Synthesis and characterization of La1+Sr2−CoMnO7− (x=0,0.2; δ=0,1)

El‐Shinawi, Hany; Bertha, A.; Hadermann, Joke; Herranz, T.; Santos, B.; Marco, José F.; Berry, Frank J.; Greaves, C.

doi:10.1016/j.jssc.2010.04.018

Cited by 10 publications

(4 citation statements)

References 26 publications

(43 reference statements)

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“…We also note that such marked anisotropy of the U ii has not been observed in reduced Co-based n ¼ 2 RP phases where oxygen is lost from the axial sites linking the octahedra within the double perovskite layer. 29,30 The behaviour of the composition x ¼ 0.2 clearly differs from that of x ¼ 0.0, principally because of the presence of a higher concentration of anions on the interstitial site. This will lead to stronger O int -O ax repulsions and hence increase the anisotropic nature of the displacements of the oxide ions in the as-prepared sample (Table 3).…”

Section: Discussionmentioning

confidence: 99%

High-temperature redox chemistry of La1.5+xSr0.5−xCo0.5Ni0.5O4+δ (x = 0.0, 0.2) studied in situ by neutron diffraction

et al. 2011

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International audienceNeutron powder diffraction has been used to investigate the redox behaviour of two n = 1 Ruddlesden-Popper (RP) oxides, La(1.5+x)Sr(0.5-x)Co(0.5)Ni(0.5)O(4+delta) (x = 0.0, 0.2) in situ and in real time during cycling through the temperature range 20 < T/degrees C < 600 under flowing 5% H(2). Both compositions retained I4/mmm symmetry throughout the heating and cooling cycle. Rietveld refinement of data collected at room temperature showed the presence of interstitial oxygen in the original samples (delta approximate to 0.06(1) and 0.12(1) for x 0.0 and 0.2, respectively). When heated in flowing H(2), both compositions were reduced over the temperature range 300 < T/degrees C < 600 (delta approximate to -0.22(2) and -0.06(2) for x 0.0 and 0.2, respectively). In the case of the x = 0.2 material, reduction clearly occurred first at the interstitial site (O(int)), then at the equatorial site (O(eq)). The changes in composition were accompanied by changes in unit-cell parameters and bond lengths. Rietveld refinements revealed residual partial occupation of the O(int) site in the reduced x = 0.2 sample. This is the first structural evidence of the coexistence of both anion vacancies and interstitial anions in a hypostoichiometric n = 1 RP oxide. The temperature dependence of the atomic displacement parameters is consistent with the presence of local rotations of the anion-deficient coordination polyhedra. On heating the reduced x = 0.2 material in an O(2) flow, the refilling of both the O(eq) and O(int) sites began at 200 degrees C and the stoichiometry of the original as-prepared sample was recovered by 250 degrees C

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Section: Discussionmentioning

confidence: 99%

High-temperature redox chemistry of La1.5+xSr0.5−xCo0.5Ni0.5O4+δ (x = 0.0, 0.2) studied in situ by neutron diffraction

et al. 2011

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“…Both Sr 2 LaFeMnO 7 [20,30] and Sr 2 LaCoMnO 7 [20,35] have a bilayered RP structure, i. e., n = 2 in A n-1 A' 2 B n O 3n + 1 , where La and Sr are located on A and A' sites, respectively, while Fe/Mn or Co/Mn share the B-site. The structure consists of bilayer stacks of BO 6 octahedra, where La and Sr are located within and between the stacks, respectively.…”

Section: Resultsmentioning

confidence: 99%

Pseudocapacitive Properties of Isostructural Oxides Sr₂LaBMnO₇ (B=Co, Fe)

Kananke‐Gamage,

Alom,

Ramezanipour

2023

ChemPhysChem

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Pseudocapacitors promise to fill the gap between traditional capacitors and batteries by delivering reasonable energy densities and power densities. In this work, pseudocapacitive charge storage properties are demonstrated for two isostructural oxides, Sr2LaFeMnO7 and Sr2LaCoMnO7. These materials comprise spatially separated bilayer stacks of corner sharing BO6 units (B = Fe, Co or Mn). The spaces between stacks accommodate the lanthanum and strontium ions, and the remining empty spaces are available for oxide ion intercalation, leading to pseudocapacitive charge storage. Iodometric titrations indicate that these materials do not have oxygen‐vacancies. Therefore, the oxide ion intercalation becomes possible due to their structural features and the availability of interstitial sites between the octahedral stacks. Electrochemical studies reveal that both materials show promising energy density and power density values. Further experiments through fabrication of a symmetric two‐electrode cell indicate that these materials retain their pseudocapacitive performance over hundreds of cycles of galvanostatic charge‐discharge cycles, with little degradation even after 1000 cycles.

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“…Analogous compounds La 1+x Sr 2-x CoMnO 7-d contain a mixture of Co and Mn in a double layer of perovskite. 12 In the oxidised compounds these species are present as the Co 3+ /Mn 4+ couple and both cations are reduced to give Co 2+ /Mn 3+ in LaSr 2 CoMnO 6 and La 1.2 Sr 1.8 CoMnO 6 prepared by heating the oxidised phases under reducing conditions. This reduction in oxide content leads to a change in coordination environment from octahedral, in the as-prepared compounds, to squarebased pyramidal by removing the central oxide ion from the perovskite slab and so breaking the link between the two transition metal cations as shown in Fig.…”

Section: Oxidesmentioning

confidence: 99%

“…Polyhedra represent the transition metal coordination environment and black spheres represent A cations. 12 This reduction changes the magnetic interactions from ferromagnetic to antiferromagnetic although disorder in these materials prevents the formation of a magnetically-ordered phase. A triple layer of perovskite is found in the new compound NiClSr 2 Ta 3 O 10 13 which is formed from a precursor compound RbSr 2 Ta 3 O 10 by reaction with NiCl 2 in a sealed evacuated pyrex tube at 340 1C.…”

Section: Oxidesmentioning

confidence: 99%