fuel cell

Composition and structure of proton-exchange membrane (PEM) fuel cell catalytic layers were investigated. The maximum FC efficiency was observed at the polymer content in a layer 25-30 vol. % at work on air and 30-35 vol. % at work on oxygen. At a variation of quantity of catalytic composition the maximum current density have been received at layer load 1.75 mg/sm2, thus decrease in it value in 2 times leads to falling of current density only on 10 %. 

A model connecting the weight, volume, and chemical changes of heterogeneous borohydride fuel occurring at discharge of the direct borohydride fuel cell is presented. The experimental data measured with a fuel on the basis of water-alkaline solution of potassium borohydride КВН, at temperature 25°C are compared with theoretically calculated curves. Good conformity is acknowledgement of the 8-electron mechanism of borohydride ion oxidation.

A study of the solubility in the ternary systems NaOH-NaBO,-H,O and КОН-КВО,-Н.О is of special interest from a fundamental and practical point of view. These systems represent the discharged products of the borohydrides fuel cells. The performance of such mixtures is determined by the solubility of their components. Therefore, in the present work the solubility in the ternary systems was studied by means of isothermal saturation within 10+50°C.

A study of the solubility in the ternary systems NaBH₄–NaOH–H₂O, KBH₄–KOH–H₂O, NaOH–NaBO₂–H₂O и KOH–KBO₂–H₂O is of special fundamental and practical interest. The first two systems are used as a fuel and as a hydrogen source in hydrogen power engineering that includes the low-temperature fuel cells; borohydrides are converted into metaborates. Hence, the last two systems represent the discharged by-product.

Composition and structure of proton-exchange membrane fuel cell catalytic layers were investigated. Modelling of catalytic layer vas considered. This model allows to calculate layers containing particles of polymer and the catalyst of various forms and sizes. Dependence of conductivity and active layer surface area on concentration of polymer particles is shown. Best performance of a fuel cell is observed at the polymer concentration in a layer of 30–35% vol.

The article contains the review of scientific-technical publications concerning a use of borohydrides in fuel cells and chemical generator over a period of 2000–2009. Their scientific basis principles of operation, prospects of utilization, and possible technologies are examined.

The paper deals with some questions concerning carbonization and decarbonization of alkaline electrolyte in matrix fuel cell (FC). It is shown that there is an equilibrium ultimate level of carbonization that depends on CO₂ content in gases delivered into FC and FC electric loading. Electrolyte decarbonization takes place at the increase of FC load current with CO₂ emission at hydrogen electrode end. The possible mechanisms of electrolyte carbonization and decarbonization are suggested.

In the current paper electrospun nanofiber mats were derived from polyacrylonitrile (PAN). The temperature influence on the volumetric and surface composition of the resulting pyropolymers was studied by means of elemental analysis and X-ray photoelectron spectroscopy.

Electrochemical activity of anodes on the basis of a nickel mesh grid for water electrolysis is investigated. Activation of anodes was made by three ways:
1) chemical covering sulfur-containing compounds of nickel and iron;
2) immersing in solution Na₂S₂O₃ + H₂SO₄ (till pH=3);
3) immersing in solution Na₂S + H₂SO₄ (till pH=3).

The reasons, that lead to the performance loss of alkaline matrix electrochemical generator (ECG) based on hydrox cell and therefore reduce the fuel cell stack cycle life, are highlighted in this article. It is shown that storage of ECG, preserved with a special gas mixture within up to 20 years, doesn't lead to noticeable characteristic fluctuation.