In-Situ X-Ray Characterization of LiMn2O4: A Comparison of Structural and Electrochemical Behavior

1997 ◽  
Vol 496 ◽  
Author(s):  
Mark A. Rodriguez ◽  
David Ingersoll ◽  
Daniel H. Doughty
Keyword(s):  
Crystal Structure ◽  
Structural Changes ◽  
Phase Changes ◽  
X Ray ◽  
In Situ Xrd ◽  
Electrochemical Cycling ◽  
Kinetic Effects ◽  
Carbon Anodes

ABSTRACTLixMn2O4 materials are of considerable interest in battery research and development. The crystal structure of this material can significantly affect the electrochemical performance. The ability to monitor the changes of the crystal structure during use, that is during electrochemical cycling, would prove useful to verify these types of structural changes. We report in-situ XRD measurements of LiMn2O4 cathodes with the use of an electrochemical cell designed for in-situ X-ray analysis. Cells prepared using this cell design allow investigation of the changes in the LiMn2O4 structure during charge and discharge. We describe the variation in lattice parameters along the voltage plateaus and consider the structural changes in terms of the electrochemical results on each cell. Kinetic effects of LiMn2O4 phase changes are also addressed. Applications of the in-situ cell to other compounds such as LiCoO2 cathodes and carbon anodes are presented as well.

Studied on Structural Characterization of Lanthanum Doped Barium Titanium Ceramics

2015 ◽  
Vol 819 ◽  
pp. 198-203
Author(s):  
Nur Farahin Abdul Hamid ◽  
Rozana Aina Maulat Osman ◽  
Mohd Sobri Idris ◽  
Tze Qing Tan
Keyword(s):  
Crystal Structure ◽  
Lattice Parameter ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tetragonal Crystal ◽  
Tetragonal Crystal Structure ◽  
La Doped ◽  
Conventional Solid State Synthesis

La-doped barium titanate (BaTiO3) was prepared using conventional solid state synthesis route. All peaks for sample x=0 are approaching the phase pure of BaTiO3 structure with tetragonal crystal structure (P4mm). Sintering of pressed powder are performed at 1300oC, 1400oC and 1450oC for overnight for pure BaTiO3 and 1350oC for 3 days for BaTiO3 doped lanthanum with intermittent grinding. Phase transition was studied by different x composition. The changes in the crystal structure of the composition x=0.1 and 0.2 were detected by using X-ray diffraction (XRD). The phase changes between tetragonal-cubic and cubic-tetragonal depending on the temperature. Rietveld Refinement analysis is carried out to determine the lattice parameter and unit cell for BaTiO3.

scholarly journals Effects of Cr Doping and Water Content on the Crystal Structure Transitions of Ba2In2O5

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1548
Author(s):  
Raphael Finger ◽  
Marc Widenmeyer ◽  
Thomas C. Hansen ◽  
Dirk Wallacher ◽  
Stanislav Savvin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Water Content ◽  
Structural Changes ◽  
Equimolar Amount ◽  
Co2 Conversion ◽  
Temperature Dependent ◽  
X Ray ◽  
Photocatalytic Co2 Conversion ◽  
Cr Doping

Temperature-dependent crystal structure alterations in the brownmillerite-type material Ba2In2O5 play a fundamental role in its applications: i) photocatalytic CO2 conversion; ii) oxygen transport membranes; and iii) proton conduction. This is connected to a reversible uptake of up an equimolar amount of water. In this study, in situ X-ray and neutron diffraction were combined with Raman spectroscopy and solid-state nuclear magnetic resonance experiments to unravel the effects of Cr doping and water content on the crystal structure transitions of Ba2In2O5(H2O)x over a wide temperature range (10 K ≤ T ≤ 1573 K, x < 1). A mixture of isolated and correlated protons was identified, leading to a highly dynamic situation for the protons. Hence, localisation of the protons by diffraction techniques was not possible. Cr doping led to an overall higher degree of disorder and stabilisation of the tetragonal polymorph, even at 10 K. In contrast, a further disordering at high temperatures, leading to a cubic polymorph, was found at 1123 K. Cr doping in Ba2In2O5 resulted in severe structural changes and provides a powerful way to adjust its physical properties to the respective application.

Dichloro(diphosphine)(2-pyridyl-ketone)ruthenium(II) complexes

2003 ◽  
Vol 81 (11) ◽  
pp. 1263-1269 ◽  
Author(s):  
Salete L Queiroz ◽  
Alzir A Batista ◽  
Marcio P de Araujo ◽  
Roberto C Bianchini ◽  
Glaucius Oliva ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Synthesis And Characterization ◽  
X Ray

Described are the synthesis and characterization of Ru(II) complexes of the type RuCl2L2(N-O), where L2 is either 1,4-bis(diphenylphosphino)butane (dppb) or (PPh3)2, and N-O represents chelated 2-benzoylpyridine (2-bzpy) or 2-acetylpyridine (2-acpy); the Ru presursors used were [RuCl2(dppb)]2(µ-dppb) or RuCl2(PPh3)3. The crystal structure of cis-RuCl2(dppb)(2-bzpy) is presented, and three other RuCl2L2(N-O) complexes with cis-chlorines are isolated and characterized spectroscopically; of the trans-dichloro species, RuCl2(PPh3)2(N-O) complexes are isolated, while the corresponding dppb species are characterized in situ. In all cases, thermodynamically stable cis-complexes are formed from initially formed trans-species.Key words: ruthenium, phosphines, 2-benzoylpyridine, 2-acetylpyridine, X-ray structures.

Changes in Delta-Plutonium Due to Aging as Observed by Continuous in-situ X-Ray Scattering

2006 ◽  
Vol 986 ◽  
Author(s):  
Cheng K Saw ◽  
Mark A. Wall ◽  
Brandon W. Chung
Keyword(s):  
Physical Properties ◽  
Structural Changes ◽  
Uranium Atom ◽  
Life Time ◽  
Weight Percent ◽  
Phase Changes ◽  
Thin Sample ◽  
X Ray ◽  
The Stability

AbstractThe aging in plutonium is predominantly caused by its internal self irradiation. The self-irradiation in Pu-239 is by the decay process of transmuting the Pu atom into uranium atom and emitting an α-particle. Most of the lattice damage comes from the uranium recoil resulting in Frenkel type defects consisting of vacancies and self-interstitial atoms, helium in growth and defect clusters and possibly even though it is not yet observed, the generation of voids. As part of the stockpile stewardship, it is important to understand the changes in the structure and microstructures and their correlations to the physical properties. Changes in the physical properties has direct relationship to the quality of the structure, in terms of formation of defects and defect clustering, accumulation of voids, grain boundaries, phase changes and etc. which can adversely affects the stability of the material. These changes are very difficult to monitor because of the high activity of the sample, high atomic number making x-ray and synchrotron probe into the bulk very difficult (neutron probe is not feasible) and the long life time which normally requires decades to measure. In this paper we describe the development of an in-situ in-house transmission x-ray diffraction (XRD) experimental technique used to monitor the structural changes in these materials. This technique calls for a very thin sample of less that 2 μm and to accelerate the aging process due to self-irradiation, spiked alloy of 7.5 weight percent of Pu-238 is used. This is equivalent to roughly 17 times the normal rate of aging. Current results suggest that over a period of 2.8 equivalent years, an increase of 0.5% in unit cell parameter is observed. The increase appears to be an abrupt jump at about 1.1 equivalent years, brought about by the collapsing of the atoms from the interstitials to the lattice sites. Further data analysis is on the way.

scholarly journals Characterization of Highly Dispersed Rod- and Particle-Shaped CuFe19Ox Catalysts and Their Shape Effects on WGS

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 635
Author(s):  
Lingjuan Ma ◽  
Dawei Han ◽  
Hongbin Ma ◽  
Longgang Liu ◽  
Huichao Guo
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Xrd ◽  
Transmission Electron ◽  
Highly Dispersed ◽  
Shape Effects ◽  
Temperature Programmed ◽  
Water Gas

Highly dispersed CuFe19Ox catalysts with different shapes were prepared and further characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR), and in-situ XRD. XRD and TEM results showed that the synthesized CuFe19Ox nanoparticles consisted of CuO and Fe2O3, while CuFe19Ox nanorods consisted of CuFe2O4 and Fe2O3. The reduction properties of CuFe19Ox samples were finely studied by H2-TPR, and the phase composition was identified by in-situ XPS, HR-TEM, and surface TPR (s-TPR). In-situ X-ray photoelectroscopy (XPS) indicated that the metallic Cu and Fe3O4 were the main species after reduction. Moreover, s-TPR studies showed that the reduction performance of copper was significantly affected by the shapes of the Fe3O4 supports. Low-temperature water gas shift (LT-WGS) was chosen to characterize the Cu species on the surface. It was found that reduced CuFe19Ox nanorods had no activity. On the contrary, reduced CuFe19Ox particles showed higher initial WGS activity, where the active Cu0 should originate from the reduction of Cu2O at lower temperatures, as confirmed by the s-TPR profiles.

In situ XRD investigation of the evolution of surface layers on Pb-alloy anodes

2017 ◽  
Vol 32 (S2) ◽  
pp. S54-S60 ◽  
Author(s):  
Marie Clancy ◽  
Mark J. Styles ◽  
Colleen J. Bettles ◽  
Nick Birbilis ◽  
Justin A. Kimpton ◽  
...  
Keyword(s):  
Electrochemical Behaviour ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
X Ray ◽  
In Situ Xrd ◽  
Industry Standard ◽  
Electrochemical Cycling ◽  
Significant Factors

The electrochemical behaviour of a number of Pb-based anode alloys, under simulated electrowinning conditions, in a 1.6 M H2SO4 electrolyte at 45 °C was studied. Namely, the evolution of PbO2 and PbSO4 surface layers was investigated by quantitative in situ synchrotron X-ray diffraction (S-XRD) and subsequent Rietveld-based quantitative phase analysis (QPA). In the context of seeking new anode alloys, this research shows that the industry standard Pb-0.08Ca-1.52Sn (wt%) anode, when exposed to a galvanostatic current and intermittent power interruptions, exhibited poor electrochemical performance relative to select custom Pb-based binary alloys; Pb–0.73Mg, Pb–5.05Ag, Pb–0.07Rh, and Pb–1.4Zn (wt%). The in situ S-XRD measurements and subsequent QPA indicated that this was linked to a lower proportion of β-PbO2, relative to PbSO4, on the Pb-0.08Ca-1.52Sn alloy at all stages of the electrochemical cycling. The best performing alloy, in terms of minimisation of overpotential during normal electrowinning operation and minimising the deleterious effects of repeated power interruptions – both of which are significant factors in energy consumption – was determined to be Pb–0.07Rh.

scholarly journals Fast operando X-ray pair distribution function using the DRIX electrochemical cell

2020 ◽  
Vol 27 (5) ◽  
pp. 1190-1199
Author(s):  
Maria Diaz-Lopez ◽  
Geoffrey L. Cutts ◽  
Phoebe K. Allan ◽  
Dean S. Keeble ◽  
Allan Ross ◽  
...  
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Structural Changes ◽  
Structural Information ◽  
Scattering Data ◽  
Cell Design ◽  
Total Scattering ◽  
X Ray ◽  
Electrochemical Cycling

In situ electrochemical cycling combined with total scattering measurements can provide valuable structural information on crystalline, semi-crystalline and amorphous phases present during (dis)charging of batteries. In situ measurements are particularly challenging for total scattering experiments due to the requirement for low, constant and reproducible backgrounds. Poor cell design can introduce artefacts into the total scattering data or cause inhomogeneous electrochemical cycling, leading to poor data quality or misleading results. This work presents a new cell design optimized to provide good electrochemical performance while performing bulk multi-scale characterizations based on total scattering and pair distribution function methods, and with potential for techniques such as X-ray Raman spectroscopy. As an example, the structural changes of a nanostructured high-capacity cathode with a disordered rock-salt structure and composition Li4Mn2O5 are demonstrated. The results show that there is no contribution to the recorded signal from other cell components, and a very low and consistent contribution from the cell background.

Three-Dimensional X-Ray Structural Microscopy Using Polychromatic Microbeams

MRS Bulletin ◽  
2004 ◽  
Vol 29 (3) ◽  
pp. 170-176 ◽  
Author(s):  
Gene E. Ice ◽  
Bennett C. Larson
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
X Rays ◽  
Actual Structure ◽  
X Ray ◽  
Elastic And Plastic Deformation ◽  
Strain Tensors ◽  
Microprobe Technique

AbstractIn this article, the authors describe the principle and application of differential-aperture x-ray microscopy (DAXM). This recently developed scanning x-ray microprobe technique uses a confocal or traveling pinhole camera approach to determine the crystal structure, crystallographic orientation, and elastic and plastic strain tensors within bulk materials. The penetrating properties of x-rays make the technique applicable to optically opaque as well as transparent materials, and it is nondestructive; this provides for in situ, submicrometer-resolution characterization of local crystal structure and for measurements of microstructure evolution on mesoscopic length scales from tenths to hundreds of micrometers. Examples are presented that illustrate the use of DAXM to study grain and subgrain morphology, grain-boundary types and networks, and local intra- and intergranular elastic and plastic deformation. Information of this type now provides a direct link between the actual structure and evolution in materials and increasingly powerful computer simulations and multiscale modeling of materials microstructure and evolution.

A furnace forin situX-ray diffraction studies of insertion processes in electrode materials at elevated temperatures

2001 ◽  
Vol 34 (5) ◽  
pp. 654-657 ◽  
Author(s):  
T. Eriksson ◽  
A. M. Andersson ◽  
Ö. Bergström ◽  
K. Edström ◽  
T. Gustafsson ◽  
...  
Keyword(s):  
Structural Changes ◽  
Electrode Materials ◽  
Elevated Temperatures ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Flat Cell ◽  
And Storage

A furnace is described forin situX-ray diffraction studies, in transmission mode, of structural changes in electrode materials for Li-ion (polymer) batteries in the ambient to 300°C temperature range. The method exploits the thin flat-cell geometry of the lithium-polymer battery concept. The flat sample is able to oscillate about a horizontal axis in its own plane in the X-ray beam, to provide better averaging during the diffraction experiment. The use of the device is demonstrated in a study of lithium intercalation in graphite (a commonly used anode material in lithium-ion batteries) during electrochemical cycling and storage at 70°C.

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