Recently, lithium atomic columns have been visualized by a new method of scanning transmission electron microscopy (STEM) called as annular bright field (ABF) imaging. We show that the number of lithium atoms in individual columns can be countable by quantitative analysis and the atoms at the surface layer can be detectable by using large convergent electron beam. We also show local structural transformation accompanied by the displacement of lithium ions for LiV₂O₄ crystals by in-situ ABF observation. We briefly present operand TEM observation of the lithium ion battery, consisting of LiMn₂O₄ cathode nanowire, ionic liquid electrolyte and Li₄Ti₅O₁₂ anode.

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  Detection of lithium in local area of materials is important subject for the development of electrode materials for Li-ion batteries. Electron energy loss spectroscopy (EELS) with scanning transmission electron microscopy (STEM) is powerful technique to investigate the materials for Li-ion batteries. STEM-EELS has high spatial resolution and high sensitivity for Li and Li compounds. Practical methods to visualize the Li distribution in electrode materials using STEM-EELS spectrum imaging method are reviewed. Applications of STEM-EELS method to the analyses of oxide coated LiCoO₂ were also presented briefly.

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  The X-ray absorption fine structure (XAFS) imaging with two-dimensional detector is a powerful tool to analyze the reaction distribution of lithium ion secondary battery. We have achieved the distribution analysis of transitional metal elements in the active material of lithium ion secondary battery by analyzing their XAFS spectra, which represent the chemical state of the transition metal element directly related to the existence of the lithium ion. The appearance of reaction channels caused by the electron conduction network was evaluated for the LiFePO₄ electrode. The distribution maps of the lithium ion during the charging/discharging processes were thus identical for the LiFePO₄ electrode, whereas the map for the LiNiO₂ electrode during the charging process was opposite to that during the discharging process. It is considered that the reaction distribution of the LiNiO₂ electrode is generated by the disturbed lithium ion diffusion due to the generated side products, which cover the electrode surface.

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  The demand for measurement tools to detect Li with high spatial resolution and precise chemical sensitivity is increasing with the spread of lithium-ion batteries (LIBs) for use in a wide range of applications. In this article, a brief review will be given on recent progress in the chemical state imaging of Li using scanning Auger electron microscopy (SAM). We report a novel method that enables a precise evaluation of oxidation states of Li by the combined use of Auger electron spectroscopy and electron energy loss spectroscopy signals for elemental mapping. Also, we summarize the characterization of spatial distribution of Li in electrochemically lithiated graphite anodes, as an example of application of SAM to the evaluation of actual LIB materials.

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  Permeation behavior of hydrogen from the backside of a stainless steel membrane (SUS304) was investigated by electron stimulated desorption (ESD) method. Detection system of ESD ion and a sample holder with hydrogen reservoir were incorporated in the scanning electron microscope. The distributions of hydrogen concentration on the sample surface were observed by ESD ion images. The thickness of stainless steel membrane is 100 μm. The membrane has austenite structure including martensite dislocations, and the size of austenite grains, 100-150 μm, is comparable to the thickness of membrane. The ESD ion images are observed at different temperatures, which are controlled from RT to 573 K with 50 K steps. High concentration sites of hydrogen at 323 K are different from the incremental sites at 473 K, suggesting that the former increase is due to the diffusion through martensite phase and the latter is due to austenite phase.

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  A compact inductively-coupled plasma etching reactor with inner diameter of 38 mm without diffusion chamber (i.e., chamber diameter of plasma etching area is the same as that of plasma discharge area) has been developed. An external magnetic field, created by a solenoid current of ≳10 A that means magnetic field strength of ≳0.02 T at the center of solenoid coil, can effectively reduce losses of plasma at the chamber wall. At low RF power of around 50 W, a discharge-mode transited from capacitively- to inductively-coupled plasmas, high electron density plasma was generated and the optical emissions of fluorine increased in intensity. In summary, the external magnetic field maintains the high plasma density and the compact reactor for a processing area as small as 10 mm diameter has been demonstrated. The basic etching characteristics were evaluated in the case of a Si wafer masked with a SiO₂ film. Typical etching rate of ≳0.3 μm/min was obtained at conditions with a solenoid current of 30 A, a RF power of 500 W, a pulsed plasma discharge with duty ratio of 10%, and a chamber pressure at 0.2 Pa.

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