Electrochemical Properties of APCVD alpha-Fe2O3 Nanoparticles at 300 degrees C

The growth of hematite (FeIII oxide) by atmospheric pressure chemical vapor deposition was possible at 300 oC by controlling the nitrogen flow rate through the iron precursor bubbler. An increase of crystallinity along with the presence of compact interconnected nanoparticles was observed upon increasing the nitrogen flow rate. The amount of incorporated charge was the highest for the 0.6 L min−1 coating presenting reversibility after a period of 1400 s as obtained from chronoamperometry measurements. Additionally, the charge transfer of lithium‐ions across the FeIII oxide / electrolyte interface was easier enhancing its performance presenting capacitance retention of 94 % after 500 scans. The importance of nitrogen flow rate towards the deposition of an anode with good stability and effective electrochemical behavior is highlighted

Influence of the 6^1S_0-6^3P_1 Resonance on Continuous Lyman-alpha Generation in Mercury

Continuous coherent radiation in the vacuum-ultraviolet at 122 nm (Lyman-alpha) can be generated using sum-frequency mixing of three fundamental laser beams in mercury vapour. One of the fundamental beams is at 254 nm wavelength, which is close to the 6^1S_0-6^3P_1 resonance in mercury. Experiments have been performed to investigate the effect of this one-photon resonance on phasematching, absorption and the nonlinear yield. The efficiency of continuous Lyman-alpha generation has been improved by a factor of 4.5.Comment: 8 pages, 7 figure

Enhanced generation of VUV radiation by four-wave mixing in mercury using pulsed laser vaporization

The efficiency of a coherent VUV source at 125 nm, based on 2-photon resonant four-wave mixing in mercury vapor, has been enhanced by up to 2 orders of magnitude. This enhancement was obtained by locally heating a liquid Hg surface with a pulsed excimer laser, resulting in a high density vapor plume in which the nonlinear interaction occurred. Energies up to 5 μJ (1 kW peak power) have been achieved while keeping the overall Hg cell at room temperature, avoiding the use of a complex heat pipe. We have observed a strong saturation of the VUV yield when peak power densities of the fundamental beams exceed the GW/cm2 range, as well as a large intensity-dependant broadening (up to ~30 cm-1) of the two-photon resonance. The source has potential applications for high resolution interference lithography and photochemistry

Hydrothermal Growth of MnO2 at 95 oC as an Anode Material

The hydrothermal growth of manganese dioxide was carried out on indium tin dioxide coated glass substrates using potassium permanganate at 95 oC for 24 h and adjusting the pH solution to 3 and 4 through nitric acid. The best capacitive response was observed from the hexagonal ε-manganese dioxide at pH 4 having a specific charge of 129 ± 1 A g-1 and specific discharge capacity of 943 mAh g-1 with capacitance retention of 98 % after 500 scans at 4 A g-1 presenting high rate performance and good stability. The importance of achieving crystalline electrodes with high specific surface area towards the improvement of their capacitive performance for power devices is highlighted

Towards High Performance Chemical Vapour Deposition V2O5 Cathodes for Batteries Employing Aqueous Media

The need for clean and efficient energy storage has become the center of attention due to the eminent global energy crisis and growing ecological concerns. A key component in this effort is the ultra-high performance battery, which will play a major role in the energy industry. To meet the demands in portable electronic devices, electric vehicles, and large-scale energy storage systems, it is necessary to prepare advanced batteries with high safety, fast charge ratios, and discharge capabilities at a low cost. Cathode materials play a significant role in determining the performance of batteries. Among the possible electrode materials is vanadium pentoxide, which will be discussed in this review, due to its low cost and high theoretical capacity. Additionally, aqueous electrolytes, which are environmentally safe, provide an alternative approach compared to organic media for safe, cost-effective, and scalable energy storage. In this review, we will reveal the industrial potential of competitive methods to grow cathodes with excellent stability and enhanced electrochemical performance in aqueous media and lay the foundation for the large-scale production of electrode materials

Ionization and fragmentation of aromatic and single-bonded hydrocarbons with 50 fs laser pulses at 800 nm

Laser-induced ionization and dissociation of aromatic and single-bonded hydrocarbons, benzene, toluene, cyclopropane, cyclohexane and n-hexane, have been investigated at intensities of 2×1013–2.5×1014 W cm−2. Time-of-flight mass spectra, obtained with 800 nm, 50 fs laser pulses, show extensive fragmentation for all molecules above 1×1014 W cm−2. At 1.3×1013 W cm−2, the parent ion contribution to the total ionization signal is 30% for benzene, toluene and cyclopropane, and is negligible for cyclohexane and n-hexane. Double-charged parent ions and peak splitting for some of the lighter fragments are observed at high intensity. The correlation between ionization and relative dissociation yields and molecular properties and the participation of field ionization mechanisms are discussed.Financial support has been provided by the Ultraviolet Laser Facility operating at FORTH–IESL under the Large Installations Plan of EU and by Spanish Project DGICYT (PB96-0844-C02-01)