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Agency: European Commission | Branch: FP7 | Program: JTI-CP-FCH | Phase: SP1-JTI-FCH.2009.3.3 | Award Amount: 5.65M | Year: 2011

Long-term stable operation of Solid Oxide Fuel Cells (SOFC) is a basic requirement for introducing this technology to the stationary power market. Degradation phenomena limiting the lifetime can be divided into continuous (baseline) and incidental (transient) effects. This project is concerned with understanding the details of the major SOFC continuous degradation effects and developing models that will predict single degradation phenomena and their combined effect on SOFC cells and single repeating units. The outcome of the project will be an in-depth understanding of the degradation phenomena as a function of the basic physico-chemical processes involved, including their dependency on operational parameters. Up to now research has rarely succeeded in linking the basic changes in materials properties to the decrease in electro-chemical performance at the level of multi-layer systems and SOFC cells, and even up to single repeating units.

Medvedev D.,RAS Institute of High Temperature Electrochemistry | Murashkina A.,RAS Institute of High Temperature Electrochemistry | Pikalova E.,RAS Institute of High Temperature Electrochemistry | Demin A.,RAS Institute of High Temperature Electrochemistry | And 2 more authors.
Progress in Materials Science | Year: 2014

The characteristic of a number of oxide materials, which include BaCeO 3-systems, is their ability to show the proton conductivity along with oxygen-ion conductivity. Such atypical behavior for other oxides attracts great interest in theoretical and experimental solid state electrochemistry. The present review aims at: (a) summarizing the evolution of new functional BaCeO3-based materials with respect to their properties, and properties' optimization (importance of ceramics' technology preparation, structural and thermodynamic stability of materials, enhanced ionic conductivity of electrolytes with low electronic contribution, thermal and chemical compatibility with other oxide components), and (b) examining the possibility of their application in various solid oxide electrochemical devices. © 2013 Elsevier Ltd. All rights reserved.

Muzyukin I.L.,RAS Institute of High Temperature Electrochemistry
IEEE Transactions on Plasma Science | Year: 2011

Fluxes of ions and electrons from plasma of a nanosecond high-voltage vacuum spark have been studied. Differences in the determination of the plasma expansion velocities by the probe method, the method of recording the flux of particles, and the Thomson spectrometer have been established. It has been shown that the spectrum of explosive emission electrons includes a high-energy part with energies higher than the discharge voltage. It has been assumed that the plasma stream contains high-energy electrons formed by intensive plasma oscillations. © 2011 IEEE.

Smolenski V.,RAS Institute of High Temperature Electrochemistry | Novoselova A.,RAS Institute of High Temperature Electrochemistry
Electrochimica Acta | Year: 2012

This work presents the electrochemical study of TmCl 3 solutions in NaCl-2CsCl eutectic at the temperature range 823-973 K using inert and reactive electrodes, i.e. Mo and Al, respectively. On an inert electrode, Tm 3+ ions are reduced to metallic thulium through two consecutive steps: Tm 3+ + e - → Tm 2+ and Tm 2+ + 2e - → Tm. The electroreduction of Tm 3+ to Tm 2+ ions was found to be reversible at low scan rates being controlled by the rate of the mass transfer and irreversible at high scan range (>0.1 V s -1) being controlled by the rate of charge transfer. The diffusion coefficient of [TmCl 6] 3- complex ions was determined at different temperatures. Arrhenius law was verified by plotting the variation of the logarithm of the diffusion coefficient vs. reverse temperature. The apparent standard potential of the soluble-soluble redox system Tm 3+/Tm 2+ was obtained by cyclic voltammetry. The electrode reactions of Tm 3+ solutions at an Al electrode were also investigated. The results showed that for the extraction of thulium from molten chlorides, the use of a reactive electrode made of aluminum leading to Al-Tm alloys seems to be a pertinent route. © 2011 Elsevier Ltd. All rights reserved.

Galashev A.Y.,RAS Institute of High Temperature Electrochemistry
Journal of Physical Chemistry C | Year: 2016

Most sorbents display poor capacity for elemental mercury at elevated temperatures. Graphene is the potential candidate among different high-temperature sorbents. We have studied the physical properties of mercury films on partially hydrogenated imperfect graphene, as well as their heating and bombardment with xenon clusters, by means of molecular dynamics. Hydrogenated edges of a graphene sheet containing Stone-Wales defects withstand heating to 1100 K. Formation of the droplet leads to a decrease in the blunt contact angle. The bombardment of a target with a Xe13 cluster beam at energies of 5-30 eV and incidence angles of 0-60° aiming to remove a mercury film from imperfect graphene has been performed. The graphene is completely cleaned of mercury at a cluster energy of EXe ≥ 15 eV. Mercury is removed from the graphene film via sputtering of single atoms and droplet detachment. A stress in graphene resulting from forces normal to the sheet plane is noticeably higher than that due to forces acting in its plane. Bombardment at an angle of incidence of 45° is the most efficient and leads to lower graphene roughness. Thus, mercury can be removed from graphene by heating or bombarding with heavy noble gas clusters. © 2016 American Chemical Society.

Samgin A.L.,RAS Institute of High Temperature Electrochemistry
Solid State Communications | Year: 2012

This communication is inspired by recent results on the observation of "giant" rates for proton transfer in rutile TiO 2 at low temperatures in pump-probe experiments. An important point is that this is not a tunneling effect. We show that this classical looking effect has a quantum mechanical origin and may be called lattice-assisted hopping. To explore the possibility of formulating transport properties in terms of mode vibrations, we use a "quantum" fluctuationdissipation theorem, thus providing a concept of dynamic activation energy for ion hopping, which had been used in the above experimental study, rather heuristically, to fit the low-temperature "over the barrier" motion data. The resulting expression of hopping activation energy is more general than the standard one defined in units of kBT and is able to describe the crossover from the high to low-temperature regime of proton jumps. © 2012 Elsevier Ltd. All rights reserved.

Krotov V.Y.,RAS Institute of High Temperature Electrochemistry
Electrochimica Acta | Year: 2014

This paper describes an empirically demonstrated mechanism of UO 2-ZrO2 cathode deposit formation during the (NaCl-KCl)equim.-UO2Cl2-ZrCl4 melts electrolysis. The first layer of the cathode product was formed through UO 2 2+ ion reduction to uranium dioxide followed by an exchange reaction with Zr4+ ions, which are present in the electrolyte. The subsequent reactions proceeded through simultaneous reduction and exchange reactions at the cathode. © 2013 Elsevier Ltd. All rights reserved.

Novoselova A.,RAS Institute of High Temperature Electrochemistry | Smolenski V.,RAS Institute of High Temperature Electrochemistry
Electrochimica Acta | Year: 2013

This work presents the electrochemical study of NdCl3 solutions in fused low-melting LiCl-KCl-CsCl eutectic and individual CsCl at the temperature range 573-943 K using inert molybdenum electrodes. The mechanism of the electrochemical reduction was investigated by transient electrochemical technique. It has been shown that Nd3+ ions are reduced to metallic neodymium through two consecutive steps: Nd3+ + ē → Nd2+ and Nd2+ + 2ē → Nd0. The chemical stability of Nd2+ ions in fused chloride melts was studied at different temperatures. It was determined that the compound NdCl2 is not stable in molten solutions at high temperatures (above 810-840 K). The results of a study of the Nd3+/Nd2+ couple redox potentials vs. Cl-/Cl2 reference electrode at a wide temperature range in molten LiCl-KCl-CsCl eutectic was carried out by direct potentiometric method. Apparent standard redox potentials of the couple ENd 3+/Nd2+* were determined. Basic thermodynamic properties of the reaction NdCl2(l) + 1/2Cl2(g) ⇔ NdCl3(l) were calculated. © 2012 Elsevier Ltd.

Samgin A.L.,RAS Institute of High Temperature Electrochemistry
Journal of Physics and Chemistry of Solids | Year: 2013

Stimulated diffusion of protons in oxides such as ABO3 crystals and rutile TiO2 is discussed in the context of quantum Brownian motion. A self-consistent lattice-assisted proton hopping (LAPH) model is developed by going from white noise (characteristic of the standard stochastic theory of superionic conduction) to colored noise in the Markovian limit. This model differs from the commonly used ion jump models in that the hydrogen diffusion rate prefactor is identified as a quantity proportional to the frequency of phonon assistance. Application of the quantum fluctuation- dissipation theorem suggests that the dynamic activation energy for diffusion is a function of a bath-mode frequency. The LAPH model can predict enhanced rates of barrier jumping at room temperature compared to thermally activated proton diffusion. This indicates that low-temperature solid oxide devices are potential candidates for use in hydrogen energy research. The LAPH model offers a valid explanation for the mechanism of high protonic mobility recently observed for TiO2 in a picosecond transient pump-probe experiment. This unexpected dominant lattice relaxation channel must be considered as a new classical-like (but low-temperature) proton transfer mechanism. For vibration-assisted protonic jumps to occur at low temperature, the phonon assistance must be classified as a low-frequency vibration specific to each lattice. © 2013 Elsevier Ltd.

Shmelev D.L.,RAS Institute of High Temperature Electrochemistry
IEEE Transactions on Plasma Science | Year: 2013

A kinetic 1-D model of an ultrashort (10 μ{m}) vacuum arc was developed to research the vacuum arc near-anode region and the influence of anode plasma on the cathode attachment self-consistently. The kinetic model is a model of 1D3V particle-in-cell and direct siμlation Monte Carlo type. The model takes into account the main types of elastic and inelastic collisions of particles in the plasma as well as evaporation and thermofield electron emission from both of the electrodes. The model has three task parameters: cathode temperature, anode temperature, and voltage drop applied to the gap. The plasma state in the gap, current density, and energy flux density to the electrodes are the outcome of the model. The calculations have shown that the anode temperature variation strongly influences both the plasma column parameters and the cathode attachment. It was shown that, at the ratio T-a T-c sim 1 (with Ta and Tc being the anode and cathode temperatures, respectively), the plasma in the gap changes the direction of motion. © 2012 IEEE.

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