Analysis of Composition and Valence States in Positive Electrode Materials (Fe-Substituted Li2MnO3) for Lithium Ion Batteries by Analytical Transmission Electron Microscopy

2006 ◽  
Vol 972 ◽  
Author(s):  
Jun Kikkawa ◽  
Tomoki Akita ◽  
Mitsuharu Tabuchi ◽  
Masahiro Shikano ◽  
Kuniaki Tatsumi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electrode Materials ◽  
Specific Capacity ◽  
Positive Electrode ◽  
Analytical Transmission Electron Microscopy ◽  
Local Composition ◽  
Valence States ◽  
Transmission Electron ◽  
Fe And Mn

AbstractAnalytical transmission electron microscopy (ATEM) was applied to investigate local variation of composition of transition metals in each particle of Fe-substituted Li2MnO3, which reveals high specific capacity and high voltage as a positive electrode. Crystal lattice images of primary particles were observed by means of high-resolution TEM (HRTEM), where local composition of Fe and Mn was determined by electron energy-loss spectroscopy (EELS). It was found that there exist both manganese (Mn)-rich and iron (Fe)-rich regions in a primary particle, where concentration of Fe and Mn fluctuates irregularly in nanometer scale. The relationship between composition and crystal structure in each local region is discussed.

Characterization of submicrometer fluid Inclusions in minerals by Analytical/Transmission Electron Microscopy and electron diffraction

1990 ◽  
Vol 48 (4) ◽  
pp. 424-424
Author(s):  
George Guthrie ◽  
David Veblen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Light Microscopy ◽  
Fluid Inclusions ◽  
Energy Dispersive Spectrometer ◽  
Analytical Transmission Electron Microscopy ◽  
Transmission Electron

The nature of a geologic fluid can often be inferred from fluid-filled cavities (generally <100 μm in size) that are trapped during the growth of a mineral. A variety of techniques enables the fluids and daughter crystals (any solid precipitated from the trapped fluid) to be identified from cavities greater than a few micrometers. Many minerals, however, contain fluid inclusions smaller than a micrometer. Though inclusions this small are difficult or impossible to study by conventional techniques, they are ideally suited for study by analytical/ transmission electron microscopy (A/TEM) and electron diffraction. We have used this technique to study fluid inclusions and daughter crystals in diamond and feldspar.Inclusion-rich samples of diamond and feldspar were ion-thinned to electron transparency and examined with a Philips 420T electron microscope (120 keV) equipped with an EDAX beryllium-windowed energy dispersive spectrometer. Thin edges of the sample were perforated in areas that appeared in light microscopy to be populated densely with inclusions. In a few cases, the perforations were bound polygonal sides to which crystals (structurally and compositionally different from the host mineral) were attached (Figure 1).

scholarly journals Ce-Doped PANI/Fe3O4 Nanocomposites: Electrode Materials for Supercapattery

2021 ◽  
Vol 3 ◽  
Author(s):  
Subash Pandey ◽  
Shova Neupane ◽  
Dipak Kumar Gupta ◽  
Anju Kumari Das ◽  
Nabin Karki ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrode Material ◽  
High Performance ◽  
Electrode Materials ◽  
Specific Capacity ◽  
Maximum Energy ◽  
Potential Range ◽  
X Ray Diffraction ◽  
Active Electrode ◽  
Transmission Electron

In this study, we report on a combined approach to preparing an active electrode material for supercapattery application by making nanocomposites of Polyaniline/Cerium (PANI/Ce) with different weight percentages of magnetite (Fe3O4). Fourier-transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) analyses supported the interaction of PANI with Ce and the formation of the successful nanocomposite with magnetite nanoparticles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses showed the uniform and porous morphology of the composites. Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) were used to test the supercapattery behavior of the nanocomposite electrodes in 1.0 M H2SO4. It was found that the supercapattery electrode of PANI/Ce+7 wt.% Fe3O4 exhibited a specific capacity of 171 mAhg−1 in the potential range of −0.2 to 1.0 V at the current density of 2.5 Ag−1. Moreover, PANI/Ce+7 wt.% Fe3O4 revealed a power density of 376.6 Wkg−1 along with a maximum energy density of 25.4 Whkg−1 at 2.5 Ag−1. Further, the cyclic stability of PANI/Ce+7 wt.% Fe3O4 was found to be 96.0% after 5,000 cycles. The obtained results suggested that the PANI/Ce+Fe3O4 nanocomposite could be a promising electrode material candidate for high-performance supercapattery applications.

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