PLR (Plastic Lithium Rechargeable) Batteries Using Nanoscale Materials: A Convenient Electrical Energy Power for the Future?

This communication describes the synthesis of: (i) non toxic and low cost nanocrystalline electrode materials which can be advantageously prepared at low temperature; (ii) highly conductive electrolyte membranes formed by the nano-encapsulation within a poly (acrylonitrile)-based polymer matrix of a solution of LiPF6 in organic solvants. The performances of rechargeable PLR (Plastic Lithium Rechargeable) batteries using the above mentioned components are presented

Modificación del comportamiento tribológico de zirconio y titanio mediante implantación de nitrógeno

This paper gathers the studies of the effects introduced by Nitrogen implantation on Ti and Zr. Atomic and molecular Nitrogen have been implanted on Titanium and Zirconium samples to investigate the role of these elements in the nitrides precipitation. In all cases an increase in microhardness, which in some cases was greater than 80% was found out. Moreover was observed improvements in the wear resistance and a decrease in the friction coefficient. AES and XPS spectroscopy revealed that nitride precipitation in titanium is more significant for the high atomic doses of Nitrogen implantation.<br><br>En el presente trabajo se estudian los efectos introducidos por la implantación de nitrógeno atómico y molecular en Ti y Zr comercialmente puros. Se relacionan los cambios en la dureza superficial y coeficiente de fricción con los cambios en la composición química superficial. En todos los casos se ha encontrado que la implantación iónica proporciona aumentos de dureza que en algunos de los casos llega hasta el 80%. Se encontraron así mismo mejoras en la resistencia al desgaste y disminuciones del coeficiente de fricción de hasta un 50%. La caracterización AES y XPS pone de manifiesto la aparición de precipitados de nitruros, con mayor concentración para la implantación de altas dosis de nitrógeno atómico sobre titanio

Topotactic fluorination of intermetallics as an efficient route towards quantum materials

Intermetallics represent an important family of compounds, in which insertion of light elements (H, B, C, N) has been widely explored for decades to synthesize novel phases and promote functional materials such as permanent magnets or magnetocalorics. Fluorine insertion, however, has remained elusive so far since the strong reactivity of this atypical element, the most electronegative one, tends to produce the chemical decomposition of these systems. Here, we introduce a topochemical method to intercalate fluorine atoms into intermetallics, using perfluorocarbon reactant with covalent C-F bonds. We demonstrate the potential of this approach with the synthesis of non-stoichiometric mixed anion (Si-F) LaFeSiFx single-crystals, which are further shown to host FeSi-based superconductivity. Fluorine topochemistry on intermetallics is thus proven to be an effective route to provide functional materials where the coexistence of ionic and metallo-covalent blocks, and their interactions through inductive effects, is at the root of their functional properties

Oxidation induced superconductivity and Mo/Cu charge equilibrium in Mo0.3Cu0.7Sr2ErCu2Oy

A detailed study of the structure-composition-properties correlation is reported for the as-prepared (AP) and two oxygenated (oxygenation carried out at ambient pressure and under high pressure) Mo0.3Cu0.7Sr2ErCu2Oy samples. Their crystal structures were characterized by combining the x-ray/neutron powder diffraction (NPD) and electron diffraction techniques. All the samples show tetragonal symmetry, crystallizing in the P4/mmm space group. The influence of oxygenation in the electronic states for the Mo0.3Cu0.7Sr2ErCu2Oy system associated with an oxidation reaction leading from a non-superconducting to a superconducting state has also been investigated by means of x-ray photoelectron spectroscopy (XPS). XPS measurements show the predominance of the MoV oxidation state over the MoVI one in the AP sample; annealing under flowing oxygen enhances both the MoVI and CuII amounts. The AP sample shows the existence of ferromagnetic clusters originated from the short-range magnetic correlations of the paramagnetic MoV cations. On the other hand, all the oxygenated samples are not magnetic but superconducting. The high-pressure oxygenated sample shows the highest superconducting transition temperature of TC = 84 K. A partial oxygen ordering in the (Mo/Cu)O1+δ chain and a decrease in the charge transfer energy after oxygenation induces superconductivity in the oxygenated samples

Synthesis and characterization of WO3 thin films by surfactant assisted spray pyrolysis for electrochromic applications

Thin films of WO3 were prepared by surfactant assisted spray pyrolysis on F-doped SnO2 (FTO) conductive glass by using hexadecyltrimethylammonium bromide (HTAB) and polyethylene glycol (PEG400):HTAB as growth controlling agents. The surface tension of the spraying solutions was experimentally evaluated and was correlated with the deposition processes (nucleation and growth) of very smooth and homogenous films. The effect of the surfactant, alone and associated with PEG, on the structure (XRD), morphology (AFM), surface composition (XPS), FTIR and hydrophilicity (contact angle) were investigated and their influence on the electrochromic activity was discussed. Using surfactants and PEG, the coloration efficiency, transmission modulation and cycling stability of the WO3 thin films can be enhanced

Dual lithium insertion and conversion mechanisms in a titanium-based mixed-anion nanocomposite

The electrochemical reaction of lithium with a vacancy-containing titanium hydroxyfluoride was studied. On the basis of pair distribution function analysis, NMR, and X-ray photoelectron spectroscopy, we propose that the material undergoes partitioning upon initial discharge to form a nanostructured composite containing crystalline Li(x)TiO(2), surrounded by a Ti(0) and LiF layer. The Ti(0) is reoxidized upon reversible charging to an amorphous TiF(3) phase via a conversion reaction. The crystalline Li(x)TiO(2) is involved in an insertion reaction. The resulting composite electrode, Ti(0)-LiF/Li(x)TiO(2) ⇔ TiF(3)/ Li(y)TiO(2), allows reaction of more than one Li per Ti, providing a route to higher capacities while improving the energy efficiency compared to pure conversion chemistries