Novel handling routines for electron-microscopic studies of highly reactive materials
Highly reactive or environmentally sensitive materials pave the way to the development of new technologies in various fields of application such as energy generation and storage, medicine or electronic devices. Those classes of materials range from elemental alkali (earth) metals to inorganic compounds to polymers to novel 2D materials, all of which are difficult to handle under ambient conditions. Especially, to gain a fundamental understanding of the microstructure-property relations, detailed microscopic studies of pristine materials to complete devices are needed. However, one of the biggest challenges is the preservation of the native state of these reactive samples during preparation or characterization even in evacuated tools such as electron microscopes. Consequently, the elaboration of sophisticated handling and characterization routines is essential to systematically reduce reactivity and mobility of the involved species like Li or H. This contribution demonstrates, how uninterrupted cryogenic/inert-gas sample handling, well established in sample synthesis, is also applicable on transfer chains between different preparation sites and characterization tools. Thereby, the detailed investigation of fundamental aspects like structure formation, device degradation and failure along the different length scales is routinely enabled. Recent successful applications will be presented to demonstrate the capabilities of the proposed routines and to justify the efforts spent. As one example, cryo-TEM, well known from life sciences, was established to systematically study highly reactive Li-based battery nanomaterials . Moreover, to evaluate performance and failure mechanisms of complete devices, advanced cross-sectioning by cryo-microtomy is employed.
 Li et al., Science 358 (2017) 506-510, DOI: 10.1126/science.aam6014