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We present new evidence supporting the quasi-unit-cell description of the Al72Ni20Co8 decagonal quasicrystal which shows that the solid is composed of repeating, overlapping decagonal cluster columns with broken tenfold symmetry. We propose an atomic model which gives a significantly improved fit to electron microscopy experiments compared to a previous proposal by us and to alternative proposals with tenfold symmetric clusters.

All-solid-state lithium-ion batteries (LIBs) are one of the promising candidates to overcome some issues of conventional LIBs with liquid electrolytes. However, high interfacial resistance of Li-ion transfer at the electrode/solid electrolyte limits their performance. Thus, it is important to clarify interfacial phenomena in a nanometer scale. Here, we present a new method to dynamically observe the Li-ion distribution and Co-ion electronic states in a LiCoO cathode of the all-solid-state LIB during charge and discharge reactions using operando scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). By applying a hyperspectral image analysis of non-negative matrix factorization (NMF) to the STEM-EELS, we succeeded in clearly observing the quantitative Li-ion distribution in the operando condition. We found from the operando observation with NMF that the Li ions did not uniformly extract/insert during the charge/discharge reactions, and the activity of the electrochemical reaction depended on the Li-ion concentration in a pristine state. An electrochemically inactive region was formed about 10-20 nm near the LiCoO/LiO-AlO-TiO-PO-based solid electrolyte interfaces. The STEM-EELS, electron diffraction, and Raman spectroscopy experimentally showed that the inactive region was a mixture of LiCoO and CoO, leading to the higher interfacial resistance of the Li-ion transfer because CoO does not have pathways of Li-ion diffusion in its crystal.

Lithium-ion transport in cathodes, anodes, solid electrolytes, and through their interfaces plays a crucial role in the electrochemical performance of solid-state lithium-ion batteries. Direct visualization of the lithium-ion dynamics at the nanoscale provides valuable insight for understanding the fundamental ion behaviour in batteries. Here, we report the dynamic changes of lithium-ion movement in a solid-state battery under charge and discharge reactions by time-resolved operando electron energy-loss spectroscopy with scanning transmission electron microscopy. Applying image denoising and super-resolution via sparse coding drastically improves the temporal and spatial resolution of lithium imaging. Dynamic observation reveals that the lithium ions in the lithium cobaltite cathode are complicatedly extracted with diffusion through the lithium cobaltite domain boundaries during charging. Even in the open-circuit state, they move inside the cathode. Operando electron energy-loss spectroscopy with sparse coding is a promising combination to visualize the ion dynamics and clarify the fundamentals of solid-state electrochemistry.

The present study experimentally examines how an electron vortex beam with orbital angular momentum (OAM) undergoes diffraction through a forked grating. The nth-order diffracted electron vortex beam after passing through a forked grating with a Burgers vector of 1 shows an OAM transfer of nℏ. Hence, the diffraction patterns become mirror asymmetric owing to the size difference between the electron beams. Such a forked grating, when used in combination with a pinhole located at the diffraction plane, could act as an analyzer to measure the OAM of input electrons.