Prospective Cohort Study

Energy production and storage have become key issues concerning our welfare in daily life. Present challenges for batteries are twofold. In the first place, the increasing demand for powering systems of portable electronic devices and zero-emission vehicles stimulates research towards high energy and high voltage systems. In the second place, low cost batteries are required in order to advance towards smart electric grids that integrate discontinuous energy flow from renewable sources, optimizing the performance of clean energy sources. Na-ion batteries can be the key for the second point, because of the huge availability of sodium, its low price and the similarity of both Li and Na insertion chemistries. In spite of the lower energy density and voltage of Na-ion based technologies, they can be focused on applications where the weight and footprint requirement is less drastic, such as electrical grid storage. Much work has to be done in the field of Na-ion in order to catch up with Li-ion technology. Cathodic and anodic materials must be optimized, and new electrolytes will be the key point for Na-ion success. This review will gather the up-to-date knowledge about Na-ion battery materials, with the aim of providing a wide view of the systems that have already been explored and a starting point for the new research on this battery technology.

Na-ion batteries, recent advances and present challenges to become low cost energy storage systems

The General Utility Lattice Program (GULP) has been extended to include the ability to simulate polymers and surfaces, as well as adding many other new features, and the current status of the program is fully documented. Both the background theory is described, as well as providing a concise review of some of the previous applications in order to demonstrate the range of its use. Examples are presented of work performed using the new compatibilities of the software, including the calculation of Born effective charges, mechanical properties as a function of applied pressure, calculation of frequency-dependent dielectric data, surface reconstructions of calcite and the performance of a linear-scaling algorithm for bond-order potentials.

The general utility lattice program (GULP)

Although known since the late 19th century, organic–inorganic perovskites have recently received extraordinary research community attention because of their unique physical properties, which make them promising candidates for application in photovoltaic (PV) and related optoelectronic devices. This review will explore beyond the current focus on three-dimensional (3-D) lead(II) halide perovskites, to highlight the great chemical flexibility and outstanding potential of the broader class of 3-D and lower dimensional organic-based perovskite family for electronic, optical, and energy-based applications as well as fundamental research. The concept of a multifunctional organic–inorganic hybrid, in which the organic and inorganic structural components provide intentional, unique, and hopefully synergistic features to the compound, represents an important contemporary target.

Organic–Inorganic Perovskites: Structural Versatility for Functional Materials Design

Synthesis, properties, and applications of magnetic iron oxide nanoparticles

Magnetic Ordering in the Garnet YCa2SbFe4O12

A short overview is given of the possibilities of electron microscopy in the determination of the local, atomic scale structure of high Tc superconducting materials. Examples include the detection of weak oxygen ordering, description and characterization of deformation modulations in layered superconductors, and analysis of very long period superstructures. The ordering principles for tetrahedral chains in Ga-, Co-, or Al-substituted YBCO are discussed and their complex defect structures are described. The incommensurate modulation in YBCO-based materials containing SO4-tetrahedra, centered on the Cu(1) sites of the CuO-chain plane is attributed to the ordering of b-oriented SO4-rich chains in the Cu(1)-S-O layer; the structure is described in terms of an SO4-concentration wave. As examples of the new mercury-based superconducting family we discuss Y0.6Ca0.4Ba2Hg1−xMxCu2O6+y, which crystallizes in the space group P4/mmm with a = 0.3870(1) nm, c = 1.2537(1) nm. This cuprate belongs to the 1212 series; susceptibility measurements show a Tc (onset) of 90K, with a diamagnetic volume fraction of 27% at 4.2K to be reached. A second example is related to the compound Tl2HgBa4Cu2O10+y, in which ordering between single Hg layers and double Tl layers is observed. © 1995 Wiley-Liss, Inc.

Structural investigations of recently discovered high Tc superconductors.

Facile syntheses, crystal structures and magnetic properties of NdBaMnCoO5 and NdBaMnCoO6

The partial substitution of Ga at the Cu(1) (chain) sites of the YBa2Cu3O7 structure allows synthesis at ambient pressure of Ba-free analogs, e.g., YSr2Cu2.7Ga0.3O7−δ. Materials with this composition have been found to be nonsuperconducting, but superconductivity has been induced by one or more of the following methods: Ca substitutions at the Y site; Ba substitutions at the Sr site; annealing in high-pressure oxygen. The influence of these chemical manipulations onT c has been monitored and all methods have been found to enhanceT c . The electronic effects of Ba substitutions have been deduced indirectly using powder neutron diffraction, and such substitutions appear to result in a redistribution of hole density into the Cu(1) sites from the superconducting CuO2 planes.

Chemical control of superconducting properties of (Y, Ca)(Sr, Ba)2Cu2.7Ga0.3O7−δ

Versiliaite and apuanite are two minerals containing Fe(2+) and Fe(3+) in a low-dimensional structure exhibiting chains of edge-linked FeO6 octahedra. The chemistry of these minerals has not been fully examined because of their rarity. We demonstrate that chemical synthesis of these minerals is possible to allow measurement of their magnetic properties and a more complete description of their structural features using neutron powder diffraction. We also show that chemical manipulation is possible to provide isostructural phases with different chemical compositions.

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Colin Greaves

Papers

Magnetic Ordering in the Garnet YCa2SbFe4O12

Structural investigations of recently discovered high Tc superconductors.

Facile syntheses, crystal structures and magnetic properties of NdBaMnCoO5 and NdBaMnCoO6

Chemical control of superconducting properties of (Y, Ca)(Sr, Ba)2Cu2.7Ga0.3O7−δ

Synthetic analogues of Fe(ii)-Fe(iii) minerals containing a pentagonal 'Cairo' magnetic lattice.