Influence of Lanthanum Doping on Structural and Electrical/Electrochemical Properties of Double Perovskite Sr₂CoMoO₆ as Anode Materials for Intermediate-Temperature Solid Oxide Fuel Cells

Abstract

Lanthanum (La3+)-doped double perovskites Sr2CoMoO6 (Sr2–x La x CoMoO6, 0.00 ≤ x ≤ 0.03) were synthesized via the citrate–nitrate autocombustion route. The Reitveld refinement analysis of X-ray diffraction reveals the tetragonal symmetry as the main phase with space group I4/m and also confirms the presence of some peaks corresponding to extra phase SrMoO4. The SEM micrograph images reflect that grains are in irregular shape and sizes for all samples. Average grain size gradually decreases with the increase of the SrMoO4 phase. The X-ray photoelectron spectroscopy (XPS) analysis confirms the presence of mixed valence states of Mo5+/Mo6+, Co2+/Co3+, and O-lattice/O-chemisorbed/O-physisorbed species. Coefficient of thermal expansion (CTE) analysis shows that the particular composition Sr1.97La0.03CoMoO6 has the lowest CTE value among the compositions studied. The electrical conductivity of Sr2CoMoO6 is enhanced effectively by doping La at Sr sites. The measured area-specific resistance (ASR) for the composition Sr1.97La0.03CoMoO6 (SLCM03) is found to be appreciably low, ∼0.053 Ohm cm–2 at 800 °C. The obtained highest electrical conductivity with the lowest activation energy and low ASR value for the composition Sr1.97La0.03CoMoO6 encompasses it as a promising candidate for anode material in the intermediate-temperature solid oxide fuel cell (IT-SOFC) application.

Evaluating the Effect of B-Site Cation Doping on the Properties of Pr0.4Sr0.5Fe0.9Mo0.1O3 for Reversible Single-Component Cells

“…It is well known that perovskites are mixed ionic electron conductors, which can transfer both oxygen ions and electrons. 38,39 The electrical conductivities of PSCFM11, PSCFM27, and PSNFM27 in air are shown in Figure 6a. The conductivity of the three samples is in the order of PSNFM27 > PSCFM27 > PSCFM11.…”

Redox-Reversible Electrode Material for Direct Hydrocarbon Solid Oxide Fuel Cells

“…As versatile electrochemical energy conversion devices, solid oxide fuel cells (SOFCs) are capable of converting chemical energy stored in the fuel directly into electricity with fuel flexibility, high efficiency, and environmental friendliness, which has recently attracted a great deal of attention worldwide. − SOFCs have a broad spectrum of potential applications such as portable power, backup power, distributed generation systems, and stationary central power systems. The current focus of SOFCs is primarily on the Ni-based anode, which has advantages of excellent electrical conductivity, high catalytic activity, and low cost.…”

Recent advances in electrode material for symmetrical solid oxide fuel cells and way forward sustainability based on local mineral resources

“…Lanthanum, for example, has been widely used in fuel cell applications, whether as ceramic interconnects in SOFCs or as a dopant in perovskite-based electrode systems. 230 Doping of La at the A-site to form La x Sr 1Àx TiO 3±δ has been shown to form oxygen-rich planes in the crystal structure, thereby increasing both ionic and electrical conductivity. 231 In general, research focusing on utilising local products is generally new and completely limited in utilising local material for developing a new source of energy.…”

“…The extraction of monazite produces a number of important elements, including lanthanum, cerium, and neodymium as well as the radioactive elements thorium and uranium. Lanthanum, for example, has been widely used in fuel cell applications, whether as ceramic interconnects in SOFCs or as a dopant in perovskite‐based electrode systems 230 . Doping of La at the A‐site to form La x Sr 1−x TiO 3±δ has been shown to form oxygen‐rich planes in the crystal structure, thereby increasing both ionic and electrical conductivity 231 …”