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

The title compound is synthesized by solid state reaction of a stoichiometric mixture of Bi2O3, TiO2, and Cr2O3 (air, 800—1000 °C, 12 h; annealing at 1025 °C for 12 h in air).

Synthesis, Structure and Characterization of the n = 4 Aurivillius Phase Bi5Ti3CrO15.

We report on X-ray and neutron diffraction and thermopower ( S ) as a function of temperature of Y 1− x Pr x Sr 2 Cu 2.8 Re 0.2 O 6+ z ( x =0 and 0.6). Our structural data indicate that Re occupies the Cu1 chain site in agreement with the recently reported results obtained on single crystal X-ray data. The value of S at 300 K for x =0 indicates that the sample is relatively underdoped. Whereas superconductivity is destroyed for x (Pr)≥0.55 in Y 1− x Pr x Ba 2 Cu 3 O 6+ z (YPBCO) we found that T c =25 K for x =0.6. Both the apical distance and the hole density decrease slowly as a function of x (Pr) in our samples unlike the case of YPBCO. This may explain why 60% of Pr does not suppress superconductivity in our samples.

Neutron diffraction and thermopower of y1-xprxsr2cu2.8re0.2o6+z (x=0 and 0.60)

Neutron-diffraction experiments have shown that the title compound A1-2212 has an average tetragonal structure closely related to the quasi-tetragonal YBa 2 Cu 3 O 7 structure, but with the Y layer replaced means of electron diffraction and high-resolution electron microscopy have refined the existing model. A superstructure of corner-linked oxygen tetrahedra coordinating the A1O ions is shown in the AlO layer. The weakness of corrrelations between adjacent AlO layers, and the presence of two orientational variants, may explain why this superstructure was overlooked by neutron-diffraction investigations.

Determination of the superstructure in (Y0.75Ce0.25)2(Sr0.85Y0.15)2AlCu2O9+x by means of electron microscopy

The (Nd,Ce)2Sr2Cu2MOx (M=Ga,Ta) are structurally related to YBCO with yttrium replaced by a fluorite-type block of composition (Nd,Ce)2O2 , and barium by strontium. Neutron powder diffraction studies on these materials have been performed to compare structural order within the layers containing the M atoms. For M=Ga, long-range ordering of the corner-linked GaO4 tetrahedra along the (110) direction of the simple perovskite cell results in an orthorhombic supercell. These zigzag chains of tetrahedra are of two types which are distinguished by the direction of atomic displacements in the chains; equal quantities of both types occur in (Nd,Ce)2Sr2Cu2GaOx. When the tetrahedral Ga ions are replaced by octahedral Ta, the oxygen positions in the basal plane are fully occupied, and the tetrahedral chains are converted into octahedral layers to give a smaller tetragonal unit cell. Cooperative rotation of the TaO6 octahedra within these layers has been confirmed.

Colin Greaves

Papers

Synthesis, Structure and Characterization of the n = 4 Aurivillius Phase Bi5Ti3CrO15.

Neutron diffraction and thermopower of y1-xprxsr2cu2.8re0.2o6+z (x=0 and 0.60)

Determination of the superstructure in (Y0.75Ce0.25)2(Sr0.85Y0.15)2AlCu2O9+x by means of electron microscopy

A neutron powder diffraction study of (Nd1.5Ce0.5)(Sr2-yNdy)Cu2MOx(M=Ga,Ta).

Structure and magnetic properties of LiMVO4 (M = Mn, Cu)