Novel La2-x Cu x NiO4±δ /La4Ni3O10-δ composite materials for intermediate temperature solid oxide fuel cells, IT-SOFC

Abstract

Phases constituted by La 2-x Cu x NiO 4±δ (0.01≤x≤ 0.1) of the Ruddlesden-Popper family (La n+1 Ni n O 3n+1 ; n=1) were prepared and then mixed with La 4 Ni 3 O 10 , in a weight ratio of 50:50 wt%, in order to be used as solid oxide fuel cell cathodes. ASR values relative to the symmetrical cells constituted by yttria-stabilized zirconia electrolyte and the following e l ec t r o d es , L a 1 . 9 8 C u 0 . 0 2 N i O 4 + δ + La 4 N i 3 O 1 0 an d La 1.95 Cu 0.05 NiO 4+δ + La 4 Ni 3 O 10 , are of 11.8 Ω cm 2 at 650°C for both and, respectively, of 3.5 and 2.9 Ω cm 2 at 750°C. In the case of the second cell, the electrode material reacts with the electrolyte forming an insulating phase at the interface, contrarily to the first cell, which stability could be explained by the combination of low doping amounts of copper and the presence of La 4 Ni 3 O 10 acting as a stabilizer of the material at high temperature.

Electrochemical and morphological characterizations of La 2⿿x NiO 4±d (x = 0.01, 0.02, 0.03 and 0.05) as new cathodes materials for IT-SOFC

“…X-ray patterns of powders obtained after heat treatment at 1000 °C during 5 h, were recorded as reported in Fig.1. Eventually the phase obtained is pure K 2 NiF 4 -type and no secondary phases were detected, which is in agreement with the results obtained by other authors [3,24,[29][30][31] and confirmed by (JCPDS, ref. 27-1180).…”

“…La 2-x NiO 4±δ (LXNO) with x varying between 1 % and 5 % (x = 0.01, 0.02, 0.03, 0.05) powders samples was prepared by the citrate method [3,24,29]. Starting materials were:…”

“…The c-axis is perpendicular to the layers and thus directly sensitive to the amount of oxygen, measures between 12.55°A < c < 12.7Å according to the stoichiometry [27][28][29]. At the same time the intercalation of a very small amount of oxygen in a stabilized La 2 NiO 4±δ tetragonal phase will modify the valence of Ni and so its electronic properties.…”

Toward Superb Perovskite Oxide Electrocatalysts: Engineering of Coupled Nanocomposites

“…Conventionally, the composite is the mixture of pre-synthesized components by physically mixing, for example, ball-milling (Figure 2A). [33][34][35][36][37][38][39] However, some disadvantages, such as the inhomogeneous distribution of the different parts, large grain size, and poor stability under the harsh operational atmosphere, significantly limit the catalytic performances. Surface modification via physical deposition techniques is an effective route for getting uniform size distribution of the second component to get multifunctional composites (Figure 2B).…”

“…Electrochemical devices, such as fuel cells that directly con-One apparent and practicable solution to overcome the drawbacks of single-phase perovskite oxide is the formation of composite electrocatalysts. [28,[33][34][35][36][37][38][39] For instance, for perovskite oxide with high ionic conductivity but lacks electronic conductivity, physically mixing another perovskite oxide with suitable electronic conductivity to form a composite is the easiest way to improve overall performance. [40][41][42] This strategy has widely been used and showed modestly improved performances of anodes or cathodes in solid oxide fuel cells (SOFCs) based on oxygen ionconducting electrolyte and protonic ceramic fuel cells (PCFCs) based on proton-conducting electrolyte, where the electrodes require both high ionic (O 2− or H + ) and electronic conductivity.…”