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  • 1
    Electronic Resource
    Electronic Resource
    Measurement of the ionic conductance of regenerated cellulose membranes in alkaline solutions with attention to current refraction (1991)
    Springer
    Journal of applied electrochemistry 21 (1991), S. 327-330 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A novel cell is described for making measurements of membrane conductivity by an a.c. technique. Membrane resistance was determined from measurements of the cell resistance for various numbers of membrane layers. Plots of resistance vs. membrane thickness were curved due to current refraction into the region clamped between the mating faces of the cell. A non-empirical correction was made for this refraction which linearized the data and enabled accurate values of membrane conductance to be achieved. Conductance and thickness values for regenerated cellulose membranes in CsOH, KOH, NaOH and LiOH over a wide range of concentrations are reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01020217
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  • 2
    Electronic Resource
    Electronic Resource
    The manganese dioxide electrode Part XII: Gibbs free energy of H insertion compounds and a planar model (1995)
    Springer
    Journal of applied electrochemistry 25 (1995), S. 425-432 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Experimental values for the Gibbs ‘free energy of mixing’ of solid solutions produced by electrochemical H insertion into a commercial synthetic γ-Mn02 have been derived from published electrode potential measurements carried out in Leclanche electrolyte. Calculated values are based on the reasonable assumption that the solid solutions are thermodynamically ideal so that the Gibbs free energy of mixing can be estimated from the positional entropy of the inserted species. Comparison of the two sets of values provides strong evidence that the inserted H is present as two thermodynamically independent species H+ and e at least up to 40% fill. Additional insight is provided by a planar random insertion model. The model shows the development of microdomains of fully H inserted material at the higher levels of insertion but prior to complete insertion as is required to explain published experimental phenomena. The model also allows the calculation of the Gibbs free energy of mixing to be refined to take into account either the stabilisation of certain We pair types or restriction in the movement of the H+ and e species of pairs caused by adjacent pairs blocking pathways. The latter refinement gives very good agreement with the experimental data using one adjustable parameter namely a blocking efficiency of 50%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00260684
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  • 3
    Electronic Resource
    Electronic Resource
    The manganese dioxide electrode: Part XIII: An FTIR study of H-insertion into EMD (1997)
    Springer
    Journal of applied electrochemistry 27 (1997), S. 243-253 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Two battery active γ-manganese dioxides, coded R2 and IBA 19, with ~100% microtwinning and ~40% de Wolff disorder were inserted with H by chemical methods in a nonaqueous environment. Compounds with compositions varying from the starting material to the fully H-inserted material were prepared and investigated by FTIR spectroscopy. Both series of compounds exhibited little change in their FTIR patterns until an H-insertion level expressed by s in MnOnHs of s = 0.63 (R2) and s = 0.55 (IBA 19) consistent with the idea that H and e− are mobile in the structure and present as independent thermodynamic components in an ideal solid solution. Beyond this level H location occurred as evidenced by a sharp change in integrated areas of regions of the spectra associated with O—H bond formation. Simultaneously a change in the position of one of the vibrations associated with that of the [MnO6] octahedra occurred. The assignment of bands in the spectra is discussed and evidence presented using a modified cusum procedure which supports the proposal that a demicrotwinning of the structure occurs as H begins to locate and the structure expands anisotropically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018420527831
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of charge rate and cycling on the morphology of Cd and Cd(OH)2 in sintered plate electrodes (1976)
    Springer
    Journal of applied electrochemistry 6 (1976), S. 431-444 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Optical and scanning electron microscopy have been used to study the growth and redistribution of Cd and Cd(OH)2 in sintered plate electrodes as a function of charge rate and cycle number. As expected, the growth of both components was found to increase with increasing cycle number and decreasing charge rate. Because the deposits, particularly after extended cycling, always contained appreciable quantities of Cd metal in both the charged and discharged state, the sizes of Cd(OH)2 crystallites were difficult to quantify. High charge and discharge rates promoted greater aggregation and redistribution of active material towards the electrode edge. This resulted in a considerable decrease in the available pore volume per unit mass of active material and in extreme cases to localized pore blockage. The trapping of Cd metal by highly crystalline, unchargeable hexagonal platelets of (δ-Cd(OH)2 resulted in about 50% of the active material becoming obsolete after 100 cycles at high charge and discharge rates. At this stage only the finely divided Cd metal in the electrode interior continued to function. Low charge rates gave deposits of more uniform size and distribution but these contained a high percentage of large Cd particles which discharged less efficiently than those produced at the high charge rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00616543
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  • 5
    Electronic Resource
    Electronic Resource
    Cyclic charge-discharge behaviour of sintered plate and planar cadmium electrodes (1976)
    Springer
    Journal of applied electrochemistry 6 (1976), S. 107-118 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The cyclic charge-discharge behaviour of sintered plate and planar cadmium electrodes has been studied using galvanostatic and potentiostatic sweep techniques. The cycling inefficiency of sintered electrodes reflected more the discharge process as shown by analytical monitoring of cadmium levels before and after charge. The effect of discharge rate on cycling efficiency was also investigated. Open-circuit recovery experiments indicated that a critical potential was reached at which passivation occurs subsequent to which a plateau region was observed for sintered electrodes. Potentiostatic sweeps on partially discharged electrodes and X-ray diffraction suggested the formation of a nickel-cadmium alloy during charge. Comparison of cyclic sweeps on sintered and planar electrodes showed the distribution effects of active material through the sinter and also the improved charge acceptance of sintered electrodes. Cyclic sweeps on planar electrodes indicated the involvement of forms of cadmium of different activity, whilst cathodic sweeps after prolonged retention at potentials anodic to passivation indicated a more complex reduction route.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00615375
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  • 6
    Electronic Resource
    Electronic Resource
    Discharge performance of electrodeposited manganese dioxides in Leclanché cells (1971)
    Springer
    Journal of applied electrochemistry 1 (1971), S. 45-52 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Electrodeposited manganese dioxide is finding increasing use as the cathode in high performance Leclanché cells. In this study a number of commercial and pilot plant materials together with experimental variants were examined in Leclanché R.20 size cells and found to have widely different performances on a simulated motor discharge. The initial X-ray diffraction diagrams of the manganese dioxides, viewed in order of decreasing discharge performance, show a gradual diminution of theγ phase peak and the emergence of aβ phase peak. X-ray diffraction thus provides a means of recognizing a preferred electrodeposited manganese dioxide for the simulated motor discharge.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00615746
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  • 7
    Electronic Resource
    Electronic Resource
    The cause of residual capacity in nickel oxyhydroxide electrodes (1980)
    Springer
    Journal of applied electrochemistry 10 (1980), S. 61-70 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Chemical analysis, X-ray diffraction and linear sweep voltammetry have been used to examine the cause of the secondary discharge plateau associated with the inefficient reduction of sintered plate NiOOH electrodes. The techniques confirm the presence ofβ-Ni(OH)2,β-NiOOH andγ-NiOOH in electrodes after failure at high rates. No evidence was obtained in support of the plateau arising from a new intrinsically less active compound. In disagreement with previous claims theγ-phase formed on overcharging was found to discharge as efficiently as theβ-phase. Inefficient discharge is considered to be caused by an insulating barrier layer ofβ-Ni(OH)2 between the charged active material and the current collector. The complex non-linear current-potential behaviour, exhibited by the secondary discharge plateau near −200 mV, is considered to be caused by the removal of Ni3+ or Ni3+ defects from the electronically conducting Ni(OH)2 prior to returning it to the poorly conducting divalent state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00937339
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  • 8
    Electronic Resource
    Electronic Resource
    Studies concerning charged nickel hydroxide electrodes I. Measurement of reversible potentials (1980)
    Springer
    Journal of applied electrochemistry 10 (1980), S. 109-125 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Reversible potentials (E R) have been measured for nickel hydroxide/oxyhydroxide couples over a range of KOH concentrations from 0·01–10 M. It is shown that the couples derived from the parentα- andβ-Ni(OH)2 systems can be distinguished by the relative change in KOH level on oxidation and reduction. In the case of couples derived from theα-class of materials a dependence of 0·470 moles of KOH per 2e change is found compared with 0·102 moles of KOH per 2e change for theβ-class of materials. Couples derived from theα- andβ-Ni(OH)2 systems can be encountered in a series of ‘activated’ and ‘de-activated’ forms having a range of formal potentialsE 0 ′ . ‘Activated’. and ‘de-activated’β-Ni(OH)2/β-NiOOH couples are found to lie in the range 0·443–0·470 V whilstα-Ni(OH)2/γ-NiOOH couples lie in the range 0·392–0·440 V w.r.t. Hg/HgO/KOH. It is demonstrated for ‘de-activated’,β-Ni(OH)2/β-NiOOH couples thatE R is independent of the degree of oxidation of the nickel cation between states of charge of 25% and 70%. SimilarlyE R is constant for states of charge between 12% and 60% for ‘activated’α-Ni(OH)2/γ-NiOOH couples. The constant potential regions are considered to be derived from heterogeneous equilibria between pairs of co-existing phases both containing nickel in upper and lower states of oxidation. Differences inE 0 ′ between the ‘activated’ and ‘de-activated’ couples are considered to be related to the degree of order/disorder in the crystal lattice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00937345
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  • 9
    Electronic Resource
    Electronic Resource
    Studies concerning charged nickel hydroxide electrodes. II. Thermodynamic considerations of the reversible potentials (1980)
    Springer
    Journal of applied electrochemistry 10 (1980), S. 127-141 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract In this paper the thermodynamics of mixing are applied to account for the independence of the discharge potential of the nickel hydroxide electrode as a function of nickel oxidation state. The constant potential region is considered to arise from the formation of a pair of co-existing solid solutions having a composition predetermined by the magnitude of the interactions between the oxidized and reduced species. From considerations of the excess-energy terms, it can be shown for a symmetrical potential/ composition profile, that the constant potential region is identical with the standard potentialE 0. The influence of asymmetry on the changes inE 0 are discussed. Consideration has also been made of the influence of dissociation of oxidized and/or reduced species on the potential determining equations. The removal of n-type defects from the nickel(II)-rich phase on discharge is considered to be responsible for the observed secondary discharge plateau at potentials ∼ 300 mV more cathodic than normal. This non-equilibrium behaviour can be explained in terms of a mixed pn-semiconducting material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00937346
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  • 10
    Electronic Resource
    Electronic Resource
    Corrigendum (1981)
    Springer
    Journal of applied electrochemistry 11 (1981), S. 401-401 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00613961
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