Search

The aerosol deposition (AD) method is a technique for the formation of thin and thick, gas-tight, and porous layers by deposition of microscopic powder particles. In the present work, the AD was used to deposit thin-film electrolyte and protective buffer layers for planar anode-supported solid oxide fuel cells (SOFCs). The high quality of deposited layers was confirmed by scanning electron microscopy, as well as electrochemical measurements, including the measurements of current-voltage characteristics and impedance spectroscopy. At working temperature of 800°C the anode-supported cell with bi-layered electrolyte deposited by AD demonstrated the open-circuit voltage of more than 1.04 V, as well as specific power of more than 780 mW/cm2. The difficulties, advantages, and peculiarities associated with the formation of thin-film electrolyte and buffer layers of SOFCs by the AD method have been discussed.

The formation of stable contact layers with minimum electrical resistivity at the electrode/interconnector interface is an important task for planar SOFC stack fabrication. This work was centered on the search for optimum processing conditions of the La0.8Sr0.2MnO3±?(LSM) based contact pastes without inorganic additives. The ball-milling conditions and contact paste composition were optimized taking into account the LSM particle size, sintering, a possibility of partial phase decomposition, and electrical conductivity of the resultant cathode contacts. Testing of the model SOFC stack with Crofer 22H interconnectors revealed sufficient adhesion, porosity, conductivity, and stability of porous LSM contact layers.

Combined technique and setup have been created that combines capabilities of electrochemical methods, as well as high-temperature Raman spectroscopy (RS) at Osipyan Institute of Solid State Physics RAS. In order to study the processes in the electrochemically active zone, a special geometry of samples was developed on basis of optically transparent single crystal membranes of an anionic conductor with a toroidal shape counter-electrode. With the use of this combined technique and special geometry, studies of the kinetics of reduction of nickel in composite SOFC anodes were carried out. The influence of the composition of fuel on Raman spectra obtained from the internal interface in the current load mode was also investigated, and the correlations with the cell voltage were studied. RS is also used to study the structure of single-crystal samples of anionic conductors, including at SOFCs operating temperature. The new combined technique was used to study other components: sealing glasses for SOFCs and optical glasses.

Studies of the internal methane conversion process were carried out on an experimental short stack of two 100x100 mm electrolyte-supported SOFCs. A whole series of experiments were carried out on H2+CH4+H2O mixtures with different sets of conditions - an increase in the ratio and consumption of methane, and then a decrease in temperature. The results of experiments at an operating temperature of 850°C showed that the kinetics of internal conversion was largely underestimated. The assembly of two SOFCs converts methane up to concentrations not exceeding the calculated equilibrium ones, up to the maximum available flow rate on the equipment used - 187 ml/min - even without current passing. This fuel flow rate can provide a current of up to 53 A, while the rated operating current of these SOFCs is about 20 A, up to 30 A on methane-rich fuel. The current further stimulates the conversion by generating additional steam.

Anode-supported solid oxide fuel cells with thin electrolytes show good electrochemical performance. In this work, 4-?m-thick YSZ electrolyte with 2-?m-thick GDC barrier layer is deposited onto the substrates by reactive magnetron sputtering. It is shown that high power density can be obtained for 5 × 5 cm2 cells under planar stacks conditions with stainless steel current collectors. Electrochemical investigations are performed in the temperature range of 600-800°C. High power density of 0.29, 0.83, 1.4 W cm-2is achieved at a voltage 0.7 V and 600, 700, and 800°C, respectively.

The results of investigation the electrochemical characteristics of innovating sulfur based electrodes, and modified anodes based on lithium are presents. The sulfur electrode has been manufactured using the innovative method of saturating the carbon matrix with a solution of sulfur in an organic solvent. In the process of evacuation, the solvent evaporates, and sulfur crystallizes in the pores of the carbon matrix. The effect of storage of a sulfur electrode on its impedance characteristics also has been investigated. Two types of anodes based on lithium have been used: 1) metal lithium as is; 2) lithium with a surface modified by lithium-aluminum alloy with the goal to reducing the impedance of the negative electrode/electrolyte interface. In addition, a layer modified with a Li Al alloy has a protective role, preventing the reduction of lithium polysulfides in the electrolyte. Using the impedance method, we investigated the effect of cycling of negative electrodes with a modified and unmodified surface on the resistance of interface the Li electrode and the electrolyte.

The effect of temperature on 1) impedance and discharge -charging characteristics of Li-S cells during cycling, and 2) the conductivity of non-aqueous electrolyte that is used in this system have been investigated. Particular attention is paid to the hysteresis of the conductivity in the temperature range from minus 25 degC to plus 60 degC and then back to plus 25 degC.

The comparative characteristics of sulfur allotropes (orthorhombic and polymeric) in Li -S cells have been presented. The difference in the structure and physico-chemical properties of the initial material has been shown. The electrochemical properties of S-based cathodes in non-aqueous liquid electrolyte (0.7 M LiIm, 0.25 M LiNO3, DME: DOL (2:1) in lithium rechargeable batteries have been investigated.

Previously, we transformed the linear drain bias asymptote equation for the MOSFET drain current in the saturation regime from the "intrinsic" case into "extrinsic" case with accounting for the velocity saturation effect. We obtained the equation for the drain current that yielded the nonlinear dependence on the "extrinsic" drain bias in saturation regime in an implicit form. We derived the equation for the differential conductance of the MOSFET at the "saturation point" and proposed a linear approximation for the dependence of the drain current on the "extrinsic" drain bias in the saturation regime for not very high drain bias when nonlinear effects can be neglected. In this paper, we investigate the asymptotic behavior of the implicit equation for the drain current in case when "extrinsic" drain bias tends to infinity. We propose the nonlinear approximation for the drain current asymptotic that describes a slow current rise to its limiting value when the "extrinsic" drain bias tends to infinity. This approximation is based on analytical solution of quartic equation that can be solved easily enough using Ferrari's method.

Nanostructured transparent polymer (NSTP) developed by Enerize Corporation for encapsulate solar cell / PV module allows to solve the problems of the traditional PV modules that laminated with glass. The traditional PV modules are complex, non-flexible, & expensive, requirement the antireflection coating and adhesive polymer between glass and semiconductor. Encapsulation and protective coating using single layer nanostructured polymer with high level transparency provide new design of thin film flexible photovoltaic modules. Additional benefit of using the NSTP includes: increasing the efficiency of solar cells by 20% relative, reducing price and weight by 30%; flexible design solution and long time durability.

The value of contact resistance between metallic current lead and electrode mass composite is one of the key parameters for determination of performance of energy storage devices, such as batteries, supercapacitors, etc. During discharge process of batteries the resistance of interface between electrode mass layer & the current collector influences on the battery voltage The surface of the aluminum foil, which used as a current collector for positive electrodes in lithium batteries is passivated by Al2O3 film that has a low electric conductivity. As result the energy and power battery are decreased. Our article is connected with technology for Li electrode production that insures the low interface resistance between electrode collector and electrode mass, the increasing the power of batteries, and stability the cycling. We have the strong opinion that the success of technology must be supported by nondestructive testing the initial materials, semi- and final product during batteries production.

Lithium-sulfur batteries are promising in terms of reducing their cost and increasing specific energy. The cost reduction is possible due to the low price and availability of sulfur, and the increase of the specific energy - due to the high specific electrochemical capacity of this material, which is 1,680 mAh/g. In the future, lithium-sulfur batteries can replace modern lithium-ion batteries. In the past few years, great progress has been made in the development of lithium-sulfur batteries. The stability of cycling sulfuric electrodes is achieved by introducing nanostructured carbon materials. This article will consider an innovative method of manufacturing sulfuric electrodes based on the method of impregnation of a porous carbon matrix with sulfur solution.

The ab initio methods of GAMESS package have been used to calculate the adsorption and the surface diffusion properties of H, O and C adatoms on graphene sheet. The graphene sheet was presented by cluster model with hydrogen atoms on perimeter. The potential-energy profiles of interaction of the adatoms with graphene have been obtained. The essential difference of the profiles and the energy barriers has been found for all adsorbate species.

The results of investigation the electrochemical characteristics of innovating sulfur based electrodes, and modified anodes based on lithium are presents. The sulfur electrode has been manufactured using the innovative method of saturating the carbon matrix with a solution of sulfur in an organic solvent. In the process of evacuation, the solvent evaporates, and sulfur crystallizes in the pores of the carbon matrix. The effect of storage of a sulfur electrode on its impedance characteristics also has been investigated. Two types of anodes based on lithium have been used: 1) metal lithium as is; 2) lithium with a surface modified by lithium-aluminum alloy with the goal to reducing the impedance of the negative electrode/electrolyte interface. In addition, a layer modified with a Li Al alloy has a protective role, preventing the reduction of lithium polysulfides in the electrolyte. Using the impedance method, we investigated the effect of cycling of negative electrodes with a modified and unmodified surface on the resistance of interface the Li electrode and the electrolyte.

The comparative characteristics of sulfur allotropes (orthorhombic and polymeric) in Li –S cells have been presented. The difference in the structure and physico-chemical properties of the initial material has been shown. The electrochemical properties of S-based cathodes in non-aqueous liquid electrolyte (0.7 M LiIm, 0.25 M LiNO3, DME: DOL (2:1) in lithium rechargeable batteries have been investigated.

The effect of temperature on 1) impedance and discharge –charging characteristics of Li-S cells during cycling, and 2) the conductivity of non-aqueous electrolyte that is used in this system have been investigated. Particular attention is paid to the hysteresis of the conductivity in the temperature range from minus 25 °C to plus 60 °C and then back to plus 25 °C.

Previously, we transformed the linear drain bias asymptote equation for the MOSFET drain current in the saturation regime from the “intrinsic” case into “extrinsic” case with accounting for the velocity saturation effect. We obtained the equation for the drain current that yielded the nonlinear dependence on the “extrinsic” drain bias in saturation regime in an implicit form. We derived the equation for the differential conductance of the MOSFET at the “saturation point” and proposed a linear approximation for the dependence of the drain current on the “extrinsic” drain bias in the saturation regime for not very high drain bias when nonlinear effects can be neglected. In this paper, we investigate the asymptotic behavior of the implicit equation for the drain current in case when “extrinsic” drain bias tends to infinity. We propose the nonlinear approximation for the drain current asymptotic that describes a slow current rise to its limiting value when the “extrinsic” drain bias tends to infinity. This approximation is based on analytical solution of quartic equation that can be solved easily enough using Ferrari's method.

Nanostructured transparent polymer (NSTP) developed by Enerize Corporation for encapsulate solar cell / PV module allows to solve the problems of the traditional PV modules that laminated with glass. The traditional PV modules are complex, non-flexible, & expensive, requirement the antireflection coating and adhesive polymer between glass and semiconductor. Encapsulation and protective coating using single layer nanostructured polymer with high level transparency provide new design of thin film flexible photovoltaic modules. Additional benefit of using the NSTP includes: increasing the efficiency of solar cells by 20% relative, reducing price and weight by 30%; flexible design solution and long time durability.

The value of contact resistance between metallic current lead and electrode mass composite is one of the key parameters for determination of performance of energy storage devices, such as batteries, supercapacitors, etc. During discharge process of batteries the resistance of interface between electrode mass layer & the current collector influences on the battery voltage The surface of the aluminum foil, which used as a current collector for positive electrodes in lithium batteries is passivated by Al2O3film that has a low electric conductivity. As result the energy and power battery are decreased. Our article is connected with technology for Li electrode production that insures the low interface resistance between electrode collector and electrode mass, the increasing the power of batteries, and stability the cycling. We have the strong opinion that the success of technology must be supported by nondestructive testing the initial materials, semi- and final product during batteries production.

Lithium-sulfur batteries are promising in terms of reducing their cost and increasing specific energy. The cost reduction is possible due to the low price and availability of sulfur, and the increase of the specific energy - due to the high specific electrochemical capacity of this material, which is 1,680 mAh/g. In the future, lithium-sulfur batteries can replace modern lithium-ion batteries. In the past few years, great progress has been made in the development of lithium-sulfur batteries. The stability of cycling sulfuric electrodes is achieved by introducing nanostructured carbon materials. This article will consider an innovative method of manufacturing sulfuric electrodes based on the method of impregnation of a porous carbon matrix with sulfur solution.

A modified organic waste of the caprolactam production is investigated by electrochemical impedance spectroscopy technique as a corrosion inhibitor of carbon steel in 20% hydrochloric solution. It is shown that cyclohexylidenecyclohexanon is a basic inhibiting component in such inhibitor. The inhibitor is investigated also as surfactant at the solution – air interface by means of the maximum bubble pressure technique. It is shown that the Langmuir adsorption of inhibitor takes place at solution – air and solution – steel interfaces. Equilibrium adsorption constant values make (1.7±0.4)×103M-1 and (4.0±0.8)×103M-1respectively. Free adsorption energy was estimated as (–28±0.5) kJ mol-1 and (–30±0.6) kJ mol-1respectively. The closeness of the adsorption constant and the free adsorption energy values suggest that the inhibitor adsorption on steel is caused basically by the hydrophobic interaction of inhibitor molecules with the solution molecules and less depends on the interaction with steel.

The ab initio methods of GAMESS package have been used to calculate the adsorption and the surface diffusion properties of H, O and C adatoms on graphene sheet. The graphene sheet was presented by cluster model with hydrogen atoms on perimeter. The potential-energy profiles of interaction of the adatoms with graphene have been obtained. The essential difference of the profiles and the energy barriers has been found for all adsorbate species.