Ionic conductivity of apatite-type solid electrolyte material, La10−Ba Si6O27−/2 (X= 0–1), and its fuel cell performance

Synthesis and characterization of calcium and iron co-doped lanthanum silicate oxyapatites by sol–gel process for solid oxide fuel cells

“…La 2 SiO 5 was not detected. These results indicate that the co-doped oxyapatite powders can be successfully synthesized by SGP with a substantially reduced phase formation temperature, similar to the previous results on La 10 Si 6 O 27 [35] and La 9.33 Si 6 O 26 [36] powders. The low phase formation temperature is most likely due to the better homogeneity of the precursor formed during the gel formation step.…”

“…The activation energies of LCSFO oxyapatites are in the range of 80e90 kJmol À1 in this study, generally lower than~100 kJmol À1 [49]. Even low activation energies of~50e60 kJ/mol for oxygen excess lanthanum silicate electrolyte were reported by Mineshige et al [16] and for Ba doped lanthanum silicate electrolyte [10]. Low activation energies were also reported in lanthanum silicate-based electrolytes by others [46].…”

Sinterability and conductivity of barium doped aluminium lanthanum oxyapatite La9.5Ba0.5Si5.5Al0.5O26.5 electrolyte of solid oxide fuel cells

“…As shown by Nojiri et al [33], the conductivity of La 10−x Ba x Si 6 O 27−x/2 exhibited a maximum around x = 0.5-0.6. Thus, Ba doped aluminium lanthanum apatite with composition La 9.5 Ba 0.5 Si 5.5 Al 0.5 O 26.5 was selected for this study.…”

“…An increase of conductivity was observed when lanthanum was partly substituted with an alkaline earth element and the conductivity increases with the dopant size. Arikawa et al [31] reported the best conductivity on La 9.75 Sr 0.25 Si 6 O 26.875 ( = 3.7 × 10 −2 S cm −1 at 800 • C), while for Slater and Sansam [32], best results were obtained on La 9 BaSi 6 O 26.5 with = 1.3 × 10 −2 S cm −1 at 800 • C. A substitute of La with Ba (rBa 2+ (VII) = 1.39Å), whose radius is larger than Sr and La (rSr 2+ (VII) = 1.21Å, rLa 3+ (VII/IX) = 1.06/1.20Å), would lead to enhanced conductivity [32][33][34]. Thus it would be interesting to study the effect of Ba doping on the sintering and conduction properties of aluminium lanthanum oxyapatite.…”

Development of layered anode structures supported over Apatite-type Solid Electrolytes

“…Fe-and Al-doped apatite-type lanthanum silicates (ATLS) have attracted the interest due to their thermodynamic stability, robustness and their high ionic conductivity at intermediate temperatures [5][6][7][8]. Not many researchers have tried to fabricate and study ATLS electrolyte based fuel cells for an estimation of cell performance and degradation with state of the art electrodes [9][10][11][12].…”