Experimental validation of high electrical conductivity in Ni-rich LaNi_1−xFe_xO₃solid solutions (x≤ 0.4) in high-temperature oxidizing atmospheres

Abstract

LaNi1-xFexO3 solid solutions are an interesting system exhibiting a composition-controlled metal-insulator transition and are also potential cathode materials for solid oxide fuel cells, but the composition dependence of their electrical...

Rare Earth Ion-Doped α-MnO2Nanorods for an Asymmetric Supercapacitor

“…Additionally, transition metal oxides have high electrical conductivity like TiO 2 (10 3 S m −1 ), 15 Cr 2 O 3 (5.8 × 10 3 S m −1 ), 15 TiO (5882 S cm −1 ), 16 LaCoO 3 (1000 S cm −1 ), 17 LaNiO 3 (2500 S cm −1 ), 18 La 0.7 Sr 0.3 CoO 3 (1650 S cm −1 ), 17 Fe 2 O 3 (5.5 × 10 3 S m −1 ), 15 β-MnO 2 (10 3 S m −1 ), 15 etc. and can undergo reversible redox reactions, which means that they can rapidly store and release energy.…”

Nickel-Containing Perovskites, PrNi0.4Fe0.6O3–δ and PrNi0.4Co0.6O3–δ, as Potential Electrodes for Protonic Ceramic Electrochemical Cells

“…In the present work, we characterize PrNi 0.4 M 0.6 O 3–δ (where M = Fe, Co) compounds as possible electrode materials for PCFCs. The justification for selecting these compositions is based on the parent lanthanum-based perovskite phases, i.e., LaNi 1–x Fe x O 3–δ (LNF), which demonstrate a good combination between thermal expansion and electrical conductivity [ 30 , 31 , 32 , 33 , 34 ]. In detail, LNF exhibit extremely low thermal expansion coefficients (around (11.5–12.5)·10 −6 K −1 [ 30 ]) compared to complex oxides based on simple (Ba 0.5 Sr 0.5 CoO 3–δ , Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3–δ ) or double (GdBaCo 2 O5 5+δ NdBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ ) cobaltites; the thermal expansion coefficients of the latter are much higher, falling in a range of (15–30)·10 −6 K −1 [ 32 ].…”

“…In detail, LNF exhibit extremely low thermal expansion coefficients (around (11.5–12.5)·10 −6 K −1 [ 30 ]) compared to complex oxides based on simple (Ba 0.5 Sr 0.5 CoO 3–δ , Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3–δ ) or double (GdBaCo 2 O5 5+δ NdBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ ) cobaltites; the thermal expansion coefficients of the latter are much higher, falling in a range of (15–30)·10 −6 K −1 [ 32 ]. Along with desirable thermal functions, the total conductivity of LNF attains 200–1000 S cm −1 depending on the iron/nickel ratio [ 33 ]; this allows such materials to be utilized as current collectors instead of the Pt electrodes or as an electronic component of composite materials [ 31 , 34 ]. However, electrochemical performance of the LNF electrodes is insufficient [ 35 ], since they exhibit predominantly electronic behavior instead of mixed ionic–electronic conduction; this fact can be explained by a low oxygen deficiency variation in LNF (3–δ ≈ 3) that provides a negligible amount of oxygen vacancies and, correspondingly, low oxygen-ionic conductivity.…”