Solid Oxide Electrolytes for High Temperature Fuel Cells

“…After the first calcination step at 1250ºC for 4 h, the LSGM phase (indicated by *) has already been formed. Nevertheless, as the reaction among the several starting materials is incomplete, some diffraction peaks of impurity phases are detected, especially La 4 Ga 2 O 9 (3), LaSrGa 3 O 7 (4) and LaSrGaO 4 (5). The subsequent steps of calcination and attrition milling promoted a decrease in the relative fraction of undesired phases, such that the final powder mixture consists primarily of the LSGM phase and minor amounts (less than 5%, estimated by intensity ratios) of the usually observed impurity phases.…”

Section: Characterization Methodsmentioning

confidence: 99%

“…x Sr x Ga 1-y Mg y O 3-δ , with 0.1 ≤ x,y ≤ 0.2) have been thoroughly investigated, due to their high ionic conductivity along with wide electrolytic domain, as described in recent reviews 5,6 .…”

Section: Introductionmentioning

confidence: 99%

Influence of Yttria-Stabilized Zirconia on Microstructure and Electrical Properties of Doped Lanthanum Gallate

2019

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Lanthanum gallate with partial substitutions for strontium and magnesium shows higher ionic conductivity than traditional ionic conductors such as yttria-stabilized zirconia (8YSZ), and has been considered for application as solid electrolyte and electrode in Solid Oxide Fuel Cells operating at intermediate temperatures (500-700ºC). Parallel to the development of new solid electrolytes, improvement of the already known electrolytes has been one goal. In this work, the effects of adding 8YSZ to La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3-δ (LSGM), on the microstructure and electrical performance were investigated. Compound electrolytes consisting of up to 20 wt.% 8YSZ were prepared by solid state reactions. Sintered pellets with up to 10 wt.% 8YSZ achieved near full density after sintering at 1450ºC and reduction in the fraction of impurity phases. Addition of 8YSZ promoted grain growth to LSGM. The higher ionic conductivity was obtained for 1 wt.% 8YSZ addition with slight decrease of the apparent activation energy.

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“…Solid solutions based on ZrO 2 stabilized with Sc 2 O 3 are promising materials for use as membranes in solid oxide fuel cells (SOFC).The material shows the highest ionic conductivity among solid solutions of zirconium dioxide [1][2][3][4].In practice, solid electrolytes are mainly used as gas-tight ceramic membranes manufactured using various ceramic technologies. The functional properties of these ceramic membranes CHEMICAL PROBLEMS 2019 no.…”

Section: Introductionmentioning

confidence: 99%

TRANSPORT PROPERTIES OF SINGLE CRYSTALS OF SOLID ELECTROLYTES BASED ON ZrO2-Sc2O3 CO-DOPED BY SCANDIA, YTTRIA, YTTERBIA AND CERIA

Агарков¹,

Борик²,

Бредихин³

et al. 2019

Chemical Problems

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Results of structural studies and ionic conductivity of solid solutions (ZrO 2) 1x (Sc 2 O 3) x (x = 0.08-0.10) doped with 1 mol.% Y 2 O 3 , Yb 2 O 3 иСeO 2 are presented. Crystals were grown by directional crystallization of melt in cold container. Studies of phase compositions were carried out by means of X-ray diffraction and Raman spectroscopy. Transport properties were studied by impedance spectroscopy in the temperature range of 400-900°С. It was shown that uniform transparent single crystals were obtained only for compositions of (ZrO 2) 0.89 (Sc 2 O 3) 0.1 (Y 2 O 3) 0.01 and (ZrO 2) 0.90 (Sc 2 O 3) 0.09 (Yb 2 O 3) 0.01. Stabilization of highly-symmetric phase in crystals codoped with Yb 2 O 3 happens for a lower concentration of Sc 2 O 3 in solid solution than for crystals co-doped with Y 2 O 3. Co-doping by ceria did not give an opportunity to obtain the single-phase cubic solid solution. It was also shown, that the conductivity ofcrystalsdepends on the amount of Sc 2 O 3 in solid solutions. It was detected that conductivity values for tetragonal crystals at 900 o C are close and they equal to about 0.1 S/cm by the order of magnitude. Crystals with the composition of (ZrO 2) 0.9 (Sc 2 O 3) 0.09 (Yb 2 O 3) 0.01 have maximal conductivity in all the temperature range studied. The conductivity value of these crystals at a temperature of 900°С is comparable to the similar value for (ZrO 2) 0.9 (Sc 2 O 3) 0.1 crystals. However, unlike the (ZrO 2) 0.9 (Sc 2 O 3) 0.1 crystal containing the rhombohedral phase, the (ZrO 2) 0.90 (Sc 2 O 3) 0.09 (Yb 2 O 3) 0.01 sample is a single-phase pseudo-cubic.

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Solid Oxide Electrolytes for High Temperature Fuel Cells

Cited by 38 publications

References 68 publications

Thermodynamic and kinetic considerations on degradations in solid oxide fuel cell cathodes

Thermodynamic and kinetic considerations on degradations in solid oxide fuel cell cathodes

Influence of Yttria-Stabilized Zirconia on Microstructure and Electrical Properties of Doped Lanthanum Gallate

TRANSPORT PROPERTIES OF SINGLE CRYSTALS OF SOLID ELECTROLYTES BASED ON ZrO2-Sc2O3 CO-DOPED BY SCANDIA, YTTRIA, YTTERBIA AND CERIA

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