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  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 256 (1975), S. 398-399 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We have investigated the properties of electrolytes based on silver iodide with various sulphonium iodides, and we have shown that the solids so prepared are good ionic conductors. Conductivities of pressed pellets were measured as a function of the molar ratio of the components and the composition ...
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 259 (1976), S. 656-657 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] As a representative of the Agl-Sel system, (CH3)3SeI, prepared from (CH3)2Se and CH3I (ref. 10) was mixed with varying amounts of Agl to produce samples containing 90, 85 and 80 mol % Agl. The powdered samples were suspended in distilled water and heated to 90 ± 5 C for a total of 16 h. The ...
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The impedance characteristics of undischarged alkaline manganese cells of various sizes (LR20, LR6 and LR03) have been investigated over the frequency range 100 kHz to 1 mHz. Specially constructed reference electrode probes have been inserted into the cells in two basic positions such as to obtain a complete analysis of the contribution to the total impedance from the individual cell components. It is shown that the impedance of standard cells is determined by the cathode-can assembly, the anode-separator impedance being negligible by comparison. The cathode-can impedance is further resolved into two components. Firstly, a component due to a nickel oxide layer present on the surface of the nickel-plated steel can. This takes the form of a high frequency semicircle in the complex plane. Secondly, a component due to the cathode itself (manganese dioxide + graphite mixture) which takes the form of a higher frequency semicircle and a low-frequency straight line of slope ∼32°. The latter is interpreted in terms of porous electrode behaviour involving slow proton diffusion in the solid state. Some evidence for a porous-planar transition has also been obtained at a critical frequency of ∼3 mHz.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The extent to which the initial impedance characteristics of a batch of LR6 alkaline manganese cells determine their life and therefore capacity during a typical 2 A/10 s pulse discharge regime has been investigated, and the importance of thermodynamic factors have also been considered. It is shown that the potential drop (E-V pulse) for the initial discharge cycle can be calculated approximately from a knowledge of the initial internal resistance value, and the recovery voltage,V rec, can be calculated using a simple thermodynamic theory for the homogeneous phase discharge of γ-MnO2. During subsequent cycles the polarization of the cathode-can assembly remains approximately constant at 300 mV while that of the anode-separator system increases progressively from 100 mV to 〉300 mV. The constancy of the former parameter can be attributed to constancy in the cathode contribution to the internal resistance, whereas the changes in the latter can be ascribed to increases in anode resistance polarization and anode concentration polarization. Minimization of cell internal resistance and anode polarization are therefore of primary concern if cell performance is to be maximized.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The theory relating the short-circuit or flash current behaviour of alkaline manganese and Leclanché cells to their internal resistance values has been reviewed. It is shown that the relationship SCC=VOC/R i pertains for both cell types where SCC is the short-circuit current, VOC the voltage at open circuit andR i the internal cell resistance which is a composite of several components. In the case of alkaline manganese cells these can be independently resolved usingin situ impedance measurements into three major components: the electrolyte resistance within the anode-separator-cathode porous matrices; the resistance of the cathode (MnO2 + graphite mixture); and the resistance of the nickel oxide layer on the surface of the nickel-plated steel positive current collector (cell container). In the case of Leclanché cells three components also control the internal resistance, but these cannot be so easily resolved. They are: the electrolyte resistance within the cathode separator matrices; the resistance of the cathode (MnO2 + carbon); and contact resistance between the cathode and positive current collector (carbon rod). Equivalent circuits for both alkaline manganese and Leclanché cells are proposed. Galvanostatic 2-A pulse discharge measurements have been made on LR20 alkaline manganese cells and directly correlated with the impedance measurements, thus providing confirmatory evidence for the equivalent circuit proposed. It is shown that the resistance calculated from the potential drop at 10 ms correlates closely with the internal resistance and hence short-circuit current value. It is also shown that ohmic polarization at long times (10 s) constitutes 67% of the total potential loss within the cell. Hence for a typical repetitive 2 A/10 s pulse discharge regime, the discharge life is critically dependent on the cell internal resistance value.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied electrochemistry 10 (1980), S. 109-125 
    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
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied electrochemistry 10 (1980), S. 127-141 
    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
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied electrochemistry 11 (1981), S. 401-401 
    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
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied electrochemistry 13 (1983), S. 89-95 
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract After repetitive potential cycling employing a high positive potential limit (〉700 mV wrt Hg/HgO/ KOH) three anodic and one cathodic peak can be observed using aβ-Ni(OH)2 starting material. Anodic peaks found at 425, 470 and 555 mV in 5 mol dm−3 KOH shift to less positive potentials as the alkali concentration is increased appearing at 365, 410 and 455 mV respectively in 12.5 mol dm−3 KOH. Four anodic processes involving various pairs of coexisting phases within both theβ andα-/γ-phase system can be identified as summarized below in order of increasing positive potential: Peak A $$\begin{gathered} Peak A{\text{ }}U_\alpha ^A \to {\text{ }}V_\gamma ^A \hfill \\ Peak B{\text{ }}U_\beta ^B \to {\text{ }}V_\beta ^B \hfill \\ {\text{ }}\mathop C\limits^ + {\text{ }}U_\alpha ^C \to {\text{ }}V_\gamma ^C \hfill \\ Peak E{\text{ }}V_\beta ^B \to {\text{ }}V_\gamma ^E \hfill \\ \end{gathered} $$ Observed shifts in anodic and cathodic peak potentials are consistent with the known influence of alkali and water activity on the reversible potentials for the above processes.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied electrochemistry 14 (1984), S. 187-196 
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The growth of dendritic cadmium during electrodeposition in alkaline and acid media has been investigated. By combining electrochemical data with measurements taken from scanning electron micrographs, a selection of which have been presented in parts I and II, it is shown that the theoretical approach of Diggle, Despic and Bockris [5] is in good agreement with the experimental results. The total current versus time behaviour for the alkaline system can be predicted using the exponential limiting form of the equations with the assumption that the dendrites approximate to rectangular rods and follow a first order progressive initiation law. The very different behaviour in the acidic media is predicted from the linear limiting form of the equations with the assumption that the dendrites approximate to cylindrical rods and follow an instantaneous initiation law.
    Type of Medium: Electronic Resource
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