Chemical diffusivity and ionic conductivity of GdBaCo2O5+δ

Choi, Min Sun; Jeon, Sang-Yun; Lee, J.-S.; Hwang, Hae Jin; Song, Sun-Ju

doi:10.1016/j.jpowsour.2009.08.074

Cited by 46 publications

(31 citation statements)

References 18 publications

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“…The one-dimensional displacement in the direction of the specimen length was measured using a Netzh L75 PT1600 ͑Bacarian Town of Selb, Germany͒, dilatometer from room temperature to 1000°C at 2°C/min with an air purge at a flow rate of 100 cm 3 /min. 17 The overall measurements were repeated over the temperature range of 25 ഛ T/°C ഛ 1000. For the chemical expansion relaxation measurements, the specimen was completely equilibrated in a given thermodynamic condition and then the oxygen chemical potential was abruptly changed to a different value while recording the specimen's total expansion versus time until a new equilibrium was reached.…”

Section: Methodsmentioning

confidence: 99%

Determination of Oxygen Chemical Diffusivity from Chemical Expansion Relaxation for BaCo[sub 0.7]Fe[sub 0.22]Nb[sub 0.08]O[sub 3−δ]

Choi¹,

Jeon²,

Yang³

et al. 2011

J. Electrochem. Soc.

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The thermal and chemical expansion properties of BaCo 0.7 Fe 0.22 Nb 0.08 O 3−␦ , a potential candidate for oxygen permeable membranes and cathodes in solid oxide fuel cells, are reported here. The average thermal expansion coefficient is about 14 ϫ 10 −6 K −1 below 500°C, about 19 ϫ 10 −6 K −1 between 600 and 900°C, and about 29 ϫ 10 −6 K −1 between 900 and 1000°C, which consists of the previous weight change in a thermal gravimetric analysis experiment. The transient behavior in the thermochemical expansion can be best fitted with Fick's second law for a small displacement from the equilibrium. The chemical diffusivity of oxygen and the surface exchange kinetics are successfully extracted.

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Section: Methodsmentioning

confidence: 99%

Determination of Oxygen Chemical Diffusivity from Chemical Expansion Relaxation for BaCo[sub 0.7]Fe[sub 0.22]Nb[sub 0.08]O[sub 3−δ]

Choi¹,

Jeon²,

Yang³

et al. 2011

J. Electrochem. Soc.

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“…All peaks that corresponded to the double perovskite (GdBaCo 2 O 5.42 ) appeared when the sintering temperature was increased to 850°C. All the patterns ranging from 850 to 1150°C were indexed to the orthorhombic structure with pmmm space group, which meant that the double perovskite structure could be obtained at 850°C for 10 h. The current sintering method showed to be very economical and efficient compared to the conventional solid state reaction method [26][27][28][29][30]. Moreover, the obtained samples synthesized at 1050 and 1150°C showed the secondary phase-CaO, as represented in Fig.…”

Section: Effect Of the Sintering Temperaturesmentioning

confidence: 99%

“…Among various types of TMOs, GaBaCo 2 O 5?d (GBCO) has attracted a lot of attention due to its certain interesting properties, such as insulator-metal transition (IMT) [12], total conductivity [13], charge ordering [14], magnetic transition [15] and non-stoichiometry in thermogravimetric analysis [16]. GBCO 2 ] stacked sequentially along the c axis [17].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and conductivity properties of Gd0.8Ca0.2BaCo2O5+δ double perovskite by sol–gel combustion

Zhang

Lü

Wei

et al. 2015

J Mater Sci: Mater Electron

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Double perovskite oxides Gd 0.8 Ca 0.2 BaCo 2-O 5?d have been successfully prepared by EDTA-citrate complexation process. The prepared samples were characterized by means of thermogravimetry-differential analysis, X-ray diffraction, Fourier transform infrared spectroscopy techniques. These analyses suggested that pure Gd 0.8 Ca 0.2 BaCo 2 O 5?d phase could be formed when the pH value was maintained above three and calcination temperature was higher than 850°C. The conductivity properties analyzed by means of four probes method, scanning electron microscopy and X-ray photoelectron spectroscopy indicated an improvement in conductivity with a high value of nearly 1200 S/cm, which was due to an increase in the number of small polaron hopping conduction units, Co 3? -O-Co 4? . Interestingly, the Gd 0.8-Ca 0.2 BaCo 2 O 5?d samples exhibited a semiconducting behavior through a wide range of temperature below 100°C and a metallic behavior at 100-500°C, thereby demonstrating that Gd 0.8 Ca 0.2 BaCo 2 O 5?d could meet the requirements of a smart material.

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“…The obtained powders were characterized by X-ray diffraction (XRD; www.elsevier.com/locate/ceramint Available online at www.sciencedirect.com Ceramics International 37 (2011) 49-53 D/MAX Ultima III, Rigaku, Japan) equipped with a Cu target Xray tube at a scan rate of 18/min between scanning angles of (2u) 108 and 908. The obtained XRD pattern was refined using the Full-Prof program according to the Rietveld method [13]. The scanning electron micrograph (SEM; Shimadzu, SS-550) image of the as-sintered fracture surface, in Fig.…”

Section: Methodsmentioning

confidence: 99%