• Hanzu, Ilie
• Jodlbauer, Anna
• Fisslthaler, Evelin
• Simic, Nikola
• Knez, Daniel

Abstract

Recent advances in electron microscopical techniques now enable valuable insights into ion<br/>transport chemical and crystallographic processes of in battery materials. Influences The<br/>influence of battery cycling on the local crystal behavior structure and chemistry was<br/>successfully shown on LiFePO4 cathodes at the atomic level, [1] using utilizing the electron<br/>dose efficient integrated Differential Phase Contrast (iDPC) Imaging in a scanning<br/>transmission electron microscope (STEM) (iDPC) [2], as well asin combination with Electron<br/>Energy Loss Spectroscopy (EELS) in combination withand Selected Area Electron Diffraction<br/>(SAED) [1,2]. For the more complex and way more beam sensitive, polycrystalline LiVPO4,<br/>which exhibits polycrystalline behavior with crystals in ranging in the size offrom 10 nm to<br/>100 nm, the usage application of these techniques is less straightforward. Orientation of<br/>individual phases is rather problematic due to the main challenges lie in the small crystal size<br/>and their rapid amorphization under electron beam illumination. We therefore employ 4DScanning<br/>Confocal Electron Diffraction (4D-SCED) [3] for analyzing local crystal phases in<br/>combination with High-Resolution and spectroscopic techniques. [3]. This technique is well<br/>suited even for very beam sensitive materials, combining both the signal-to-noise ratio of<br/>SAED with the high lateral resolution of conventional Nanobeam-Diffraction in the range of<br/>~1 nm while still retaining low local electron dose requirements. Combining 4D-SCED with<br/>zero-loss filtering allows for even better signal to noise ratio in k-space imaging. We further<br/>discuss the advantages of 4D-SCED regarding the possibility of real-space phase mapping<br/>as well as combination with other imaging techniques and show these advantages on triedand-<br/>tested materials such as LiFePO4.

Topics

• impedance spectroscopy
• phase
• electron diffraction
• laser emission spectroscopy
• electron energy loss spectroscopy