fuel cell

DOI: 10.18500/1608-4039-2015-15-4-175-179

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.

В работе рассмотрена металлизация электролитной матрицы щелочного матричного топливного элемента, обусловленная растворением платинового катализатора на кислородном электроде этого элемента. Показано, что уровень металлизации зависит от условий функционирования топливного элемента и структурных особенностей его составляющих.

The work reviews the influence of gas impurities in fuel and oxidizing chemical on the alkaline oxyhydrogen fuel cell functioning. It shows that methane impurities act differently on anode and cathode, while other gases (except noble gases), including carbon monoxide, which is a poison for fuel cell with acid solution, influence the operation of alkaline fuel cell through the reaction with potassium hydroxide (KOH). Substitution electrolyte for fresh recovers fuel cell performance.

Using complex models, including the solution percolation problem and electrochemical kinetics calculations are considered the features of a solid polymer fuel cell catalyst layers with a catalyst based on nanoscale carbon materials, including graphene nanowires. These calculations are consistent with the experimental data presented by optimizing the composition of the catalyst layers. It is shown that the addition of 20 wt.\% nanofibres graphene can reduce ohmic losses from the ion current and improve the performance of the fuel cell is 20%

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. Rotating disc electrode (RDE) and rotating ring disc electrode (RRDE) methods were used to determine the catalytic properties of PAN pyropolymers, derived at carbonization temperature interval of 600–1200°C, as well as composite PAN/support catalysts, carbonized at 900°C, in the oxygen reduction reaction in H₂SO₄ и KOH solutions. The methods of cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic polarization were utilized to characterize the charge capacitive properties. An equivalent scheme modeling the electrochemical response of PAN pyropolymer in H₂SO₄ solution was proposed. An assumption was made of interrelation between the PAN-T catalytic activity and the occurrence of condensed parquet aromatic structure comprising of nitrogen-carbon bonds. Evidence was given that Fe atoms play the key role in the synthesis of active non-precious catalysts with high selectivity towards the 4-electron O₂ reduction. The possibility of the catalysts synthesis for 2-electron ORR without the use of metal precursors was evidently shown. Prominent correlation of capacitive and catalytic properties for these materials was observed in H₂SO₄ solution. The optimal PAN pyropolymers synthesis temperature was determined to be in the range of 750–950°C. The mats of PAN-T were shown to be feasible as the negative electrodes of supercapacitors.