A study has been made of mass transfer to a circular disk electrode Ioo cated in the stagnation region of an impinging jet. A semiempirical solution of a convective diffusion model is presented in the form of an asymptotic series to permit an estimate of the transfer rate for 0.7 ~ Sc < ~. Experimental results reveal that the electrode possesses a property of "uniform accessibility" to the diffusing species if the electrode radius is less than 1 nozzle diameter for turbulent jet and Y2 nozzle diameter for laminar jet. Within this region, the mass transfer is relatively independent of radial positions, and the semiempirical correlations are presented for both laminar and turbulent flows over a range of nozzle heights from 0.2 to 6 nozzle diameters. The result indicates that the impinging jet electrode is a feasible tool for electroanalytical applications. 'I ~s geometry can be easily adopted in process streams and closed systems at a pressure other than the ambient atmosphere.

An experimental and theoretical study has been made to determine the feasibility of a hydrogen‐bromine cell for energy storage applications. The laboratory data were collected for the cell performance and the membrane characteristics during the charge and the discharge operations. An unsteadystate heat balance was used to predict the temperature change and the overall electric‐to‐electric efficiency. The results indicate that the hydrogen‐bromine system can achieve an efficiency greater than 70% when the operating cell current density is less than 160 mA/cm2.

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Recently, lithium iodide has been suggested as an additive for secondary lithium batteries to prevent the oxidation of organic electrolytes during charging operations. In this study, the charge and discharge reactions of lithium iodide in 1.5M LiAsF6/tetrahydrofuran (THF) solution on platinum are investigated with the cyclic voltammetric and rotating disk electrode techniques. At the anodic potentials, lithium iodide is found to undergo a two-step process of oxidation of iodide ion to tri-iodide ion and further oxidation of tri-iodide ion to iodine. The diffusion coefficients of iodide and tri-iodide ions in the electrolyte and the kinetic parameters of the redox reactions on platinum are evaluated from the rotating disk data. It is found that iodine initiates the polymerization of THF in the presence of lithium hexafluoroarsenate. To provide overcharge protection of the lithium batteries using LiAsFJrHF electrolytes, large excess of lithium iodide must be present in the cell to form stable lithium tri-iodide with the iodine generated during the charging of lithium batteries.) unless CC License in place (see abstract).

A generalized theory is presented for pulse electrolysis with rectangular current pulses, periodical pulse reverse, and double rectangular pulses with relaxations. It is shown that very high instantaneous mass transfer rates corresponding to a current density of 100–1000 A/cm2 can be attained by short current pulses at high pulse frequencies. Numerical results for the concentration fluctuations and potential responses have also been calculated for the deposition/dissolution of copper on a rotating disk electrode in acid copper sulfate solution. The results indicate that the current pulses can profoundly change the current‐potential relationships and thus the current distribution and the morphology of electrodeposits on the electrode surface.

The oxygen reduction reaction was investigated at platinum electrodes in phosphoric acid in the concentration range 0.7M (6.6%) to 17.5M (95%) at 25°C using the rotating ring‐disk electrode technique. As a complement, cyclic voltammograms on platinum and potentials of zero charge of mercury were obtained as a function of phosphoric acid concentration. The mechanism of the oxygen electrode reaction is discussed in terms of the direct four‐electron transfer reduction to water and the formation of hydrogen peroxide as an intermediate in a parallel two‐electron transfer reaction. The rate constants of the intermediate reaction steps were calculated from the ring‐disk data for various potentials and electrolyte concentrations. The characteristics of the reaction were found to be markedly dependent on the concentration of phosphoric acid. These results are interpreted in terms of changes in oxygen solubility, proton activity, and double layer characteristics when passing over from a water to a phosphoric acid solvent structure.