In situ Synchrotron X-ray Studies on Novel Mn Oxide Spinel Cathodes for Li-ion Batteries: Influence of Other Transition Elements

1998 ◽  
Vol 548 ◽  
Author(s):  
S. Mukerjee ◽  
X. Q. Yang ◽  
X. Sun ◽  
S. J. Lee ◽  
J. Mcbreen ◽  
...  
Keyword(s):  
Transition Element ◽  
Cycle Life ◽  
Partial Substitution ◽  
Exact Nature ◽  
Transition Elements ◽  
Potential Region ◽  
X Ray ◽  
Jahn Teller ◽  
Oxide Spinel

ABSTRACTPartial substitution of Mn in lithium manganese oxide spinel materials by Cu and Ni greatly affects the electrochemistry and the cycle life characteristics of the cathode. Substitution with either metal or a combination of both shortens the 4.2 V plateau associated with the conversion of Mn3+ to Mn4+. A higher voltage plateau associated with oxidation of the substituted transition element is also observed. These substituent also significantly alter the onset of Jahn Teller distortions in the 3 V plateau. Synchrotron based in situ x-ray absorption (XAS) is used to determine the exact nature of the oxidation state changes in order to explain the overall capacities at the different voltage plateaus. Synchrotron based in situ x-ray diffraction (XRD) studies on LiCu0.5Mn1.504 shows single phase behavior in the 4-5 V region and a good cycle life. Lower cycle life characteristics for LiNi0.5Mn1.504 and LiNi0.25Cu0.25Mn1.504 are accounted for on the basis of several phase coexistence in this potential region. In the 3 V plateau however, the LiCu0.5Mn1.504 shows onset of the Jahn Teller distortions, in contrast to the LiNi0.5Mn1.504 and LNi0.25Cu0.25WMn1.504.

scholarly journals Pressure-induced Jahn-Teller Switch in the Homoleptic Hybrid Perovskite [(CH3)2NH2]Cu(HCOO)3: Orbital Reordering by Unconventional Degrees of Freedom

2021 ◽  
Author(s):  
Rebecca Scatena ◽  
Michał Andrzejewski ◽  
Roger D Johnson ◽  
Piero Macchi
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Coordination Polymer ◽  
Degrees Of Freedom ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hybrid Perovskite ◽  
Jahn Teller

Through in-situ, high-pressure x-ray diffraction experiments we have shown that the homoleptic perovskite-like coordination polymer [(CH3)2NH2]Cu(HCOO)3 undergoes a pressure-induced orbital reordering phase transition above 5.20 GPa. This transition is distinct...

In situ synchrotron X-ray studies on copper–nickel 5 V Mn oxide spinel cathodes for Li-ion batteries

2004 ◽  
Vol 49 (20) ◽  
pp. 3373-3382 ◽  
Author(s):  
S Mukerjee ◽  
X.Q Yang ◽  
X Sun ◽  
S.J Lee ◽  
J McBreen ◽  
...  
Keyword(s):  
Li Ion Batteries ◽  
X Ray ◽  
Copper Nickel ◽  
Mn Oxide ◽  
Oxide Spinel ◽  
Li Ion

Thermal effects in polyelectrolyte ion exchange reactions: the Jahn–Teller effect

1988 ◽  
Vol 66 (4) ◽  
pp. 974-978 ◽  
Author(s):  
Kang Sun ◽  
George E. Boyd
Keyword(s):  
Ion Exchange ◽  
Thermal Effects ◽  
Divalent Cations ◽  
Transition Element ◽  
Electronic Configuration ◽  
Standard State ◽  
Transition Elements ◽  
Exchange Reactions ◽  
Cubic Symmetry ◽  
Jahn Teller

Microcalorimetric determinations were made of the thermal effects accompanying the exchange of the divalent cations of Mn, Fe, Co, Ni, Cu, and Zn in dilute aqueous perchlorate solutions with Mg2+ ion initially bound in a crosslinked polyelectrolyte gel. The calorimetric measurements, together with microchemical equilibrium distribution determinations with the same cations, were employed to estimate the standard state Gibbs energy, enthalpy, and entropy changes associated with their ion exchange reactions.All the transition elements were selectively absorbed relative to Mg2+ with the sequence being: Mn < Fe < Co < Ni > Cu > Zn, showing divalent Ni(II) cation to possess the greatest affinity for the polyelectrolyte phase. The sequence of standard state reaction enthalpy change, ΔH0, revealed that Ni2+ also was the most exothermic of all 3d transition element cations. However, the ΔH0 values became more negative in the order: Mn < Fe < Co < Ni > Cu < Zn, showing that Cu2+ ion behaved anomalously in being less negative than expected. This behavior (and that in the ΔS0 values also) suggested that a destabilization of the octahedrally coordinated Cu2+ in aqueous solutions must occur, possibly because of Jahn–Teller effects on its d9 electronic configuration when the cation is placed in an environment of cubic symmetry. Because of a thermodynamic compensation of the magnitudes of ΔH0 and ΔS0, the position of Cu2+ in the ΔG0 value sequence was regular.

In Situ XAFS of the LixNi0.8Co0.2O2 Cathode for Lithium-Ion Batteries

1999 ◽  
Vol 590 ◽  
Author(s):  
A. J. Kropf ◽  
C. S. Johnson
Keyword(s):  
Lithium Ion ◽  
Edge Structure ◽  
X Ray ◽  
Metal Metal ◽  
Jahn Teller ◽  
A Cell ◽  
X Ray Absorption ◽  
Content Range ◽  
Li Content

ABSTRACTThe layered LiNi0.8AsCo0.2O2 system is being considered as a new cathode material for the lithium-ion battery. Compared with LiCoO2, the standard cathode formulation, it possesses improved electrochemical performance at a projected lower cost. In situ x-ray absorption fine-structure spectroscopy (XAFS) measurements were conducted on a cell cycled at a moderate rate and normal Li-ion operating voltages (3.0-4.1 V). The XAFS data collected at the Ni and Co edges approximately every 30 min. revealed details about the response of the cathode to Li insertion and extraction. These measurements on the LixNi0.8AsCo0.2O2 cathode (0.29<×<0.78) demonstrated the excellent reversibility of the cathode's short-range structure. However, the Co and Ni atoms behaved differently in response to Li insertion. This study corroborates previous work that explains the XAFS of the Ni atoms in terms of a Ni3+ Jahn-Teller ion. An analysis of the metal-metal distances suggests, contrary to a qualitative analysis of the x-ray absorption near-edge structure (XANES), that the Co3+ is oxidized to the maximum extent possible (within the Li content range of this experiment) at x = 0.47 ± 0.04, and further oxidation occurs at the Ni site.

Distinct nanoscale reaction pathways in a sulfide material for sodium and lithium batteries

2017 ◽  
Vol 5 (23) ◽  
pp. 11701-11709 ◽  
Author(s):  
Matthew G. Boebinger ◽  
Michael Xu ◽  
Xuetian Ma ◽  
Hailong Chen ◽  
Raymond R. Unocic ◽  
...  
Keyword(s):  
Lithium Batteries ◽  
Copper Sulfide ◽  
Electrochemical Reaction ◽  
Cycle Life ◽  
Reaction Pathways ◽  
X Ray Diffraction ◽  
X Ray

Copper sulfide is found to exhibit excellent cycle life in Na-ion batteries, and multiscale in situ techniques (TEM and X-ray diffraction) are used to reveal unique aspects of the electrochemical reaction of sodium with this material.

scholarly journals Application of Operando X-ray Diffractometry in Various Aspects of the Investigations of Lithium/Sodium-Ion Batteries

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2963 ◽  
Author(s):  
Wen Zhu ◽  
Yuesheng Wang ◽  
Dongqiang Liu ◽  
Vincent Gariépy ◽  
Catherine Gagnon ◽  
...  
Keyword(s):  
High Performance ◽  
Electrode Materials ◽  
Rechargeable Batteries ◽  
Operating Conditions ◽  
Cycle Life ◽  
Side Reactions ◽  
X Ray ◽  
The Impact ◽  
Working Mechanisms

The main challenges facing rechargeable batteries today are: (1) increasing the electrode capacity; (2) prolonging the cycle life; (3) enhancing the rate performance and (4) insuring their safety. Significant efforts have been devoted to improve the present electrode materials as well as to develop and design new high performance electrodes. All of the efforts are based on the understanding of the materials, their working mechanisms, the impact of the structure and reaction mechanism on electrochemical performance. Various operando/in-situ methods are applied in studying rechargeable batteries to gain a better understanding of the crystal structure of the electrode materials and their behaviors during charge-discharge under various conditions. In the present review, we focus on applying operando X-ray techniques to investigate electrode materials, including the working mechanisms of different structured materials, the effect of size, cycling rate and temperature on the reaction mechanisms, the thermal stability of the electrodes, the degradation mechanism and the optimization of material synthesis. We demonstrate the importance of using operando/in-situ XRD and its combination with other techniques in examining the microstructural changes of the electrodes under various operating conditions, in both macro and atomic-scales. These results reveal the working and the degradation mechanisms of the electrodes and the possible side reactions involved, which are essential for improving the present materials and developing new materials for high performance and long cycle life batteries.

A Tetranuclear Mixed-Valence Manganese Complex of a Diimine Ligand Derived from 1,4-Diformyl-2,3-dihydroxybenzene: Synthesis, Structure, and Magnetic Properties

2009 ◽  
Vol 62 (9) ◽  
pp. 1119 ◽  
Author(s):  
Humphrey L. C. Feltham ◽  
Rodolphe Clérac ◽  
Sally Brooker
Keyword(s):  
Mixed Valence ◽  
Manganese Ions ◽  
One Pot ◽  
X Ray ◽  
Magnetic Analysis ◽  
Diimine Ligand ◽  
Jahn Teller ◽  
Planar Array ◽  
Ground Spin State

An acyclic hexadentate diimine ligand, H4L1, was prepared in situ in methanol by the condensation of 1,4-diformyl-2,3-dihydroxybenzene (1) with 2-aminoethanol, and complexed directly with two equivalents of MnII(OAc)2·4H2O or MnIII(OAc)3·2H2O, or with one equivalent of each. All three of these one-pot reactions gave the mixed-valent tetrametallic complex [MnII2MnIII2(L1)2(OAc)2(solvents)4], [2(solvents)4]. An X-ray crystal structure determination on [2(MeOH)4]·2MeOH revealed a centre of inversion in the middle of the complex. The four metal ions are in an almost planar array, sandwiched by two offset ligands which provide all of the equatorial donors, with the axial sites occupied by acetate ions and methanol molecules. The two manganese(II) ions are seven coordinate and centrally located, whereas the two manganese(III) ions are Jahn–Teller elongated octahedra and are located in the outer sites. Magnetic analysis of an air-dried sample, [2(MeOH)2(H2O)2]·3H2O, showed that weak antiferromagnetic interactions between the manganese ions dominate, resulting in a low ground spin state.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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