Two-dimensional transition metal carbides, that is, MXenes and especially Ti3C2, attract attention due to their excellent combination of properties. Ti3C2 nanosheets could be the material of choice for future flexible electronics, energy storage, and electromechanical nanodevices. There has been limited information available on the mechanical properties of Ti3C2, which is essential for their utilization. We have fabricated Ti3C2 nanosheets and studied their mechanical properties using direct in situ tensile tests inside a transmission electron microscope, quantitative nanomechanical mapping, and theoretical calculations employing machine-learning derived potentials. Young’s modulus in the direction perpendicular to the Ti3C2 basal plane was found to be 80–100 GPa. The tensile strength of Ti3C2 nanosheets reached up to 670 MPa for ∼40 nm thin nanoflakes, while a strong dependence of tensile strength on nanosheet thickness was demonstrated. Theoretical calculations allowed us to study mechanical characteristics of Ti3C2 as a function of nanosheet geometrical parameters and structural defect concentration.

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...

The thermal stability of all-inorganic halide perovskites is their key advantage over organic/hybrid halide perovskites. Here, in situ highresolution transmission electron microscopy (HRTEM) was used to directly investigate crystallography dynamics of a CsPbBr 3 perovskite at high temperature (up to 690 K). In high vacuum TEM conditions (∼10 −5 Pa), CsPbBr 3 nanocrystals possessed superb stability at temperatures below 690 K. By sealing the crystals in amorphous carbon, their melting and solidification processes were directly observed at temperatures of 840 K and 838 K, respectively. This study should be valuable for future perovskite-containing solar cells, lasers, light-emitting diodes, and photodetectors working at high temperatures.

No abstract

The world is currently in the midst of a climate crises and many across the globe are competing to find new technologies to create clean, and effective ways of harnessing renewable energy sources. However, this energy needs to be stored and the current systems simply would not last. Zinc‐ion batteries (ZIBs) with vanadium‐containing cathodes are a recently arising technology providing a cheap, safe, and eco‐friendly alternative to the current systems. Vanadium is a material that has long been used for electrochemical systems due to its large range of stable oxidation states. Most common is the vanadium oxide (V2O5) renowned for its open layered framework and manipulatable structure. However, this is not the only vanadium‐containing material that is proposed for use in ZIBs. The vanadium family is comprised of four main sub‐categories under which materials can be classified: vanadium oxides, vanadium phosphates, vanadates, and O2‐free vanadium compounds. This report delves into the specifics of each of these sub‐families to further develop the understanding of their functionality by highlighting their structural and morphological characteristics, aptitude for modification, and the corresponding electrochemical properties. Through this investigation, the application of these materials in ZIB systems is highlighted and future development aims considered.