thermal stability of the deposited copper layers, and the influence of the Cu distribution on cell performance when operating with humidified H 2 as the fuel are also presented. AbstractIn this study we report on how different impregnation procedures affect the distribution and morphology of the Cu component in Cu/CeO 2 /YSZ composite anodes and how this affects anode performance. Two different methods for Cu addition to the porous YSZ anode were investigated: impregnation using aqueous solutions of Cu(NO 3 ) 2 and impregnation using aqueous solutions of Cu(NO 3 ) 2 plus urea. The latter method produced a homogeneous distribution of Cu throughout the anode while the former resulted in a higher concentration of Cu near the exposed surface relative to that in the bulk. Studies of the thermal stability of the deposited copper layers, and the influence of the Cu distribution on cell performance when operating with humidified H 2 as the fuel are also presented.

An Examination of SOFC Anode Functional Layers Based on Ceria in YSZ

“…Independent of functional layer thickness, the conductivity values ranged from 0.020 to 0.015 S/cm, values that are in good agreement with the conductivity reported from four-probe measurements of ceria impregnated into porous YSZ. 19 The agreement with previous four-probe measurements also shows that conductivity in these anodes cannot be due to penetration of the Ag ink into the porous YSZ.…”

“…The nonohmic impedance of the cell with 20 wt % ceria was also larger but this may be related to the increased ohmic contribution. 19 Given that 20 wt % ceria corresponds to less than 10 vol % of the anode functional layer, a value well below the 30 vol % required to achieve the percolation threshold required for random media, it is not surprising that this loading is insufficient.…”

(La,Sr)TiO_3+δ en lugar de (La,Sr)TiO_3+d

“…Therefore the differences observed in the present study may be attributed to the better catalytic activity of Pt compared to Au. In the case of n=14 the polarisation using Au as current collector is lower possibly due to a better electrical contact, as the polarisation is not completely independent of the ohmic losses [15,17], and we observed an anomalously high series resistances (50-60% larger) for this composition as mentioned above. …”

“…This could be due to a number of parameters affecting the microstructure, although the corresponding SEM images reveal that the microstructure is very similar in all cases in terms of porosity, and electrode thickness ranging 20-50 µm, and should not cause a major change in the electrocatalytic response ( Figure 4). The polarisation resistance depends strongly on both the microstructure and the catalytic activity and some previous reports suggest that other a priori "external" parameters such as the electronic conductivity may also play an important role [15,17]. Indeed in the present case, the series resistances (R s ) for cells using n=14-based anodes where somewhat higher, which might explain the poorer electrocatalytic activity.…”

Plasma Glow Discharge as a Tool for Surface Modification of Catalytic Solid Oxides: A Case Study of La0.6Sr0.4Co0.2Fe0.8O3−δ Perovskite

“…The other is the fabrication of nano-structured electrodes with an extremely high amount of electrochemically active sites [6]. Chemical infiltration has been considered an effective tool to make nano-scale microstructures while permitting the use of more combinations of conductors and catalysts [7][8][9][10][11]. However, the infiltration method has not been developed maturely for industrial applications, most likely due to the following reasons.…”