Novel K₂NiF₄‐Type Materials for Solid Oxide Fuel Cells: Compatibility with Electrolytes in the Intermediate Temperature Range

Abstract

Many new materials have been identified as being of potential interest to solid oxide fuel cell developers. Recent work has suggested that materials of the La2NiO4 composition possess sufficient activity to act as an effective cathode. Whilst there have been many studies of the transport properties of materials of this family the reactivity with electrolyte compositions has received relatively little attention. In this work we have investigated the compatibility of La2NiO4 + d (LNO) with LSGM and ceria gadolinium oxide (CGO) electrolytes. It is clear that under an air atmosphere LNO reacts readily with CGO electrodes with the formation of a higher order Ruddlesden–Popper (Lan + 1NinO3n + 1) phase as one of the reaction products. In contrast, there is no evidence of secondary phase formation with LSGM electrolytes from the obtained diffraction data over a period of 72 h at temperatures up to 1,273 K.

Oxygen surface exchange kinetics of erbia-stabilized bismuth oxide

“…7 shows a graphical collection of data obtained for the surface oxygen exchange rate observed on various oxides using different techniques. It is seen that BE25 shows a comparatively high surface exchange rate, much higher than well-known solid electrolytes YSZ and gadolinia-doped ceria, and even higher than La 2 NiO 4 , which has been proposed as a cathode material for intermediate-temperature SOFCs [19,20].…”

Advances in Cathode Materials for Solid Oxide Fuel Cells: Complex Oxides without Alkaline Earth Metal Elements

“…[ 275 ] The La 2 NiO 4 is the most classical material among the K 2 NiF 4 -type oxides, and its electrochemical performance for ORR has been extensively studied. [276][277][278][279][280][281][282][283][284][285][286][287][288][289] A single cell with La 2 NiO 4 cathode and LSGM electrolyte showed maximum power densities of 160, 226, and 322 mW cm −2 at 750, 800 and 850 °C, respectively, and a stable cell performance at 800 °C for a test period of 144 h was obtained under a polarization current density of 448 mA cm −2 . [ 277 ] This may be attributed to its good chemical compatibility with LSGM electrolyte.…”

“…It was demonstrated that La 2 NiO 4 had no observable phase reaction with LSGM electrolyte over a period of 72 h at temperatures up to 1000 °C. [ 276,277 ] To further improve the cell performance, composite electrode was formed by introducing ionic conductivity into the La 2 NiO 4 electrode. [ 278 ] The performance of a cell with a composite electrode composed of 80 facilitate the charge transfer process.…”

Anisotropic oxygen diffusion in tetragonal La2NiO4+δ: molecular dynamics calculations

“…In particular, La 2 NiO 4 and related materials with the K 2 NiF 4 structure (A 2 BO 4 or the first members of the RP series) are considered for oxygen sensors, oxygen separation membranes and as cathodes for intermediate temperature SOFCs (ITSOFCs). [1][2][3][4][5][6][7][8][9][10][11][12] These materials exhibit an oxygen hyperstoichiometry that significantly influences the oxygen transport (see for example ref. 3 and references therein).…”