Fuel cells

The influence off different factors on the temperature distribution in the battery solid oxide fuel cells

The thermal model of the power plant based on the solid oxide fuel cells (SOFC) fed with methane is developed. The power plant includes three heat-generating zones: a fuel-cell stack, a reactor of partial oxidation (RPO), and an afterburner. It is shown that temperature distribution along the battery depends on three factors: a methane consumption, a methane to air relation in the flow fed to the RPO, and a battery current. Results of modeling well correlate with the experimental data received on the power plant prototype with the SOFC stack consisted on 16 tubular cells.

Catalytic layers on the composites of polymers, carbon nanotubes and adsorbed platinum particles

The composites contained ultra low amounts of platinum, polymers and carbon nanotubes (SWCNTs) were investigated. The main goal were to elucidate the influence of the polymer functional groups nature on the structure and on electrocatalytic activity of the composites. The structure of the composite Platinum/sodium polystyrensulfonate (PSS)/SWCNTs/GC has been studied by TEM, HRSTEM, HAADF STEM and SAED methods. The loading of platinum was detected by ICP–AES. The electrochemical studies show high catalytic activity of the prepared composite in methanol oxidation reaction comparing to commercial catalyst Pt/C ETEK and other previously studied composites.

Catalytic activity of lali0.1co0.1fe0.8o3-d cathode in (Li0.62K0.38)2CO3 melt. Part II. The reaction mechanisms and catalytic activity of the oxide electrode

The oxygen reduction mechanisms on an oxide electrode are proposed. It was found, that in the temperature range 870–1020 K mechanism involving superoxide ions dominates, whereas in T < 870 К region the reaction mechanisms involving molecular oxygen apparently take place.

Catalytic activity of LaLi0.1Co0.1Fe0.8O3-d cathode in (Li0.62K0.38)2CO3 melt. Part I. Experimental results and equivalent circuit for oxide – melt boundary

The results of the study of kinetics of oxygen reduction on the dense LaLi0.1Co0.1Fe0.8O3-d electrode in (Li0.62K0.38)2CO3 eutectic melt using coulostatic technique are reported. It was found, that the equivalent circuit that includes heterogeneous charge transfer step in series with heterogeneous chemical reaction most closely fits the kinetics of electrode processes.

Heat balance analysis of solid oxide fuel cell battery

The paper analyzes the energy balance of the solid oxide fuel cell (SOFC) battery. The existence of three temperature points satisfying the equation of SOFC battery energy balance is found out. The first point is trivial and corresponds to the cooled state of the battery. The second temperature point corresponds to an unstable state of the battery and finally, the third point is stable and corresponds to the normal operating state of the battery. The difference between the third and second point defines the temperature interval within the battery is able to self-heating. Analogy with the Semenov diagram for chemical reactors is noted.

Long-term testing of hydrogen-oxygen alkaline matrix fuel multicell stacks

The paper generalizes a many years' experience in manufacturing and testing of multicell PHOTON stacks based on hydrogen-oxygen alkaline matrix fuel cells. Inter-cell processes effecting the stack lifetime are concerned, the main of which is the current flow between cells along a thin electrolyte film in gas collectors. This process is accompanied by electrolyte redistribution among elements resulting in their polarity reversal, and electrochemical corrosion in metal gas collectors of stacks.

Carbon nanotubes supported core–shell catalysts Pt-Ru/Ni, Pt-Ru/Pb and Pt-Ru/Ni for methanol oxidation reaction in fuel cell

The core-shell type catalysts were obtained by spontaneous surface substitution of electrodeposited Pb, Ni and Cu by platinum metals Pt-Ru. The surface layer of obtained catalysts was tested by EDAX; the amount of platinum was determined by ICP-AES. The catalytic activity of obtained catalysts was examined in methanol oxidation reaction. The stationary state currents were referred to EAS, determined from hydrogen adsorption. For all investigated systems the catalytic effect was registered thus confirming the activity of core–shell catalyst.

Electrochemical oxidation of borohydride-ion on nickel electrode: a study by the method of ir-spectroscopy

The study of the anodic oxidation of borohydride-ion BH4 on catalytically active nickel electrode by methods of potentiostatic inclusion, galvanostatically inclusion, cyclic voltammetry and infrared spectroscopy with Fourier transformation. The composition of some intermediates of the process of electrochemical oxidation of BH4 and the mechanism of decomposition of borohydride, which includes the following basic stages: BH4 → BH3(OH) → BH2(OH)2 → BH(OH)3 → B(OH)4, is determined. The regularities of the kinetics of the electrochemical oxidation of BH4 – ion Ni-electrode is determined. The diffusion coefficient BH4 ion in aqueous solution at a temperature of 25°C, measured by electrochemical methods, ranges from 5.3·10–5 to 1.6·10–5, the average value of 2·10–5 cm2/s.

Electrochemical activity of the electrodes with electrocatalytic coatings

Electrochemical activity of electrodes for electrolysis of water is investigated. As catalysts coating Ni-S-Co, suspension LaNi2.5Co2.4Al0.1 or their combinations were applied. As electrolyte at test of electrodes 30% KOH or NaOH is used. Current density varied in a range from 10 to 600 мА/cm2 at temperature 20-80°C. When the temperature increases from 20 to 80°C the current density on cathodes with composite LaNi2.5Co2.4Alo.i/Ni-S-Co catalyst increases 4 times at constant potential E = –1.10 V (rel. Hg/HgO). When the current density of more than 100 mA/cm2 cathodes with all catalysts offered by us in this work have lower value of potential than the similar cathodes described in the scientific literature. In contrast to the cathodes, catalyst LaNi2.5Co2.4Al0.1/Ni–S–Co does not render influence on electrochemical activity of the anode.

The equilibrate concentration of the electro-active species in (Li0.62K0.38)2CO3 melt and reaction mechanisms of the oxygen reduction on the gold electrode

The concentrations of the main components of the (Li0.62K0.38)2CO3 melt have been evaluated by the thermodynamic modeling technique, and the Warburg coefficients of electroactive particles as a function of temperature and CO2/O2 gas mixture composition have been calculated. The same dependences of Warburg coefficient and charge transfer resistance were studied on Au cathode using coulostatic technique. It is shown that O2 ions and O2 molecules are the main electroactive species in the melt. Their relative concentration determines which reaction mechanism dominates.