Structural and electrical properties of La2−xCaxNiO4+δ (0 ≤ x < 0.4) with regard to the oxygen content δ

Structural, magnetic and dielectric properties of La2−xCaxNiO4+δ (x=0, 0.1, 0.2, 0.3)

“…Poirot et al [33] confirmed the amount of oxygen concentration in La 2−x Ca x NiO 4+ı (x < 0.5) by thermo-gravimetric analysis and found out even for x = 1/3, ␦ is still larger than zero. Besides, Ruck et al [34] pointed out if the La 2−x Ca x NiO 4+ı system is tetragonal with space group I4/mmm, it has excessive amount of oxygen. More details about oxygen transport in La 2 NiO 4+ı can refer to a review by Chroneos et al [35].…”

Preparation and electrical properties of Ca-doped La2NiO4+δ cathode materials for IT-SOFC

“…Therefore, the substitution limit of Ca in La 2Àx Ca x NiO 4+d is x o 0.4, agreeing with the result by K. Ruck. 11 The room-temperature lattice parameters a and c, and the cell volume of samples La 2Àx Ca x NiO 4+d (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) are presented in Table 1. For the samples with x = 0-0.…”

“…At the same time, holes are created to satisfy the electroneutrality conservation and thus cause partial oxidation of Ni 2+ into Ni 3+ in LaNiO 3 layers. 11 In the La 2 NiO 4 -based materials, oxygen transport occurs via a complex mechanism combining interstitial migration in the rock-salt layers and vacancy migration in the perovskite planes. 12,13 It is demonstrated that the interstitial mechanism makes the main contribution to the oxygen ionic transport.…”

Electrical and Electrochemical Properties of La2NiO4+δ-Based Cathodes in Contact with Ce0.8Sm0.2O2-δ Electrolyte

“…Among the materials investigated, La 2 NiO 4+δ (LNO) was found to possess the highest value of the oxygen surface heteroexchange constant k, which is higher by one or two orders of magnitude than that for the best mixed conductors with perovskite structure, but its performance as a cathode is limited by its electronic conductivity [4]. The last mentioned can be increased, particularly, by appropriate doping on the A-site with Sr 2+ or Ca 2+ , what have been shown in some works, presented by different scientific groups [5][6][7]. Alternatively, the fabrication of functionally graded electrodes is being developed as a means to improve of their electrochemical activity [8,9].…”