Preparation and characterization of a rechargeable battery based on poly-(3,4-ethylenedioxythiophene) and aluminum in ionic liquids

This paper presents a feasibility study of a non-aqueous rechargeable battery based on aluminum and poly-(3,4-ethylenedioxythiophene) conductive polymer in a chloroaluminate ionic liquid. The polymer was electrodeposited on a vitreous carbon working electrode in a chloride aqueous solution and the structure was analyzed by scanning electron microscopy. The doping/de-doping mechanism of chloride ions into the polymer structure was studied using a quartz crystal microbalance and cyclic voltammetry. The deposition/dissolution of the aluminum negative electrode were investigated by electrochemical and microscopic methods. Performance data were obtained with a laboratory-scale aluminum-conductive polymer battery at constant current showing an average cell discharge voltage of 1 V and specific energies of at least 84 Wh kg−1 referred to the mass of the polymer and aluminum. The system is novel and the paper outlines further research to improve the cell performance

Deuterium Isotope Separation by Combined Electrolysis Fuel Cell

The framework about combined electrolysis fuel cell (CEFC) was reported previously [H. Matsushima et al., Energy, 2005; 30; 2413]. The purpose of the present study focused on measuring the separation factor and the energy reduction by assembling CEFC system. The separation of deuterium was studied with a 1-M KOH electrolyte containing 10 at% deuterium. Polarization plots of alkaline water electrolysis (AWE) revealed relationships between the catalytic activity of the hydrogen evolution reaction and the deuterium separation factor. The power loss was mainly attributed to gas bubble evolution. For polymer electrolyte fuel cells (PEFCs) with a Pt catalyst, approximately 21% of the electrical energy could be recovered by reusing hydrogen gas produced by the AWE. Furthermore, the PEFC could efficiently dilute protium in the gas phase, resulting in a high separation factor of 30.2 for the CEFC

State of the art of rechargeable aluminum batteries in non-aqueous systems

The main challenges to implement sustainable energy storage technologies are the utilization of earth-abundant recyclable materials, low costs, safe cell reactions and high performance, all in a single system. Aluminum batteries seem to cover these requirements. However, their practical performance is still not comparable with the state of the art high performance batteries. A key aspect to further development could be the combination of aluminum with charge storage materials like conductive polymers in non-aqueous electrolytes taking advantage of the properties of each material. This review presents the approaches and perspectives for rechargeable aluminum-based batteries as sustainable high-performance energy storage device

Distance determination of molecular clouds in the 1st quadrant of the Galactic plane using deep learning : I. Method and Results

Machine learning has been successfully applied in varied field but whether it is a viable tool for determining the distance to molecular clouds in the Galaxy is an open question. In the Galaxy, the kinematic distance is commonly employed as the distance to a molecular cloud. However, there is a problem in that for the inner Galaxy, two different solutions, the ``Near'' solution, and the ``Far'' solution, can be derived simultaneously. We attempted to construct a two-class (``Near'' or ``Far'') inference model using a Convolutional Neural Network (CNN), a form of deep learning that can capture spatial features generally. In this study, we used the CO dataset toward the 1st quadrant of the Galactic plane obtained with the Nobeyama 45-m radio telescope (l = 62-10 degree, |b| < 1 degree). In the model, we applied the three-dimensional distribution (position-position-velocity) of the 12CO (J=1-0) emissions as the main input. The dataset with ``Near'' or ``Far'' annotation was made from the HII region catalog of the infrared astronomy satellite WISE to train the model. As a result, we could construct a CNN model with a 76% accuracy rate on the training dataset. By using the model, we determined the distance to molecular clouds identified by the CLUMPFIND algorithm. We found that the mass of the molecular clouds with a distance of < 8.15 kpc identified in the 12CO data follows a power-law distribution with an index of about -2.3 in the mass range of M >10^3 Msun. Also, the detailed molecular gas distribution of the Galaxy as seen from the Galactic North pole was determined.Comment: 29 pages, 12 figure

Aging of Passive Oxide on SUS304 Stainless Steel in a Sulfuric Acid Solution

The passive oxide film on SUS 304 stainless steel (SS) was studied in a 0.1 mol dm−3 sulfuric acid solution as a function of passivation time. The passive oxide films were measured by ellipsometry and X-ray photoelectron spectroscopy (XPS). A Mott-Schottky plot of the film capacitance was employed to determine the donor density in the n-type semiconducting oxide film, and current measurements of the Fe3+/Fe2+ redox couple were employed to investigate the electronic transfer process on the passive oxide film. The passive oxide consists of Cr-Fe-Ni oxides in which enrichment of Cr to 57 mol% occurs as the potential increases. During the aging of the passive oxide at 0.6 V vs. Ag/AgCl/saturated KCl (SSC) for 43 ks, the current decreased from 30 μA cm−2 at 10 s to 0.025 μA cm−2 at 43 ks, and the Cr ratio in the oxide increased from 49 to 57 mol% with an increase in the O2– ratio. Notably, the film thickness remained nearly constant at 1.3 nm during the aging process. Enrichment of the Cr content resulted in a decrease in the donor density of the n-type semiconducting passive oxide and the inhibition of electronic charge transfer from/to the Fe3+/Fe2+ redox couple in the electrolyte

Surface Finishing of Mg Alloys by Al Electroplating in AlCl3-EMIC Ionic Liquid

In order to improve the corrosion resistance of Mg and its alloys, Al layer was electrodeposited on their surface from aluminum chloride-1-ethyl-3-methylimidazolium chloride ionic liquid (AlCl3-EMIC). Mirror-like Al surface can be electroplated in AlCl3-EMIC ionic liquid by pulse electrolysis at 323 K, though Al layer was not dense and homogeneous. A dense and flat Al layer was successfully electroplated on Mg alloys in the AlCl3-EMIC ionic liquid at lower temperature of 283 K

Electrodeposition of Sb-Te Alloy in AlCl3-NaCl-KCl Molten Salt

The Electrodeposition of Sb-Te alloy was carried out in AlCl3-NaCl-KCl molten salt containing SbCl3 and TeCl4 at 423 K by constant potential electrolysis. The voltammogram on a glassy carbon (GC) electrode in a melt containing 1.0×10−2 kmol m−3 SbCl3 and 1.0×10−2 kmol/m3 TeCl4 revealed the cathodic current waves at 1.5, 1.1, and 0.9 V vs. Al/Al(III). A stable Sb-Te alloy deposit was obtained at 0.85 V in the melt containing SbCl3 and TeCl4. At the higher concentration ratio of the Sb(III) to (Sb(III) + Te(IV)), a good linear relation was found between the atomic ratio of Sb in the deposit and the concentration ratio of Sb (III) in the melt. The Sb-Te alloy deposit of atomic ratio of 38:62% which was assume to be suitable for a thermoelectric device was obtained with the molten salt containing 7.0×10−3 kmol/m3 SbCl3 and 1.0×10−2 kmol/m3 TeCl4. The XRD pattern of the deposit corresponds to that of Sb2Te3 intermetallic compound. The deposit had homogeneous disk-like granule with the disk size of about 10 μm

Study of Deuterium Isotope Separation by PEFC

Hydrogen evolution and oxidation reactions were studied on a polycrystalline platinum electrode in 0.05 M D2SO4 solution at 298 K by using a rotating disk electrode, focusing on the kinetic isotope effect on reactivity. The polarization measurements in the evolution reaction regime, on the one hand, revealed two Tafel regions: at low overpotentials close to the equilibrium potential, the Tafel slope was 0.039 V dec(-1), suggesting a Volmer-Tafel mechanism; and at potentials around 0.05 V or lower, a slope of 0.168 V dec(-1) indicated that a transition to a Heyrovsky-Tafel mechanism occurred. In the oxidation reaction regime, on the other hand, a single Tafel slope of 0.055 V dec(-1) was observed at potentials of 0.08 V or lower. Comparing between the deuterium and protium data for the kinetic factors supported the presence of an isotope effect, whereby the deuterium was more easily dissociated on the platinum electrode. The present kinetic result supported the deuterium separation of polymer electrolyte fuel cell (PEFC) in which the mixture gases of H-2 and D-2 were purged. The deuterium separation factor increased with increasing in the hydrogen utilization. This suggests a new isotope separation technique and also provides useful data for fuel cells. (C) 2016 The Electrochemical Society. All rights reserved

Electroreflning reaction of sodium in sodium-bis(trifluoremethylsulfonyl)imide and tetraethylammonium-bis(trifluoremethylsulfonyl)imide mixture ionic liquid

To develop a electrorefining process of sodium for the recycling of used sodium-sulfur secondary battery, a non-aqueous electrolytic melt was investigated as a candidate for the process. A mixed ionic liquid of NaTFSI (sodium-bis(trifluoremethylsulfonyl)imide)-TEATFSI (tetraethylammonium-bis(trifluoremethylsulfonyl)imide) was selected for the electrolyte, since it has a wide potential window and a weak reactivity with metallic sodium. From AC impedance measurements, the maximum electric conductivity of 36 mS cm(-1) was found for a concentration of 20 mol% NaTFSI-TEATFSI at 433 K. The cathodic deposition of liquid sodium, 99.99% pure, was obtained on a glassy carbon electrode by constant current electrolysis. The calcium concentration in the sodium was decreased from 500 to 12 ppm by the electrorefining. A cathodic current efficiency at 88% was achieved in these electrorefining experiments. (C) 2012 Elsevier Ltd. All rights reserved

Co-deposition of Al-Cr-Ni alloys using constant potential and potential pulse techniques in AlCl3-NaCl-KCl molten salt

To improve the oxidation resistance of TiAl intermetallic compound under high temperature condition, cathodic co-deposition of Al-Cr and Al-Ni alloy was carried out by constant potential control or potential pulse control in AlCl3-NaCl-KCl molten salt containing CrCl2 and/ or NiCl2 at 423 K. Cathodic reduction of Ni and Cr starts at potential of 0.8 and 0.15 V vs. Al/Al3+ in the molten salt, respectively. The co-deposition of Al, Cr, and Ni occurred at potentials more negative than -0.1 V to form a mixture of intermetallic compounds of Cr2Al, Ni3Al, and Al3Ni. Concentration of Cr in the deposit was enhanced to 43 at% at –0.1V; however, concentration of Ni in the deposit was 6 at% at the same potential. The concentration of Ni further decreased with more negative potential to 1 at% at -0.4 V. The potential pulse technique enhanced the Ni concentration in the deposit to about 30 at%, due to anodic dissolution of Al content from the deposit at the higher side of potential on the potential pulse electrolysis