Synthesis of O3-Na0.8Fe0.6Mn0.3O2 Positive Electrode and Its Application to Sodium Ion Batteries

2021 ◽  
pp. 1-15
Author(s):  
M. Alam Khan
Keyword(s):  
Substantial Reduction ◽  
Group Behavior ◽  
Teller Distortion ◽  
Space Group ◽  
High Performing ◽  
Vacancy Ordering ◽  
Jahn Teller ◽  
P Type ◽  
Jahn Teller Distortion ◽  
Discharge Capacities

Herein, we report precise variation of Fe and Mn constituent in the sodium magnate layered cathodes with the compositions of Na0.8Fe0.4Mn0.5O2, Na0.8Fe0.5Mn0.4O2, Na0.8Fe0.6Mn0.3O2, Na0.8Fe0.6Mn0.4O2, Na0.8Fe0.7Mn0.4O2, Na0.9Fe0.6Mn0.3O2 in order to attain a high performing cathode. Based on this transition metal stoichiometry, an interesting sodium magnate combination of Na0.8Fe0.6Mn0.3O2, with O3-type crystal phase, possess R3m space group along with the superior electrochemical behavior is obtained. On charge-discharge capacities in the range of 2.0-3.8 V at 0.1 C, it shows the comparatively higher performance of the first and the second charge capacity of 115 and 180 mAhg-1 and discharge capacity of 184 and 181 mAhg-1, respectively. The best sample was then compared with the closely related Na0.8Fe0.6Mn0.4O2, Na0.9Fe0.6Mn0.3O2 combination in terms of valence ratio and influence of excess sodium for the structure robustness, stability along with purity. The best sample with the composition Na0.8Fe0.6Mn0.3O2 does not show detectable impure phase while Na0.8Fe0.6Mn0.4O2 and Na0.9Fe0.6Mn0.3O2 shows a tendency of P-type (Cmca space group) behavior with 30.8% and 32.8%, respectively. The enhancement of iron constituent increases not only the performances but also the stabilization of sodium vacancy ordering and substitution of Mn with a substantial reduction of Jahn-Teller distortion, mounting biphasic characteristics and high peak intensity of 41.5 °.

scholarly journals Die Jahn-Teller-Verzerrung in den Kristallstrukturen der Dinatrium-Tetrafluorometallate Na2CuF4 und Na2CrF4 / The Jahn-Teller Distortion in the Crystal Structures of the Disodium-Tetrafluorometallates Na2CuF4 and Na2CrF4

1989 ◽  
Vol 44 (7) ◽  
pp. 715-720 ◽  
Author(s):  
Dietrich Babel ◽  
Michael Otto
Keyword(s):  
Crystal Structures ◽  
Chain Structure ◽  
Teller Distortion ◽  
Space Group ◽  
X Ray ◽  
Edge Sharing Octahedra ◽  
Jahn Teller ◽  
A Chain ◽  
Jahn Teller Distortion ◽  
Ray Methods

The crystal structures of the isotypic monoclinic fluorides Na2CuF4 (a = 326.7(1), b = 937.0(2), c = 561.2(1) pm, β = 92.49(1)°; V = 171.63 x10-30 m3) and Na2CrF4 (a = 334.8(1), b = 954.9(2), c = 566.5(3) pm, β = 92.85(3)°; V = 180.89 × 10-30 m3) have been redetermined by single crystal X-ray methods. The compounds are Jahn-Teller distorted variants of the orthorhombic Sr2PbO4type (space group Pbam) and crystallize with Z = 2 in space group P21/c, a subgroup of Pbam. They form a chain structure of edge-sharing octahedra which are strongly elongated. The following distances were obtained: Cu-F = 190.4/193.8/235,7(2) pm and Cr-F = 199.1/199.7/241.7(4) pm. The geometry is compared to that of the corresponding distorted rutile type difluorides; relations to further compounds are discussed.

Zur Struktur der Kupfer-Weberite Na2CuCrF7 und Na2CuFeF7 / Concerning the Structures of the Copper Weberites Na2CuCrF7 and Na2CuFeF7

1988 ◽  
Vol 43 (6) ◽  
pp. 694-701 ◽  
Author(s):  
S. Kummer ◽  
W. Massa ◽  
D. Babel
Keyword(s):  
Crystal Structure ◽  
The Body ◽  
Intermediate Type ◽  
Teller Distortion ◽  
Mean Values ◽  
Space Group ◽  
Preliminary Results ◽  
Jahn Teller ◽  
Jahn Teller Distortion

AbstractThe crystal structure of the compound Na-CuCrF7 (orthorhombic, a = 710.0, b = 1033.8, c = 751.8 pm, Z = 4) was refined in space group Pmnb to Rg= 0.028 (1545 independent reflections). The Jahn-Teller distortion of the CuF6 -octahedra (Cu-F = 191.1/193.8/212.4 pm. mean 199.1 pm) reduces the symmetry compared to the body-centered orthorhombic weberite type, to which it is otherwise closely related. The CrF6 -octahedra. interconnecting parallel chains of CuF6 -octahedra, are nearly undistorted (mean Cr-F = 190.6 pm). Na2CuFeF7 exhibits a supercell with a different structure (monoclinic, a = 2468.7, b = 734.7, c = 1245.2 pm, β = 99.29°, Z = 16). It may be interpreted as a new intermediate type between orthorhombic and trigonal weberites. Preliminary results obtained from refinement in space group A2/n (Rg = 0.076) are given and discussed (mean values Cu-F = 199 pm, Fe - F = 192 pm).

scholarly journals Mitigation of Jahn–Teller distortion and Na+/vacancy ordering in a distorted manganese oxide cathode material by Li substitution

2021 ◽  
Author(s):  
Yanchen Liu ◽  
Chenchen Wang ◽  
Shuo Zhao ◽  
Lin Zhang ◽  
Kai Zhang ◽  
...  
Keyword(s):  
Cathode Material ◽  
Rate Capability ◽  
Sodium Ion ◽  
Sodium Ion Batteries ◽  
Teller Distortion ◽  
Oxide Cathode ◽  
Vacancy Ordering ◽  
Jahn Teller ◽  
Jahn Teller Distortion ◽  
Li Substitution

Li-Substitution in P′2-Na0.67MnO2 mitigates the anisotropic change of Mn–O bonds and Na/vacancy ordering, and hence significantly promotes its cycling stability and rate capability as a cathode material for sodium-ion batteries.

Die Kristallstrukturen von Na2CoFeF7 und einer zweiten Modifikation von Na2CuFeF7: Eine weitere Weberit-Variante / The Crystal Structures of Na2CoFeF7 and a Second Modification of Na2CuFeF7: Another Weberite Variant

1992 ◽  
Vol 47 (5) ◽  
pp. 685-692 ◽  
Author(s):  
Matthias Welsch ◽  
Dietrich Babel
Keyword(s):  
Crystal Structures ◽  
The Other ◽  
Intermediate Type ◽  
Teller Distortion ◽  
Space Group ◽  
Jahn Teller ◽  
Structural Relations ◽  
Jahn Teller Distortion

The monoclinic weberites Na2CoFeF7 (a = 1262.2(10), b = 736.0(4), c = 2451.6(20) pm, β = 99.71(5)°) and a second modification of Na2CuFeF7 (a = 1244.4(2), b = 734.3(1), c = 2467.2(5) pm, β = 99.27(3)°), crystallize isotypically in space group C 2/c, Ζ = 16. The structure is an intermediate type between orthorhombic and trigonal weberites, characterized by pairs ofparallel chains of octahedra [MF4F2/2]3- (M = Co, Cu) which run in turn along [110] and [110]. The average distances are Fe-F = 192 pm in the [FeF63- octahedra of both compounds. Considerable splitting of distances occurs in the [CoF6- octahedra (av. Co-F = 201 pm), and by Jahn-Teller distortion even more in those of [CuFJ4- (av. Cu-F = 199 pm). One of the copper surroundings is (pseudo)tetragonally elongated (av. 209/194 pm), the other exhibits an unusual splitting into three long and three short bonds (av. 204/193 pm) in meridional positions. Some structural relations are discussed.

The Preparation and Crystal Structure of Ammonium Bis[citrato(3-)]cuprate(II)

1991 ◽  
Vol 44 (10) ◽  
pp. 1495 ◽  
Author(s):  
RC Bott ◽  
DS Sagatys ◽  
DE Lynch ◽  
G Smith ◽  
CHL Kennard ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Citric Acid ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Teller Distortion ◽  
Space Group ◽  
X Ray ◽  
Jahn Teller ◽  
A Cell ◽  
Jahn Teller Distortion

The copper(II) complex with citric acid (NH4)4 [Cu(C6H5O7)2] has been prepared, and its structure determined by X-ray diffraction, giving a residual R 0.035 for 1208 observed reflections. Crystals are monoclinic, space group P21/c with Z 2 in a cell of dimensions a 8.755(3), b 13.185(4), c 9.364(2)Ǻ, β 113.73(2)°. The complex is a centrosymmetric six-coordinate monomer which is isomorphous with ammonium zinc(II) citrate. However, the Cu-O(hydroxyl) bonds [2.341(3)Ǻ] show Jahn-Teller distortion relative to the Cu-O(carboxyl) bonds [1.969(3) and 1.977(3)Ǻ].

The crystal structures of the Hexakis(pyridine 1-oxide) complexes of copper(II), cobalt(II) and iron(II) perchlorates

1978 ◽  
Vol 31 (4) ◽  
pp. 713 ◽  
Author(s):  
D Taylor
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Teller Distortion ◽  
Space Group ◽  
X Ray ◽  
Perchlorate Ion ◽  
Fourier Techniques ◽  
Jahn Teller ◽  
Jahn Teller Distortion ◽  
Block Diagonal

The crystal structures of the isomorphous complexes [M(pyridine 1-oxide)6] (ClO4)2 M = Cu (1), Co (2) and Fe (3), have been determined from X-ray diffractometer data collected at 293 K. The complexes crystallize in the rhombohedral space group R3 with Z = 1; cell constants for (1): a 9.605(1)Ǻ, α 81.10(1)°; for (2): a 9.619(1)Ǻ, α 81.19(1)°; for (3): a 9.640(1)Ǻ, α 81.06(1)°. The structures were solved by Fourier techniques and refined by block-diagonal least squares to convergence at R, R': (1) 0.037, 0.039 for 1009 reflections; (2) 0.030, 0.038 for 812 reflections; (3) 0.032, 0.041 for 780 reflections with I ≥ 3σ(I). The cations have exact S6 symmetry with the MO6 moiety having almost exact Oh symmetry, which implies for (1) a lack of a static Jahn-Teller distortion. The M-O distances increase (1) 2.076(2), (2) 2.090(1), (3) 2.112(2)Ǻ in the order expected. The geometries of the pyridine 1-oxide ligand and the perchlorate ion are consistent over the three determinations and are normal.

scholarly journals Synthesis and Performance Elucidation of Ternary O3-Na0.8Fe0.4Mn0.3Co0.2O2 Layered Positive Electrode for Sodium Ion Batteries

2021 ◽  
pp. 54-65
Author(s):  
M. Alam Khan ◽  
Sunil Singh
Keyword(s):  
Transition Metal ◽  
Substantial Reduction ◽  
Positive Electrode ◽  
Sodium Ion ◽  
Cyclic Voltammograms ◽  
Teller Distortion ◽  
Jahn Teller ◽  
And Performance ◽  
Discharge Capacities ◽  
Charge Discharge

We report here a combination of transition metal-based ternary sodium magnate layered cathodes with the compositions of Na0.8Fe0.4Mn0.3Co0.2O2, Na0.8Fe0.4Mn0.3Ni0.2O2, Na0.8Fe0.4Mn0.3V0.2O2, Na0.8Fe0.4Mn0.3Ti0.2O2, in order to elucidate the precise metal contents for the superb performing positive electrode. Based on their stoichiometry, the transition metal combination of Na0.8Fe0.4Mn0.3Co0.2O2, O3-type crystal structure with R3m space group possess superior electrochemical behavior under the test of sodium-ion battery. When the charge-discharge capacities in the range of 2.0-4.2 V at 0.1 C are measured, it shows the comparatively higher performance of the first and second charge capacities of 162 mAhg-1, 170 mAhg-1 and discharge capacities of 157 mAhg-1, 154 mAhg-1, respectively. Moreover, it was remarkable to observe that the increasing/decreasing Co constituent substantially affects the performance and stability, but using the ternary combination in cathodes, a substantial reduction of Jahn-Teller distortion and increased biphasic characteristics were observed. The as-synthesized samples were characterized by FE-SEM, XRD, charge-discharge curve, EIS and cyclic voltammograms.

The Interplay of Open-Shell Spin-Coupling and Jahn-Teller Distortion in Benzene Radical Cation Probed by X-ray Spectroscopy

2020 ◽  
Author(s):  
Marta L. Vidal ◽  
Michael Epshtein ◽  
Valeriu Scutelnic ◽  
Zheyue Yang ◽  
Tian Xue ◽  
...  
Keyword(s):  
High Harmonic ◽  
Open Shell ◽  
Spin Coupling ◽  
High Symmetry ◽  
Teller Distortion ◽  
Spectral Window ◽  
X Ray ◽  
Jahn Teller ◽  
X Ray Absorption ◽  
Jahn Teller Distortion

We report a theoretical investigation and elucidation of the x-ray absorption spectra of neutral benzene and of the benzene cation. The generation of the cation by multiphoton ultraviolet (UV) ionization as well as the measurement of<br>the carbon K-edge spectra of both species using a table-top high-harmonic generation (HHG) source are described in the companion experimental paper [M. Epshtein et al., J. Phys.<br>Chem. A., submitted. Available on ChemRxiv]. We show that the 1sC -> pi transition serves as a sensitive signature of the transient cation formation, as it occurs outside of the spectral window of the parent neutral species. Moreover, the presence<br>of the unpaired (spectator) electron in the pi-subshell of the cation and the high symmetry of the system result in significant differences relative to neutral benzene in the spectral features associated with the 1sC ->pi* transitions. High-level calculations using equation-of-motion coupled-cluster theory provide the interpretation of the experimental spectra and insight into the electronic structure of benzene and its cation.<br>The prominent split structure of the 1sC -> pi* band of the cation is attributed to the interplay between the coupling of the core -> pi* excitation with the unpaired electron<br>in the pi-subshell and the Jahn-Teller distortion. The calculations attribute most of<br>the splitting (~1-1.2 eV) to the spin coupling, which is visible already at the Franck-Condon structure, and estimate the additional splitting due to structural relaxation to<br>be around ~0.1-0.2 eV. These results suggest that x-ray absorption with increased resolution might be able to disentangle electronic and structural aspects of the Jahn-Teller<br>effect in benzene cation.<br>

Jahn-Teller Effect in Hexahydroxocuprate(II) Complexes

1995 ◽  
Vol 60 (9) ◽  
pp. 1429-1434
Author(s):  
Martin Breza
Keyword(s):  
Hydrogen Bonding ◽  
Quantum Chemical ◽  
Potential Surface ◽  
Hydroxyl Group ◽  
Chemical Calculation ◽  
Teller Distortion ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Extremal Values ◽  
Jahn Teller Distortion

Using semiempirical CNDO-UHF method the adiabatic potential surface of 2[Cu(OH)6]4- complexes is investigated. The values of vibration and vibronic constants for Eg - (a1g + eg) vibronic interaction attain extremal values for the optimal O-H distance. The Jahn-Teller distortion decreases with increasing O-H distance. The discrepancy between experimentally observed elongated bipyramid of [Cu(OH)6]4- in Ba2[Cu(OH)6] and the compressed one obtained by quantum-chemical calculation is explainable by hydrogen bonding of the axial hydroxyl group.

Unveiling the role of Mn-interstitial defect and particle size on the Jahn-Teller distortion of the LiMn2O4 cathode material

2021 ◽  
Vol 490 ◽  
pp. 229519
Author(s):  
Renier Arabolla Rodríguez ◽  
Nelcy Della Santina Mohallem ◽  
Manuel Avila Santos ◽  
Demetrio A. Sena Costa ◽  
Luciano Andrey Montoro ◽  
...  
Keyword(s):  
Particle Size ◽  
Cathode Material ◽  
Teller Distortion ◽  
Interstitial Defect ◽  
Jahn Teller ◽  
Limn2o4 Cathode ◽  
Jahn Teller Distortion
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