A capillary flow viscometer was developed to measure the viscosity Of high vapor pressure organic solvent electrolytes over a wide temperature range. Inert electrodes and associated circuits were used to observe the passage of the meniscus through the viscometer. The viscometer was kept inside a sealed aluminum container to minimize the pressure differential between the test solution and the ambient and to contain the high vapor pressure solutions if the viscometer should rupture. Measurements were made on sulfur dioxide/ organic solvent electrolytes containing lithium bromide at temperatures between --60 ~ and 70~ and at vapor pressures to 15 arm. The viscosity varied between 0.6 and 22 cp, being higher the lower the temperature and the lower the SO2 concentration. The activation energy calculated from the temperature effect was about 4 kcal/mole for electrolyte compositions close to those used in Li/SO2 batteries. The data indicated the occurrence of strong ion/solvent interactions in this system.The rate capability of high energy density lithium batteries depends more strongly on the transport properties of the electrolyte than does that of an alkaline battery because of the generally low electrolytic conductivity of organic solvent electrolytes. The search for high-rate lithium batteries is, therefore, in part a search for suitable high-conductivity organic electrolytes. An important property that affects the conductivity of a solution is the viscosity of the medium in which ionic transfer takes place, and the analysis of the conductivity of organic solvent electrolytes requires the availability of viscosity data.The sulfur dioxide/organic solvent electrolytes have a high conductivity and a low activation energy for ionic transfer over a wide temperature range, and they provide an interesting model system on which to study the structural and other factors that affect the solution conductivity.

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Zur Messung wird ein Kapillarströmungsviskosimeter entwickelt.