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General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Etude des interfaces, Study of interfaces, Dépôt électrolytique, Electrodeposition, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Matériel électrique divers, Various equipment and components, Condensateurs. Résistances. Filtres, Capacitors. Resistors. Filters, Analyse, Analysis, Análisis, Capacité électrique, Capacitance, Capacitancia, Condensateur électrochimique, Electrolytic capacitor, Condensador electroquímico, Couche mince, Thin film, Capa fina, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Manganèse Oxyde, Manganese Oxides, Manganeso Óxido, Microbalance quartz, Quartz microbalance, Microbalanza cuarzo, Réaction électrochimique, Electrochemical reaction, Reacción electroquímica, Spectrométrie ICP, Inductive coupling plasma spectrometry, Espectrometría ICP, Spectrométrie optique, Optical spectrometry, Espectrometría óptica, Spectrométrie émission, Emission spectrometry, Espectrometría emisión, Supercondensateur, Supercapacitor, Supercondensador, EQCM, ICP-OES, Manganese dioxide, and Supercapacitors

For an accurate estimate of the specific capacitance it is imperative that the mass of active material be known. This is of particular importance for thin films of electrodeposited manganese dioxide, where the conventional determination of active material is not possible. Here we compare three indirect methods of mass analysis; namely, by integration of chronoamperometric i-t data, through the use of the electrochemical quartz crystal microbalance, and via manganese analysis of the deposit via ICP-OES. Each of these approaches was shown to be complicated by a range of experimental artefacts; however, it was concluded that the integration method was the preferred approach because of its focus only on the electroactive manganese species within the electrode.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Calixarène, Calixarene, Calixareno, Composé inclusion, Inclusion compound, Compuesto inclusión, Cyclophane, Ciclofano, Détecteur électrochimique, Electrochemical detector, Detector electroquímico, Electrode, Electrodes, Electrodo, Macrocycle, Macrociclo, Matériau modifié, Modified material, Material modificado, Neurotransmetteur, Neurotransmitter, Neurotransmisor, Sérotonine, Serotonin, Serotonina, Voltammétrie, Voltammetry, Voltametría, C-undecylcalix[4]resorcinarene, Electrochemical sensor, and Modified electrode

A simple but highly sensitive and selective electrochemical sensor for the determination of serotonin (5-HT) was presented. Pretreated glassy carbon electrode (GCE) as enhancer of electron transfer and C-undecylcalix[4]resorcinarene film as molecular receptor are integrated in the electrochemical sensor system. The electrochemical behavior of 5-HT at the modified electrode had been investigated in pH 7.0 phosphate buffers solutions by cyclic voltammetry, square wave voltammetry and chronocoulometry. Compared with bare GCE, the proposed integrated sensor showed improved analytical performance characteristics in catalytic oxidation of 5-HT. Under the selective conditions, the modified electrode showed a linear voltammetric response for the 5-HT within a concentration range of 1.0 x 10―7 to 1.0 × 10―5 mol L―1, and a value of 3.0 x 10―8 mol L―1 was calculated for the detection limit. Besides, due to the difference of potentials, the modified electrode exhibited an excellent immunity from dopamine, epinephrine, ascorbic acid and folic acid interference.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Sciences appliquees, Applied sciences, Energie, Energy, Energie. Utilisation thermique des combustibles, Energy. Thermal use of fuels, Appareils de production et de conversion d'énergie: énergie thermique, énergie électrique, énergie mécanique, etc, Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc, Piles à combustible, Fuel cells, Champ écoulement, Flow field, Campo flujo, Distribution courant, Current distribution, Distribución corriente, Pile combustible membrane échangeuse proton, Proton exchange membrane fuel cells, Spectrométrie impédance électrochimique, Electrochemical impedance spectroscopy, PEMFC, Segmented cell, and Spatial EIS

A serpentine flow field is a commonly used design in proton exchange membrane fuel cells (PEMFCs). Consequently, optimization of the flow field parameters is critically needed. A segmented cell system was used to study the impact of the flow field's parameters on the current distribution in a PEMFC, and the data obtained were analyzed in terms of voltage overpotentials. 6-Channel and 10-channel serpentine flow field designs were investigated. At low current the segments performance was found to slightly decrease for a 10-channel serpentine flow field. However, increasing the number of channels increased the fuel cell performance when operating at high current and the cell performance became more uniform downstream. The observed improvement in fuel cell performance was attributed to a decrease in mass transfer voltage losses (permeability and diffusion), due to an increased pressure drop. Spatially distributed electrochemical impedance spectroscopy (EIS) data showed differences in the local segment impedance response and confirmed the performance distribution and the impact of the flow field design.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Divers (électroosmose, électrophorèse, électrochromisme, électrocristallisation, ...), Miscellaneous (electroosmosis, electrophoresis, electrochromism, electrocrystallization, ...), Amine aromatique, Aromatic amine, Amina aromática, Aniline copolymère, Aniline copolymer, Anilina copolímero, Copolymère, Copolymer, Copolímero, Electrochromisme, Electrochromism, Electrocromismo, Emissivité thermique, Thermal emissivity, Emisividad térmica, Polymère conducteur, Conducting polymers, Aniline, Electrochromic film, Emissivity, and O-Anisidine

A novel electrochromic film based on the copolymer of aniline and o-anisidine was obtained by electrochemical polymerization method. The electrochromic properties of the novel film were investigated by cyclic voltammetry and amperometric i-t curve. The optical properties of the film were investigated by UV-vis spectrophotometer and FT-IR spectroscopy. The results show that different colors of the electrochromic film could be achieved, which exhibits as light grass green, emerald green and blue-violet. The maximum difference of the UV-vis absorption of the film is about 60% between -0.6V and 1.0 V, respectively. The biggest different average emissivity dynamic of the film is 0.408 in the wavelength of 8―14 μm region.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Photoélectrochimie. Electrochimiluminescence, Photoelectrochemistry. Electrochemiluminescence, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Corrosion, Protection contre la corrosion, Corrosion prevention, Application, Aplicación, Anwendung, Couche mince, Thin film, Capa fina, Duennschicht, Courant induit, Induced current, Corriente inducida, Densité courant, Current density, Densidad corriente, Stromdichte, Photoélectrochimie, Photoelectrochemistry, Fotoelectroquímica, Protection cathodique, Cathodic protection, Protección catódica, Kathodischer Schutz, Protection corrosion, Corrosion protection, Protección corrosión, Korrosionsschutz, Rayonnement visible, Visible radiation, Radiación visible, Lichtstrahlung, Tension circuit ouvert, Open circuit voltage, Photo-induced current density, Photo-induced open circuit potential, Photoelectrochemical cathodic protection, Visible light, and g-C3N4

This study investigated the photo-to-current conversion properties and photoelectrochemical cathodic protection performance of g-C3N4 in 304 stainless steel under visible or white light illumination for the first time. The results showed that the g-C3N4 thin film could provide 304 stainless steel with very good cathodic protection in the presence of light irradiation. The application of this material represents a potential breakthrough in photoelectrochemical cathodic protection technology.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Accumulateur électrochimique, Secondary cell, Acumulador electroquímico, Borate, Borates, Borato, Bore Composé, Boron Compounds, Boro Compuesto, Conducteur ionique, Ionic conductors, Electrolyte solide polymère, Polymer solid electrolyte, Electrólito sólido polímero, Ion, Ions, Ión, Vinylique alcool polymère, Polyvinylalcohol, Vinílico alcohol polímero, Batterie lithium ion, Lithion ion batteries, Lithium ion batteries, Poly(vinyl alcohol) (PVA), Polymer electrolytes, and Single-ion conductor

In this study, a novel single-ion conducting polymer electrolyte, lithium polyvinyl alcohol oxalate borate (LiPVAOB), from the reaction of poly(vinyl alcohol) (PVA) with different molar ratio of boric acid, oxalic acid and lithium carbonate was prepared. The prepared materials were characterized by Fourier transformation infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TG), differential thermal analysis (DTA), electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry. Ionic conductivity of these polymer electrolytes from adding an assistant (about 20 wt.% propylene carbonate) is dependent on molar ratio of the reactants and can up to 6.11 x 10―6 S cm―1 at ambient temperature. Their electrochemical window can be stable up to 7 V (vs. Li+/Li), which is of great attraction for high voltage lithium ion batteries with high energy density.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Accumulateur électrochimique, Secondary cell, Acumulador electroquímico, Caractéristique électrique, Electrical characteristic, Característica eléctrica, Convection, Convección, Diffusion convective, Convective diffusion, Difusión convectiva, Décharge, Discharge, Descarga, Etude théorique, Theoretical study, Estudio teórico, Modélisation, Modeling, Modelización, Phénomène transport, Transport process, Fenómeno transporte, Solution concentrée, Concentrated solution, Solución concentrada, Solvant, Solvent, Solvente, Batterie lithium ion, Lithion ion batteries, High rate, and Lithium ion battery modeling

A solution phase transport theory considering solvent effects is developed for lithium ion cells. The solvent convection velocity is derived from a volume conservation argument, leading to a diffusive correction, a transference number gradient correction and a pore-wall flux correction to the material balance equation. The diffusive correction exactly cancels the solvent-related (1 ― d In c0/d In c) factor in the original diffusion term. The transference number gradient and pore-wall flux corrections lead to a larger effective value of the lithium ion transference number. Comparative discharge simulations are carried out for a graphite―LiMn2O4 cell with 1 M or 2 M LiPF6 solution. The convective transport theory demonstrates little cell voltage difference at low rates (1 C and 3C) compared with the original approach that neglects convection. Nevertheless, at a 6C rate, a maximum of 51.32 mV excess cell voltage is predicted by the convective theory for the 1 M cell. For the 2 M cell the convective theory predicts a slightly slower voltage drop at the beginning of discharge, but a faster drop at the end of the 6C discharge. At all rates the convective theory also gives a lower salt concentration profile within the negative electrode, but higher within the positive electrode. This implies that the concentration gradient is diminished by convection. Detailed analysis shows that the transference number gradient correction is always positive during discharge and is highly rate sensitive; the pore-wall flux correction is not only rate sensitive but also proportional to the salt concentration and is thus more prominent in the 2 M cell.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Accumulateur électrochimique, Secondary cell, Acumulador electroquímico, Batterie lithium soufre, Lithium sulfur batteries, Carbone, Carbon, Carbono, Composé non soluble, Insoluble compound, Compuesto no soluble, Electrolyte, Electrólito, Matériau composite, Composite material, Material compuesto, Matériau poreux, Porous material, Material poroso, Microporosité, Microporosity, Microporosidad, Microsphère, Microsphere, Microsfera, Mécanisme, Mechanism, Mecanismo, Propriété physicochimique, Physicochemical properties, Propiedad fisicoquímica, Soufre, Sulfur, Azufre, Carbon microsphere, Insoluble electrolyte, Lithium-sulfur battery, Microporous carbon-sulfur composite, and Solid-solid redox mechanism

In this paper, we propose a new strategy to develop high performance sulfur electrode by impregnating sulfur into the micropores of a Li+-insertable carbon matrix with the simultaneous use of a carbonate electrolyte, which does not dissolve polysulfides, to restrain the solution of the reaction intermediates of sulfur. To proof this concept, we prepared a Li+-insertable microporous carbon-sulfur composite by vaporizing sulfur into the micropores of the nanofiber-wired carbon microspheres. The experimental results demonstrate that, in the carbonate electrolyte of 1 M LiPF6/PC-EC-DEC, such S/C composite electrode exhibits not only stable cycling performance with a reversible capacity of 720 mAh g―1 after 100 cycles, but also superior high coulombic efficiency of ∼100% upon extended cycling (except the first three cycles). The structural and electrochemical analysis indicates that the improved electrochemical behaviors of the S/C composite arise from a new reaction mechanism, in which Li+ ions and electrons transport through the carbon matrix into the interior of the cathode and then react with the embedded sulfur in the S/C solid-solid interfaces, avoiding the solution of the intermediates into the bulk electrolyte. More significantly, the structural design and working mechanism of such a sulfur cathode could be extended to a variety of poorly conductive and easily soluble redox-active materials for battery applications.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Matériel électrique divers, Various equipment and components, Condensateurs. Résistances. Filtres, Capacitors. Resistors. Filters, Capacité électrique, Capacitance, Capacitancia, Condensateur électrochimique, Electrolytic capacitor, Condensador electroquímico, Forme creuse, Hollow shape, Forma hueca, Lysine, Lisina, Microsphère, Microsphere, Microsfera, Nickel Hydroxyde, Nickel Hydroxides, Niquel Hidróxido, Performance, Rendimiento, Synthèse chimique, Chemical synthesis, Síntesis química, α-Aminoacide, α-Aminoacid, α-Aminoácido, Hierarchical hollow microspheres, L-Lysine, and Nickel hydroxide

Hierarchical β-Ni(OH)2 hollow microspheres with partial open gaps have successfully been prepared via a facile hydrothermal process with the assistance of L-lysine. The as-prepared products have been characterized by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2 adsorption/desorption, respectively. The results reveal that the sample consists of a large scale of porous microspheres which is composed of nanosheets. A possible growth mechanism is proposed including the initial formation of hierarchical hollow microspheres aggregated from nuclei and the subsequent site-specific oriented growth of nanosheets by self-assembly along a preferred growth direction of [101] at the growth state. It is found that L-lysine used as a crystal growth modifier plays a key role in the formation of this hierarchical structure. This special structure is also responsible for the obvious enhancement of electrochemical properties, which exhibits a high specific capacitance of 1398.5 F g―1 at a current density of 5 mA cm-2 and excellent cycling stability. This hollow microspheres display great potential as electrode materials for electrochemical capacitors.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Accumulateur électrochimique, Secondary cell, Acumulador electroquímico, Cathode, Cátodo, Composé ternaire, Ternary compound, Compuesto ternario, Lithium Oxyde, Lithium Oxides, Litio Óxido, Manganèse Oxyde, Manganese Oxides, Manganeso Óxido, Matériau dopé, Doped materials, Matériau électrode, Electrode material, Material electrodo, Performance, Rendimiento, Spinelles, Spinels, Espinelas, Batterie lithium ion, Lithion ion batteries, LiMn2O4, (Li,Al)-co-doped LiMn2O4, Cathode material, and Li-ion batteries

(Li,Al)-co-doped manganese oxide spinel compounds, Li(Li0.1Al0.1Mn1.8)O4 are prepared at temperatures (T), 600, 650 and 750°C by polymer precursor method using polyvinyl pyrrolidone (PVP). The structure and morphology of the porous and sub-micron size particles of the compounds are characterized by the Rietveld refined X-ray diffraction (XRD), infrared and Raman spectroscopy, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM) and Brunauer, Emmett and Teller (BET) surface area techniques. Galvanostatic charge-discharge cycling in the voltage range of 3.5-4.3 V vs. Li at various current (C) rates, 0.5-3 C at 24°C up to 60 cycles and at 0.5 C and at 55 C up to 50 cycles is carried out. The influence of the Li-excess, the type of Al3+ dopant cation and the amount of fuel (polyvinyl pyrrolidone) used in the synthesis on the electrochemical behaviorof the spinel in a Li-cell at room (24 C) and at elevated temperature (55 C) has been studied. Results show that at 24°C and at 0.5°C, the phases prepared at 600°C(I) and 650 C (II) showed reversible capacities of 79 and 105 mAh g―1 and retained 99 (±1)% of the capacity after 50 cycles. At 1 C, 2 C and 3 C rates, II showed stable capacities of 97, 83 and 57 mAh g―1, respectively. At 55°C and at 0.5 C, II showed a reversible capacity of 114 mAh g―1 and retains 92% of it at the end of 50 cycles, signifying the best cathodic performance for a doped-LiMn2O4. Complementary cyclic voltammetry, impedance spectra and ex situ XRD data are described and discussed.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Accumulateur électrochimique, Secondary cell, Acumulador electroquímico, Caractéristique électrique, Electrical characteristic, Característica eléctrica, Cinétique, Kinetics, Cinética, Coefficient transfert, Transfer coefficient, Coeficiente transferencia, Constante vitesse, Rate constant, Constante velocidad, Cycle charge décharge, Discharge charge cycle, Ciclo carga descarga, Electrode, Electrodes, Electrodo, Métal Hydrure, Metal Hydrides, Metal Hidruro, Paramètre cinétique, Kinetic parameter, Parámetro cinético, Kinetics properties, Metal hydride electrode, and Rate constants

Based on the energy barrier theory, we proposed a kinetics investigation method to research the rate constants of the charging/discharging processes for the metal hydride electrodes. The Tafel polarization curves and galvanostatic intermittent titration technique (GITT) method were applied to characterize the electrochemical parameters of the electrode reactions. In this paper, the values of the standard Gibbs free energy and the rate constants obtained from different over-potentials and various depth of discharge (DOD) were compared. Both the rate constants of the charging/discharging reactions decreased with the increase of DOD, which were in agreement with the variations of the hydrogen diffusion coefficient. The proposed method is more visualized and accurate for studying the reaction rates of the metal hydride electrodes and can be used to quantitatively investigate the kinetics properties of the Ni/MH batteries.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Métal transition Complexe, Transition metal Complexes, Metal transición Complejo, Caractéristique électrochimique, Electrochemical characteristic, Característica electroquímica, Charpente organométallique, Metal organic framework, Armazòn organometálico, Chrome Complexe, Chromium Complexes, Cromo Complejo, Complexe aqua, Aqua complex, Complejo aqua, Complexe oxo, Oxo complex, Complejo oxo, Complexe trinucléaire, Trinuclear complex, Complejo trinuclear, Coordinat organique, Organic ligand, Ligando orgánico, Electrochimie, Electrochemistry, Electroquímica, Hétéropolysel, Heteropolysalt, Heteropolisal, Matériau composite, Composite material, Material compuesto, Matériau poreux, Porous material, Material poroso, Téréphtalate, Terephthalates, MIL 101, MIL-101, Metal-organic framework, and Monovacant polyoxometalates

The first electrochemical investigation of composites materials based in polyoxometalates (POMs) encapsulated in the porous Metal-Organic Framework (MOF) MIL-101 is reported. The electrochemical behaviour of the porous MIL-101 and composite materials based in two monovacant Keggin-type POMs {K7[PW11O39]·10H2O(PW11) and K8[SiW11O39]·13H2O(SiW11)} encapsulated in MIL-101 (respectively, PW11@MIL-101 and SiW11@MIL-101) were studied by cyclic voltammetry. Initially, to investigate the influence of the support MIL-101 in the electrochemical behaviour of the two monovacant POMs, the compounds were individually immobilized on the surface of a pyrolytic graphite (PG) electrode. A reversible surface-controlled redox signal attributed to the chromium metal centres (Cr3+/Cr2+) was identified in MIL-1 01, and this represents the first electrochemical studyofthis MOF material. The monovacant compounds PW11 and SiW11 also revealed surface-controlled processes corresponding to WVI ↔ WV reductions. PW11 showed two reversible signals (involving one or two electrons), whereas SiW11 showed a quasi-reversible one-electron and a reversible two-electron process for the first and second W reductions, respectively. For the latter, an extra process was detected and attributed to the formation of β-isomer (β-SiW11). When the composites materials PW11@MIL-101 and SiW11@MIL-101 were immobilized on the surface of the electrode, the support MIL-101 maintained its characteristic electrochemistry and the redox potentials of the POMs were not significantly changed. However, when encapsulated inside the cages of the support material the POMs revealed a distinct electrochemical behaviour, given that their redox processes became diffusion-controlled, indicating that the POMs have some degree of mobility inside the support framework.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Caractérisation, Characterization, Caracterización, Courant induit, Induced current, Corriente inducida, Distribution courant, Current distribution, Distribución corriente, Distribution potentiel, Potential distribution, Distribución potencial, Double couche électrochimique, Electrochemical double layer, Doble capa electroquímica, Géométrie, Geometry, Geometría, Impédance électrique, Electrical impedance, Impedancia eléctrica, Interface électrode électrolyte, Electrode electrolyte interface, Interfase electrodo electrolito, Schéma équivalent, Equivalent circuit, Esquema equivalente, Spectrométrie impédance électrochimique, Electrochemical impedance spectroscopy, Constant-phase element, Double-layer capacitance, Electrochemical impedance, Equivalent electrical circuit, and Geometry-induced current and potential distributions

Electrode geometry is abruptly truncated at the metal insulating boundary. A theoretical analysis has shown that disk-electrode geometry induces current and potential distributions that influence the impedance response in the high frequency domain. In this paper we investigate the extent of this influence on an experimental system displaying constant-phase element (CPE) behavior. We shall focus on the influence of these current distributions on the characterization of underlying CPE behavior from the analysis of the imaginary part of the impedance, although we shall also address results obtained from the complex non-linear fitting of impedance data to an equivalent circuit. The crossover from CPE behavior to this geometry-dominated regime establishes an upper cutoff in the experimental frequency range employed to characterize CPE response. We discuss the experimental conditions for which this crossover may prevent the analysis of experimental results to reveal the real underlying CPE behavior. The results and conclusions here obtained agree with previous theoretical modeling. Taking into account the limitations presented here can help to a better characterization and a deeper understanding of the frequency dispersion in the response of solid electrodes.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Sciences appliquees, Applied sciences, Energie, Energy, Energie. Utilisation thermique des combustibles, Energy. Thermal use of fuels, Appareils de production et de conversion d'énergie: énergie thermique, énergie électrique, énergie mécanique, etc, Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc, Piles à combustible, Fuel cells, Cathode, Cátodo, Conducteur mixte, Mixed conductors, Cristallinité, Crystallinity, Cristalinidad, Dimension particule, Particle size, Dimensión partícula, Matériau électrode, Electrode material, Material electrodo, Nébulisation ultrasonique, Ultrasonic nebulization, Nebulización ultrasónica, Pile combustible oxyde solide, Solid oxide fuel cell, Pila combustible oxido sólido, Poudre, Powder, Polvo, Propriété électrochimique, Electrochemical properties, Propiedad electroquímica, Pyrolyse, Pyrolysis, Pirólisis, Spectrométrie impédance électrochimique, Electrochemical impedance spectroscopy, Dépôt par pyrolyse d'aérosol, Spray pyrolysis, Mixed ionic and electronic conductor, Nickelates, and Ultrasonic spray pyrolysis

This paper is dedicated to the study of the relationship between the Nd2NiO4+δ powder micro-structural properties (especially particle size and crystallinity) and electrochemical properties when the oxide is used as SOFC cathode deposited on 8YSZ electrolyte coated with thin doped ceria. Nano-structured particles of Nd2NiO4+δ with controlled crystallinity, size and morphology have been synthesized using ultrasonic spray pyrolysis (USP). The series and polarization resistances measured on symmetrical half cells Nd2NiO4+δ/YDC/8YSZ/YDC/Nd2NiO4+δ are both found to be dependent on the cathode microstructure and present a similar evolution with temperature. The best results are obtained for highly crystalline cathode powders combined with a small particle size.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Spectrométrie UV visible, Ultraviolet visible spectrometry, Espectrometría UV visible, Spectroélectrochimie, Spectroelectrochemistry, Espectroelectroquímica, Sélénophène dérivé, Sélénophène polymère, Alkyl, Polyselenophene, Selenophenes, and UV-vis spectroelectrochemistry

During the study, the electronic and optical properties of selenophene compounds were observed to change. The analysis of the selenophene compounds involved the examination of the effect of alkyl chains on polymers obtained during electrochemical polymerization. Four (E,E)-1,4-dialkoxy-2,5-bis[2-(selenophen)-2-yl)ethenyl]benzene derivatives were electrochemically polymerized and characterized. Significant optical differences were observed in the comparison of branched alkyl substituents to linear ones.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Métal transition, Transition metal, Metal transición, Activité électrochimique, Electrochemical activity, Actividad electroquímica, Couple redox, Redox couple, Pareja redox, Fer II Ion, Iron II Ions, Hierro II Ión, Fonctionnalisation, Functionalization, Funciónalización, Graphite, Grafito, Peroxyde d'hydrogène, Hydrogen peroxide, Peróxido de hydrogeno, Propriété électrochimique, Electrochemical properties, Propiedad electroquímica, Vanadium, Vanadio, Batterie circulation, Flow battery, Fenton's reagent, Graphite felt, Hydroxylated-functionalization, and Vanadium redox flow battery

An environmental, economic and highly effective method for carbon fiber hydroxylated-functionalization based on Fenton's reagent treatment is used to improve the electrochemical activity of graphite felt (GF) as the positive electrode in all vanadium redox flow battery (VRFB). The effect of H2O2 content in Fenton's reagent on the structure and electrochemical properties of GF is investigated. The scanning electron microscope (SEM) indicates that the surface of the treated GF is etched increasingly with the content of H2O2. The Fourier transformation infrared (FTIR) spectroscopy shows that the peak intensity of hydroxyl groups on the treated felt is increased with the H2O2 concentration, which is further verified by X-ray photoelectron spectroscopy (XPS). Cyclicvoltammetry (CV)and electrochemical impedance spectroscopy (EIS) show that the treated sample exhibits a higher electrochemical activity. A VRFB with the treated GF as electrodes exhibits higher coulombic, voltage and energy efficiency (98.8%, 75.1% and 74.2%) than that with the untreated GF (93.9%, 72.1% and 67.7%) at 60 mA cm―2, and this method is even superior when compared with the reported methods.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Sciences appliquees, Applied sciences, Energie, Energy, Energie. Utilisation thermique des combustibles, Energy. Thermal use of fuels, Appareils de production et de conversion d'énergie: énergie thermique, énergie électrique, énergie mécanique, etc, Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc, Piles à combustible, Fuel cells, Dioxyde de carbone, Carbon dioxide, Carbono dióxido, Membrane échangeuse anion, Anion exchange membrane, Membrana cambiadora aniónica, Mobilité ion, Ion mobility, Movilidad ión, Mécanisme, Mechanism, Mecanismo, Performance, Rendimiento, Perméation, Permeation, Permeación, Pile combustible électrolyte alcalin, Alkaline electrolyte fuel cells, Pile combustible, Fuel cell, Pila combustión, Alkaline fuel cell, C02 permeation, and Self-purge mechanism

Influence of CO2 dissolution into anion exchange membranes (AEMs) on fuel cell performance was investigated. The conductivity of AEM decreased with an increase in carbonate ion species. For the power generation test with a supply of humidified H2/O2, the IR-free cell potential difference for the membrane electrode assembly (MEA) with the HCO―3 form membrane was lower than that with the OH-form membrane. This low cell potential difference became noticeable by the supply of CO2 to either anode or cathode. The increment of ohmic resistance was confirmed by the supply of CO2 to cathode, but no obvious change in ohmic resistance was observed by the supply of CO2 to anode. Then, a CO2 permeation flux was determined by a gas chromatograph analysis of exhaust gas, and the correlation between the AEM fuel cell performance and the composition of ion species in the membrane was discussed.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Sciences appliquees, Applied sciences, Energie, Energy, Energie naturelle, Natural energy, Energie solaire, Solar energy, Conversion photovoltaïque, Photovoltaic conversion, Cellules solaires. Cellules photoélectrochimiques, Solar cells. Photoelectrochemical cells, Application, Aplicación, Cellule solaire à colorant, Dye-sensitized solar cell, Célula solar sensibilizada tinte, Electrolyte solide polymère, Polymer solid electrolyte, Electrólito sólido polímero, Ethylène oxyde polymère, Ethylene oxide polymer, Etileno óxido polímero, Molécule petite, Small molecule, Molécula pequeña, Phénomène transport, Transport process, Fenómeno transporte, Spectrométrie UV visible, Ultraviolet visible spectrometry, Espectrometría UV visible, Transfert charge, Charge transfer, Transferencia carga, Dye solar cells, Polymer electrolyte, and UV-visible spectroscopy

A Poly (ethylene oxide) based polymer electrolyte impregnated with 2-Mercapto benzimidazole was comprehensively characterized by XRD, UV-visible spectroscopy, FTIR as well as electrochemical impedance spectroscopy. It was found that the crystallization of PEO was dramatically reduced and the ionic conductivity of the electrolyte was increased 4.5 fold by addition of 2-Mercapto benzimidazole. UV―visible and FTIR spectroscopes indicated the formation of charge transfer complex between 2-Mercapto benzimidazole and iodine of the electrolyte. Dye-sensitized solar cells with the polymer electrolytes were assembled. It was found that both the photocurrent density and photovoltage were enhanced with respect to the DSC without 2-Mercapto benzimidazole, leading to a 60% increase of the performance of the cell.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Généralités, General, Etude des interfaces, Study of interfaces, Dépôt électrolytique, Electrodeposition, Métal transition, Transition metal, Metal transición, Platinoïde, Platinoid, Platinoide, Alliage binaire, Binary alloy, Aleación binaria, Codépôt, Codeposition, Codeposición, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Iridium, Iridio, Nickel alliage, Nickel alloy, Níquel aleación, Rhénium alliage, Rhenium alloy, Renio aleación, Réaction électrochimique, Electrochemical reaction, Reacción electroquímica, Induced codeposition, and Rhenium-iridium-nickel alloys

Rhenium (Re), a refractory metal that has gained significant recognition as a high performance engineering material, is mostly used in military, aircraft and aerospace applications, as well as for catalysis in the petrochemical industry. However, its performance at high temperature in humid air is limited by the formation of rhenium heptoxide (Re2O7), which penetrates the grain boundaries and causes brittleness. Improvement of this is being sought through the incorporation of iridium (Ir) into Re deposits. To this end, suitable plating baths for Re-Ir-Ni coatings were developed. These alloys were deposited from different aqueous solutions on copper substrates under galvanostatic conditions, in a three-electrode cell. The plating bath consisted of iridium tri-chloride, ammonium perrhenate and nickel sulfamate as the electroactive species, and citric acid as the complexing agent. The effects of bath composition and operating conditions on the Faradaic efficiency (FE), partial current densities, as well as on the thickness of the coatings and their composition were studied. Re―Ir―Ni coatings as thick as 18 μm, with Re-content as high as 73 at.% and Ir-content as high as 29 at.%, were obtained, using different plating baths. A mechanism of the electrochemical process was suggested. It was found that both an HCP Ir0.4Re0.6 phase and an HCP Ni phase with nanometric crystallites were formed, possibly together with a hexagonal nickel hydride (Ni2H) phase.