Synthesis, structure and conductivity of sulfate and phosphate doped SrCoO3

Hancock, Cathryn A.; Slade, Robert C. T.; Varcoe, John R.; Slater, Peter R.

doi:10.1016/j.jssc.2011.08.040

Cited by 46 publications

(37 citation statements)

References 37 publications

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“…In particular, we have shown that the partial substitution of these oxyanions at the In/Sc site in Ba 2 (In/Sc) 2 O 5 leads to the introduction of disorder on the oxygen sublattice and a corresponding enhancement in the low temperature ionic conductivity [14][15][16][17][18]. In terms of electronic conducting materials, we have also reported the successful incorporation of silicate, phosphate and sulphate into SrMO 3 (M = Co, Mn), leading to a large enhancement in the electronic conductivity [19,20]. In these latter examples, this large enhancement in the conductivity could be explained by a change from a 2H-perovskite (containing face sharing of octahedra) to a 3C-perovskite (containing corner sharing of octahedra).…”

Section: Introductionmentioning

confidence: 70%

Synthesis and characterisation of oxyanion-doped manganites for potential application as SOFC cathodes

et al. 2012

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In this paper we report the successful incorporation of borate and phosphate into CaMnO 3 and borate into La 1Ày Sr y MnO 3Àd . For CaMnO 3 , an increase in the electronic conductivity was observed, which can be correlated with electron doping due to the oxyanion doping favoring the introduction of oxide ion vacancies (as well as the higher valence of P 5+ compared to Mn 4+ in the case of phosphate doping). The highest conductivity at 800 C was observed for CaMn 0.95 P 0.05 O 3Àd , 43.0 S cm À1 , in comparison with 7.6 S cm À1 for undoped CaMnO 3 at the same temperature. For La 1Ày Sr y MnO 3Àd the conductivity suffers a decrease for all compositions on borate doping, attributed to a reduction in the hole (Mn 4+ ) concentration. In order to investigate the potential of these materials as SOFC cathodes, the chemical compatibility with Gd 0.1 Ce 0.9 O 1.95 (CGO10) has also been investigated. For the calcium manganites, the lowest temperature examined without reaction was 900 C, with minor amounts of Ca 4 Mn 3 O 10 observed at 1000 C. Composites of these cathode materials with 50% CGO10 were examined on dense CGO10 pellets and the area specific resistances (ASR) in symmetrical cells were determined. The ASR values, at 800 C, were 1.50, 0.37 and 0.30 U$cm 2 for CaMnO 3 , CaMn 0.95 B 0.05 O 3Àd and CaMn 0.95 P 0.05 O 3Àd , respectively. For the lanthanum strontium manganites, the B-doped compositions showed an improvement in the ASR values with respect to the parent compounds, despite the lower electronic conductivity. This may be due to an increase in ionic conductivity due to borate incorporation leading to the formation of oxide ion vacancies. Thus these preliminary results show that oxyanion doping has a beneficial effect on the performance of perovskite manganite cathode materials, and suggests that this doping strategy warrants further investigation in other perovskite cathode systems.

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Section: Introductionmentioning

confidence: 70%

Synthesis and characterisation of oxyanion-doped manganites for potential application as SOFC cathodes

et al. 2012

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“…Further work showed that this doping strategy could also be extended to potential electrode systems, with Si, P doping into SrMO 3-y (M=Mn, Co) shown to enhance the electronic conductivity, associated with a conversion from a hexagonal perovskite system to a cubic perovskite system [19,20] In this paper, we extend this oxyanion doping work to examine the potential synthesis of used to demonstrate phase purity, as well as for preliminary structure determination. For the latter, the GSAS suite of programs was used [24].…”

Section: Introductionmentioning

confidence: 95%

Synthesis and characterization of proton conducting oxyanion doped Ba2Sc2O5

et al. 2012

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In this paper we report the successful synthesis of the cubic oxyanion containing perovskites, Ba 2 Sc 2-x P x O 5+x (x=0.4, 0.5), with the samples analysed through a combination of X-ray diffraction, NMR, TGA, Raman spectroscopy and conductivity measurements. Conductivity measurements indicate a p-type contribution to the conductivity in oxidizing conditions at elevated temperatures, with evidence for proton conduction in wet atmospheres. For the latter bulk conductivities of 5.9 x 10 -3 and 1.3 x 10 -3 Scm -1 at 500 ○ C were obtained for x=0.4 and 0.5 respectively, comparable to other perovskite proton conductors, while the stability towards CO 2 containing atmospheres was improved compared to BaCeO 3 based systems.Related Si doped systems have also been prepared, although in this case small Ba 2 SiO 4 impurities are observed. We also provide evidence to suggest that "undoped" Ba 2 Sc 2 O 5 contains carbonate groups, which accounts for its thermal instability.

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“…19), (La,Sr)(Co,Fe)O 3−δ (refs 20, 21) and Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ 422, which are claimed to exhibit high ORR activity in the intermediate temperature range 600–750 °C because of their relatively high mixed conductivities2324. The perovskite structure of SC, which is favoured for ORR, is usually stabilized by partial B -site substitution with high oxidation-state cations25, such as Nb2627, Mo28, Sb2930 and P3132, and these cations lead to low area-specific resistances (ASRs) at reduced temperature272829313334. Besides the single doped SCs, Zhou et al 10.…”

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confidence: 99%

A niobium and tantalum co-doped perovskite cathode for solid oxide fuel cells operating below 500 °C

et al. 2017

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The slow activity of cathode materials is one of the most significant barriers to realizing the operation of solid oxide fuel cells below 500 °C. Here we report a niobium and tantalum co-substituted perovskite SrCo0.8Nb0.1Ta0.1O3−δ as a cathode, which exhibits high electroactivity. This cathode has an area-specific polarization resistance as low as ∼0.16 and ∼0.68 Ω cm2 in a symmetrical cell and peak power densities of 1.2 and 0.7 W cm−2 in a Gd0.1Ce0.9O1.95-based anode-supported fuel cell at 500 and 450 °C, respectively. The high performance is attributed to an optimal balance of oxygen vacancies, ionic mobility and surface electron transfer as promoted by the synergistic effects of the niobium and tantalum. This work also points to an effective strategy in the design of cathodes for low-temperature solid oxide fuel cells.

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Synthesis, structure and conductivity of sulfate and phosphate doped SrCoO3

Cited by 46 publications

References 37 publications

Synthesis and characterisation of oxyanion-doped manganites for potential application as SOFC cathodes

Synthesis and characterisation of oxyanion-doped manganites for potential application as SOFC cathodes

Synthesis and characterization of proton conducting oxyanion doped Ba2Sc2O5

A niobium and tantalum co-doped perovskite cathode for solid oxide fuel cells operating below 500 °C

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