Figure1

Imaging inter - and intra-particle features in crystalline cathode materials for Li-ion batteries using nano-focused beam techniques at 4th generation synchrotron sources

Figure 1. Scanning X-ray Diffraction Microscopy (SXDM) experimental schematics (A). A nanofocused beam (with wave-vector ki) is rastered across the sample (using piezo motors x and y) imaging crystals found in Bragg conditions in the scanned area. For each step of the map local scattering vector, Qlocal is measured which is defined as the difference between ki and kf, incident and scattered wave vectors, respectively. It corresponds to the studied Bragg reflection and contains local diffraction data of the illuminated portion of the crystal. Maps are obtained at distinct rocking curve angles η to probe the 3D volume of the reciprocal space. The slices measured at each rocking curve angle by the 2D detector define the studied volume in the reciprocal space, which contains the Bragg reflection of the particle (B). SXDM is sensitive to the magnitude variation of the Qlocal scattering vector (orange) relative to the averaged scattering vector (Q (gray)) across the measured particle (C). These local variations can be visualized as maps of absolute d-spacing (D) or "strain" relative to average d-spacing of the particle (E). Rotation of Qlocal vector in the reciprocal space due to lattice mosaicity/misorientation can also be detected (F). The direction of Qlocal vector can be expressed in spherical coordinates as tilt magnitude (Altitude) and tilt direction (Azimuth) (G) (Tilt magnitude is exaggerated for clarity). Lattice mosaicity can also be visualized on the map of the same scanned area (H) by color coding the altitude and azimuth values with saturation and hue, respectively (I).

Microstructures
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