Intra-layer ordering and inter-layer disordering of the Li2MnO3phase in Li1.07Mn1.93O4–δcathode materials: electron diffraction investigation andDIFFaXsimulation of X-ray diffraction patterns

2014 ◽  
Vol 47 (3) ◽  
pp. 879-886 ◽  
Author(s):  
He Zheng ◽  
Jianbo Wang ◽  
Zhongling Xu ◽  
Jianian Gui

A previous transmission electron microscopy (TEM) analysis revealed the existence of monoclinic Li2MnO3in the lithium-rich and oxygen-deficient Li1.07Mn1.93O4−δpowder. Interestingly, the monoclinic phase exhibits different nanoscale lamellar variants involving a rotation of the stacking direction by 120 or 240° along the pseudo-threefold axis,i.e.the [103]M//[111]C(M and C denote the monoclinic and cubic phases, respectively) zone axis. Here, a theoretical X-ray diffraction (XRD) study of Li2MnO3employing theDIFFaXprogram is presented. It is found that, with the occurrence of different stacking configurations, the characteristic superstructure reflections with 2θ between 20 and 35° (Cu Kα) in the XRD pattern become more and more broadened with the increasing degree of stacking disorder, indicating that XRD may fall short in detecting the presence of the monoclinic Li2MnO3phase. Moreover, selective peak asymmetry appears when the stacking sequence becomes extremely disordered. Further selected-area electron diffraction and theoretical neutron diffraction investigation may clarify the similar ambiguity concerning the crystal phases of other structurally related compound cathode materials for lithium-ion batteries (e.g.LiNi1/2Mn1/2O2, LiNi1/3Co1/3Mn1/3O2).

2007 ◽  
Vol 7 (2) ◽  
pp. 525-529 ◽  
Author(s):  
Bo Zhou ◽  
Jun-Jie Zhu

A chemical co-reduction route in aqueous solution was developed to synthesize Bi100−xSbx alloys at room temperature. The hydrolyses of Bi(III) and Sb(III) were effectively avoided by selecting proper raw materials and coordinator. X-ray diffraction analysis indicated that the as-prepared Bi100−xSbx alloys were homogeneous and phase-pure, and the Bi/Sb ratios in the alloys were very close to those in the aqueous solutions. The transmission electron microscope observation showed that the as-prepared Bi100−xSbx (x = 0∼100) alloys were particles with a size of tens of nanometers. The selected area electron diffraction patterns confirmed the high crystallinity, the homogeneousness, and the composition controllability of as-prepared alloys. All these characters and the nanometer-scaled size of the alloys are believed to be beneficial to the thermoelectric property of the Bi100−xSbx alloys.


Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2484
Author(s):  
Minshu Du ◽  
Lishan Cui ◽  
Feng Liu

Ti3Sn has received increasing attention as a high damping metallic material and as an anode material for rechargeable lithium-ion batteries. However, a heated dispute concerning the existence of solid state phase transformation of stoichiometric Ti3Sn impedes its development. Here, thermal-induced reversible phase transformation of Ti3Sn is demonstrated to happen at around 300 K by the means of in-situ variable-temperature X-ray diffraction (XRD) of Ti3Sn powder, which is also visible for bulk Ti3Sn on the thermal expansion curve by a turning at 330 K. The new phase’s crystal structure of Ti3Sn is determined to be orthorhombic with a space group of Cmcm and the lattice parameters of a = 5.87 Å, b = 10.37 Å, c = 4.76 Å respectively, according to selected area electron diffraction patterns in transmission electron microscope (TEM) and XRD profiles. The hexagonal → orthorhombic phase transformation is calculated to be reasonable and consistent with thermodynamics theory. This work contributes to a growing knowledge of intermetallic Ti3Sn, which may provide fundamental insights into its damping mechanism.


2004 ◽  
Vol 854 ◽  
Author(s):  
Abdullah Ceylan ◽  
C. Ni ◽  
S. Ismat Shah

ABSTRACTAg-Cu alloy nanoparticles were prepared by rapid condensation of metal flux obtained by the simultaneous evaporation of high purity Cu and Ag wires on a tungsten boat in the presence of circulating He gas. Structural properties of the samples prepared at different conditions were investigated by using X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected area diffraction (SAD) patterns. X-ray diffraction patterns showed that particles were phase separated. The particle size obtained either from Scherer's formula or the TEM images show no systematic change on the size of either Cu or Ag particles in the evaporation temperature range between 800 and 1400 °C. By using lattice constant values and Vegard's law, the composition of the particles was calculated to be 6.6 vol% Cu in Ag. Electron diffraction images revealed that particles were softly agglomerated; these electron diffraction results were also consistent with XRD results regarding phase separation. Individual diffraction rings of the Cu and Ag were observed in the SAD patterns.


1996 ◽  
Vol 60 (402) ◽  
pp. 799-804
Author(s):  
Ishmael Hassan ◽  
Yasuhiro Kudoh ◽  
Peter R. Buseck ◽  
Eui Ito

AbstractSelected-area electron diffraction patterns for the [110] zone of MgSiO3 perovskite are consistent with the orthorhombic unit cell obtained by X-ray diffraction (a = 4.775, b = 4.929, c = 6.897 Å). Various areas of a crystal fragment show diffuse streaking along c*, and well-developed satellite reflections that give a 3-fold repeat along [10]*. Another fragment shows doubled cell dimensions when viewed down [30]. The variable occurrence of the satellite reflectioncs and diffuse streaking indicate subtle variations in ordering, chemistry, or both. Images obtained by high-resolution transmission electron microscopy contain perfectly ordered regions, out-of-phase boundaries, and intergrowths of the two orthorhombic forms of perovskite.


Author(s):  
H. Brigitte Krause ◽  
Donald L. Gibbon

AbstractSelected-area electron-diffraction patterns and x-ray diffraction powder patterns were taken of crushed single crystals of Pb


1992 ◽  
Vol 7 (3) ◽  
pp. 542-545 ◽  
Author(s):  
Peter C. Van Buskirk ◽  
Robin Gardiner ◽  
Peter S. Kirlin ◽  
Steven Nutt

Epitaxial BaTi3 films have been grown on NdGaO3 [100] substrates by reduced pressure MOCVD for the first time. The substrate temperature was 1000 °C and the total pressure was 4 Torr. Electron and x-ray diffraction measurements indicate highly textured, single phase films on the NdGaO3 substrate which are predominantly [100], with [110] also present. TEM and selected area electron diffraction (SAED) indicate two specific orientational relationships between the [110] and the [001] diffraction patterns.


1997 ◽  
Vol 475 ◽  
Author(s):  
J.D. Jarratt ◽  
T.J. Klemmer ◽  
J.A. Barnard

ABSTRACTThe microstructure of Co90Feio/Ag giant magnetoresistive multilayer films has been investigated using x-ray diffraction (XRD) and cross-sectional transmission electron microscopy. Columnar grains with a (111) fiber growth texture is observed. A comparison is made between the observed layering structure and earlier multilayer schematics based on the literature and magnetic and magnetoresistive measurements as a function of layer thickness. A direct correlation is made between superlattice satellite peak signals from selected area electron diffraction patterns and XRD scans.


2014 ◽  
Vol 70 (a1) ◽  
pp. C1080-C1080
Author(s):  
Yifeng Yun ◽  
Wei Wan ◽  
Faiz Rabbani ◽  
Jie Su ◽  
Sven Hovmöller ◽  
...  

Electron Crystallography is an important technique for studying micro- and nano-sized crystals[1]. Crystals considered as powder by X-ray diffraction behave as single crystals by electron diffraction. Recently we developed a new method, Rotation Electron Diffraction (RED) for three-dimensional diffraction data collection by combining electron beam tilt with goniometer tilt on a transmission electron microscope (TEM)[2]. Here we apply the RED method on an unknown oxide sample in a Ni-Se-Cl-O system, which may show special physical properties, for example magnetic properties. The crystals in the sample were less than a few micrometers in sizes. Powder X-ray diffraction patterns of the sample could not be indexed by existing known phases. The sample was thus studied by TEM. Five 3D RED datasets were collected from five crystals with different morphologies using the software package RED. The data processing was also performed using the software RED-processing. The unit cell and space groups of all the five phases were obtained using RED and the structures of four of five phases were solved. Nearly all peaks in the powder X-ray diffraction pattern could be indexed using these five phases. To conclude, five phases from a powder sample have been identified using RED. RED is a powerful method for phase identification of multiphasic samples with nano-sized crystals.


Author(s):  
Robert M. Glaeser ◽  
David W. Deamer

In the investigation of the molecular organization of cell membranes it is often supposed that lipid molecules are arranged in a bimolecular film. X-ray diffraction data obtained in a direction perpendicular to the plane of suitably layered membrane systems have generally been interpreted in accord with such a model of the membrane structure. The present studies were begun in order to determine whether selected area electron diffraction would provide a tool of sufficient sensitivity to permit investigation of the degree of intermolecular order within lipid films. The ultimate objective would then be to apply the method to single fragments of cell membrane material in order to obtain data complementary to the transverse data obtainable by x-ray diffraction.


2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Claudia Maria Simonescu ◽  
Valentin Serban Teodorescu ◽  
Camelia Capatina

This paper presents the obtaining of copper sulfide CuS (covelite) from Cu(CH3COO)2.H2O and thioacetamide (TAA) system. The reaction was conducted in presence or absence of sodium-bis(2-ethylhexyl) sulfosuccinate (Na-AOT). The effects of various reaction parameters on the size and on the shape of nanoparticles have been examined. CuS obtained was characterized by X ray diffraction, IR spectroscopy, TEM � transmission electron microscopy and SAED selected area electron diffraction. The influence of surfactant to the shape and size of CuS (covellite) nanocrystals was established. The size of the nanocrystals varied from 10-60 nm depending on the reaction conditions such as quantity of surfactant.


Sign in / Sign up

Export Citation Format

Share Document