The behavior of fibrous nickel electrodes working in Ni-H2 batteries has been studied in order to lighten these cells. The characteristics of the electrodes have been chosen taking into account the fact that a compromise between the swelling of electrodes and their capacity had to be defined. Cycling tests in accelerated geostationary mode are reported with this type of cell; 900 cycles have already been obtained without any decrease in performance. The end of discharge cell voltage is practically constant and a capacity equal to approximately 90% of the nominal capacity is recovered

Alcohol oxidation at PTFE-bonded electrodes has been studied with anodes fed with gaseous methanol. Polarization curves show activities 500 times higher than those obtained with methanol in solution.

Specific energies greater than 70 Wh-kg-1 can only be achieved for a 24 V Ni-Cd battery by reducing the weight of the bipolar collecting support. SORAPEC-NITECH has developed a lightweight foam substrate with which it is now possible to obtain bipolar electrodes with a collector thinner than 0.1 mm. These high volumetric energy density structures are well adapted for sealed battery applications. The performances of these batteries were studied as well as the optimization measures necessary to regulate the gas evolution in the cell during end of charge. The characteristic curves obtained with such cells during these tests are given

This paper describes experimental work relating to the development of long cycle life Ni-Zn cells. In all cases, these cells were constructed with a large excess of electrolyte such that, at the oxidized state, the greater part of the zinc was dissolved as zincate ions. Two cell types were investigated: cells with flowing electrolyte and cells with stationary electrolyte. The second type required a combination of additives in solution and pulsed current during charge in order to obtain good cycle life.

The activity of nickel—zinc and smooth nickel electrodes for methanol oxidation is investigated in KOH 1 M + CH 3 OH 1 M at 60°C. Nickel—zinc alloys of different composition are easily obtained from electrodeposition. After their attack in KOH 1 M, the electrodes contain about 50% of zinc and they have the βNiZn alloy structure. The I(V) curves are compared. On smooth nickel the oxidation of methanol is strongly inhibited by the superficial oxides whereas on nickel—zinc electrodes superficial oxides are easier to reduce. The effect of adsorbed hydrogen and of mixed oxides is discussed.

Chemischer InformationsdienstVolume 12, Issue 6 Physical Inorganic Chemistry ChemInform Abstract: EFFECT OF PH IN BASIC MEDIUM ON THE KINETICS OF OXIDATION OF HYDROGEN AT A PLATINUM ELECTRODE L. ANGELY, L. ANGELYSearch for more papers by this authorG. BRONOEL, G. BRONOELSearch for more papers by this author L. ANGELY, L. ANGELYSearch for more papers by this authorG. BRONOEL, G. BRONOELSearch for more papers by this author First published: February 10, 1981 https://doi.org/10.1002/chin.198106023Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume12, Issue6February 10, 1981 RelatedInformation

Les courbes de polarisation caractéristiques de l'oxydation de l'hydrogène en divers milieux alcalins (le pH variante de 7 à 14) ont été tracées à l'aide d'un montage à électrode rotative. Les électrodes sont soit des disques de platine lisse, soit des disques en platine recouvert d'un film de platine divisé. On montre que quelque soit le pH, le processus limitatif est toujours la diffusion de l'hydrogène dissous dans l'électrolyte, vers l'électrode.

Oxygen evolution was studied at a nickel electrode in alkaline medium. The study of the relation i = f(OH−-η) allowed us to choose a probable reaction mechanism. This mechanism comprises a step of OH− discharge followed by a chemical recombination of the OHads and the OH− ions to give O−ads which is then oxidized. The last step, recombination of two oxygen atoms to give an oxygen molecule, is a rapid step. We show how this mechanism takes account, at the same time, of the variation of the current as a function of the OH− activity in solution and of the existence of two Tafel regions in the log i = f(η) curves.

The electrochemical behaviour of ferrites having the composition La1-xSrxFeO3-y in the oxygen reaction has been studied. The catalytic activity of these compounds was compared with that of copper manganite Cu1.4Mn1.6O4 and that of lanthanum strontium cobaltite La0.5Sr0.5CoO3 as well as with that of surface oxides developed on nickel and its alloys. It was shown that in the evolution of oxygen, nickel and its alloys (NiBe-NiCo2) are the least polarizable materials.

The polarization curves of hydrogen oxidation in several alkalines media are determined by the rotating disc method. The electrode are made of smooth platinum or platinum covered by a thin layer of black platinum. For the total range of pH we show that the limiting process is always the diffusion of dissolved hydrogen to the electrode.