Impedance Study of Anodic Properties of Ni-Fe Impregnated SDC

Abstract

Bimetallic Ni 1-x Fe x /SDC powders containing 20wt% Ni-Fe were prepared and their anodic properties for SOFC were evaluated. The impedance spectra of the Ni 1-x Fe x /SDC anodes at 800 o C consisted of the ohmic component, R ohmic , and depressed arcs, R HF and R LF . The R ohmic component was due to the solid electrolyte layer, (ScO 1.5 ) 0.18 (CeO 2 ) 0.01 (ZrO 2 ) 0.81 . The R HF component was significantly reduced by the Fe addition, but apparent dependence was not observed for the R LF component. The x=0.5 composition possessed the small R HF and R LF values. Accordingly, the single cell performance at 800 o C was the maximum at x=0.5, and that was in the order of x=0.5  0.2 > 0.8  0 >1.0. The mean crystallite size of Ni-Fe alloy increased approximately in this order. Therefore, we concluded that Fe addition to Ni decreases the particle size of Ni-Fe alloy, resulting in the enhancement of the catalytic activity of Ni 1-x Fe x /SDC anode.

Effect of Fe on high performing nanostructured Ni/Gd-doped ceria electrocatalysts

“…Interestingly, this previous work only reported observation of Ni-Fe alloys from XRD, but no CeFeO3 formation. Studies of samaria-doped ceria (SDC) infiltrated with Fe and Ni also report presence of Ni, Fe and Ni-Fe alloys after reduction, but not CeFeO3 [23,24]. On the other hand, a study of Ni-CGO infiltrated FeCr/YSZ fuel electrode backbone reports formation of a Ce-Fe-O compound having a chemical composition compatible with that of CeFeO3 [22].…”

“…Presence of significant amount of Fe within the Ni/CGO electrocatalyst layer may alter the ionic conductivity and electrocatalytic properties of CGO in Ni/CGO, which is decisive for both, the cell performance and the durability. Furthermore, diffusion of Fe into Ni can result in FeNi alloying for certain Fe to Ni ratios and such alloying has been reported to improve both the performance [23][24] [25] and the durability [26].…”

Electrophoretically Deposited Ni-Loaded (SmO1.5)0.2(CeO2)0.8Anode for Ammonia-Fueled Solid Oxide Fuel Cell

“…If the RHF component in the present case is also attributable to the electrochemical oxidation process, the addition of Ni would rather inhibit the reaction process. We previously reported the impedance analyses of Ni1-xFex-SDC anodes in H2 [31]. The RHF component was variable with x-value, which correlated with the Ni-Fe alloy particles.…”

Effect of Ni-loading on Sm-doped CeO₂ anode for ammonia-fueled solid oxide fuel cell

“…We previously reported the impedance analyses of Ni 1¹x Fe x SDC anodes in H 2 . 29) The R HF component was variable with x-value, which correlated with the size of NiFe alloy particles. In the present study, the Ni particle tends to increase with increasing Ni content as estimated from the XRD result in Fig.…”

“…The anode films were deposited by electrophoretic deposition (EPD). 29) To prepare the starting EPD bath, 0.24 g of the anode powders were added to 30 mL of acetylacetone containing 0.016 g of I 2 as a charging agent. The above mixture was sonicated for 20 min to yield a suspension.…”