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

Effect of Sr and Al or Fe co-doping on the sinterability and conductivity of lanthanum silicate oxyapatite electrolytes for solid oxide fuel cells

“…In addition, a small tail or arc at low frequencies (below 100 Hz) is most likely related to the electrode interface reaction. The impedance responses for LSO, LSSAO and LSSFO are dominated by the high and medium frequency arcs, indicating the dominance of the grain bulk and grain boundary resistances to the oxide ion conductivity of the oxyapatite electrolytes, similar to the previous studies [37,43,48,49]. The impedance arcs at the high and medium frequencies of LSO are substantially bigger than that of LSSAO and LSSFO sintered under the identical conditions.…”

“…1). The similar phase distribution was also observed for the La 9 SrSi 6 O 26.5 [43] and La 9.5 Ba 0.5 Si 5.5 Al 0.5 O 26.5 [37]. In the case of La 9 SrSi 6 O 26.5 , the i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 3 9 ( 2 0 1 4 ) 1 9 0 9 3 e1 9 1 0 1 atomic ratios of La/Si is 1.6 for the grains and 5.4 for the segregated phases at the grain boundaries [43].…”

“…The raw materials were weighed in appropriate ratio to elaborate the compounds with compositions La 10 Si 6.0 O 26.5 (LSO), La 9.5 Sr 0.5 Si 5.5 Al 0.5 O 26.5 (Sr and Al co-doping, LSSAO) and La 9.5 Sr 0.5 Si 5.5 Fe 0.5 O 26.5 (Sr and Fe co-doping, LSSFO), and mixed in plastic vessels for 24 h. The details of the procedures for the synthesis of apatite powders by solid state reaction can be found in a previous publication [37].…”

Synthesis and characterization of Al3+ and M (M = W6+, In3+, Nb5+, Mg2+) co-doped lanthanum silicate oxy-apatite electrolytes

“…Recently, some research also has been reported on the oxyapatite lanthanum silicates with the cations co-doping on both La 3þ and Si 4þ site, such as Ba and Al co-doping [39], Sr and Al or Fe co-doping [40], Ca and Fe co-doping [41]. However, the research of the co-doping strategy on Si 4þ site is limited.…”

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

“…The traditional method to prepare the lanthanum silicate oxyapatite is the high-temperature solid state reaction process (SSP) [28]. However, lanthanum silica oxyapatites with a high purity level are very difficult to obtain, as the samples are often contaminated with either La 2 SiO 5 or La 2 Si 2 O 7 secondary phases [29e31].…”