Mössbauer 57Fe spectra exhibiting “ferrous character”

Fatséas, G. A.; Goodenough, John B

doi:10.1016/0022-4596(80)90123-1

Cited by 30 publications

(10 citation statements)

References 87 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The major one (90%) has an isomer shift of 0.48 mm/s which stands between what is expected for HS Fe 2+ and HS Fe 3+ , alike what has been seen in Fe3S4 and FeV2S4. 53 The second doublet with a 10 % contribution to the overall spectrum is indicative of the HS-Fe 3+ signature, as seen in NaFeS2. 53 Overall, the average oxidation state of Comp.…”

mentioning

confidence: 97%

“…53 The second doublet with a 10 % contribution to the overall spectrum is indicative of the HS-Fe 3+ signature, as seen in NaFeS2. 53 Overall, the average oxidation state of Comp. 2 is higher than Fe 2+ but not fully reaching Fe 3+ .…”

mentioning

confidence: 97%

“…The Mössbauer spectra for pristine Li1.13Ti0.57Fe0.3S2, that can neatly be fitted with four doublets (see Table S5), highlights the presence of a distribution of high-spin (HS) Fe 2+ , as already encountered for FeS and various other iron (II)-based sulfides. 53,54 The necessity of four doublets is simply due to different local arrangements of intermixed Ti/Li/Fe cations around a given Fe site. The evolution of the spectra obtained during in situ cycling is shown as a contour plot in Figure 5b, with the spectra analyzed using principal component analysis (PCA), as described in Supplementary Note S1.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Exploring the bottlenecks of anionic redox in Li-rich layered sulfides

et al. 2019

View full text Add to dashboard Cite

To satisfy the long-awaited need of new lithium-ion battery cathode materials with higher energy density, anionic redox chemistry has emerged as a new paradigm that is responsible for the high capacity in Li-rich layered oxides, for example, in Li1.2Ni0.13Mn0.54Co0.13O2 (Li-rich NMC). However, their marketimplementation has been plagued by certain bottlenecks originating intriguingly from the anionic redox activity itself. To fundamentally understand these bottlenecks (voltage fade, hysteresis and sluggish kinetics), we decided to target the ligand by switching to isostructural Li-rich layered sulfides. Herein, we designed new Li1.33-2y/3Ti0.67-y/3FeyS2 cathodes that enlist sustained reversible capacities of ~245 mAh•g-1 due to cumulated cationic (Fe 2+/3+) and anionic (S 2-/ S n-, n < 2) redox processes. In-depth electrochemical analysis revealed nearly zero irreversible capacity during the initial cycle, very small voltage fade upon long cycling, with low voltage hysteresis and fast kinetics, which contrasts positively with respect to their Li-rich NMC oxide analogues. Our study, further complemented with DFT calculations, demonstrates that moving from oxygen to sulfur as the ligand is an adequate strategy to partially mitigate the practical bottlenecks affecting anionic redox, although with an expected penalty in cell voltage. Altogether the present findings provide chemical clues on improving the holistic performance of anionic redox electrodes via ligand tuning, and hence strengthen the feasibility to ultimately capitalize on the energy benefits of oxygen redox.

show abstract

mentioning

confidence: 97%

mentioning

confidence: 97%

mentioning

confidence: 99%

See 1 more Smart Citation

Exploring the bottlenecks of anionic redox in Li-rich layered sulfides

et al. 2019

View full text Add to dashboard Cite

show abstract

“…In the Raman spectrum ( Figure 3) In the Mössbauer spectrum a doublet is seen with an isomer shift (IS) of 0.90 mm · s Ϫ1 and a quadrupole (ΔE q ) splitting of 1.48 mm · s Ϫ1 (Figure S3). Both values indicate Fe 2ϩ in the high-spin state [46,47]. For high-spin Fe 2ϩ the IS decreases with increasing covalency of the FeϪligand bond.…”

Section: Resultsmentioning

confidence: 99%

[Fe(C₆H₁₄N₂)₂][Sb₆S₁₀] – Using a Transition Metal Complex Acting as a Pillar for the Generation of a Three‐dimensional Thioantimonate(III) Network

Kiebach

Warratz

Näther

et al. 2009

Zeitschrift anorg allge chemie

View full text Add to dashboard Cite

The new three-dimensional thioantimonate [Fe(C 6 H 14 N 2 ) 2 ][Sb 6 S 10 ] was obtained under solvothermal conditions. The compound crystallizes in space group P1 with a ϭ 6.174(4), b ϭ 9.679(2), c ϭ 12.772(3) Å , Ͱ ϭ 72.08(3), β ϭ 88.15(3), γ ϭ 89.51(3)°, Z ϭ 2. Trigonal pyramidal [SbS 3 ] units and [SbS 4 ] groups are joined to form a two-dimensional [Sb 6 S 10 ] 2Ϫ layer. The in-situ formed [Fe(C 6 H 14 N 2 ) 2 ] 2ϩ complexes act like pillars joining the layers into a three-dimensional framework through FeϪS

show abstract

“…Here we should mention that the IS and HF parameters are both a measure of the charge density of the ion (Fe m+ ). Indeed the experimental values of IS and HF indicate that m≈2.6 thus corresponding to a formal electronic configuration of 3d 5+δ with δ= 0.4 [9]. Kobayashi et al [3] have shown that the spin up subband of Fe ions is full for a 3d 5 configuration.…”

mentioning

confidence: 97%

Cationic ordering control of magnetization in Sr2FeMoO6 double perovskite

Balcells¹,

Navarro²,

Bibès³

et al. 2001

Applied Physics Letters

385

260

View full text Add to dashboard Cite

The role of the synthesis conditions on the cationic Fe/Mo ordering in Sr 2 FeMoO 6 double perovskite is addressed. It is shown that this ordering can be controlled and varied systematically. The Fe/Mo ordering has a profound impact on the saturation magnetization of the material. Using the appropriate synthesis protocol a record value of 3.7µ B /f.u. has been obtained. Mössbauer analysis reveals the existence of two distinguishable Fe sites in agreement with the P4/mmm symmetry and a charge density at the Fe m+ ions significantly larger than 3d 5 suggesting a Fe contribution to the spin-down conduction band. The implications of these findings for the synthesis of Sr 2 FeMoO 6 having optimal magnetoresistance response are discussed. PACs: 75.30.Cr; 75.50.Gg;76.80.+y;81.40.Rs § To whom all correspondence should be send. 14-07-00 SFMO-01 2/13Although oxides of the type A 2 BB'O 6 where A is an alkaline earth (A=Sr, Ca, Ba) and B, B' are heterovalent transition metals such as B=Fe, Cr, .. and B'= Mo, W, Re,... , have known since long ago [1,2] they are receiving a renewed great deal of attention. This is motivated by the recent report that Sr 2 FeMoO 6 is a half-metallic ferromagnet with a relatively high Curie temperature (about 410-450K) [3]. Its half metallic nature leads to an ideal full polarization of the itinerant carriers and thus these materials are viewed as a serious alternative to the much investigated manganese perovskites but with the added advantage of having a wider temperature range for practical applications as magnetoresistive materials.The structure is built up by ordering perovskite blocks in a rock salt superlattice and the properties of the material are thought to critically depend on this ordering. Sr 2 FeMoO 6 is believed to be ferrimagnetic-like, i.e. the B and B' sublattice are antiferromagnetically coupled. In the simplest ionic picture Fe 3+ (3d 5 , S=5/2) ions in B sites are antiferromagnetically coupled to its six Mo 5+ (4d 1 , S=1/2) neighbors occupying the B' sites and thus a saturation magnetization M S =4µ B is predicted. Accordingly, it is expected that M S should be sensitively dependent on the ordering of Fe/Mo ions among the B/B' sublattices. Indeed, the M S values reported so far are systematically much smaller (3.1µ B [3], 3.5µ B [4] 3.2 µ B [5]), than the predicted 4µ B value. It is commonly thought that this significant decrease is due to antisite defects resulting from the partial disorder of Fe and Mo ions among the B/B' sublattices. Montecarlo simulations have indeed predicted a reduction of M S as a function of the antisite disorder that could account for the experimental observations [6].However, there are no strong experimental evidences that Fe/Mo disorder is the reason for the observed reduction of M S and thus strategies to enhance M S are lacking.We also note that the simple Fe 3+ /Mo 5+ ionic picture needs to be validated as neutron

show abstract

Mössbauer 57Fe spectra exhibiting “ferrous character”

Cited by 30 publications

References 87 publications

Exploring the bottlenecks of anionic redox in Li-rich layered sulfides

Exploring the bottlenecks of anionic redox in Li-rich layered sulfides

[Fe(C₆H₁₄N₂)₂][Sb₆S₁₀] – Using a Transition Metal Complex Acting as a Pillar for the Generation of a Three‐dimensional Thioantimonate(III) Network

Cationic ordering control of magnetization in Sr2FeMoO6 double perovskite

Contact Info

Product

Resources

About

Mössbauer 57Fe spectra exhibiting “ferrous character”

Cited by 30 publications

References 87 publications

Exploring the bottlenecks of anionic redox in Li-rich layered sulfides

Exploring the bottlenecks of anionic redox in Li-rich layered sulfides

[Fe(C6H14N2)2][Sb6S10] – Using a Transition Metal Complex Acting as a Pillar for the Generation of a Three‐dimensional Thioantimonate(III) Network

Cationic ordering control of magnetization in Sr2FeMoO6 double perovskite

Contact Info

Product

Resources

About

[Fe(C₆H₁₄N₂)₂][Sb₆S₁₀] – Using a Transition Metal Complex Acting as a Pillar for the Generation of a Three‐dimensional Thioantimonate(III) Network