Recent Progress of In Situ Transmission Electron Microscopy for Energy Materials

Abstract

replacing gasoline, diesel, or other types of fuels with electricity, it is expected that our world will become more environmentally friendly by storing energy directly from sustainable sources, such as solar, wind, geothermal, bioenergy, and the ocean. Even Australia, as a country with abundant energy resources, has identified energy as one of the key scientific research priorities. It is clear that the efficiency of energy harvesting and consumption must be improved, emissions must be reduced, and the integration of various energy sources into the electricity grid and chemical storage must be implemented. A desirable outlook is one with a variety of energy sources and mechanisms that significantly reduces carbon emissions and is economical for consumers and society. Recent fast-growing research should boost the development of reliable, highly efficient, low-cost, and sustainable energy materials that are effective for new technologies and that satisfy the growing demand for energy storage and climate change solutions.The progress in energy materials is indeed significant, however, as the expectations of energy materials research are always quite high, it is not sufficient. Particularly, the material performances are always theoretically predicted but are limited by the underlying mechanisms in real applications. As a wellknown example, silicon is expected to deliver a high theoretical capacity of 4200 mAh g −1 in the form of Li 4.4 Si, and is thought to replace the currently commercial graphite with a capacity of 372 mAh g −1 . However, in real applications, it is found that Si exhibits more than 360% of volume expansion during lithiation, which leads to battery anode failure. In the last few years, TEM, especially in situ TEM, has provided exceptional advantages in investigating the lithiation process of silicon anodes: direct imaging, full crystallography information, and real-time recording have all become possible. By directly observing the charge/discharge processes of Si anodes, the dynamics of expansion have been well understood. The research has then been focused on structural designs of composites containing Si to overcome the expansion. The Si composites (for instance, carbon-wrapped Si nanoparticles with different sizes) were directly analyzed by in situ TEM to determine the best structural design. [12] From 2012, in situ TEM became an essential tool to review and evaluate structural designs for high-capacity anodes with significant volume expansions. The same scenarios apply to similar research topics. In situ transmission electron microscopy (TEM) is one of the most powerfulapproaches for revealing physical and chemical process dynamics at atomic resolutions. The most recent developments for in situ TEM techniques are summarized; in particular, how they enable visualization of various events, measure properties, and solve problems in the field of energy by revealing detailed mechanisms at the nanoscale. Related applications include rechargeable batteries such as Li-ion, Na-ion, Li-O 2 , Na-O 2 , Li...

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Local Strain Distribution in ZnO Microstructures Visualized with Scanning Nano X‐Ray Diffraction and Impact on Electrical Properties

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Recent Progress in Using Graphene as an Ultrathin Transparent Support for Transmission Electron Microscopy

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