Oxygen anion diffusion in double perovskite GdBaCo2O5+δ and LnBa0.5Sr0.5Co2−xFexO5+δ (Ln = Gd, Pr, Nd) electrodes

Anjum, Uzma; Vashishtha, Saumye; Agarwal, Manish; Tiwari, Pankaj; Sinha, Nishant K.; Agrawal, Ankit; Basu, Suddhasatwa; Haider, M. Ali

doi:10.1016/j.ijhydene.2016.02.090

Cited by 30 publications

(17 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our previous work, oxygen anion diffusion in GBCO5.5 was calculated using MD simulations [16]. The diffusion of oxygen anion was observed to take place preferentially in the a-b plane [16]. The diffusion coefficient was calculated to be 2.8 x10 -7 cm 2 s -1 at 1173 K ( Figure 2a) which was comparable to the experimentally measured value [17].…”

Section: Resultssupporting

confidence: 75%

Nanoparticle Synthesis and Oxygen Anion Diffusion in Double Perovskite GdBaCo_2-xFe_xO_5+δ Electrodes for SOFC

et al. 2016

Self Cite

View full text Add to dashboard Cite

Development of an intermediate temperature solid oxide fuel cell essentially require the synthesis of electrocatalytically active nanostructured cathode materials with fast oxygen anion transport and surface exchange properties. Double perovskite structured GaBaCo2O5+δ (GBCO) electrode showing an average particle size of less than 20 nm was synthesized by a bio-milling approach. In parallel, molecular dynamics (MD) simulations were utilised to calculate the effect of Fe doping at the B-site on the oxygen anion diffusivity of GdBaFexCo2-xO5.5 double perovskites. The oxygen diffusion was observed to be preferential in the a-b plane of GBCO with a value of D=2.8 x 10-7 cm2 s-1, calculated at 1173 K. The change in diffusion coefficient (D=1.95 x 10-7 cm2 s-1 at 1173 K) was negligible on doping 50% Fe in the structure. However, in 100% Fe substituted structure, GdBaFe2O5.5 (GBFO5.5), the diffusivity was significantly reduced (D=2 x 10-8 cm2 s-1 at 1173 K).

show abstract

Section: Resultssupporting

confidence: 75%

Nanoparticle Synthesis and Oxygen Anion Diffusion in Double Perovskite GdBaCo_2-xFe_xO_5+δ Electrodes for SOFC

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…For example, the oxygen non-stoichiometry properties of perovskites (represented by their oxygen vacancies and interstitial sites) can enhance oxide ion transport through vacancy and interstitialcy mechanisms [28,29]. Such an effective increase in the oxygen ion transport through the electrode can improve electrochemical properties via the reduction in ion diffusion resistance [28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Sr Substituted La2−xSrxNi0.8Co0.2O4+δ (0 ≤ x ≤ 0.8): Impact on Oxygen Stoichiometry and Electrochemical Properties

et al. 2022

View full text Add to dashboard Cite

Lanthanide nickelate Ln2NiO4+δ (Ln = La, Pr, or Nd) based mixed ionic and electronic conducting (MIEC) materials have drawn significant attention as an alternative oxygen electrode for solid oxide cells (SOCs). These nickelates show very high oxygen diffusion coefficient (D*) and surface exchange coefficient (k*) values and hence exhibit good electrocatalytic activity. Earlier reported results show that the partial substitution of Co2+ at B-site in La2Ni1−xCoxO4+δ (LNCO) leads to an enhancement in the transport and electrochemical properties of the material. Herein, we perform the substitution at A-site with Sr, i.e., La2−xSrxNi0.8Co0.2O4+δ, in order to further investigate the structural, physicochemical, and electrochemical properties. The structural characterization of the synthesized powders reveals a decrease in the lattice parameters as well as lattice volume with increasing Sr content. Furthermore, a decrease in the oxygen over stoichiometry is also observed with Sr substitution. The electrochemical measurements are performed with the symmetrical half-cells using impedance spectroscopy in the 700–900 °C temperature range. The total polarization resistance of the cell is increased with Sr substitution. The electrode reaction mechanism is also studied by recording the impedance spectra under different oxygen partial pressures. Finally, the kinetic parameters are investigated by analyzing the impedance spectra under polarization. A decrease in exchange current density (i0) is observed with increasing Sr content.

show abstract

“…Indeed, as a fact, the Ba−O plane in the double perovskite structure is known to be least diffusive as compared to the planes formed by other cations. 26,27,53 Following this, the surface energy of each terminal surface was calculated using DFT simulations and are reported in Table 3. The corresponding structures of the terminal surfaces are shown in Figure 6.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Interestingly, as reported by us and many other authors, 25,55 because of anisotropic diffusion and difficulty in oxygen vacancy formation, the BaSr plane in general is least diffusive, as compared to the planes formed by Gd, Nd, Pr, and transition-metal cations. 25,26 The γ values for the terminal surfaces in the (110) direction were calculated to be significantly higher than those in the corresponding (001) direction and are not included in this discussion.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Identifying the Origin of the Limiting Process in a Double Perovskite PrBa_0.5Sr_0.5Co_1.5Fe_0.5O_5+δ Thin-Film Electrode for Solid Oxide Fuel Cells

Anjum

Khan

Agarwal

et al. 2019

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

Oxygen reduction reaction in a double perovskite material, PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (PBSCF), was studied for application as a cathode in a solid oxide fuel cell (SOFC). Electrochemical measurements were performed on a geometrically welldefined dense thin-film (0.8−2 μm thickness) electrode, fabricated as a symmetric cell. In combination with density functional theory (DFT) and molecular dynamics (MD) simulations, experiments provided an insight into the operating mechanism of the SOFC material tested at an open-circuit voltage. The dense thin-film electrode of PBSCF showed a thickness-dependent electrochemical performance, suggesting bulk diffusion limitation. To understand the origin of this diffusion-limiting electrochemical performance, DFT calculations were utilized to calculate the surface (γ) and oxygen vacancy formation (E OV ) energies. For example, E OV in the Pr plane (190 kJ/mol) of PBSCF was measured to be lower than that of the BaSr plane (E OV = 297 kJ/ mol). In addition, oxygen vacancies were difficult to be created in the BaSr/CoFe terminal surface (E OV = 341.6 kJ/mol) as compared to other terminal surfaces. MD simulations further elaborated on the nature of cation disordering in the surface and subsurface regions, consequently leading to the preferential segregation of the Ba cations to the surface, which is a known phenomenon in such double perovskite materials. Because of cation disordering and segregation of Ba species, the oxygen anion diffusivity (∼10 −12 cm 2 s −1 ), calculated from MD, in the near-surface region was observed to be 2 orders of magnitude lesser than that of the bulk (D = 2.98 × 10 −10 cm 2 s −1 ) of the material at 973 K. Surface characterization of the thin-film electrode using X-ray photoelectron spectroscopy was indicative of a nonperovskite Ba 2+ phase on the electrode surface. The segregation of Ba cations was linked with the transport of oxygen anions, which was limiting the electrochemical performance of the electrode.

show abstract

Oxygen anion diffusion in double perovskite GdBaCo2O5+δ and LnBa0.5Sr0.5Co2−xFexO5+δ (Ln = Gd, Pr, Nd) electrodes

Cited by 30 publications

References 54 publications

Nanoparticle Synthesis and Oxygen Anion Diffusion in Double Perovskite GdBaCo_2-xFe_xO_5+δ Electrodes for SOFC

Nanoparticle Synthesis and Oxygen Anion Diffusion in Double Perovskite GdBaCo_2-xFe_xO_5+δ Electrodes for SOFC

Sr Substituted La2−xSrxNi0.8Co0.2O4+δ (0 ≤ x ≤ 0.8): Impact on Oxygen Stoichiometry and Electrochemical Properties

Identifying the Origin of the Limiting Process in a Double Perovskite PrBa_0.5Sr_0.5Co_1.5Fe_0.5O_5+δ Thin-Film Electrode for Solid Oxide Fuel Cells

Contact Info

Product

Resources

About

Oxygen anion diffusion in double perovskite GdBaCo2O5+δ and LnBa0.5Sr0.5Co2−xFexO5+δ (Ln = Gd, Pr, Nd) electrodes

Cited by 30 publications

References 54 publications

Nanoparticle Synthesis and Oxygen Anion Diffusion in Double Perovskite GdBaCo2-xFexO5+δ Electrodes for SOFC

Nanoparticle Synthesis and Oxygen Anion Diffusion in Double Perovskite GdBaCo2-xFexO5+δ Electrodes for SOFC

Sr Substituted La2−xSrxNi0.8Co0.2O4+δ (0 ≤ x ≤ 0.8): Impact on Oxygen Stoichiometry and Electrochemical Properties

Identifying the Origin of the Limiting Process in a Double Perovskite PrBa0.5Sr0.5Co1.5Fe0.5O5+δ Thin-Film Electrode for Solid Oxide Fuel Cells

Contact Info

Product

Resources

About

Nanoparticle Synthesis and Oxygen Anion Diffusion in Double Perovskite GdBaCo_2-xFe_xO_5+δ Electrodes for SOFC

Nanoparticle Synthesis and Oxygen Anion Diffusion in Double Perovskite GdBaCo_2-xFe_xO_5+δ Electrodes for SOFC

Identifying the Origin of the Limiting Process in a Double Perovskite PrBa_0.5Sr_0.5Co_1.5Fe_0.5O_5+δ Thin-Film Electrode for Solid Oxide Fuel Cells