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Abstract: Calcium stannate (CaSnO3) and malayaite (CaSnSiO5) were synthesized by means of a high temperature solid-state reaction. Their crystal structures and morphologies were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy; their electrochemical properties were analyzed by galvanostatic tests. The amorphization of the initial electrode materials was followed by XRD. The first discharge of the oxides CaSnO3 and CaSnSiO5 shows a plateau at low potential, which is due to the progressive formation of Li–Ca–Sn and/or Li–Sn alloys as shown by 119Sn Mössbauer spectroscopy. The results reveal similar electrochemical mechanisms for CaSnO3 and CaSnSiO5 but they completely differ from those related to SnO2. [Copyright &y& Elsevier]

The electrochemical reaction of lithium with the skutterudite-type CoP3 compound has been studied. To follow the reaction mechanism, X-ray diffraction (XRD), 7Li nuclear magnetic resonance (NMR) and X-ray absorption (XAS) experiments have been carried out. During the first reaction of the CoP3 phase, cobalt is reduced and lithium-phosphide is formed. The reversible process observed during subsequent cycles consists of the formation of Li3P from its elements, giving a maximum in reversible gravimetric capacity of 487 mAh/g. [Copyright &y& Elsevier]

Abstract: Crystalline FeSb2 powder prepared by ceramic route is examined as negative electrodes for lithium-ion batteries. The complete reaction mechanism of FeSb2 is investigated by 121Sb and 57Fe Mössbauer spectroscopy as well as magnetic measurements and the results are correlated with a previous in situ XRD characterization. On the first discharge the reaction with Li proceeds through a biphasic process transforming FeSb2 into a new LixFeySb2 phase, and this ternary phase is then converted into fcc Li3Sb and metallic Fe nanoparticles. The combination of Mössbauer spectroscopy and magnetic analyses leads i) to a better understanding of the FeSb2 →ternary phase reaction and concomitantly allowed ii) to specify the stoichiometry of the new ternary phase. On charge, the extrusion of lithium includes the back conversion of the Li3Sb/Fe mixture into both Li4Fe0.5Sb2 and metallic Sb, which are the main active species for the following cycles, responsible for the poor cycling life of the FeSb2 electrode. The nature of these resulting products is quite different from that previously observed for the isotype NiSb2 electrode which is characterized by a highly reversible mechanism. [Copyright &y& Elsevier]

Abstract: A nanostructured composite with overall atomic composition Ni0.14Sn0.17Si0.32Al0.037C0.346 has been prepared combining powder metallurgy and mechanical milling techniques for being used as anode material in Li-ion battery. Chemical and structural properties of the nanocomposite have been determined by X-ray diffraction (XRD), 119Sn Transmission Mössbauer Spectroscopy (TMS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The composite consists of Si particles with typical size ∼150nm embedded in a poorly crystallized and complex multielemental matrix. The matrix is composed mostly by Ni3.4Sn4, and disordered carbon. Electrochemical evaluation shows a high reversible capacity of 920mAhg−1, with reasonable reversible capacity retention (∼0.1% loss/cycle) over 280 cycles. [Copyright &y& Elsevier]

Abstract: The phase equilibrium diagram of the SnSe–Bi2Se3 system has been re-investigated using X-ray powder diffraction, thermal analysis (DTA and DSC) and 119Sn Mössbauer spectroscopy data. It shows solid solutions based on Bi2Se3 and SnSe (α and β forms) and three intermediate phases: well-defined, SnBi4Se7, SnBi4Se7, and a new phase Sn2Bi2Se5. The new phase Sn2Bi2Se5 exists in the composition range 25–55mol% Bi2Se3. Its structure is still under study. However, 119Sn Mössbauer spectroscopy study of the latter allowed to achieve a well knowledge of the local environment of tin atoms and could contribute to the actual structural study. [Copyright &y& Elsevier]

Abstract: Thirteen clay samples from four deposits in the Ivory Coast (West Africa) were studied using X-ray diffraction, thermogravimetric analysis and chemical analysis. Mineralogical, crystallographic and morphological characteristics of these samples are given. Kaolinite is the principal mineral but other minerals are present in small quantities: illite, quartz, anatase and iron oxides (oxides and oxyhydroxides). The crystallographic, morphological and surface characteristics are influenced by the presence of these impurities. In particular, the presence of iron oxides was associated with reduced structural ordering and thermal stability of kaolinite and increased specific surface area. These clays could be used in the ceramics industry to make tiles and bricks, and also in agronomy as supports for chemical fertilizers or for environmental protection by immobilising potentially toxic waste products. [Copyright &y& Elsevier]