Conductance and viscosity of LiAlCl4‐SOCl2 solutions covering a wide range of concentration (10−4–2.0M) have been measured at 25°C and for concentrated solutions these measurements have been made at several temperatures. Parameters characteristic of ion‐ion and ion‐solvent interactions and the energy of activation for conductance and for viscous flow have been obtained. Cyclic voltammograms of LiAlCl4‐SOCl2 solutions at several concentrations have been obtained and the effect of the additives, such as S2Cl2 , SCl2 , SO2 , and SO2Cl2 on the reduction behavior of SOCl2 has been studied as some of these are reduction products of SOCl2 . The implications of these studies on the performance and safety of the lithium‐thionyl chloride battery are discussed.

SPUTTEREDHAFNIUM FILMS 403 6. Before insertion into the vacuum chamber, the hafnium cathode was etched in a 1% hydrofluoric solution and rinsed in boiling distilled water. ABSTRACTThe GaAs-H20-H2 etch reaction has been studied as a function of flow rate, temperature, and GaAs surface area. Experimental and calculated equilibrium constants for the reaction have been compared. The formation of Ga203(s) is considered. The variation of sample surface texture with gas composition is examined.

Conductance, viscosity, and density of AlCl3‐SOCl2‐normalbased electrolyte solutions with and without sulfur dioxide and sulfur and varying concentration of lithium chloride have been determined as a function of temperature. While the data on AlCl3‐SOCl2 system can be interpreted in terms of solute‐solvent interaction forming adducts, those in the presence of sulfur dioxide and lithium chloride have been interpreted in terms of ion‐ion and ion‐solvent interactions and equilibria involving ion pairs and triple ions with complex anions such as Al2Cl7− and Al3Cl10− . Data on energy of activation for conductance and for viscous flow along with Walden product are in agreement with this interpretation. The unusually high electrolytic conductance observed for these concentrated electrolyte solutions and the energy of activation data are interpreted in terms of the hopping mechanism for conductance. The implication of increased complexity of solution structure on mass transport during normalLi/SOCl2 battery discharge is discussed.

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The lithium-thionyl chloride (Li/SOCI2) battery has the highest energy density of any known electrochemical system today '(1-2). The solvent thionyl-chloride is also the cathode active material and this battery system has the potential for applications needing high rate discharge.Though the overall cell reaction is known to some extent, there is very little information on the reaction intermediates and the chemical reaction(s) following electrochemical reaction during the cell discharge process (3-6).The Li/SOCIo battery has shown a tendency to explode under a variety of conditions such as short circuit, forced over discharge and resistive load overdischarge (3,4,6).It has been postulated that during the discharge of SOC12, the radical SO is formed according to SOCI 2 + 2Li § SO + LiCI and SO may dimerize and then decompose to S and SO2(7 ). 2S0 § (SO) 2 § SO 2 + S. There is no definite experimental evidence for the formation of SO during electrochemical reduction and the following chemical reaction. This paper presents cyclic voltametric data on SOCI 2 carried out as a function of SOCI 2 concentration and scan rate in different aprotic organic solvents such as dimethylsulfite (DMSI), dimethylformamide (DMF) and acetonitrile (ACN) with lithium aluminum chloride and tetrabutylammonium hexafluorophosphate as supporting electrolytes.The cyclic voltammetric data have been treated using the diagnostic criteria of Nicholson and Shain (8) and the plots of current function versus voltage sweep rate are consistent with an irreversible charge transfer followed by chemical reaction.Studies have also been carried out using constant potential electrolysis and ultraviolet spectroscopy of solutions of SOCI 2 in acetonitrile with 0.1M tetrabutylammonium hexafluorophosphate.E_xperimental Procedure.--The cyclic voltammetry and constant potential electrolysis * Electrochemical Society Membe~ Key words:Lithium battery, Thionyl chloride, cyclic voltammetry, chemical reactions were carried out in a three compartment cell with fritted disc separator using a PAR 173 potentiostat/galvanostat and PAR 175 universal programmer and PAR 179 digital coulometer. The working electrode was glassy carbon, the counter electrode was platinum spiral and the reference electrode was lithium. The solvents DMF and ACN were Burdick and Jackson distilled in glass.The solvent DMSI was Eastman Kodak. All these solvents were redistilled using Perkin Elmer Spinning band column and the water content was found to be between 50 and 70 ppm as determined by an aquatest.Spectroscopic measurements were carried out using Beckman spectrometer.The supporting electrolytes were dried under vacuum and ~ighed inside a drybox.All experiments were carried out under dry and inert conditions. Results and Discussion.--The cyclic voltammograms of 40 mM SOCI 2 in DMF containing 0.1M (C4H9)4NPF6 and i0 mM SOCI 2 in DMSI containing 0.1M LiAICI 4 are shown in Figures 1 and 2 respectively. Similar voltammograms have been obtained with different concentrations of SOCI 2. In the case o...

Accelerating rate calorimetry (ARC) has been used to define the thermal and pressure behavior of normalLi/SO2 cells during overdischarge as a function of cell balance and operating temperature. Lithium‐limited cells are shown to be intrinsically safe while cells containing excess lithium at end of life have been shown to be capable of undergoing thermal runaway through a series of coupled reactions. The most serious thermal hazards occurred upon overdischarge at low temperature. ARC analyses of cell components, in situ FTIR analyses, and mass spectroscopic analyses of discharged cathodes have been used to investigate the chemistry associated with the thermal behavior of normalLi/SO2 cells. As expected, the lithium/acetonitrile reaction and the thermal decomposition of lithium dithionite contribute to the thermal runaway process observed in cells overdischarged at ambient temperature. In addition, however, two other reactions have been identified; one initiating at approximately 140°C involving lithium and the electrolyte solution and another initiating at approximately 190°C which is believed to involve lithium and the decomposition products of lithium dithionite. Further investigations are needed to elucidate the chemistry involved in the low temperature safety problems.

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The conductances of LiClO4 , LiBF4 , and LiAsF6 in methyl formate and LiAsF6 in propylene carbonate have been measured from dilute solution to very high concentration. Anomalous conductance behavior has been observed for the concentrated solutions of these salts in methyl formate. From conductance data, equivalent conductance at infinite dilution, ion‐pair dissociation constant, and information on the formation of triple ions and more complex aggregates are obtained. The detectability of water in methyl formate and the effect of water on solvent spectrum are studied by Raman spectra. In concentrated solutions, ion‐ion and ion‐solvent interactions have been studied by Raman spectra.