Ionics
Several olivine phosphates were investigated in the last years as cathode materials for secondary lithium ion batteries. Among these compounds, LiFe x Co1 − x PO4 solid solutions might be interesting candidates because they should combine the high potential value of Co3+/Co2+ (higher than 4.5 V vs Li+/Li) with the relatively high charge–discharge rate of LiFePO4. Solid solutions were prepared by solid-state...
The present work deals with the design, development, and implementation of an angle detector using n-ATO/p-PSi photovoltaic sensor. Nanoporous structures have been developed over p-type porous silicon wafers by anodization technique under optimized conditions. Photoluminescence studies of porous silicon show emission between 700 and 702 nm for the constant excitation at 350 nm, which illustrates that...
P-type porous silicon (PS) structure has been prepared by anodic electrochemical etching process under optimized conditions. Photoluminescence studies of the PS structure show emission at longer wavelengths (red) for the excitation at 365 nm. Scanning electron microscope investigations of the PS surface confirm the formation of uniform porous structure, and the pore diameter have been estimated as...
All-solid-state proton-conducting polymeric batteries have been fabricated in the cell configurations: Zn + ZnSO4·7H2O (anode) || polyethylene oxide (PEO):NH4HSO4 + SiO2 || MnO2 + C (cathode) and Zn + ZnSO4·7H2O (anode) || PEO:NH4HSO4 + SiO2 || PbO2 + V2O5 + C (cathode). Nano-composite proton-conducting polymeric membrane in wt.% composition, 92PEO: 8 NH4HSO4 + 3 SiO2, synthesized by solution cast...
Solid polymer electrolytes based on poly(vinyl alcohol) (PVA) doped with NH4Br have been prepared by the solution-casting method. The complex formation between the polymer and the salt has been confirmed by Fourier transform infrared spectroscopy. The highest conductivity at 303 K has been found to be of the order of 10−4 Scm−1 for 25 mol% NH4Br-doped PVA system. The ionic transference number of polymer...
Nanocomposite electrodes of recently identified polyanion cathode materials comprising Li x M2(MoO4)3 {0 ≤ x < 3} [M = Co, Ni] and nanosized carbon having ~10 nm particle size were found to show remarkable improvement in their discharge capacity compared to the one prepared with acetylene black. The addition of nanosized carbon as a conductive additive offered improved initial...
Ceria-stabilized zirconia (CSZ) thin films have been developed over Ni-based alloy substrate by vacuum evaporation method using an electron beam. X-ray diffraction (XRD) analysis of the film heat treated at different temperatures reveals monoclinic phase stabilization. Transmission measurements of the films annealed at different temperatures, in the wavelength region 300–1,100 nm, indicate that the...
Gas sensors has been currently in great demand because of serious concern over environmental pollution and public health considerations resulting from tremendous growth of industrialisation. Concurrently, there have been continuous efforts to obtain sensors with improved performance. The performance of any solid-state electrochemical gas sensor has been always rated on its response time, thermodynamic...
We present a review of the structural properties of LiFePO4. Depending on the mode of preparation, different impurities can poison this material. These impurities are identified and a quantitative estimate of their concentrations is deduced from the combination of X-ray diffraction analysis, Fourier transform infrared spectroscopy, Raman spectroscopy, and magnetic measurements. An optimized preparation...
Thin films of molybdenum trioxide were deposited on glass substrates employing direct current (DC) magnetron sputtering by sputtering of molybdenum at different oxygen partial pressures in the range 8 × 10−5–1 × 10−3 mbar and at a substrate temperature of 473 K. The glow discharge characteristics of magnetron cathode target of molybdenum were studied. The influence of oxygen partial pressure on the...
Thin solid polymer electrolytes based on polyethylene oxide (PEO) and silver triflate (AgCF3SO3) dispersed with various concentrations of aluminum oxide (Al2O3) nanoparticles have been prepared by solution casting technique. These thin polymer films are found to have thickness of the order of 30 to 100 μm. The X-ray diffraction (XRD) patterns have indicated the amorphous nature of the polymer electrolyte...
A sodium ion conducting polymer electrolyte based on poly (vinyl alcohol) (PVA) complexed with sodium bromide (NaBr) was prepared using solution cast technique. Several experimental techniques such as XRD, FTIR, SEM, temperature-dependant conductivity and transference number measurements have been performed. XRD and FTIR studies confirm the complexation of salt with the polymer. Surface morphology...
This paper presents results of studies on dc electrical conductivity and transference number measurements on potassium bromate (KBrO3) complexed polyvinyl chloride (PVC) films prepared by solution cast technique. Temperature dependence of dc electrical conductivity and transference number data indicated the dominance of ion type charge transport in these specimens. The magnitude of conductivity increased...
LiCoO2 thin films were prepared by electron beam evaporation technique using LiCoO2 target with Li/Co ratio 1.1 in an oxygen partial pressure of 5 × 10−4 mbar. The films prepared at substrate temperature T s < 573 K were amorphous in nature, and the films prepared at T s > 573 K exhibited well defined (104), (101), and (003) peaks among which the (104) orientation predominates. The X-ray photoelectron...
Samarium-doped Ceria powders for solid electrolyte ceramics were synthesized by a combustion process. Cerium nitrate and samarium nitrate were used as the starting materials, and glycine was used as fuel. Decomposition of unburned nitrogen and carbon residues was investigated by simultaneous thermogravimetry analysis and differential thermal analysis experiments. The X-ray diffraction results showed...
Carbon is an exceptionally versatile fuel source, with excellent conductivity properties and an extraordinarily high energy density. This paper describes the evolution of carbon–air fuel cells to produce electrical energy, the use of renewable carbon in carbon-neutral processes and greenhouse gas reduction and the long-term future of such cells.
The effect of thickness of oxide-sensing electrode (SE) on NO2 sensitivity of the planar sensor based on yttria-stabilized zirconia (YSZ) was examined at high temperatures. The sensitivity of the sensor increased with decreasing thickness of SE, and the highest sensitivity was obtained by using the thinnest layer of Cr2O3–SE (2.7 μm) at 700 °C. In the case of NiO–SE, the highest sensitivity was observed...
LiMn2O4 thin films were deposited by reactive pulsed laser deposition technique and studied the microstructural and electrical properties of the films. The LiMn2O4 thin films deposited in an oxygen partial pressure of 100 mTorr and at a substrate temperature of 573 K from a lithium rich target were found to be nearly stoichiometric. The films exhibited predominantly (111) orientation representing...
Fluorine substituted Li1.27Cr0.2Mn0.53O2 electrode, prepared by sol–gel method, was investigated in the present work. Thermal analysis was done on this cathode material and found to be thermally stable with a loss of weight near 300 °C. Influence of fluorine substitution on the structural and electrochemical properties of the Li1.27Cr0.2Mn0.53O2 electrode was studied by X-ray diffraction (XRD) and...