Ceramic materials with perovskite structure have recently attracted attention as possible redox stable, sulfur- and carbon tolerant cathode materials for solid oxide electrolysis cells. In this study ceramic SOE single cell was fabricated using impregnation method. La0.8Sr0.2Cr0.5Mn0.5O3–δ-Zr0.94Sc0.06O2–δ cathode was activated with CeO2 and Pd nanoparticles and investigated as potential solid oxide co-electrolysis cell cathode at various working temperatures, cell potentials and inlet gas compositions. Based on the electrochemical measurements data the single cell performed the same in co-electrolysis and water electrolysis modes having total polarization resistance 0.52 Ω cm2 (at 750°C at 1.3 V). Analysis of gas chromatography data shows that the ratio between produced H2 and CO gases decreased with increase of temperature, from 10.5 to 0.76 at 650°C and 800°C, respectively. Also the H2/CO ratio decreased with steam content in inlet gas.

Perovskite‐based mixed ionic electronic conductive (MIEC) oxides have been synthesized and studied as promising redox‐stable solid oxide cell (SOC) electrode materials. In order to enhance performance of MIEC electrode materials, influence of porous electrolyte structure as well as the loading of the electroactive material on the performance of La0.8Sr0.2Cr0.49Mn0.49Ni0.02O3‐δ – (Sc2O3)0.1(CeO2)0.01(ZrO2)0.89 (LSCMN‐ScCeSZ) and Sr2Fe1.5Mo0.5O6‐δ (Sc2O3)0.1(CeO2)0.01(ZrO2)0.89 (SFM‐ScCeSZ) MIEC electrodes have been studied. The results indicated that pre‐calcination and milling process of ScCeSZ electrolyte powder increased the average pore sizes and the overall porosity of scaffolds by about 10 vol.%. However, due to the use of pre‐calcined electrolyte powder with increased particle sizes, specific area of electrolyte scaffolds and catalytic activity decreased at lower MIEC loadings. Porous scaffold with highest open porosity of 81% was used to study the influence of different MIEC materials at high loadings on the performance of composite electrodes. Results indicated that optimal loading depends on the properties of MIEC material and it was found to be 30 and 50 wt.% for SFM and LSCMN, respectively. The highest current density values 1.11 and 0.78 A cm−2 were measured for electrolysis mode at 850 °C, at potential 1.5 V and 30% of absolute humidity for SFM and LSCMN composite electrodes, respectively.

Influence of A-site deficiency and chemical composition of B-site (concentration of Ni, Mn, and Cr) on electrochemical performance of hydrogen electrode in (La 1-x Sr x ) y Cr 0.5-z Mn 0.5-w Ni z+w O 3-δ |(Sc 2 O 3 ) 0.10 (CeO 2 ) 0.01 (ZrO 2 ) 0.89 |La 0.8 Sr 0.2 FeO 3-δ reversible solid oxide fuel cell has been studied. Electrochemical characterization has been carried out in fuel cell and electrolysis regimes. Results indicate that in fuel cell regime most notable limiting steps were detected around 0.5 Hz frequency range and were attributed to gas-solid adsorption-desorption processes. pO 2 variation in the oxygen electrode compartment led to small variations in a total impedance of single cells but was not the limiting process. In electrolysis mode, the dissociative adsorption was shown as an important limiting stage and limitations in kinetic region of charge transfer step were remarkable. Increase of A-site deficiency caused a significant increase in high-frequency series resistance as well as some increase of total polarization resistance. Variation in B-site composition had a significant influence on electrochemical performance with very different frequency dependence of impedance. Highest current density values of 0.27 and 0.66 A cm −2 at unit cell potentials of 0.9 and 1.5 V, respectively, at 850°C were measured for La 0.75 Sr 0.25 Cr 0.3 Mn 0.5 Ni 0.2 O 3-δ (fuel cell mode) and (La 0.8 Sr 0.2 ) x Cr 0.49 Mn 0.49 Ni 0.02 O 3-δ (electrolysis mode) in hydrogen fuel gas with pH 2 O = 0.03 and 0.30 atm, respectively.

A novel La0. 2Sr0.7-xCaxTi0.95Fe0.05O3-δ (LSCFT-x) fuel electrode compositions for high-temperature solid oxide fuel cell application are synthesized using glycine-nitrate synthesis method. To understand the influence of Sr/Ca ratio on electrical conductivities of different compositions of LSCFT, the DC four-probe conductivity measurements of porous electrode layers has been performed. Conductivities have been measured at three different atmospheres: air, 1% H2 + 3% H2O + 96% Ar, and 97% H2 + 3% H2O. The crystal structure and microstructure have been studied using X-ray diffraction and SEM, respectively to confirm the phase purity and visualize the microstructure of studied electrode layers. It has been shown that the LSCTF material behave like semiconductor and the conductivity is significantly dependent of Ca concentration in A-site. The maximal total electrical conductivity of porous electrode layer made of LSCFT was 5.5 S cm− 1 at 850°C characteristic for the LSCFT-45 material in 97% H2 + 3% H2O atmosphere.

The electrochemical and crystalline structure of mixed ionic‐electronic conductive La0.75Sr0.25Cr0.5Mn0.3Ni0.2O3–δ (LSCMN) electrode in porous scandia ceria stabilized zirconia (ScCeSZ) electrolyte matrix during the first 140 h has been studied in an operando XRD experiment. Intense degradation of electrochemical performance in a fuel cell as well as in electrolysis modes has been observed. However, the mechanism of the degradation was seen to be different for the two operation modes. The formation of the new ceramic phase was observed on the surface of the electrode using the Grazing incidence X‐ray diffraction at the pulsed laser deposited LSCMN model electrode. Instability of the LSCMN phase in the ScCeSZ matrix at SOFC working conditions has been demonstrated using the novel operando XRD technique. The decrease in wt.% of the LSCMN during degradation was approximately 27 ± 4.5%. A slow increase of the ScCeSZ lattice parameter was observed and attributed to the doping of electrolytes with some LSCMN components.