Narrow Results

Thin films of V₂O₅ were deposited on glass substrates by dip-coating technique using sol–gel route. The vanadium pentoxide sol was prepared by dissolving V₂O₅ powder in H₂O₂ solution. The solutions were kept in water bath and heated at five different temperatures for 30 min. The samples were annealed at 150^°C for 60 min. The optical, structural, and morphological measurements were performed for characterization of samples. The effect of viscosity on optical constants (n, k, and E_g) of V₂O₅ were studied. The indirect optical band gap energy of sol–gel V₂O₅ thin films are about 2.33 eV and independent of viscosity within the error limits. The results show that the water-bath temperature strongly influences the viscosity of sol. The viscosity of sol was changed from 12.5 to 75 m Pa s. with increasing water-bath temperature from 50 to 90^°C. The XRD measurements show that the structure of the V₂O₅ films and powders is polycrystalline after annealing at 450^°C. A correlation exists between the viscosity, morphology, and optical characteristics.

Glasses from the two systems, xFe₂O₃ · (100-x)[P₂O₅ · CaO] and x(Fe₂O₃ · V₂O₅) · (100-x)[P₂O₅ · CaO] with 0 ≤ x ≤ 50 mol% were prepared under the same conditions and characterized by IR spectroscopy. The way in which Fe₂O₃ and (Fe₂O₃ · V₂O₅) influences the local structure of these glasses was analyzed.

Glasses of the x(Fe₂O₃·V₂O₅)·(100-x)[P₂O₅·Li₂O] system, with 0≤x≤50 mol%, were prepared and investigated by FTIR spectroscopy in an attempt to determine the local structure of glasses. The interpretation of the obtained IR spectra revealed the presence and the dependence of the local structural units in the studied glasses on the iron and vanadium ions content. The results showed that phosphate units are the main structural units of the glass system and the iron and vanadium ions are located in the network. The increasing of iron and vanadium ions content indicate a gradual decreasing in the number of bridging oxygen ions and an increasing in the number of nonbridging oxygen ions.

Amorphous V₂O₅, LiPON and Li₂Mn₂O₄ thin films were fabricated by RF magnetron sputtering methods and the morphology of thin films were characterized by scanning electron microscopy. Then with these three materials deposited as the anode, solid electrolyte, cathode, and vanadium as current collector, a rocking-chair type of all-solid-state thin-film-type Lithium-ion rechargeable battery was prepared by using the same sputtering parameters on stainless steel substrates. Electrochemical studies show that the thin film battery has a good charge–discharge characteristic in the voltage range of 0.3–3.5 V, and after 30 cycles the cell performance turned to become stabilized with the charge capacity of 9 μAh/cm², and capacity loss of single-cycle of about 0.2%. At the same time, due to electronic conductivity of the electrolyte film, self-discharge may exist, resulting in approximately 96.6% Coulombic efficiency.