Electrolytic conductance, history

In PEO electrolytes, conductivity values are very sensitive to the amount of crystaUine phase present, which is related to the thermal history of the sample. A large difference in PE0/LiC104 conductivity at 25 C was obtained in relation to the sample s thermal history. High conductivity was obtained just after sample cooling, with o = 10 S/cm,then conductivity fell dramatically after the electrolyte had been kept for two weeks at room temperature in a vacuum, o = 10 S/cm. It is difficult to compare conductivity data obtained at room temperature however, conductivity is generally improved below the PEO melting point after the sample has been previously heated. This improvement is associated with a decrease in the amount of electrolyte in the crystalline phase present and a reduction in crystallisation kinetics due to the incorporation of fillers. 

We can recognize four main periods in the history of the study of aqueous solutions. Each period starts with one or more basic discoveries or advances in theoretical understanding. The first period, from about 1800 to 1890, was triggered by the discovery of the electrolysis of water followed by the investigation of other electrolysis reactions and electrochemical cells. Developments during this period are associated with names such as Davy, Faraday, Gay-Lussac, Hittorf, Ostwald, and Kohlrausch. The distinction between electrolytes and nonelectrolytes was made, the laws of electrolysis were quantitatively formulated, the electrical conductivity of electrolyte solutions was studied, and the concept of independent ions in solutions was proposed. 

Armand (1994) has briefly summarised the history of polymer electrolytes. A more extensive account can be found in Gray (1991). Wakihara and Yamamoto (1998) describe the development of lithium ion batteries. Sahimi (1994) discusses applications of percolation theory. Early work on conductive composites has been covered by Norman (1970). Subsequent edited volumes by Sichel (1982) and Bhattacharya (1986) deal with carbon- and metal-filled materials respectively. Donnet et al. (1993) cover the science and technology of carbon blacks including their use in composites. GuF (1996) presents a detailed account of conductive polymer composites up to the mid-1990s. Borsenberger and Weiss (1998) discuss semiconductive polymers with non-conjugated backbones in the context of xerography. Bassler (1983) reviews transport in these materials. 

The developmental history of the Ni-Cd battery can be traced back to the late 19th and early 20th centuries. The initial work was conducted by Jungner and others, who brought the alkaline electrolytes concept into... 

The maximum ionic conductivity in ZrO2-based systems is observed when the content of acceptor-type dopant cations with the smallest radii (Sc, Yb, Y) is close to the minimum necessary to completely stabilize the cubic fiuorite-type phase in the operating temperature range [9,11,16, 32-35]. This concentration (often referred to as the low stabilization limit) and the conductivity of the ceramic electrolytes are dependent, to a finite extent, on the pre-history and various micro structural features. In addition to the metastable states discussed above, critical microstructural factors... 

An excellent review of the early history of noise studies of different ionic systems, such as single pores in thin dielectric films, microelectrodes, and synthetic membranes, is reference 3. The review by Weissman (48) describes several state-of-the-art fluctuation spectroscopy methods that include (1) determination of chemical kinetics from conductivity fluctuations in salt solutions, (2) observation of conductivity noise that arises from enthalpy fluctuations in the electrolyte with high temperature coefficient of resistivity, and (3) detection of large conductivity fluctuations in a binary mixture near its critical point. 

History of Ionic Conductivity in Solid Polymer Electrolytes... 

Ionic conductivity in polymer-based, water-containing, solid systems has been with us for a long time. A review of that history, which is intimately associated with the history of analytical electrochemistry and the physical chemistry of electrolyte solutions, will help to put the present work into perspective. 

His three early Leipzig papers (5-7) represent a synthesis of concepts that he was well qualified to make. Working in Ostwald s laboratory, he must have absorbed some of the mass of electrochemical information which appeared a few years later in Ostwald s two-volume work on the history and theory of electrochemistry (H). He was thoroughly familiar with the second-law thermodynamics of Thomson and Clausius, and with the more recent pronouncements of van t Hoff and Helmholtz. Nernst was also imbued with the atomism of Dalton and Boltzmann, in v hich respect he differed from Ostwald and Helmholtz, and he had accepted Arrhenius s recently published (12,13) hypothesis of the complete dissociation of strong electrolyses in solution. However, his conductance work in Kohlrausch s laboratory had given him a lively appreciation of the effects of incomplete ionization of weak electrolytes. 

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