Hybrid glasses connect the emerging field of metal-organic frameworks (MOFs) with the glass formation, amorphization and melting processes of these chemically versatile systems. Though inorganic zeolites collapse around the glass transition and melt at higher temperatures, the relationship between amorphization and melting has so far not been investigated. Here we show how heating MOFs of zeolitic topology first results in a low density ‘perfect’ glass, similar to those formed in ice, silicon and disaccharides. This order–order transition leads to a super-strong liquid of low fragility that dynamically controls collapse, before a subsequent order–disorder transition, which creates a more fragile high-density liquid. After crystallization to a dense phase, which can be remelted, subsequent quenching results in a bulk glass, virtually identical to the high-density phase. We provide evidence that the wide-ranging melting temperatures of zeolitic MOFs are related to their network topologies and opens up the possibility of ‘melt-casting’ MOF glasses.

Understanding the links between chemical composition, nano-structure and the dynamic properties of silicate melts and glasses is fundamental to both Earth and Materials Sciences. Central to this is whether the distribution of mobile metallic ions is random or not. In silicate systems, such as window glass, it is well-established that the short-range structure is not random but metal ions cluster, forming percolation channels through a partly broken network of corner-sharing SiO₄ tetrahedra. In alumino-silicate glasses and melts, extensively used in industry and representing most of the Earth magmas, metal ions compensate the electrical charge deficit of AlO₄⁻ tetrahedra, but until now clustering has not been confirmed. Here we report how major changes in melt viscosity, together with glass Raman and Nuclear Magnetic Resonance measurements and Molecular Dynamics simulations, demonstrate that metal ions nano-segregate into percolation channels, making this a universal phenomenon of oxide glasses and melts. Furthermore, we can explain how, in both single and mixed alkali compositions, metal ion clustering and percolation radically affect melt mobility, central to understanding industrial and geological processes.

Nanostructured electrode materials have been studied extensively with the aim of enhancing lithium ion and electron transport, lowering the stress caused by their volume changes during the charge/discharge processes of electrodes, and decreasing overpotential of the electrode reactions in lithium ion batteries. In this work, we develop a new synthetic route to high capacity “double-sandwich-like” SnS₂-based nanocomposites (i.e., SnS₂-reduced graphene oxide, termed as SSG) which can be used as an anode material in LIBs with improved electrochemical properties, such as large initial discharge capacity (1032 mA h g⁻¹), high reversible discharge capacity (738 mA h g⁻¹, or 1421 mA h cm⁻³ at 2^nd cycle), and excellent cyclability (564 mA h g⁻¹, or 1087 mA h cm⁻³ after 60 cycles, corresponding to ∼76.5% of the initial reversible capacity), with an excellent coulombic efficiency of ∼96.9%. The electrochemical reaction mechanism of SnS₂ with lithium has been suggested to be the alloy-type storage lithium mechanism.

Graphene, an sp²hybridized single sheet of carbon atoms organized in a honeycomb lattice, is a zero band gap semiconductor or semimetal.

This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.jallcom.2017.04.070The pursuing aim of high reflection loss and broad frequency bandwidth for electromagnetic wave (EMW) absorbing materials is a long-term task and under a close scrutiny. To construct rational microstructures for the absorber have significant impacts on increasing reflection loss and broadening frequency bandwidth. Herein, we presented a sandwich microstructured expand graphite (EG)/BaFe12O19 (BF) nanocomposite successfully prepared by in-situ sol-gel auto-combustion method. The experimental results showed that EG/BF nanocomposite has better EMW absorbing performance than pure EG and BF, the sandwich microstructured EG/BF connected with carbon nanotubes (CNTs) could further improve the electromagnetic performance effectively. The obtained CNT/EG/BF nanocomposite exhibited a saturation magnetization of 26.5 emu g?1 at room temperature and an excellent EMW absorbing performance. The maximum reflection loss of the sandwich microstructured CNT/EG/BF composites with a thickness of 1 mm was up to ?45.8 dB and the frequency bandwidth below ?10 dB could reach to 4.2 GHz within the frequency range of 2?18 GHz. The research results indicated that the prepared nanocomposite showed great potential as a new type of microwave absorbing materialPeer reviewe