Investigation of Time Stability of Sr-Doped Lanthanum Vanadium Oxide Anode and Sr-Doped Lanthanum Cobalt Oxide Cathode Based on Samaria Doped Ceria Electrolyte Using Electrochemical and TOF-SIMS Methods

Abstract

The time stability of solid oxide fuel cell (SOFC) was tested using all ceramic La 0.7 Sr 0.3 VO 3-δ -Ce 0.85 Sm 0.15 O 2-δ (SDC) perovskite material as an alternative anode and La 0.8 Sr 0.2 CoO 3−δ -SDC as a cathode. Both electrodes were prepared using infiltration method. The time stability measurements were carried out for 220 h under 0.6 V cell polarization in H 2 fuel and at working temperatures of 600 • C and 700 • C. At both temperatures, the total polarization resistance, R P , increased in time and the maximal power density values decreased nearly 7% during testing. At the working temperature of 600 • C the R P reached its constant value, 0.50 cm 2 , during the first 12 h of polarization at 0.6 V. At 700 • C noticeable increase in R P was seen within 100 h operation before the constant R P value, 0.50 cm 2 , was established. The microstructure and composition of the single cells, including the mobility of Sr within the cell components, before and after time stability measurements, were analyzed using secondary ion mass spectrometry method. No degradation of cell components and Sr mobility was observed after the cell preparation process and only minor mobility of elements was seen after 24 h of operation at 600 • C and 700 • C. However, noticeable Sr, V, Co and La mobility was observed after 220 h operation at 600 • C and 700 • Solid oxide fuel cells (SOFC) are promising energy conversion systems due to their high electrical efficiency (up to 60%), fuel flexibility and environmental friendliness.1,2 Traditional materials, like Ni-YSZ anode envisaged already four decades ago, continue to dominate as the anode material for SOFC due to the issues and problems associated with the newly discovered materials for SOFC systems, for instance lower electrochemical activity, relatively small thickness of the anode, and unknown degradation and time stability.3-12 However, the main disadvantage of Ni-YSZ anode is severe deactivation in hydrocarbon and hydrocarbon derived synthetic fuels due to the carbon formation/deposition on the Ni surfaces and sulfur poisoning from the impurities of the fuel. [13][14][15][16][17][18][19][20][21][22] In spite of that the carburization and sulfidation stability of the Ni-YSZ electrodes (if using hydrocarbons) have been improved in the recent years through maneuvering of operation conditions. , are considered to be promising alternatives to Ni-cermet anodes. [6][7][8][9][10][11][12]14,15,[22][23][24][25] It has been shown that because of the relatively low catalytic activity, ceramic anodes are much more tolerant toward the carbon deposition and sulfur poisoning than Ni-cermet anodes. 13,26 However, to achieve the reasonable electrochemical activity of the ceramic anodes, the additional catalytic centers, like CeO 2 and Pd, must be deposited into/onto the anode. [6][7][8][9][10]12,22,25 In spite of the active research conducted in the recent decade on the field of alternative ceramic anode materials with perovskite structure, only few studies can be found discussing the degradatio...

Influence of A-site Deficiency and Ni/Co Ratio in B-site on Electrochemical Performance of (La0.25Sr0,25Ca0.45)yTi0.95Ni0.05-xCoxO3- d Anode

“…Mixed conducting oxides with perovskite structures (ABO3) have been widely studied as oxygen (1-6) as well as hydrogen electrodes for SOFC (7)(8)(9)(10)(11). Doped perovskite structures enable mixed ionic-and electronic conductivity (MIEC) and thermodynamic stability of lattice in reducing as well as in oxidizing environments which makes them attractive candidates for reversible solid oxide fuel cell (RSOFC) hydrogen electrode material.…”

Study of Long-Term Stability of Ni-Zr0.92Y0.08O2-δ|Zr0.92Y0.08O2-δ|Ce0.9Gd0.1O2-δ |Pr0.6Sr0.4CoO3-δ at SOFC and SOEC Mode

“…After the long-term electrochemical performance test, the Ni-YSZ|YSZ|GDC|Pr 0.6 Sr 0.4 CoO 3-δ membrane electrode assembly (MEA) was systematically characterized using the high resolution electron microscopy (HR-SEM) and time of flight secondary ion mass spectrometry (ToF-SIMS) methods. ToF-SIMS was used to conduct an oxygen isotope tracing experiment and to investigate distribution of strontium, silicon and chromium in the electrolyte, Ni-YSZ electrode and PSC electrode, respectively [22][23][24][25][26]. HR-SEM was used to evaluate the changes in the microstructure of the MEA of the fuel cell.…”

Physical and Electrochemical Characterization of La0.25Sr0.25Ca0.40Ti0.95Ni0.05-xSnxO3–δ (x=0...0.05) Reversible Solid Oxide Cell Fuel Electrode

“…components. Most notable perovskite materialgroups studied so far include La 1-x Sr x Cr 1-y Mn y O 3-δ (LSCM) (10)(11)(12)(13)(14)(15), La 1-x Sr x TiO 3-δ (LST) (16,17), La 1-x Sr x Cr 1-y Fe y O 3-δ (LSCF) (18) and La 1-x Sr x VO 3-δ (LSV) (19,20). Some titanate based materials have been prepared and have shown good conductivity under reducing atmospheres.…”